# PR CHECKLIST
Source: https://docs.uplift.ai/PR_CHECKLIST
# PR Checklist
Checklist for releasing a new PR against this repo. Merges to `main` auto-deploy to
production via the Mintlify GitHub App — there is no separate build/release step, so
everything here should happen **before** merging, not after.
## 1. Local setup
* [ ] `npm ci` (installs the pinned `mintlify` CLI version from `package-lock.json`).
Using a stray global/cached `npx mint` instead of the pinned version can silently
run an older CLI missing commands (e.g. `mint validate`) — always `npm ci` first
in a fresh clone or after pulling `package.json` changes.
## 2. Content correctness
* [ ] Verify any new/changed API behavior, limit, or guarantee is actually true in the
running system before documenting it (check the source repo / infra, don't guess).
* [ ] No personal names in customer-facing content — use neutral phrasing.
* [ ] Reuse an existing snippet from `snippets/` instead of duplicating prose, if one exists.
* [ ] New `.mdx` page? Confirm it's registered in `docs.json` nav (or intentionally left
as an orphan page linked from elsewhere, matching this repo's existing pattern for
per-metric/event sub-pages).
* [ ] Renamed/moved a page? Update its `docs.json` entry and any redirects in the same change.
## 3. Automated checks (mirrors `.github/workflows/pr-checks.yml`)
Run these locally before pushing — CI runs them again on the PR, but catching failures
locally is faster than round-tripping through Actions:
* [ ] `npx mint validate` — strict build validation (bad frontmatter, pages missing from
nav, MDX parse errors).
* [ ] `npx mint broken-links` — fails on any broken internal link.
* [ ] `npx mint openapi-check api-reference/openapi.json` — only meaningfully changes if
the spec was touched, but cheap to run every time.
* [ ] `npx -y cspell@8 "**/*.{mdx,md,py}" --no-progress --gitignore` — spellcheck. Add
real domain terms to `cspell.json`'s `words` list rather than ignoring the file;
don't add actual typos there.
## 4. Repo-specific tasks
* [ ] If `api-reference/openapi.json` changed: restart `npx mint dev` locally (hot reload
doesn't pick up spec changes) and re-check the API reference pages render correctly.
* [ ] If any biomechanics movement page listed in `scripts/MOVEMENT_PAGES` changed (or a
page/metric/event it links to changed): rerun `python3 scripts/export_movements.py`
to refresh `docs-exports/` (git-ignored, so this won't show in `git status` — it's
a local artifact, but staleness here is exactly what caused broken links previously).
* [ ] Preview locally with `npx mint dev` and click through the actual changed pages —
type checking/link checking verifies structure, not whether the page reads well or
renders as intended.
## 5. Review before pushing
* [ ] `git status` / `git diff` review of everything staged — no secrets, no unrelated
files, no accidental `docs-exports/` or `node_modules/` additions.
* [ ] Generate a PR summary describing every changed/added/removed file and why (see
below) — use it as the PR description.
## 6. PR summary generation
Before opening the PR, produce a summary covering:
* Every added, modified, and deleted file (`git status --porcelain` covers untracked +
tracked; `git diff --stat` covers tracked-file line counts).
* A one-line description of *why* each file/group of files changed, not just what.
* Group related files (e.g. "23 new softball pitching metric pages") rather than listing
every file individually when there are many similar additions.
## 7. After merge
* [ ] Confirm the Mintlify deploy succeeded (no build step to watch locally — check the
live site or the Mintlify dashboard).
* [ ] If `docs-exports/` was regenerated locally, no action needed — it's git-ignored and
not part of the deploy.
# Create Athlete
Source: https://docs.uplift.ai/api-reference/athletes/create
POST /athletes
Creates a new athlete within an organization. The user must provide at least the `first_name` field. Other standard attributes, while optional, are recommended. Any additional attributes that are not part of the predefined standard attributes should be included as `custom_attributes`.
### Custom Attributes
* **`custom_attributes`** (object)
* A set of user-defined key-value pairs for additional attributes.
* **Key Format Rules:**
* Must contain only alphanumeric characters, underscores (`_`), or dashes (`-`).
* Must start with a letter or underscore.
* Must avoid spaces and special characters (e.g., `@`, `#`, `$`, etc.).
* Reserved keywords (e.g., `first_name`, `last_name`, `date_of_birth`, `email`, `height`, `weight`, and `DOB`) cannot be used as keys.
* **Value:**
* Must be a string.
### Example Request Body
```json theme={null}
{
"first_name": "John",
"last_name": "Doe",
"date_of_birth": "1990-01-01",
"email": "john.doe@example.com",
"height": 70,
"weight": 180,
"custom_attributes": {
"team": "Team A",
"position": "left fielder"
}
}
```
# Delete Athlete
Source: https://docs.uplift.ai/api-reference/athletes/delete
DELETE /athletes/{athleteId}
Delete an athlete and all associated data in an organization.
# Get Athlete Details
Source: https://docs.uplift.ai/api-reference/athletes/get
GET /athletes/{athleteId}
Retrieves the information of an athlete in an organization.
# List Athletes
Source: https://docs.uplift.ai/api-reference/athletes/list
GET /athletes
Retrieves the information of athletes in an organization.
### Custom Attributes
The endpoint for listing athletes allows for the use of **arbitrary query parameters** that you define based on your needs. For instance, if your organization uses custom attributes for athletes, you can pass those attributes directly in the query string.
Examples of custom attributes might include:
* `sport=MLB`
* `team=XYZ`
* `age=30`
* `position=center`
* Or any other custom attribute based on your organization's data.
These custom parameters allow you to filter athletes more precisely based on your unique dataset.
To learn more about how to properly filter athletes using custom attributes and query parameters, check out examples of [Filtering Athletes](../filtering-athletes).
***
# Update Athlete
Source: https://docs.uplift.ai/api-reference/athletes/update
POST /athletes/{athleteId}
Use this endpoint to update an athlete's attributes. You can modify all attributes, following specific rules for certain fields and custom attributes. Include only the attributes you wish to update or new custom attributes to add in the request body.
#### Attribute Modification
All attributes of the athlete can be updated. Include only the attributes you wish to change — omitted attributes are left unchanged. The following rules apply:
* **String Attributes**:
* String values can be updated to any non-empty string.
* String values can be set to an empty string (`""`) or `null` to clear the attribute.
* **Integer Attributes**:
* Integer values can be updated to any valid integer.
* Integer values can be set to `0` or `null` to clear the attribute.
* **Special Rules for `first_name`**:
* The `first_name` attribute, if included, cannot be empty. It must always contain a non-empty string.
* **Custom Attributes (`custom_attributes`)**:
* Updates are merged with the athlete's existing custom attributes:
* Keys omitted from the request are left unchanged.
* Keys set to a non-empty string are created or updated.
* Keys set to `null` are deleted from the `custom_attributes` object.
* Empty strings (`""`) and non-string values are not valid custom attribute values and return a `400` error.
* New custom attributes must follow the same key rules as described in the `createAthlete` endpoint.
#### Example Request
```json theme={null}
POST /athletes/12345
{
"last_name": "",
"email": "john@example.com",
"weight": 0,
"custom_attributes": {
"team": "Team B",
"position": "pitcher",
"sport": null
}
}
```
In this example, `last_name` and `weight` are cleared, `email` is updated, the `team` and `position` custom attributes are created or updated, and the `sport` custom attribute is deleted.
# Authentication
Source: https://docs.uplift.ai/api-reference/authentication
Learn how to obtain and use authentication credentials for the Uplift API.
All API endpoints are secured with API key authentication to ensure data privacy and secure access. To authenticate API requests, you need a valid API key, which acts as your access credential to interact with the Uplift API.
> **Note:** The API key (format starting with `sk`) is the credential. You send it as a Bearer token in the `Authorization` header.
## How to Get an API Key
To obtain an API key, follow these steps:
1. Sign in to the **Uplift Platform** at [platform.uplift.ai](https://platform.uplift.ai).
2. Go to **Settings** and open **API Keys** in the Developer section.
3. Generate a new API key, used to authorize requests to Uplift's API.
Ensure you keep this API key secure—treat it like a password. It grants access to various resources and services, so it should not be shared or hard-coded in publicly accessible environments.
## Using the API Key
When making requests to any Uplift API endpoint, send your API key as a Bearer token in the `Authorization` header, like so:
```http theme={null}
Authorization: Bearer YOUR_API_KEY
```
The API key is required for all API requests to authenticate your identity and authorize access. If it is missing or invalid, the API will return a `401` Unauthorized response.
# Create Capture
Source: https://docs.uplift.ai/api-reference/captures/create
POST /captures
Reserves server-side resources for a video and returns a pre-signed Amazon S3 POST upload target. The video is not stored until the client completes the S3 POST upload within the expiry window.
**Capture creation is an Enterprise feature.** Upload video directly through the API to run it through Uplift's movement analysis pipeline. [Contact Sales](mailto:sales@uplift.ai) to enable it for your organization.
### Example Request Body
```json theme={null}
{
"athlete_id": "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee",
"session_group_id": "11111111-2222-3333-4444-555555555555",
"file_name": "swing-001.mov",
"capture_time": "2026-05-13T12:00:00.000Z",
"camera_configuration": {
"camera_setup_selection": "single.down_the_line",
"camera_orientation": "landscape"
},
"movement_attributes": {
"activity": "golf",
"movement": "full_swing"
}
}
```
#### Movement dimensions
Optional movement dimension keys for each `activity` / `movement` pair can be included in `movement_attributes`. Valid values are validated by the API.
| Activity | Movement | Dimensions |
| ----------------- | ------------------------- | ------------------------------------------------- |
| `agility` | `cutting` | `direction` |
| `baseball` | `hitting` | `bat_length`, `handedness` |
| `baseball` | `pitching` | `handedness` |
| `basketball` | `free_throw` | `handedness` |
| `basketball` | `jump_shot` | `handedness` |
| `basketball` | `layup` | `handedness` |
| `golf` | `swing` | `handedness` |
| `jump` | `broad` | `arm_position` |
| `jump` | `countermovement` | `arm_position` |
| `jump` | `drop_vertical` | `arm_position` |
| `jump` | `single_leg` | `arm_position`, `footedness` |
| `jump` | `single_leg_broad` | `arm_position`, `footedness` |
| `jump` | `squat` | `arm_position` |
| `lunge` | `forward` | `footedness` |
| `lunge` | `side` | `footedness` |
| `range_of_motion` | `ankle_flexion` | `body_position`, `footedness` |
| `range_of_motion` | `cervical_rotation` | `direction` |
| `range_of_motion` | `sfma_shoulder_extension` | `handedness` |
| `range_of_motion` | `sfma_shoulder_flexion` | `handedness` |
| `range_of_motion` | `shoulder_9090` | `handedness` |
| `range_of_motion` | `shoulder_flexion` | `handedness` |
| `range_of_motion` | `t_spine_rotation` | `handedness` |
| `softball` | `hitting` | `bat_length`, `handedness` |
| `softball` | `pitching` | `handedness` |
| `squat` | `single_leg` | `footedness` |
| `stability` | `plank` | `plank_orientation`, `plank_position` |
| `stability` | `rotary` | `handedness` |
| `stability` | `single_leg_stance` | `eyes`, `footedness` |
| `stability` | `y_balance_lower_quarter` | `footedness`, `y_balance_lower_quarter_direction` |
| `stability` | `y_balance_upper_quarter` | `handedness`, `y_balance_upper_quarter_direction` |
| `tennis` | `backhand` | `handedness` |
| `tennis` | `forehand` | `handedness` |
| `tennis` | `overhand_serve` | `handedness`, `overhand_serve_type` |
| `tennis` | `underhand_serve` | `handedness` |
| `track_and_field` | `discus` | `handedness` |
| `track_and_field` | `shot_put` | `handedness` |
Pairs with **no** published movement dimensions (for example `gait/walking`, `squat/body_weight`) accept only `activity` and `movement` in `movement_attributes`.
# Get Capture
Source: https://docs.uplift.ai/api-reference/captures/get
GET /captures/{captureId}
Returns one capture by id for the organization.
### Path parameter
**`captureId`** is the capture identifier. The capture must belong to your organization and must not be deleted.
#### Movement dimensions
The response may include additional top-level dimension fields based on `activity` and `movement`.
| Activity | Movement | Dimensions |
| ----------------- | ------------------------- | ------------------------------------------------- |
| `agility` | `cutting` | `direction` |
| `baseball` | `hitting` | `bat_length`, `handedness` |
| `baseball` | `pitching` | `handedness` |
| `basketball` | `free_throw` | `handedness` |
| `basketball` | `jump_shot` | `handedness` |
| `basketball` | `layup` | `handedness` |
| `golf` | `swing` | `handedness` |
| `jump` | `broad` | `arm_position` |
| `jump` | `countermovement` | `arm_position` |
| `jump` | `drop_vertical` | `arm_position` |
| `jump` | `single_leg` | `arm_position`, `footedness` |
| `jump` | `single_leg_broad` | `arm_position`, `footedness` |
| `jump` | `squat` | `arm_position` |
| `lunge` | `forward` | `footedness` |
| `lunge` | `side` | `footedness` |
| `range_of_motion` | `ankle_flexion` | `body_position`, `footedness` |
| `range_of_motion` | `cervical_rotation` | `direction` |
| `range_of_motion` | `sfma_shoulder_extension` | `handedness` |
| `range_of_motion` | `sfma_shoulder_flexion` | `handedness` |
| `range_of_motion` | `shoulder_9090` | `handedness` |
| `range_of_motion` | `shoulder_flexion` | `handedness` |
| `range_of_motion` | `t_spine_rotation` | `handedness` |
| `softball` | `hitting` | `bat_length`, `handedness` |
| `softball` | `pitching` | `handedness` |
| `squat` | `single_leg` | `footedness` |
| `stability` | `plank` | `plank_orientation`, `plank_position` |
| `stability` | `rotary` | `handedness` |
| `stability` | `single_leg_stance` | `eyes`, `footedness` |
| `stability` | `y_balance_lower_quarter` | `footedness`, `y_balance_lower_quarter_direction` |
| `stability` | `y_balance_upper_quarter` | `handedness`, `y_balance_upper_quarter_direction` |
| `tennis` | `backhand` | `handedness` |
| `tennis` | `forehand` | `handedness` |
| `tennis` | `overhand_serve` | `handedness`, `overhand_serve_type` |
| `tennis` | `underhand_serve` | `handedness` |
| `track_and_field` | `discus` | `handedness` |
| `track_and_field` | `shot_put` | `handedness` |
Pairs with **no** published movement dimensions return only the fixed `Capture` fields.
#### Example response
For `baseball` + `hitting`:
```json theme={null}
{
"session_id": "…",
"activity": "baseball",
"movement": "hitting",
"handedness": "…",
"bat_length": "…",
"status": "completed"
}
```
For `jump` + `countermovement`:
```json theme={null}
{
"session_id": "…",
"activity": "jump",
"movement": "countermovement",
"arm_position": "…",
"status": "completed"
}
```
# List Captures
Source: https://docs.uplift.ai/api-reference/captures/list
GET /captures
Returns a paginated list of captures for the organization with optional filters. Results are sorted newest first. All organization captures are included unless filtered; use `source=api` to restrict to captures with `source` equal to `api`. A capture linked to multiple athletes may appear more than once in `captures[]`; `total_count` is the distinct capture count.
### Query parameters
All query parameters are optional. See the operation above for types and constraints.
| Parameter | Purpose |
| ---------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **`athlete_id`** | UUID; restrict to captures for that athlete in your organization. Returns **400** `athlete_id not found` when the athlete is missing or not in your organization. |
| **`source`** | When set to **`api`**, only captures with `source` equal to **`api`** are returned. |
| **`status`** | One of **`awaiting_upload`**, **`processing`**, **`completed`**, **`error`**. |
| **`activity`** | Case-insensitive filter on `activity` (trimmed and lowercased for matching). Returned values preserve stored casing. |
| **`movement`** | Case-insensitive filter on `movement` (trimmed and lowercased for matching). Returned values preserve stored casing. |
| **`limit`** | Page size; integer **1–500**. Defaults to **100** when omitted. Out-of-range values return **400**. |
| **`offset`** | Rows to skip; non-negative integer. Defaults to **0** when omitted. Negative values return **400**. |
### List behavior
* **Scope** — Returns all captures in your organization. Captures from other sources (for example, the mobile app) are included unless you pass **`source=api`**. Deleted captures are excluded.
* **Sort order** — Newest first (by capture time).
* **Duplicate rows** — A capture linked to more than one athlete can appear more than once in **`captures[]`**. **`total_count`** is the distinct capture count matching your filters.
Successful **`200`** responses include **`captures`** (array of `Capture`), **`total_count`**, **`offset`**, and **`limit`**. The response **`offset`** and **`limit`** echo the values used for the page (from the request, or defaults when omitted).
#### Movement dimensions
Each `Capture` in **`captures[]`** may include additional top-level dimension fields based on its `activity` and `movement`.
| Activity | Movement | Dimensions |
| ----------------- | ------------------------- | ------------------------------------------------- |
| `agility` | `cutting` | `direction` |
| `baseball` | `hitting` | `bat_length`, `handedness` |
| `baseball` | `pitching` | `handedness` |
| `basketball` | `free_throw` | `handedness` |
| `basketball` | `jump_shot` | `handedness` |
| `basketball` | `layup` | `handedness` |
| `golf` | `swing` | `handedness` |
| `jump` | `broad` | `arm_position` |
| `jump` | `countermovement` | `arm_position` |
| `jump` | `drop_vertical` | `arm_position` |
| `jump` | `single_leg` | `arm_position`, `footedness` |
| `jump` | `single_leg_broad` | `arm_position`, `footedness` |
| `jump` | `squat` | `arm_position` |
| `lunge` | `forward` | `footedness` |
| `lunge` | `side` | `footedness` |
| `range_of_motion` | `ankle_flexion` | `body_position`, `footedness` |
| `range_of_motion` | `cervical_rotation` | `direction` |
| `range_of_motion` | `sfma_shoulder_extension` | `handedness` |
| `range_of_motion` | `sfma_shoulder_flexion` | `handedness` |
| `range_of_motion` | `shoulder_9090` | `handedness` |
| `range_of_motion` | `shoulder_flexion` | `handedness` |
| `range_of_motion` | `t_spine_rotation` | `handedness` |
| `softball` | `hitting` | `bat_length`, `handedness` |
| `softball` | `pitching` | `handedness` |
| `squat` | `single_leg` | `footedness` |
| `stability` | `plank` | `plank_orientation`, `plank_position` |
| `stability` | `rotary` | `handedness` |
| `stability` | `single_leg_stance` | `eyes`, `footedness` |
| `stability` | `y_balance_lower_quarter` | `footedness`, `y_balance_lower_quarter_direction` |
| `stability` | `y_balance_upper_quarter` | `handedness`, `y_balance_upper_quarter_direction` |
| `tennis` | `backhand` | `handedness` |
| `tennis` | `forehand` | `handedness` |
| `tennis` | `overhand_serve` | `handedness`, `overhand_serve_type` |
| `tennis` | `underhand_serve` | `handedness` |
| `track_and_field` | `discus` | `handedness` |
| `track_and_field` | `shot_put` | `handedness` |
Pairs with **no** published movement dimensions return only the fixed `Capture` fields.
#### Example `Capture` fields
For `baseball` + `hitting`:
```json theme={null}
{
"session_id": "…",
"activity": "baseball",
"movement": "hitting",
"handedness": "…",
"bat_length": "…",
"status": "completed"
}
```
For `jump` + `countermovement`:
```json theme={null}
{
"session_id": "…",
"activity": "jump",
"movement": "countermovement",
"arm_position": "…",
"status": "completed"
}
```
# Create Export Job
Source: https://docs.uplift.ai/api-reference/data/export/create
POST /data/export
Initiates an asynchronous data export process and returns a job ID that clients can use to poll for query results.
### Tier Services
The data export endpoint is tier-based, and there are currently 3 service tiers:
##### **Premium**
The Premium Tier has no restrictions on data export. You can access all available data without any limitations.
##### **Base**
The Base Tier does not allow historical data requests before 12/12/2024. Be mindful of this when setting the `startTime` and `endTime` parameters. If you need access to older data, we recommend contacting our sales team to discuss upgrading to the Premium Tier.
##### **Unavailable**
Data export is not available without a subscription to either the Base or Premium service. You must subscribe to one of these tiers to use the data export functionality.
### Valid activity-movement pairs
Only the following `activity` and `movement` pairs are accepted. Any other pair returns a 400 error.
| Activity | Valid movements |
| --------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **agility** | cutting, five\_ten\_five |
| **baseball** | hitting, pitching |
| **basketball** | free\_throw, jump\_shot, layup |
| **gait** | running, walking |
| **golf** | swing |
| **jump** | broad, countermovement, drop\_vertical, single\_leg, single\_leg\_broad, squat |
| **lunge** | forward |
| **other** | other |
| **range\_of\_motion** | ankle\_flexion, cervical\_flexion\_extension, cervical\_rotation, sfma\_shoulder\_extension, sfma\_shoulder\_flexion, shoulder\_9090, shoulder\_flexion, t\_spine\_rotation |
| **softball** | hitting |
| **squat** | body\_weight, overhead, sfma\_squat, single\_leg |
| **stability** | plank, push\_up, rotary, sfma\_back\_bend, sfma\_toe\_touch, single\_leg\_stance, static\_stance, y\_balance\_lower\_quarter, y\_balance\_upper\_quarter |
| **track\_and\_field** | discus, hammer\_throw, high\_jump, shot\_put |
| **tennis** | backhand, forehand, overhand\_serve, underhand\_serve |
***
# Get Job Status
Source: https://docs.uplift.ai/api-reference/data/export/job/get
GET /data/export/job/{jobId}
Retrieves the details and status of a job using the job ID.
# Get Job Results
Source: https://docs.uplift.ai/api-reference/data/export/job/results/get
GET /data/export/job/{jobId}/results
Retrieves the results of a completed job using the job ID.
# Errors
Source: https://docs.uplift.ai/api-reference/errors
HTTP status codes and what they mean when using the Uplift API.
## HTTP errors
When interacting with the API, you may encounter various HTTP status codes indicating success or failure of your requests. Here’s a quick overview of the most common error codes and what they mean:
* **400 Bad Request**: The request was invalid or malformed. Double-check your parameters or request format.
* **401 Unauthorized**: Your authorization token (API key) is missing or invalid. Ensure your API key is correct and has the necessary permissions.
* **403 Forbidden**: You do not have permission to access the requested resource. Contact your system administrator if you believe you should have access.
* **404 Not Found**: The resource you requested (e.g., job ID or athlete ID) does not exist, or the job has expired. Export job results are retained for 72 hours; after that, the job ID returns 404. Verify the resource or request a new export.
* **429 Too Many Requests**: You’ve hit the API rate limit. Try again later, or adjust your request frequency.
* **500 Internal Server Error**: Something went wrong on the server. If the issue persists, contact support for assistance.
* **503 Service Unavailable**: A temporary upstream issue prevented the request from completing. Wait a moment and retry.
# Filtering Athletes
Source: https://docs.uplift.ai/api-reference/filtering-athletes
Learn how to use custom query parameters to filter API results based on specific attributes, and understand the expected behavior of the output.
### Using Custom Query Parameters
The API allows you to include additional query parameters to filter results based on specific attributes, such as `team`, `sport`, `coach`, or any other custom attributes defined in your organization’s data schema. These parameters enable you to narrow down the results to match your specific requirements.
> **Note**: If your organization did not standardize the naming conventions or data, mismatches may occur when filtering athletes. For example, `team` could be listed as `Team`, `team`, or other variations, and `xyz` could be represented inconsistently (e.g., `XYZ`, `xyz`, or `Xyz`). These discrepancies may lead to incorrect or missing results. Ensure consistent naming conventions for both attribute names and their values to improve filtering accuracy.
### Examples of Usage
Here are some examples to demonstrate how to use custom attributes effectively:
1. **Filter by a Single Attribute**\
If you want to retrieve athletes who play a specific sport, use the `sport` parameter:
```bash theme={null}
curl -X GET 'https://api.uplift.ai/v1/athletes?limit=100&sport=MLB' \
--header 'Authorization: Bearer ' \
--header 'Content-Type: application/json'
```
2. **Filter by Multiple Attributes**\
You can combine multiple attributes to refine your search further:
```bash theme={null}
curl -X GET 'https://api.uplift.ai/v1/athletes?limit=100&sport=MLB&team=XYZ' \
--header 'Authorization: Bearer ' \
--header 'Content-Type: application/json'
```
3. **Sorting Results**\
Use the `sorted_by` parameter to organize the results by a specific field, such as `first_name`, `last_name`, or `date_of_birth`:
```bash theme={null}
curl -X GET 'https://api.uplift.ai/v1/athletes?limit=100&sorted_by=last_name' \
--header 'Authorization: Bearer ' \
--header 'Content-Type: application/json'
```
### Important Considerations
To ensure the best experience when using custom query parameters, keep the following in mind:
1. **Data Availability**:\
Custom attributes must exist and be populated in your organization’s data schema. If an attribute is not defined or empty for some records, those records will be excluded from the filtered results.
2. **Case Sensitivity**:\
Depending on the implementation, some attributes may be case-sensitive. For example, searching for `team=XYZ` may not return the same results as `team=xyz` or `team=Xyz`. Ensure you verify your data structure and consistently use the correct casing, such as uppercase, lowercase, or camel case, based on your data schema.
3. **Handling Unexpected Inputs**:\
If an attribute value does not match any records, the response will return an empty array. Ensure attribute names and values are spelled correctly to avoid unexpected results.
4. **Combining Parameters**:\
The API processes query parameters using logical AND. All conditions must match for a record to be included in the results.
For example:
```
?sport=MLB&team=XYZ&sorted_by=last_name
```
Only returns athletes who match all specified criteria.
5. **Debugging**:\
To validate your queries, use smaller limit values (e.g., `limit=10`) and inspect the response payload to ensure the filtering criteria are applied correctly.
# Filtering Metrics
Source: https://docs.uplift.ai/api-reference/filtering-metrics
Learn how to use custom query parameters to filter export data API results for specific metrics and rows.
### Using Custom Query Parameters
The API allows you to include additional query parameters to filter results of specific columns based on the `metrics` parameter and rows based on the `row_filter_column` parameter.
| Parameter | Type | Required | Description |
| ------------------- | --------------------- | -------- | ------------------------------------------------------------------------ |
| `metrics` | Array of metric names | Optional | If provided, only returns the specified columns instead of every metric. |
| `row_filter_column` | String | Optional | Controls which rows are returned in the response. |
> **Note**: Details on `row_filter_column` are below.
>
> | Value | Result | Example Use Case |
> | ----------------- | ----------------------------------------- | --------------------------------------------------------- |
> | Not provided | Return all time-series rows | Default behavior |
> | "frame" | Return a single row where frame=0 | For getting the start of the movement. |
> | Event column name | Return a single row where that column = 0 | For getting values at a specific event (ex: peak\_event). |
### Examples of Usage
Here are some examples to demonstrate how to use custom attributes effectively:
1. **Filter by metrics only**\
If you want to retrieve specific metrics such as `peak_event` and `peak_power`:
```bash theme={null}
curl --request POST \
--url https://api.uplift.ai/v1/data/export \
--header 'Authorization: Bearer ' \
--header 'Content-Type: application/json' \
--data '{
"startTime": 123,
"endTime": 123,
"athletes": [
""
],
"activity": "agility",
"movement": "cutting",
"dateMode": "last_modified",
"metrics": [
"peak_event",
"peak_power"
]
}'
```
2. **Filter by metrics and row\_filter\_column**\
You can combine metrics and row\_filter\_column to refine your search further. For example, if you want to retrieve the row of `peak_event` and `peak_power` for the `cutting` movement at the `turn_event` equal to 0:
```bash theme={null}
curl --request POST \
--url https://api.uplift.ai/v1/data/export \
--header 'Authorization: Bearer ' \
--header 'Content-Type: application/json' \
--data '{
"startTime": 123,
"endTime": 123,
"athletes": [
""
],
"activity": "agility",
"movement": "cutting",
"dateMode": "last_modified",
"metrics": [
"peak_event",
"peak_power"
],
"row_filter_column": "turn_event"
}'
```
### Important Notes
1. **Metrics Availability**:\
Verify that all requested metrics exist in the dataset before filtering.
If any specified metric is not available, the export data job will fail.
Check the `errorMessage` in the response for details about any non-existent
columns when using the `metrics` parameter.
```json theme={null}
{
"jobId": "17eafc5c-2e4d-44e9-bdfe-7617591a5f00",
"status": "FAILED",
"errorMessage": "Column 'peak_power' not found",
"createdAt": "2025-05-02T17:40:51.988Z",
"completedAt": "2025-05-02T17:40:52.592Z"
}
```
2. **Row Filter Column**:\
Ensure the specified row filter column exists in the export data. If the column
doesn't exist, the export data job will fail. The response `errorMessage`
will indicate the column specified in the `row_filter_column` parameter is invalid.
Note that row filtering only supports values equal to 0. In theory, only a single row is
returned for each session. If no rows have a value of 0 for the specified row filter
column, the query may return an empty result set.
# Introduction
Source: https://docs.uplift.ai/api-reference/introduction
Overview of the Uplift API and authentication details
## Welcome to the Uplift API
The Uplift API offers powerful tools to seamlessly integrate with Uplift's ecosystem, enabling developers to build custom applications and solutions that enhance training experiences, group interactions, and performance insights. With our API, you can interact with a broad range of resources—manage athlete assessments, gather performance data, and create engaging group experiences—all tailored for optimal human performance and engagement.
The Uplift API is organized around RESTful principles, providing clear endpoints that are easy to use, secure, and well-documented. Whether you're building web or mobile applications, our API gives you the flexibility to integrate Uplift's capabilities into your own services smoothly.
# Rate Limits
Source: https://docs.uplift.ai/api-reference/rate-limits
Understand API rate limits, usage expectations, and best practices for managing requests.
## API Rate Limiting
To ensure fair usage and maintain performance, our API has rate limits in place:
* **60 requests per minute**: You can make up to 60 requests every minute.
* **5 requests burst rate**: A short burst of up to 5 requests is allowed instantly.
### What Happens If You Exceed the Limit?
If you exceed the limit, additional requests will be **throttled** (temporarily denied) until your usage falls within the allowed limits. You will receive a `429 Too Many Requests` response.
### Best Practices
* **Monitor Your Requests**: Keep track of your request counts to avoid hitting the limit.
* **Retry After Waiting**: If you receive a 429 response, add a short delay (e.g., a few seconds) before retrying. Gradually increase the delay if the issue persists to avoid further throttling.
* **Use Efficient Calls**: Combine data requests when possible to reduce the number of calls.
By following these guidelines, you can ensure seamless integration with our API.
# Retrieving Data in Batches
Source: https://docs.uplift.ai/api-reference/retrieving-data-batches
Learn how to use limit and offset query parameters to control and paginate API requests efficiently.
#### Limit Query Parameter
The limit query parameter allows you to retrieve a specific number of results. For endpoints that support the limit query parameter, you can specify the number of results to retrieve. For example, if you only want to retrieve the first 10 available results, add `?limit=10` to the request URL:
```bash Get First 10 Results theme={null}
curl -X GET 'https://api.uplift.ai/v1/data/export/job/{id}/results?limit=10' \
--header 'Authorization: Bearer ' \
--header 'Content-Type: application/json'
```
#### Offset Query Parameter
The offset query parameter allows you to skip a specific number of results in the response. When a response contains many results, you can use the limit and offset query parameters together to break the response into pages.
For example, consider a job result response object that contains 5000 results. The Job Results API allows you to retrieve a maximum of 500 results per request. To retrieve all 5000 results, start by adding `?limit=500` to the request URL to retrieve the first 500 results:
```bash Get First 500 Results theme={null}
curl -X GET 'https://api.uplift.ai/v1/data/export/job/{id}/results?limit=500' \
--header 'Authorization: Bearer ' \
--header 'Content-Type: application/json'
```
In the next request, to retrieve the next 500 results (rows 501-1000), add `&offset=500` to the request URL:
```bash Get Results 501-1000 theme={null}
curl -X GET 'https://api.uplift.ai/v1/data/export/job/{id}/results?limit=500&offset=500' \
--header 'Authorization: Bearer ' \
--header 'Content-Type: application/json'
```
To retrieve the next 500 results (rows 1001-1500), increment the offset parameter to 1000 (`&offset=1000`) in the next request:
```bash Get Results 1001-1500 theme={null}
curl -X GET 'https://api.uplift.ai/v1/data/export/job/{id}/results?limit=500&offset=1000' \
--header 'Authorization: Bearer ' \
--header 'Content-Type: application/json'
```
Continue incrementing the offset parameter in requests until you have retrieved all 5000 results. Query with offset beyond available results will get a status OK response with empty 'rows' in it. Similar offset and limit parameters are applied in listing of athletes.
# 5-0-5 Agility
Source: https://docs.uplift.ai/biomechanics/activities/agility/5_0_5
Biomechanical analysis of the 5-0-5 change-of-direction agility drill, including sprint, deceleration, 180° turn, and re-acceleration phases.
## Overview
The 5-0-5 agility drill is a standardized change-of-direction agility test used to assess an athlete's ability to accelerate, decelerate, plant, pivot 180°, and re-accelerate over a 5-meter course.
It is commonly used in athletic assessment, return-to-sport screening, and performance monitoring as it isolates the mechanical demands of rapid direction change.
## Instructions
1. Set up two lines or cones 5 meters apart on a flat surface.
2. Place cameras 45 deg to the same side from the running line pointed at the center. Use landscape mode and ensure cameras can see the full 5-meter distance (both cones).
3. Stand at the start line in an athletic ready position.
4. On go, sprint forward toward the turn line.
5. Plant one foot on or just past the turn line, pivot 180°, and sprint back through the start line.
6. Perform with both left and right foot as the plant foot across separate trials.
7. Perform at maximal effort for fastest time.
## Dimensions
Required inputs for processing:
* **None** — direction of movement is detected automatically from the pelvis trajectory
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Description |
| ----------------- | ------------------------------------------------------------------------------------- |
| Start | When the athlete initiates movement, detected as when pelvis velocity exceeds 0.2 m/s |
| Turn | The instant of maximum pelvis displacement, corresponding to the 180° pivot |
| End | When the athlete returns to the start position |
| Left Foot Strike | All left foot contact frames between Start and End |
| Right Foot Strike | All right foot contact frames between Start and End |
| Left Foot Off | All left foot off frames between Start and End |
| Right Foot Off | All right foot off frames between Start and End |
### Phases
| Phase | Start | End |
| --------------------- | ----- | ---- |
| Approach (First Half) | Start | Turn |
| Return (Second Half) | Turn | End |
### General Metrics
| Metric | Units | Description |
| ---------------- | ------- | --------------------------------------------------------------------------- |
| Direction | string | Auto-detected direction of first sprint ('right' or 'left') |
| Total Time | seconds | Duration from Start to End |
| First Half Time | seconds | Duration from Start to Turn (approach/deceleration) |
| Second Half Time | seconds | Duration from Turn to End (re-acceleration) |
| Turn Time | seconds | Time between last foot contact before and first foot contact after the Turn |
### Ground Contact Time Metrics
Ground contact time (GCT) is reported per step for up to 5 steps per leg per half. `_1_` refers to the approach (first half); `_2_` refers to the return (second half). Step index follows temporal order.
| Metric | Units | Description |
| ------------------------------- | ------- | ---------------------------------------------- |
| Left GCT — Approach, steps 1–5 | seconds | Left foot ground contact time during approach |
| Right GCT — Approach, steps 1–5 | seconds | Right foot ground contact time during approach |
| Left GCT — Return, steps 1–5 | seconds | Left foot ground contact time during return |
| Right GCT — Return, steps 1–5 | seconds | Right foot ground contact time during return |
### Step Length Metrics
Step length (SL) is the distance traveled by the ankle joint center from foot strike to foot off for each step, up to 5 steps per leg per half.
| Metric | Units | Description |
| ------------------------------ | ------ | --------------------------------- |
| Left SL — Approach, steps 1–5 | meters | Left step length during approach |
| Right SL — Approach, steps 1–5 | meters | Right step length during approach |
| Left SL — Return, steps 1–5 | meters | Left step length during return |
| Right SL — Return, steps 1–5 | meters | Right step length during return |
### Pelvis Path Time Series
Pelvis position, velocity, and acceleration are returned as full time-series arrays, with the coordinate frame rotated to align the X axis with the direction of movement.
| Metric | Units | Description |
| ------------------- | ------ | -------------------------------------------- |
| Pelvis Position X | meters | Pelvis position along the sprint axis |
| Pelvis Position Y | meters | Pelvis vertical position |
| Pelvis Position Z | meters | Pelvis position perpendicular to sprint axis |
| Pelvis Velocity | m/s | Pelvis velocity along the sprint axis |
| Pelvis Acceleration | m/s² | Pelvis acceleration along the sprint axis |
## Notes
* Kinematic data typically captured at 120 Hz for agility drills
* Direction is detected automatically; separate trials should be performed for left and right plant foot
* Step indices are assigned in temporal order; not all 5 steps per leg may be populated depending on trial length and gait
* Turn time captures the period of foot contact at the change-of-direction pivot and may be sensitive to plant foot strategy
# Baseball: Hitting
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting
Biomechanical analysis of baseball hitting movements, including events and metrics for body and bat variables.
Break down the precise timing and sequencing of movements from the pelvis, trunk, and arms, to identify inefficiencies in swing mechanics, improve consistency, and maximize energy transfer from the lower body through the core to the bat.
Uplift offers dozens of events and metrics to track baseball hitting for little league to professional athletes.
![Example image of a man doing a mid-swing, side view]()
## Dimensions
Required Inputs for processing:
* **handedness:** the handedness of the batter \['left', 'right']
## Variables
Output variables from hitting analysis.
### Normative Ranges
See [Baseball Hitting Norms](/biomechanics/activities/baseball/hitting/baseball-hitting-norms) for the full 5th–95th percentile reference tables by competition level (Youth, High School, College, Pro).
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
Identify specific time points during the hit.
| Event | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------- | ----------------------------------- |
| [Initiation](/biomechanics/activities/baseball/hitting/events/initiation) | Lead foot begins to move prior to max knee raise. | `initiation_frame` |
| [Max Foot Raise](/biomechanics/activities/baseball/hitting/events/max-foot-raise) | Maximum height of the lead foot. | `max_foot_raise_frame` |
| [Foot Contact](/biomechanics/activities/baseball/hitting/events/foot-contact) | Front foot contacts the ground. | `foot_contact_frame` |
| [Pelvis Velocity Initiation (Launch)](/biomechanics/activities/baseball/hitting/events/pelvis-velocity-initiation) | Start of pelvis rotation (launch event). | `pelvis_initiation_frame` |
| [Max X Factor](/biomechanics/activities/baseball/hitting/events/max-x-factor) | Maximum hip-shoulder separation before the twisting motion. | `max_x_factor_frame` |
| [X Factor Zero Crossing](/biomechanics/activities/baseball/hitting/events/x-factor-zero-crossing) | Shoulder-hip separation crosses zero after Max X Factor. | `x_factor_zero_crossing_frame` |
| [Wrist Initiation](/biomechanics/activities/baseball/hitting/events/wrist-initiation) | Start of wrist movement during the swing. | `wrist_movement_initiation_frame` |
| [Twist](/biomechanics/activities/baseball/hitting/events/twist) | Average timing of peak pelvis, trunk, and arm angular velocities. | `twist_frame` |
| [Peak Pelvis Ang Vel](/biomechanics/activities/baseball/hitting/events/peak-pelvis-ang-vel) | Instant of pelvis peak angular velocity. | `peak_pelvis_velocity_frame` |
| [Peak Trunk Ang Vel](/biomechanics/activities/baseball/hitting/events/peak-trunk-ang-vel) | Instant of trunk peak angular velocity. | `peak_trunk_velocity_frame` |
| [Peak Arm Ang Vel](/biomechanics/activities/baseball/hitting/events/peak-arm-ang-vel) | Instant of lead arm peak angular velocity. | `peak_arm_velocity_frame` |
| [Peak Wrist Angular Velocity](/biomechanics/activities/baseball/hitting/events/peak-wrist-angular-velocity) | Instant of maximum wrist angular velocity. | `peak_wrist_angular_velocity_frame` |
| [Ball Contact](/biomechanics/activities/baseball/hitting/events/ball-contact) | Estimated timing of ball contact (audio signal primary, swing through secondary). | `ball_contact_frame` |
| [Swing Through](/biomechanics/activities/baseball/hitting/events/swing-through) | Rear wrist passes in front of the lead wrist — batter commits to swing. | `swing_through_frame` |
| [Pelvis Velocity Termination](/biomechanics/activities/baseball/hitting/events/pelvis-velocity-termination) | First local minimum after peak pelvis velocity. | `pelvis_velocity_termination_frame` |
| [End Twist](/biomechanics/activities/baseball/hitting/events/end-twist) | End of twisting motion — X Factor velocity returns to 0 deg/s. | `end_twist_frame` |
### Movement Flags
Find inefficiencies during the hitting motion.
| Metric | Short Description | Column Name |
| ---------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------ | ------------------------------- |
| [Leads With Wrist](/biomechanics/activities/baseball/hitting/metrics/leads-with-wrist) | Wrist initiation occurs before pelvis initiation. | `leads_with_wrist` |
| [Sway](/biomechanics/activities/baseball/hitting/metrics/sway) | Pelvis drifts backward more than 8 cm (\~3 in) around max knee raise. | `sway` |
| [Sway Leg](/biomechanics/activities/baseball/hitting/metrics/sway-leg) | Rear knee passes behind the ankle (away from pitcher). | `sway_leg` |
| [Knee Dominant](/biomechanics/activities/baseball/hitting/metrics/knee-dominant) | Rear hip and ankle angles differ \<25° at launch with >15° ankle dorsiflexion. | `knee_dominant_swing` |
| [Vertical Pelvis Hike](/biomechanics/activities/baseball/hitting/metrics/vertical-pelvis-hike) | Pelvis finishes higher at ball contact than at launch. | `vertical_pelvis_hike` |
| [Lateral Pelvis Tilt](/biomechanics/activities/baseball/hitting/metrics/lateral-pelvis-tilt) | Pelvis tilts upward more than 10 deg during the swing. | `excessive_lateral_pelvis_tilt` |
| [Drifting Forward](/biomechanics/activities/baseball/hitting/metrics/drifting-forward) | Pelvis drifts forward more than 15 cm (\~6 in) from launch to ball contact. | `drifting_forward` |
### Kinematic Sequence
Order and magnitude of pelvis, trunk, and upper arm peak rotational velocity (deg/s) during the swing.
| Metric | Units | Short Description | Column Name |
| -------------------------------------------------------------------------------------------------------------- | ----- | ------------------------------------------------------------------------------- | ---------------------------------- |
| [Kinematic Sequence](/biomechanics/activities/baseball/hitting/metrics/kinematic-sequence-order) | N/A | Order of peak segment angular velocities. Correct sequence is pelvis-trunk-arm. | `kinematic_sequence_order` |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-pelvis-angular-velocity) | deg/s | Max rotational speed of the pelvis. | `peak_pelvis_angular_velocity` |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-trunk-angular-velocity) | deg/s | Max rotational speed of the trunk. | `peak_trunk_angular_velocity` |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-arm-angular-velocity) | deg/s | Max rotational speed of the lead upper arm. | `peak_arm_angular_velocity` |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/hitting/metrics/trunk-to-arm-speed-up) | ratio | Speed increase ratio from trunk to arm. | `trunk_to_arm_velocity_speedup` |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/hitting/metrics/pelvis-to-trunk-speed-up) | ratio | Speed increase ratio from pelvis to trunk. | `pelvis_to_trunk_velocity_speedup` |
### Timing & General Metrics
Durations, sequencing info, and general session metadata.
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------ | ----- | ---------------------------------------------------------------- | -------------------------- |
| [Time to Ball Contact](/biomechanics/activities/baseball/hitting/metrics/time-to-ball-contact) | s | Duration from initiation to ball contact. | `time_to_ball_contact` |
| [Time to Launch](/biomechanics/activities/baseball/hitting/metrics/time-to-launch) | s | Duration from initiation to launch (pelvis velocity initiation). | `time_to_launch` |
| [Pelvis Acceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-acceleration-time) | s | Time from pelvis rotation start to peak pelvis angular velocity. | `pelvis_acceleration_time` |
| [Pelvis Deceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-deceleration-time) | s | Time from peak pelvis angular velocity to end of rotation. | `pelvis_deceleration_time` |
| [Handedness](/biomechanics/activities/baseball/hitting/metrics/handedness) | N/A | Batter handedness \['right' or 'left']. | `handedness` |
| [Ball Contact Method](/biomechanics/activities/baseball/hitting/metrics/ball-contact-method) | N/A | Detection method: both audio, single audio, or swing through. | `ball_contact_method` |
### Lower Body & Stride
Lower body positions, stride mechanics, and forward movement during the swing.
| Metric | Units | Short Description | Column Name |
| -------------------------------------------------------------------------------------------------------------------- | ----- | ----------------------------------------------------------------------------- | --------------------------------- |
| [Stride Length](/biomechanics/activities/baseball/hitting/metrics/stride-length) | m | Lead ankle at foot contact to rear ankle at max foot raise. | `stride_length` |
| [Hip Hinge](/biomechanics/activities/baseball/hitting/metrics/hip-hinge) | deg | Max rear hip flexion between max foot raise and foot contact. | `hip_hinge` |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/lead-knee-angle-at-ball-contact) | deg | Lead knee flexion at ball contact. | `lead_knee_angle_at_ball_contact` |
| [Drifting Forward Magnitude](/biomechanics/activities/baseball/hitting/metrics/drifting-forward-magnitude) | m | Pelvis forward drift from launch to ball contact — see Drifting Forward flag. | `drifting_forward_magnitude` |
### Trunk & X-Factor
Trunk and pelvis rotation angles, coil, and swing plane metrics.
| Metric | Units | Short Description | Column Name |
| -------------------------------------------------------------------------------------------------------------------- | ----- | ----------------------------------------------------------------------------------- | --------------------------------- |
| [Max X Factor](/biomechanics/activities/baseball/hitting/metrics/max-x-factor) | deg | Max hip-shoulder separation angle. | `max_x_factor` |
| [Trunk Coil](/biomechanics/activities/baseball/hitting/metrics/trunk-coil) | deg | Max trunk rotation away from the pitcher (0 = facing pitcher). | `trunk_coil` |
| [Trunk Tilt at Launch](/biomechanics/activities/baseball/hitting/metrics/trunk-tilt-at-launch) | deg | Side-to-side trunk tilt at launch (+ = towards pitcher). | `trunk_tilt_at_launch` |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-flexion) | deg | Trunk flexion to align with the average shoulder rotation plane. | `shoulder_rotation_plane_flexion` |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-tilt) | deg | Trunk tilt to align with the average shoulder rotation plane (+ = towards pitcher). | `shoulder_rotation_plane_tilt` |
### Arm, Hand & Connection
Upper extremity angles, distances, and hand positions relative to the body.
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------------------------------------ | ----- | ---------------------------------------------------------------------------- | ---------------------------------------- |
| [Scap Load at Launch](/biomechanics/activities/baseball/hitting/metrics/scap-load-at-launch) | deg | Rear shoulder flexion (+) or extension (-) at launch. | `rear_scap_load_at_launch` |
| [Elbow Flexion at Launch](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-launch) | deg | Rear elbow flexion at launch. | `rear_elbow_flexion_at_launch` |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-ball-contact) | deg | Rear elbow flexion at ball contact. | `rear_elbow_flexion_at_ball_contact` |
| [Rear Arm Connection](/biomechanics/activities/baseball/hitting/metrics/rear-arm-connection) | m | Avg distance from rear elbow to mid-torso between launch and ball contact. | `rear_arm_connection` |
| [Inter Elbow Distance at Elbow Slot](/biomechanics/activities/baseball/hitting/metrics/inter-elbow-distance-at-elbow-slot) | m | Elbow-to-elbow distance at elbow slot. | `inter_elbow_distance_at_elbow_slot` |
| [Inter Elbow Distance at Trunk Peak](/biomechanics/activities/baseball/hitting/metrics/inter-elbow-distance-at-trunk-peak) | m | Elbow-to-elbow distance at peak trunk angular velocity. | `inter_elbow_distance_at_trunk_peak` |
| [Inter Elbow Distance at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/inter-elbow-distance-at-ball-contact) | m | Elbow-to-elbow distance at ball contact. | `inter_elbow_distance_at_ball_contact` |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-towards-pitcher) | m | Wrist position relative to mid-shoulders along pitcher axis at foot contact. | `relative_hand_position_towards_pitcher` |
| [Relative Hand Position - Up](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-up) | m | Wrist height relative to mid-shoulders at foot contact. | `relative_hand_position_up` |
| [Relative Hand Position - Away from Body](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-away-from-body) | m | Wrist distance away from mid-shoulders (lateral) at foot contact. | `relative_hand_position_away_from_body` |
| [Linear Stretch](/biomechanics/activities/baseball/hitting/metrics/linear-stretch) | m | Lead ankle to wrist center distance along pitch direction at foot contact. | `linear_stretch` |
### Time Series Metrics
Metrics describing motion over the duration of the capture, changing values with every frame.
Use in combination with the keypoints and kinematics from [Generic Outputs](/biomechanics/generic-outputs).
| Metric | Units | Short Description | Column Name |
| ----------------------------------------------------------------------------------------------------------- | ----- | ---------------------------------------------------------- | ----------------------------- |
| [Trunk Center of Mass Position X](/biomechanics/activities/baseball/hitting/metrics/trunk-center-of-mass-x) | m | Trunk COM X position. | `trunk_center_of_mass_x` |
| [Trunk Center of Mass Position Y](/biomechanics/activities/baseball/hitting/metrics/trunk-center-of-mass-y) | m | Trunk COM Y position (vertical). | `trunk_center_of_mass_y` |
| [Trunk Center of Mass Position Z](/biomechanics/activities/baseball/hitting/metrics/trunk-center-of-mass-z) | m | Trunk COM Z position. | `trunk_center_of_mass_z` |
| [Body Center of Mass Position X](/biomechanics/activities/baseball/hitting/metrics/body-center-of-mass-x) | m | Whole-body COM X position. | `whole_body_center_of_mass_x` |
| [Body Center of Mass Position Y](/biomechanics/activities/baseball/hitting/metrics/body-center-of-mass-y) | m | Whole-body COM Y position (vertical). | `whole_body_center_of_mass_y` |
| [Body Center of Mass Position Z](/biomechanics/activities/baseball/hitting/metrics/body-center-of-mass-z) | m | Whole-body COM Z position. | `whole_body_center_of_mass_z` |
| [Trunk Global Flexion](/biomechanics/activities/baseball/hitting/metrics/trunk-global-flexion) | deg | Trunk sagittal plane flexion relative to global frame. | `trunk_global_flexion` |
| [Trunk Global Tilt](/biomechanics/activities/baseball/hitting/metrics/trunk-global-tilt) | deg | Trunk frontal plane tilt relative to global frame. | `trunk_global_tilt` |
| [Trunk Global Rotation](/biomechanics/activities/baseball/hitting/metrics/trunk-global-rotation) | deg | Trunk transverse plane rotation relative to global frame. | `trunk_global_rotation` |
| [Pelvis Global Tilt](/biomechanics/activities/baseball/hitting/metrics/pelvis-global-tilt) | deg | Pelvis frontal plane tilt relative to global frame. | `pelvis_global_tilt` |
| [Pelvis Global Rotation](/biomechanics/activities/baseball/hitting/metrics/pelvis-global-rotation) | deg | Pelvis transverse plane rotation relative to global frame. | `pelvis_global_rotation` |
### Bat Metrics
Descriptors of bat positions, speeds, and more during the swing.
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------------------------------------ | ----- | ------------------------------------------------------------------------------ | ----------------------------------------- |
| [Attack Angle](/biomechanics/activities/baseball/hitting/metrics/attack-angle) | deg | Bat path angle relative to horizontal at contact. | `attack_angle` |
| [On Plane Efficiency](/biomechanics/activities/baseball/hitting/metrics/on-plane-efficiency) | % | % of swing path within 10 deg of optimal plane (foot contact to ball contact). | `on_plane_efficiency` |
| [Launch Position](/biomechanics/activities/baseball/hitting/metrics/launch-position) | deg | Bat angle relative to spine in the sagittal plane at launch. | `launch_position` |
| [Sweet Spot Fore Aft Position At Contact](/biomechanics/activities/baseball/hitting/metrics/sweet-spot-fore-aft-position-at-contact) | m | Fore/aft position of bat sweet spot relative to pelvis at contact. | `sweet_spot_fore_aft_position_at_contact` |
| [Attack Direction](/biomechanics/activities/baseball/hitting/metrics/attack-direction) | deg | Horizontal bat angle relative to home plate (indicates hit direction). | `attack_direction` |
| [Swing Path](/biomechanics/activities/baseball/hitting/metrics/swing-path-angle) | deg | Vertical bat path angle in the 0.04 s leading up to ball contact. | `swing_path_angle` |
## Notes
* Kinematic data typically captured at 240Hz for Baseball Hitting
* All boolean variables (true/false = 1/0) return -1 if metric unable to be calculated.
# Baseball Hitting: Normative Ranges
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/baseball-hitting-norms
Full percentile reference tables (5th–95th) for baseball hitting metrics, broken out by competition level.
This page collects the complete normative reference tables for baseball hitting — the same underlying data shown as 10th/25th/50th/75th/90th percentile summaries on individual [metric pages](/biomechanics/activities/baseball/hitting), extended here to the full 5th–95th percentile range for each competition level. See [Normative Ranges](/biomechanics/normative-ranges) for how to interpret these tables.
Each competition-level dataset was built by pooling all valid hitting sessions per athlete, selecting the single session closest to that athlete's overall average across all metrics, then re-analyzing with the latest biomechanical analysis software and removing sessions that failed Uplift's quality assurance tests. Distance metrics are shown in inches to match the display units used on individual metric pages.
## Youth Sample
Reference dataset built from 239 unique youth athletes performing a hit in 2025.
### Kinematic Sequence – Peak Segment Angular Velocities & Speedup Factors
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-pelvis-angular-velocity) | 389 | 408 | 448 | 480 | 517 | 541 | 562 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-trunk-angular-velocity) | 535 | 559 | 601 | 656 | 697 | 768 | 794 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-arm-angular-velocity) | 547 | 608 | 662 | 728 | 797 | 879 | 956 | deg/s |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/hitting/metrics/trunk-to-arm-speed-up) | 0.90 | 0.94 | 1.03 | 1.12 | 1.20 | 1.32 | 1.40 | ratio |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/hitting/metrics/pelvis-to-trunk-speed-up) | 1.15 | 1.19 | 1.27 | 1.35 | 1.45 | 1.57 | 1.64 | ratio |
### Times
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------ | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Time to Ball Contact](/biomechanics/activities/baseball/hitting/metrics/time-to-ball-contact) | 0.00 | 0.59 | 0.76 | 0.85 | 1.02 | 1.15 | 1.22 | s |
| [Time to Launch](/biomechanics/activities/baseball/hitting/metrics/time-to-launch) | 0.00 | 0.00 | 0.13 | 0.23 | 0.41 | 0.57 | 0.70 | s |
| [Pelvis Acceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-acceleration-time) | 0.20 | 0.27 | 0.38 | 0.49 | 0.65 | 1.47 | 2.35 | s |
| [Pelvis Deceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-deceleration-time) | 0.15 | 0.17 | 0.21 | 0.57 | 0.72 | 1.10 | 1.24 | s |
### Distance
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------------------------ | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Stride Length](/biomechanics/activities/baseball/hitting/metrics/stride-length) | 10.7 | 11.7 | 12.9 | 15.1 | 16.7 | 20.7 | 26.7 | in |
| [Linear Stretch](/biomechanics/activities/baseball/hitting/metrics/linear-stretch) | 7.7 | 9.1 | 10.3 | 12.4 | 14.7 | 17.4 | 19.5 | in |
| [Drifting Forward Magnitude](/biomechanics/activities/baseball/hitting/metrics/drifting-forward-magnitude) | 0.3 | 1.3 | 2.6 | 4.1 | 5.5 | 7.2 | 8.3 | in |
| [Rear Arm Connection](/biomechanics/activities/baseball/hitting/metrics/rear-arm-connection) | 5.6 | 6.3 | 7.2 | 8.4 | 9.6 | 11.6 | 14.4 | in |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-towards-pitcher) | -7.8 | -7.5 | -6.4 | -5.2 | -3.4 | -2.5 | 0.3 | in |
| [Relative Hand Position - Up](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-up) | -0.7 | 0.6 | 1.7 | 2.6 | 3.7 | 4.6 | 6.2 | in |
| [Relative Hand Position - Away from Body](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-away-from-body) | 0.2 | 1.2 | 2.4 | 3.6 | 4.7 | 5.5 | 7.7 | in |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/baseball/hitting/metrics/max-x-factor) | 0 | 14 | 25 | 30 | 38 | 43 | 47 | deg |
| [Hip Hinge](/biomechanics/activities/baseball/hitting/metrics/hip-hinge) | 38 | 42 | 48 | 54 | 60 | 68 | 72 | deg |
| [Trunk Coil](/biomechanics/activities/baseball/hitting/metrics/trunk-coil) | 0 | 18 | 28 | 35 | 45 | 53 | 57 | deg |
| [Trunk Tilt at Launch](/biomechanics/activities/baseball/hitting/metrics/trunk-tilt-at-launch) | 1 | 3 | 5 | 9 | 14 | 16 | 19 | deg |
| [Scap Load at Launch](/biomechanics/activities/baseball/hitting/metrics/scap-load-at-launch) | -21 | -16 | -4 | 6 | 18 | 28 | 36 | deg |
| [Elbow Flexion at Launch](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-launch) | 65 | 99 | 110 | 118 | 124 | 128 | 129 | deg |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-ball-contact) | 58 | 62 | 70 | 81 | 90 | 101 | 107 | deg |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/lead-knee-angle-at-ball-contact) | 15 | 18 | 22 | 27 | 34 | 39 | 45 | deg |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-flexion) | 20 | 22 | 26 | 31 | 35 | 39 | 42 | deg |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-tilt) | -18 | -12 | -5 | 2 | 11 | 16 | 21 | deg |
## High School Sample
Reference dataset built from 202 unique high school athletes performing a hit in 2025.
### Kinematic Sequence – Peak Segment Angular Velocities & Speedup Factors
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-pelvis-angular-velocity) | 362 | 412 | 461 | 494 | 526 | 566 | 623 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-trunk-angular-velocity) | 568 | 587 | 624 | 666 | 738 | 796 | 922 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-arm-angular-velocity) | 574 | 608 | 675 | 740 | 911 | 1097 | 1348 | deg/s |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/hitting/metrics/trunk-to-arm-speed-up) | 0.90 | 0.96 | 1.03 | 1.12 | 1.34 | 1.49 | 1.65 | ratio |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/hitting/metrics/pelvis-to-trunk-speed-up) | 1.15 | 1.20 | 1.29 | 1.39 | 1.49 | 1.63 | 1.74 | ratio |
### Times
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------ | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Time to Ball Contact](/biomechanics/activities/baseball/hitting/metrics/time-to-ball-contact) | 0.00 | 0.53 | 0.78 | 0.89 | 1.00 | 1.14 | 1.21 | s |
| [Time to Launch](/biomechanics/activities/baseball/hitting/metrics/time-to-launch) | 0.00 | 0.00 | 0.17 | 0.29 | 0.48 | 0.65 | 0.72 | s |
| [Pelvis Acceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-acceleration-time) | 0.18 | 0.20 | 0.31 | 0.45 | 0.61 | 1.52 | 2.26 | s |
| [Pelvis Deceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-deceleration-time) | 0.15 | 0.16 | 0.41 | 0.49 | 0.74 | 1.10 | 1.16 | s |
### Distance
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------------------------ | :---: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Stride Length](/biomechanics/activities/baseball/hitting/metrics/stride-length) | 12.9 | 13.9 | 15.3 | 17.1 | 20.6 | 29.9 | 33.6 | in |
| [Linear Stretch](/biomechanics/activities/baseball/hitting/metrics/linear-stretch) | 7.2 | 10.4 | 12.0 | 13.7 | 16.3 | 26.3 | 29.1 | in |
| [Drifting Forward Magnitude](/biomechanics/activities/baseball/hitting/metrics/drifting-forward-magnitude) | 0.4 | 2.0 | 3.5 | 4.8 | 6.6 | 8.3 | 11.7 | in |
| [Rear Arm Connection](/biomechanics/activities/baseball/hitting/metrics/rear-arm-connection) | 7.0 | 7.6 | 8.9 | 9.9 | 11.7 | 15.0 | 18.4 | in |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-towards-pitcher) | -10.3 | -8.7 | -7.2 | -5.9 | -4.2 | -2.8 | -0.0 | in |
| [Relative Hand Position - Up](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-up) | -0.6 | 0.2 | 1.7 | 2.8 | 4.1 | 5.9 | 7.0 | in |
| [Relative Hand Position - Away from Body](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-away-from-body) | 0.9 | 2.0 | 3.0 | 4.5 | 5.6 | 6.6 | 7.7 | in |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/baseball/hitting/metrics/max-x-factor) | 0 | 9 | 22 | 30 | 35 | 42 | 47 | deg |
| [Hip Hinge](/biomechanics/activities/baseball/hitting/metrics/hip-hinge) | 36 | 46 | 50 | 55 | 63 | 70 | 74 | deg |
| [Trunk Coil](/biomechanics/activities/baseball/hitting/metrics/trunk-coil) | 3 | 17 | 24 | 33 | 42 | 49 | 53 | deg |
| [Trunk Tilt at Launch](/biomechanics/activities/baseball/hitting/metrics/trunk-tilt-at-launch) | -3 | 1 | 5 | 10 | 14 | 18 | 20 | deg |
| [Scap Load at Launch](/biomechanics/activities/baseball/hitting/metrics/scap-load-at-launch) | -30 | -18 | -6 | 10 | 23 | 33 | 38 | deg |
| [Elbow Flexion at Launch](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-launch) | 64 | 100 | 114 | 122 | 126 | 131 | 135 | deg |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-ball-contact) | 33 | 50 | 69 | 81 | 93 | 108 | 114 | deg |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/lead-knee-angle-at-ball-contact) | 6 | 15 | 19 | 24 | 29 | 32 | 43 | deg |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-flexion) | 22 | 25 | 29 | 34 | 38 | 45 | 48 | deg |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-tilt) | -16 | -13 | -8 | 0 | 6 | 15 | 19 | deg |
## College Sample
Reference dataset built from 156 unique collegiate athletes performing a hit in 2025.
### Kinematic Sequence – Peak Segment Angular Velocities & Speedup Factors
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-pelvis-angular-velocity) | 379 | 416 | 471 | 509 | 527 | 552 | 572 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-trunk-angular-velocity) | 523 | 532 | 593 | 631 | 680 | 738 | 768 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-arm-angular-velocity) | 532 | 559 | 647 | 743 | 915 | 1139 | 1454 | deg/s |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/hitting/metrics/trunk-to-arm-speed-up) | 0.86 | 0.91 | 1.00 | 1.19 | 1.39 | 1.76 | 2.15 | ratio |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/hitting/metrics/pelvis-to-trunk-speed-up) | 1.04 | 1.14 | 1.19 | 1.29 | 1.36 | 1.50 | 1.65 | ratio |
### Times
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------ | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Time to Ball Contact](/biomechanics/activities/baseball/hitting/metrics/time-to-ball-contact) | 0.17 | 0.60 | 0.71 | 0.92 | 1.03 | 1.13 | 1.15 | s |
| [Time to Launch](/biomechanics/activities/baseball/hitting/metrics/time-to-launch) | 0.00 | 0.00 | 0.18 | 0.35 | 0.58 | 0.77 | 0.81 | s |
| [Pelvis Acceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-acceleration-time) | 0.14 | 0.17 | 0.18 | 0.37 | 0.60 | 0.87 | 1.54 | s |
| [Pelvis Deceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-deceleration-time) | 0.14 | 0.15 | 0.34 | 0.48 | 0.65 | 0.83 | 1.08 | s |
### Distance
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------------------------ | :---: | :---: | :---: | :--: | :--: | :--: | :--: | ----- |
| [Stride Length](/biomechanics/activities/baseball/hitting/metrics/stride-length) | 18.3 | 21.1 | 23.5 | 28.3 | 33.4 | 37.3 | 39.4 | in |
| [Linear Stretch](/biomechanics/activities/baseball/hitting/metrics/linear-stretch) | 12.9 | 13.8 | 17.6 | 21.7 | 26.3 | 31.0 | 32.0 | in |
| [Drifting Forward Magnitude](/biomechanics/activities/baseball/hitting/metrics/drifting-forward-magnitude) | 2.6 | 3.6 | 5.6 | 7.7 | 10.9 | 15.1 | 15.7 | in |
| [Rear Arm Connection](/biomechanics/activities/baseball/hitting/metrics/rear-arm-connection) | 9.0 | 10.2 | 12.2 | 14.3 | 17.1 | 18.9 | 19.1 | in |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-towards-pitcher) | -12.2 | -11.4 | -10.2 | -7.6 | -5.0 | -2.8 | -1.4 | in |
| [Relative Hand Position - Up](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-up) | -0.2 | 0.3 | 2.4 | 4.5 | 5.8 | 7.4 | 7.9 | in |
| [Relative Hand Position - Away from Body](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-away-from-body) | 3.1 | 3.3 | 4.9 | 6.3 | 8.1 | 9.4 | 10.0 | in |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/baseball/hitting/metrics/max-x-factor) | 3 | 14 | 19 | 25 | 29 | 35 | 39 | deg |
| [Hip Hinge](/biomechanics/activities/baseball/hitting/metrics/hip-hinge) | 45 | 49 | 54 | 60 | 69 | 73 | 74 | deg |
| [Trunk Coil](/biomechanics/activities/baseball/hitting/metrics/trunk-coil) | 4 | 17 | 25 | 31 | 39 | 45 | 46 | deg |
| [Trunk Tilt at Launch](/biomechanics/activities/baseball/hitting/metrics/trunk-tilt-at-launch) | 2 | 3 | 7 | 10 | 14 | 16 | 18 | deg |
| [Scap Load at Launch](/biomechanics/activities/baseball/hitting/metrics/scap-load-at-launch) | -32 | -28 | -8 | 4 | 16 | 33 | 45 | deg |
| [Elbow Flexion at Launch](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-launch) | 101 | 114 | 120 | 126 | 132 | 135 | 137 | deg |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-ball-contact) | 23 | 35 | 48 | 70 | 86 | 104 | 108 | deg |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/lead-knee-angle-at-ball-contact) | 6 | 7 | 10 | 16 | 23 | 32 | 41 | deg |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-flexion) | 28 | 31 | 34 | 38 | 41 | 44 | 46 | deg |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-tilt) | -11 | -7 | 2 | 7 | 14 | 21 | 23 | deg |
## Professional Sample
Reference dataset built from 293 unique professional athletes performing a hit in 2025.
### Kinematic Sequence – Peak Segment Angular Velocities & Speedup Factors
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-pelvis-angular-velocity) | 331 | 384 | 438 | 481 | 524 | 565 | 627 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-trunk-angular-velocity) | 441 | 475 | 524 | 580 | 636 | 700 | 801 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-arm-angular-velocity) | 552 | 592 | 680 | 822 | 957 | 1160 | 1371 | deg/s |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/hitting/metrics/trunk-to-arm-speed-up) | 0.96 | 1.02 | 1.20 | 1.40 | 1.60 | 1.92 | 2.11 | ratio |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/hitting/metrics/pelvis-to-trunk-speed-up) | 0.99 | 1.05 | 1.12 | 1.19 | 1.35 | 1.48 | 1.62 | ratio |
### Times
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------ | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Time to Ball Contact](/biomechanics/activities/baseball/hitting/metrics/time-to-ball-contact) | 0.39 | 0.59 | 0.74 | 0.91 | 1.04 | 1.26 | 1.28 | s |
| [Time to Launch](/biomechanics/activities/baseball/hitting/metrics/time-to-launch) | 0.00 | 0.10 | 0.18 | 0.45 | 0.67 | 0.79 | 0.96 | s |
| [Pelvis Acceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-acceleration-time) | 0.14 | 0.15 | 0.18 | 0.23 | 0.54 | 0.75 | 0.82 | s |
| [Pelvis Deceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-deceleration-time) | 0.09 | 0.14 | 0.35 | 0.46 | 0.57 | 0.80 | 1.17 | s |
### Distance
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------------------------ | :---: | :---: | :---: | :--: | :--: | :--: | :--: | ----- |
| [Stride Length](/biomechanics/activities/baseball/hitting/metrics/stride-length) | 25.7 | 27.8 | 31.5 | 35.1 | 38.6 | 40.7 | 42.4 | in |
| [Linear Stretch](/biomechanics/activities/baseball/hitting/metrics/linear-stretch) | 14.0 | 19.3 | 23.0 | 27.0 | 29.6 | 33.4 | 35.3 | in |
| [Drifting Forward Magnitude](/biomechanics/activities/baseball/hitting/metrics/drifting-forward-magnitude) | 4.5 | 5.6 | 7.1 | 8.5 | 12.5 | 15.5 | 16.9 | in |
| [Rear Arm Connection](/biomechanics/activities/baseball/hitting/metrics/rear-arm-connection) | 12.6 | 13.0 | 14.7 | 16.3 | 18.5 | 20.6 | 21.4 | in |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-towards-pitcher) | -14.3 | -13.3 | -11.6 | -9.0 | -6.3 | -2.8 | 0.0 | in |
| [Relative Hand Position - Up](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-up) | -1.5 | 0.8 | 4.0 | 6.2 | 8.2 | 9.5 | 10.3 | in |
| [Relative Hand Position - Away from Body](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-away-from-body) | 1.5 | 3.4 | 5.8 | 7.8 | 9.0 | 11.0 | 11.7 | in |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/baseball/hitting/metrics/max-x-factor) | 4 | 8 | 12 | 16 | 23 | 29 | 30 | deg |
| [Hip Hinge](/biomechanics/activities/baseball/hitting/metrics/hip-hinge) | 40 | 47 | 54 | 60 | 66 | 70 | 76 | deg |
| [Trunk Coil](/biomechanics/activities/baseball/hitting/metrics/trunk-coil) | 6 | 12 | 22 | 27 | 35 | 39 | 41 | deg |
| [Trunk Tilt at Launch](/biomechanics/activities/baseball/hitting/metrics/trunk-tilt-at-launch) | -2 | -1 | 4 | 9 | 12 | 14 | 15 | deg |
| [Scap Load at Launch](/biomechanics/activities/baseball/hitting/metrics/scap-load-at-launch) | -38 | -31 | -16 | 0 | 17 | 29 | 41 | deg |
| [Elbow Flexion at Launch](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-launch) | 106 | 113 | 120 | 125 | 132 | 135 | 137 | deg |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-ball-contact) | 25 | 31 | 42 | 60 | 74 | 97 | 104 | deg |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/lead-knee-angle-at-ball-contact) | 5 | 6 | 8 | 11 | 17 | 21 | 24 | deg |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-flexion) | 29 | 30 | 34 | 38 | 41 | 44 | 48 | deg |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-tilt) | -7 | -2 | 2 | 8 | 15 | 21 | 24 | deg |
## Broad Sample (All Levels)
Reference dataset built from 890 unique athletes performing a hit in 2025, pooled across all competition levels.
### Kinematic Sequence – Peak Segment Angular Velocities & Speedup Factors
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-pelvis-angular-velocity) | 367 | 402 | 452 | 490 | 525 | 553 | 598 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-trunk-angular-velocity) | 490 | 527 | 582 | 637 | 694 | 769 | 817 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/hitting/metrics/peak-arm-angular-velocity) | 544 | 591 | 663 | 749 | 876 | 1060 | 1335 | deg/s |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/hitting/metrics/trunk-to-arm-speed-up) | 0.90 | 0.95 | 1.06 | 1.17 | 1.39 | 1.65 | 1.89 | ratio |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/hitting/metrics/pelvis-to-trunk-speed-up) | 1.06 | 1.12 | 1.20 | 1.32 | 1.44 | 1.57 | 1.68 | ratio |
### Times
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------ | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Time to Ball Contact](/biomechanics/activities/baseball/hitting/metrics/time-to-ball-contact) | 0.00 | 0.58 | 0.75 | 0.89 | 1.02 | 1.16 | 1.25 | s |
| [Time to Launch](/biomechanics/activities/baseball/hitting/metrics/time-to-launch) | 0.00 | 0.00 | 0.16 | 0.29 | 0.51 | 0.72 | 0.80 | s |
| [Pelvis Acceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-acceleration-time) | 0.15 | 0.17 | 0.22 | 0.42 | 0.62 | 0.89 | 1.88 | s |
| [Pelvis Deceleration Time](/biomechanics/activities/baseball/hitting/metrics/pelvis-deceleration-time) | 0.14 | 0.16 | 0.35 | 0.50 | 0.68 | 1.00 | 1.18 | s |
### Distance
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------------------------ | :---: | :---: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Stride Length](/biomechanics/activities/baseball/hitting/metrics/stride-length) | 12.3 | 13.0 | 15.5 | 21.7 | 32.7 | 37.4 | 39.7 | in |
| [Linear Stretch](/biomechanics/activities/baseball/hitting/metrics/linear-stretch) | 9.0 | 10.0 | 12.4 | 16.3 | 25.4 | 29.6 | 32.7 | in |
| [Drifting Forward Magnitude](/biomechanics/activities/baseball/hitting/metrics/drifting-forward-magnitude) | 1.2 | 2.1 | 3.8 | 5.9 | 8.4 | 12.8 | 15.1 | in |
| [Rear Arm Connection](/biomechanics/activities/baseball/hitting/metrics/rear-arm-connection) | 6.7 | 7.2 | 8.9 | 11.7 | 15.7 | 18.7 | 19.3 | in |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-towards-pitcher) | -12.3 | -11.2 | -8.7 | -6.3 | -4.2 | -2.6 | 0.0 | in |
| [Relative Hand Position - Up](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-up) | -0.8 | 0.4 | 1.9 | 3.5 | 5.6 | 7.8 | 9.1 | in |
| [Relative Hand Position - Away from Body](/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-away-from-body) | 1.0 | 1.9 | 3.3 | 4.9 | 7.1 | 9.1 | 10.3 | in |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/baseball/hitting/metrics/max-x-factor) | 0 | 9 | 17 | 26 | 33 | 40 | 45 | deg |
| [Hip Hinge](/biomechanics/activities/baseball/hitting/metrics/hip-hinge) | 38 | 44 | 51 | 57 | 64 | 71 | 74 | deg |
| [Trunk Coil](/biomechanics/activities/baseball/hitting/metrics/trunk-coil) | 2 | 16 | 24 | 31 | 41 | 48 | 53 | deg |
| [Trunk Tilt at Launch](/biomechanics/activities/baseball/hitting/metrics/trunk-tilt-at-launch) | -1 | 1 | 5 | 9 | 13 | 16 | 19 | deg |
| [Scap Load at Launch](/biomechanics/activities/baseball/hitting/metrics/scap-load-at-launch) | -32 | -25 | -8 | 5 | 19 | 31 | 40 | deg |
| [Elbow Flexion at Launch](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-launch) | 75 | 103 | 115 | 122 | 128 | 134 | 135 | deg |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-ball-contact) | 30 | 37 | 60 | 75 | 90 | 101 | 110 | deg |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/baseball/hitting/metrics/lead-knee-angle-at-ball-contact) | 6 | 8 | 13 | 21 | 28 | 35 | 41 | deg |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-flexion) | 22 | 26 | 30 | 34 | 39 | 43 | 48 | deg |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-tilt) | -14 | -11 | -2 | 4 | 13 | 19 | 22 | deg |
# Ball Contact
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/ball-contact
The estimated timing of ball contact - determined by audio signal (primary) or swing through event (secondary, if ball contact not detected or detected outside of foot contact and end twist events).
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `ball_contact_frame`
* **Required for QA:** True
* **Primary Detection:** Audio signal analysis
* **Secondary Detection:** Swing through event
* **Validation:** Audio-based ball contact must occur between foot contact and end twist events.
If not, uses swing through event (when the rear wrist passes in front of the lead wrist).
## Description
Ball contact represents the instant when the bat makes contact with the ball.
This is detected primarily through audio analysis, using a model to identify the hit "crack".
The secondary detection method ([Swing Through](/biomechanics/activities/baseball/hitting/events/swing-through)) is useful for capturing environment where other athletes are hitting.
Audio-based ball contact detection could pick up other nearby hitters nearby.
## Use Cases
* Largely determines body and bat metrics at ball contact
* Swing sequence completion
* Must occur in correct sequence, otherwise fails QA.
# Elbow Slot
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/elbow-slot
When the rear elbow drops downward in preparation for the arm swing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** TBD
* **Required for QA:** False
* **Detection Method:** Hip shoulder separation (X Factor) velocity returns to 0 deg/s
* **Timing:** Must occur after X Factor zero crossing
## Description
End twist marks the completion of the twisting motion, indicated by when hip shoulder separation
(X Factor) velocity returns to zero, indicating the end of trunk rotation.
## Use Cases
* Arm positioning during the swing
* Transition from body to arm
# End Twist
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/end-twist
Finds the end of the twisting motion: after X Factor zero crossing, when X Factor velocity returns to 0 deg/s. This marks the completion of the twisting motion and swing overall.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `end_twist_frame`
* **Required for QA:** True
* **Detection Method:** Hip shoulder separation (X Factor) velocity returns to 0 deg/s
* **Timing:** Must occur after X Factor zero crossing
## Description
End twist marks the completion of the twisting motion, indicated by when hip shoulder separation
(X Factor) velocity returns to zero, indicating the end of trunk rotation.
## Use Cases
* Twist completion analysis
* Swing sequence timing
# Foot Contact
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/foot-contact
The instant the front foot fully contacts the ground and begins accepting weight.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `foot_contact_frame`
* **Required for QA:** False
* **Detection Method:** Velocity-based analysis
* **Threshold:** 0.2 m/s vertical velocity for 5 consecutive frames
## Description
Foot contact marks the moment when the lead foot fully makes contact with the ground and begins accepting weight.\
Determined by finding the max downward velocity of the lead ankle after max foot raise,
then searching forward for 5 consecutive frames with an ankle vertical velocity below 0.2 m/s."
Foot contact is crucial for timing analysis and is used as a reference point for many other swing event and metrics.
## Use Cases
* Stride timing analysis
* Swing sequence timing
* Balance and stability assessmentS
# Initiation
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/initiation
The initiation event marks when the lead foot begins to move prior to max knee raise. This marks the starting point of the swing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `initiation_frame`
* **Required for QA:** False
* **Measurement:** First detectable movement of lead foot
* **Timing:** Before max knee raise event
## Description
The initiation event represents the very beginning of the swing sequence when the batter starts to move their lead foot.
Identified by the leading 5th percentile height of the max foot raise peak.
## Use Cases
* Swing timing analysis
* Event timing comparisons - time to launch, time to contact
# Max Foot Raise
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/max-foot-raise
The maximum height of the lead foot during the swing. This event marks the peak elevation of the lead foot and is important for analyzing stride mechanics and balance.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `max_foot_raise_frame`
* **Measurement:** Peak vertical position of lead foot
* **Timing:** During swing sequence
## Description
The max foot raise event identifies the instant when the lead foot reaches its highest point during the swing.
This is an important indicator event, helping to break down the swing into events/phases and assisting with detecting other events.
## Use Cases
* Swing Segmentation
* Swing timing evaluation
# Max X Factor
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/max-x-factor
The instant of maximum separation between shoulders and hips before the twisting motion of the swing. This represents the peak loading phase in preparation for the swing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `max_x_factor_frame`
* **Measurement:** Maximum shoulder-hip separation angle (usually negative as its backwards twisting)
* **Phase:** Loading phase before rotation
## Description
The max X factor event identifies the moment of maximum separation between the shoulders and hips, representing the maximum amount of coil before the explosive rotation begins for the swing.
## Use Cases
* Loading phase analysis
* Power generation assessment
* Swing sequence timing
* Energy transfer evaluation
# Peak Arm Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/peak-arm-ang-vel
The instant of lead arm peak angular velocity.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_arm_velocity_frame`
* **Peak Detection Parameters:**
* Minimum height: 250 deg/s
* Minimum prominence: 500 deg/s
* Distance to next peak: 24 frames (0.1 s)
* Minimum width: 0.025 s (6 frames)
## Description
This event identifies the moment when the lead upper arm reaches its maximum angular velocity during the swing, representing the peak of the arm kinetic energy.
## Use Cases
* Arm power analysis
* Upper body mechanics assessment
* Peak velocity timing
* Swing sequence evaluation
# Peak Pelvis Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/peak-pelvis-ang-vel
The instant of pelvis peak angular velocity.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_pelvis_velocity_frame`
* **Peak Detection Parameters:**
* Minimum height: 250 deg/s
* Minimum prominence: 250 deg/s
* Distance to next peak: 24 frames (0.1 s)
* Minimum width: 0.1 s (24 frames)
## Description
This event identifies the moment when the pelvis reaches its maximum angular velocity during the swing, representing the peak of the lower body kinetic energy.
## Use Cases
* Pelvis power analysis
* Lower body mechanics assessment
* Peak velocity timing
* Swing sequence evaluation
# Peak Trunk Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/peak-trunk-ang-vel
The instant of trunk peak angular velocity.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_trunk_velocity_frame`
* **Peak Detection Parameters:**
* Minimum height: 250 deg/s
* Minimum prominence: 250 deg/s
* Distance to next peak: 24 frames (0.1 s)
* Minimum width: 0.1 s (24 frames)
## Description
This event identifies the moment when the trunk reaches its maximum angular velocity during the swing, representing the peak of the trunk kinetic energy.
## Use Cases
* Trunk power analysis
* Core mechanics assessment
* Peak velocity timing
* Swing sequence evaluation
# Peak Wrist Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/peak-wrist-angular-velocity
The instant of maximum wrist angular velocity during the swing. This represents the peak of the final acceleration phase when the wrists generate maximum bat speed.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_wrist_angular_velocity_frame`
* **Measurement:** Maximum wrist angular velocity
* **Phase:** Final acceleration phase
## Description
This event identifies the moment when the wrists reach their maximum angular velocity, representing the peak of the final acceleration phase and maximum bat speed generation.
## Use Cases
* Wrist mechanics analysis
* Bat speed generation assessment
* Final acceleration timing
* Swing sequence evaluation
# Pelvis Velocity Initiation (Launch)
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/pelvis-velocity-initiation
The start of pelvis rotation - also known as launch event. Determined as the leading edge of the pelvis angular velocity waveform. This marks the beginning of the power generation phase.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `pelvis_initiation_frame`
* **Detection Method:** Last local minimum before peak pelvis angular velocity
* **Alternative Name:** Launch event
## Description
The pelvis velocity initiation event marks the beginning of the power generation phase when the pelvis starts rotating.
This is often called the "launch" event and is critical for understanding the kinetic chain sequence.
## Use Cases
* Power generation analysis
* Kinetic chain evaluation
* Swing timing assessment
* Launch position measurements
# Pelvis Velocity Termination
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/pelvis-velocity-termination
The trailing edge of the pelvis angular velocity waveform. This marks the end of the pelvis rotation phase and the completion of lower body power generation.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `pelvis_velocity_termination_frame`
* **Detection Method:** First local minimum after peak pelvis velocity
* **Phase:** End of pelvis rotation
## Description
Pelvis velocity termination marks the end of the pelvis rotation phase when the pelvis angular velocity reaches its first local minimum after peak velocity, indicating completion of lower body power generation.
## Use Cases
* Pelvis rotation analysis
* Power generation completion
* Lower body mechanics assessment
* Swing sequence timing
# Swing Through
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/swing-through
The instant the rear wrist passes in front of the lead wrist, corresponding to a batter committing to a swing (would be a strike). Swing through is used as a backup estimate for ball contact.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `swing_through_frame`
* **Measurement:** Rear wrist passing lead wrist (closer to the pitcher)
* **Significance:** Estimate for ball contact and indicator of swing commitment
## Description
Swing through marks the moment when the rear wrist passes in front of the lead wrist (closer to the pitcher), indicating that the batter has committed to the swing and it would be considered a strike.
## Use Cases
* Swing commitment analysis
* Strike zone assessment
* Swing completion timing
* Decision-making evaluation
# Twist
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/twist
The average timing of peak angular velocities for the pelvis, trunk, and arm. Used to identify the timing of the major twisting motion during the swing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `twist_frame`
* **Calculation:** Average of peak angular velocity events
* **Segments:** Pelvis, trunk, and arm
## Description
The twist event represents the average timing of peak angular velocities across the major body segments (pelvis, trunk, and arm), identifying the core of the twisting motion during the swing.
## Use Cases
* Twist timing analysis
* Segment coordination assessment
* Swing sequence evaluation
* Power transfer analysis
# Wrist Initiation
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/wrist-initiation
The start of the wrist movement during the swing. Finds the last local minimum before peak wrist angular velocity. This marks the beginning of the final acceleration phase.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `wrist_movement_initiation_frame`
* **Detection Method:** Last local minimum before peak wrist angular velocity
* **Phase:** Final acceleration phase
## Description
Wrist initiation marks the beginning of the final acceleration phase when the wrists start moving to generate bat speed. This event is crucial for understanding the complete kinetic chain sequence.
## Use Cases
* Final acceleration analysis
* Kinetic chain evaluation
* Bat speed generation assessment
* Swing sequence timing
# X Factor Zero Crossing
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/events/x-factor-zero-crossing
When the shoulder-hip separation crosses zero after Max X Factor. This marks the transition from loading to acceleration phase as the shoulders catch up to the hips.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `x_factor_zero_crossing_frame`
* **Measurement:** Zero crossing of shoulder-hip separation
* **Timing:** After max X factor event
## Description
The X factor zero crossing event marks the transition from the loading phase to the acceleration phase when the shoulder-hip separation crosses zero, indicating that the torso rotation angle catches up to the pelvis rotation angle.
## Use Cases
* Phase transition analysis
* Acceleration timing assessment
* Swing sequence evaluation
* Power transfer analysis
# Attack Angle
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/attack-angle
Angle relative to forward horizontal that the bat sweet spot moves through in the frames leading up to ball contact. Positive value indicates the bat sweet spot is moving upwards at that angle, vice versa for negative.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `attack_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Bat position relative to the front of home plate
* **Time Period:** 3 frames before ball contact to 1 frame after ball contact
* **Typical Range:** -10° to +30°
## Description
Attack angle measures the vertical angle of the bat's path relative to horizontal, indicating whether the swing is level, uppercut, or chopping.
## Use Cases
* Bat path analysis
* Swing plane assessment
* Contact angle optimization
* Launch angle correlation
# Attack Direction
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/attack-direction
Horizontal plane angle of the bat relative to the front of home plate, generally determines direction (right/left) of the hit.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `attack_direction`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Horizontal angle relative to home plate
* **Reference:** Front of home plate
* **Typical Range:** -45° to +45°
## Description
Attack direction measures the horizontal plane angle of the bat relative to the front of home plate, indicating the intended direction of the hit (right or left field).
Positive angles indicate hitting to the right, negative angles indicate hitting to the left.
## Use Cases
* Hit direction analysis
* Bat angle assessment
* Directional control evaluation
* Technique optimization
# Ball Contact Method
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/ball-contact-method
Ball contact event detection method: [both audio, single audio, swing through]. This indicates how the ball contact event was detected during analysis.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `ball_contact_method`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Values:** 'both audio', 'single audio', 'swing through'
* **Purpose:** Detection method indicator
## Description
Ball contact method indicates the method used to detect the ball contact event, providing information about the reliability and source of ball contact timing.
## Use Cases
* Detection reliability analysis
* Data quality assessment
* Method validation
* Analysis confidence evaluation
# Bat Speed - Angular to Linear
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/bat-speed-angular-to-linear
Converted angular velocity to linear velocity. This measures the bat speed calculated from angular velocity measurements.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** mph
* **Column Name:** TBD
* **Aggregation:** mean
* **Precision:** 1
* **Optimal Direction:** Higher is better
* **Measurement:** Angular velocity converted to linear velocity
* **Typical Range:** 40-90 mph
## Description
Bat speed angular to linear measures the linear velocity of the bat calculated from angular velocity measurements, providing an alternative method for bat speed calculation.
## Use Cases
* Bat speed analysis
* Angular velocity conversion
* Performance comparison
* Speed calculation validation
# Bat Speed - Resultant Sweet Spot
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/bat-speed-resultant-sweet-spot
Linear velocity of bat sweet spot during the swing. This measures the actual bat speed at the optimal contact point.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** mph
* **Column Name:** TBD
* **Aggregation:** mean
* **Precision:** 1
* **Optimal Direction:** Higher is better
* **Measurement:** Linear velocity at sweet spot
* **Typical Range:** 40-90 mph
## Description
Sweet spot bat speed measures the linear velocity of the bat at its optimal contact point (\~6 in from the bat tip), providing insight into swing power and effectiveness.
## Use Cases
* Swing power analysis
* Bat speed assessment
* Performance comparison
* Power optimization
# Body Center of Mass Position X
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/body-center-of-mass-x
Whole body center of mass X position - for use with keypoint positions. This is a time series metric that tracks the body's forward-backward position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `whole_body_center_of_mass_x`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Use:** With keypoint positions
* **Frame Rate:** 240 Hz
* **Direction:** Forward-backward
## Description
Body center of mass X position tracks the forward-backward position of the whole body's center of mass throughout the swing, providing insight into overall body movement patterns.
## Use Cases
* Body movement analysis
* Position tracking
* Overall stability assessment
* Time series analysis
# Body Center of Mass Position Y
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/body-center-of-mass-y
Whole body center of mass Y position (up/down) - for use with keypoint positions. This is a time series metric that tracks the body's vertical position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `whole_body_center_of_mass_y`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Use:** With keypoint positions
* **Frame Rate:** 240 Hz
* **Direction:** Vertical (up/down)
## Description
Body center of mass Y position tracks the vertical position of the whole body's center of mass throughout the swing, providing insight into overall body movement patterns and stability.
## Use Cases
* Body vertical movement analysis
* Position tracking
* Overall stability assessment
* Time series analysis
# Body Center of Mass Position Z
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/body-center-of-mass-z
Whole body center of mass Z position - for use with keypoint positions. This is a time series metric that tracks the body's lateral position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `whole_body_center_of_mass_z`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Use:** With keypoint positions
* **Frame Rate:** 240 Hz
* **Direction:** Lateral (side-to-side)
## Description
Body center of mass Z position tracks the lateral position of the whole body's center of mass throughout the swing, providing insight into overall body movement patterns and balance.
## Use Cases
* Body lateral movement analysis
* Position tracking
* Overall balance assessment
* Time series analysis
# Connection at Impact
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/connection-at-impact
Horizontal plane angle of the bat relative to the batter's torso at the instant of ball contact. This measures the connection between the bat and body at impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** TBD
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Horizontal angle between bat and torso
* **Timing:** At ball contact
## Description
Connection at impact measures the horizontal plane angle between the bat and the batter's torso at the moment of ball contact, indicating proper connection and timing.
## Use Cases
* Impact analysis
* Connection assessment
* Timing evaluation
* Technique optimization
# Drifting Forward
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/drifting-forward
Binary indicator of excessive forward movement, determine by whether the pelvis drifts forward (towards the pitcher) more than 15 cm (~6 in) from launch to ball contact events.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False (1/0)
* **Column Name:** `drifting_forward`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Threshold:** 15 cm (\~6 in) forward movement
* **Timing:** Launch to ball contact events
## Description
Drifting forward indicates excessive forward movement of the pelvis during the swing, which can compromise balance and reduce power generation efficiency.
## Use Cases
* Forward movement analysis
* Balance assessment
* Pelvis stability evaluation
* Technique correction
## Interventions
* [Step Back Drill](https://youtube.com/shorts/jwdxvnplEaw?si=cL8tgwA3NF6zSbA_)
* Focus Area: Back Hip Loading, Limited Separation
* [Controlled Fall Drill](https://www.youtube.com/watch?v=T-juvkH4lQE)
* Focus Area: Stride Controlled
# Drifting Forward Magnitude
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/drifting-forward-magnitude
Distance drifted forward during the swing - see Drifting Forward movement flag. This quantifies the amount of excessive forward movement of the pelvis.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `drifting_forward_magnitude`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Forward distance from launch to ball contact
* **Related Flag:** [Drifting Forward movement flag](/biomechanics/activities/baseball/hitting/metrics/drifting-forward)
* **Typical Range:** 3.8 – 8.4 in (0.097 – 0.213 m)
* **Optimal Direction:** Middle — moderate forward movement is biomechanically normal; too little or too much is suboptimal
## Description
Drifting forward magnitude quantifies the actual distance the pelvis moves forward during the swing, providing a continuous measure of the excessive forward movement identified by the Drifting Forward flag.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 2.6 – 5.5 in | 1.3 | 2.6 | 4.1 | 5.5 | 7.2 |
| High School | 3.5 – 6.6 in | 2.0 | 3.5 | 4.8 | 6.6 | 8.3 |
| College | 5.6 – 10.9 in | 3.6 | 5.6 | 7.7 | 10.9 | 15.1 |
| Professional | 7.0 – 12.5 in | 5.6 | 7.0 | 8.5 | 12.5 | 15.6 |
| Broad (All Levels) | 3.8 – 8.4 in | 2.1 | 3.8 | 5.9 | 8.4 | 12.8 |
## Use Cases
* Forward movement quantification
* Balance analysis
* Movement efficiency assessment
* Technique correction
# Elbow Flexion at Ball Contact
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-ball-contact
Amount of rear elbow flexion at ball contact event. This measures the elbow angle at the instant of impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `rear_elbow_flexion_at_ball_contact`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Rear elbow flexion angle
* **Timing:** At ball contact event
* **Typical Range:** 60 – 90 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Elbow flexion at ball contact measures the amount of rear elbow flexion at the moment of ball contact, indicating the arm position and extension during impact.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 70 – 90 ° | 62 | 70 | 82 | 90 | 101 |
| High School | 69 – 93 ° | 50 | 69 | 81 | 93 | 108 |
| College | 48 – 86 ° | 35 | 48 | 70 | 86 | 104 |
| Professional | 42 – 74 ° | 31 | 42 | 60 | 74 | 97 |
| Broad (All Levels) | 60 – 90 ° | 37 | 60 | 75 | 90 | 101 |
## Use Cases
* Impact position analysis
* Rear elbow mechanics assessment
* Contact evaluation
# Elbow Flexion at Launch
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/elbow-flexion-at-launch
Amount of rear elbow flexion at launch event. This measures the elbow angle at the start of the power generation phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `rear_elbow_flexion_at_launch`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Rear elbow flexion angle
* **Timing:** At launch event
* **Typical Range:** 115 – 128 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Elbow flexion at launch measures the amount of rear elbow flexion at the launch event, indicating the arm position and loading when starting the power generation phase.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 110 – 124 ° | 99 | 110 | 118 | 124 | 128 |
| High School | 114 – 126 ° | 100 | 114 | 122 | 126 | 131 |
| College | 120 – 132 ° | 114 | 120 | 126 | 132 | 135 |
| Professional | 120 – 132 ° | 113 | 120 | 125 | 132 | 135 |
| Broad (All Levels) | 115 – 128 ° | 103 | 115 | 122 | 128 | 134 |
## Use Cases
* Arm position analysis
* Rear elbow mechanics assessment
* Technique optimization
# Handedness
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/handedness
Handedness of the athlete ['right' or 'left'] as input parameter. This determines the swing side and affects the interpretation of all other metrics.
## Technical Details
* **Variable Type:** Dimension
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `handedness`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Values:** 'right' or 'left'
## Description
Handedness specifies which side the athlete bats from (right-handed or left-handed). This is a required input parameter that affects the interpretation of all other swing metrics.
## Use Cases
* Swing side identification
* Metric interpretation
* Data analysis
# Hip Hinge
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/hip-hinge
Max amount of rear hip flexion between max foot raise and foot contact events.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `hip_hinge`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Max rear hip flexion
* **Timing:** Max foot raise to foot contact
* **Typical Range:** 51 – 64 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Hip hinge measures the maximum amount of rear hip flexion during the stride phase, indicating the loading and preparation of the rear hip for power generation.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 48 – 60 ° | 42 | 48 | 54 | 60 | 68 |
| High School | 50 – 63 ° | 46 | 50 | 55 | 63 | 70 |
| College | 54 – 69 ° | 49 | 54 | 60 | 69 | 73 |
| Professional | 54 – 66 ° | 47 | 54 | 60 | 66 | 70 |
| Broad (All Levels) | 51 – 64 ° | 44 | 51 | 57 | 64 | 71 |
## Use Cases
* Hip loading analysis
* Stride mechanics assessment
# Inter Elbow Distance at Ball Contact
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/inter-elbow-distance-at-ball-contact
Distance between the lead and rear elbows at ball contact event. This measures the separation between elbows at the instant of impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `inter_elbow_distance_at_ball_contact`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Distance between lead and rear elbows
* **Timing:** At ball contact event
* **Typical Range:** 0.24-0.38 meters
## Description
Inter elbow distance at ball contact measures the distance between the lead and rear elbows at the moment of ball contact, indicating the arm separation and positioning during impact.
## Use Cases
* Arm positioning
* Transfer of body's rotational power to bat
# Inter Elbow Distance at Elbow Slot
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/inter-elbow-distance-at-elbow-slot
Distance between the lead and rear elbows at the elbow slot event. This measures the separation between elbows during the slot position.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `inter_elbow_distance_at_elbow_slot`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Distance between lead and rear elbows
* **Timing:** At elbow slot event
* **Typical Range:** 0.28-0.41 meters
## Description
Inter elbow distance at elbow slot measures the distance between the lead and rear elbows at the elbow slot event, indicating the arm separation and positioning during the slot phase of the swing.
## Use Cases
* Arm positioning
* Transfer of body's rotational power to bat
# Inter Elbow Distance at Trunk Peak
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/inter-elbow-distance-at-trunk-peak
Distance between the lead and rear elbows at the trunk peak angular velocity event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `inter_elbow_distance_at_trunk_peak`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Distance between lead and rear elbows
* **Timing:** At trunk peak angular velocity event
* **Typical Range:** 0.27-0.41 meters
## Description
Inter elbow distance at trunk peak measures the distance between the lead and rear elbows when trunk rotation reaches its peak angular velocity, indicating arm separation during maximum trunk rotation.
## Use Cases
* Arm positioning
* Transfer of body's rotational power to bat
# Kinematic Sequence Order
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/kinematic-sequence-order
Sequence of segment peak angular velocities (twist speed) during the swing. Correct sequencing is pelvis-trunk-arm, representing the optimal kinetic chain transfer.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `kinematic_sequence_order`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Optimal Sequence:** pelvis-trunk-arm
* **Measurement:** Order of peak angular velocities
## Description
Kinematic sequence order tracks the timing sequence of peak angular velocities across body segments. The optimal sequence is pelvis-trunk-arm, ensuring efficient energy transfer through the kinetic chain.
## Use Cases
* Kinetic chain analysis
* Sequencing evaluation
* Power transfer assessment
## Interventions
* [Medicine Ball Rotational Throws - Sequence Focus](https://youtube.com/shorts/9fyhs2aNu3A?si=ajHDFXGhmPK8S0r9)
* Focus Area: Improper Sequencing
# Knee Dominant
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/knee-dominant
Binary indicator if swing is knee-dominant, determined by comparing rear knee flexion with hip and ankle angle at launch event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False (1/0)
* **Column Name:** `knee_dominant_swing`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Timing:** At launch event
## Description
Knee dominant indicates a swing pattern where the lower body mechanics are primarily driven by the knees rather than the hips, which can limit power generation and efficiency.
## Use Cases
* Lower body mechanics analysis
* Power generation assessment
* Hip mobility evaluation
* Technique correction
## Interventions
* [Kershaw Drill](https://youtu.be/r3wazOZE-MQ)
* Focus Area: Back Hip Loading, Front-Side Stability
* [Front Side Block Drill](https://youtube.com/shorts/qhjY_Ao5xjU?si=jfGncV5-jJsoHifS)
* Focus Area: Front Side Stability
# Lateral Pelvis Tilt
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/lateral-pelvis-tilt
Binary indicator of excessive lateral pelvis tilt, determined by whether the pelvis tilts upwards or downwards more than 10 deg during the swing (initiation to ball contact).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False (1/0)
* **Column Name:** `excessive_lateral_pelvis_tilt`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Threshold:** 10 ° tilt (upwards or downwards)
* **Timing:** Initiation to ball contact
## Description
Lateral pelvis tilt indicates excessive side-to-side tilting of the pelvis during the swing, which can compromise balance and power transfer efficiency.
## Use Cases
* Pelvis stability analysis
* Lateral movement assessment
* Balance evaluation
* Technique correction
# Launch Position
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/launch-position
Launch position indicates how the bat is positioned relative to the spine when the swing begins. A proper launch position helps ensure optimal bat path and contact point.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** Degrees (°)
* **Column Name:** `launch_position`
* **Range:** 0° to 180°
* **Calculation:** Sagittal plane (somersault) angle between bat and spine
* **Measurement Point:** At pelvis velocity initiation (launch event)
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
## Interpretation
* **Higher values:** (over 90°) Bat angled downward relative to spine, bat tip is lower
* **Lower values:** (under 90°) Bat angled upward relative to spine, bat tip is higher and bat is closer to being in line with spine.
* **Optimal range:** Typically 30-90° for most hitters, preferably closer to 90°
## Use Cases
* Swing analysis and coaching
* Bat path optimization
* Pre-swing position consistency
# Lead Knee Angle at Ball Contact
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/lead-knee-angle-at-ball-contact
Amount of lead knee flexion at ball contact. This measures the knee angle of the front leg at the instant of impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `lead_knee_angle_at_ball_contact`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Lead knee flexion angle
* **Timing:** At ball contact event
* **Typical Range:** 13 – 28 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Lead knee angle at ball contact measures the amount of flexion in the lead knee at the moment of ball contact, indicating the front leg position and stability during impact.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 22 – 34 ° | 18 | 22 | 27 | 34 | 39 |
| High School | 19 – 29 ° | 15 | 19 | 24 | 29 | 32 |
| College | 10 – 23 ° | 7 | 10 | 16 | 23 | 32 |
| Professional | 8 – 17 ° | 6 | 8 | 11 | 17 | 21 |
| Broad (All Levels) | 13 – 28 ° | 8 | 13 | 21 | 28 | 34 |
## Use Cases
* Front leg stability analysis
* Knee mechanics assessment
* Impact position evaluation
* Balance optimization
# Leads With Wrist
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/leads-with-wrist
Binary indicator if wrist leads the swing: if wrist initiation event occurs before pelvis initiation event. This identifies improper swing sequencing where the upper body initiates before the lower body.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `leads_with_wrist`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Calculation:** Wrist initiation event \< Pelvis initiation event (launch)
* **Optimal Value:** False (pelvis should initiate first)
## Description
This flag indicates whether the wrist initiation occurs before pelvis initiation, which represents improper swing sequencing. In an optimal swing, the pelvis should initiate before the wrists.
## Use Cases
* Swing sequencing analysis
* Technique correction
* Upper body timing assessment
* Kinetic chain evaluation
# Interventions
* [Connection Ball Drill](https://youtube.com/shorts/niIx3NlyJO4?si=O95jAeR_0CKqZ4dc)
* Focus Area: Improper Sequencing
# Linear Stretch
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/linear-stretch
Distance between the lead ankle and center of both wrists along the pitch direction at foot contact. This measures the linear stretch of the body during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `linear_stretch`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Distance from lead ankle to center of wrists
* **Direction:** Along pitch direction
* **Timing:** At foot contact event
* **Typical Range:** 12.4 – 25.4 in (0.316 – 0.646 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Linear stretch measures the distance between the lead ankle and the center of both wrists along the pitch direction at foot contact, indicating the body's linear extension during the swing.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 10.3 – 14.7 in | 9.1 | 10.3 | 12.4 | 14.7 | 17.4 |
| High School | 12.0 – 16.3 in | 10.4 | 12.0 | 13.7 | 16.3 | 26.3 |
| College | 17.6 – 26.3 in | 13.8 | 17.6 | 21.7 | 26.3 | 31.0 |
| Professional | 23.0 – 29.6 in | 19.3 | 23.0 | 27.0 | 29.6 | 33.4 |
| Broad (All Levels) | 12.4 – 25.4 in | 10.0 | 12.4 | 16.3 | 25.4 | 29.6 |
## Use Cases
* Body extension analysis
* Stretch assessment
* Linear mechanics evaluation
# Max X Factor
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/max-x-factor
Max amount of twist hip shoulder separation during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `max_x_factor`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** maximum twist angle difference between shoulders and hips (torso and pelvis)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Max amount of hip shoulder separation (X Factor) during the swing.
Usually occurs as the pelvis begins its rotation, while the torso is relatively stable.
Greater amounts of X Factor may permit greater range of motion through which to rotate for the swing.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 25 – 38 ° | 14 | 25 | 30 | 38 | 43 |
| High School | 22 – 35 ° | 9 | 22 | 30 | 35 | 42 |
| College | 19 – 29 ° | 14 | 19 | 25 | 29 | 35 |
| Professional | 12 – 23 ° | 8 | 12 | 16 | 23 | 28 |
| Broad (All Levels) | 17 – 33 ° | 9 | 17 | 26 | 33 | 40 |
## Use Cases
* Pre-swing loading
* Range of motion assessment
## Interventions
* [Separation Drill](https://www.youtube.com/watch?v=EczxevOOVLY)
* Focus Area: Limited Separation
* [Hook'Em Drill](https://youtu.be/IyCE0hey7-I)
* Focus Area: Back Hip Loading, Limited Separation
# On Plane Efficiency
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/on-plane-efficiency
Percentage of swing (within 10 deg) aligned with swing plane between foot contact and ball contact events. This measures swing consistency and efficiency.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** %
* **Column Name:** `on_plane_efficiency`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Tolerance:** Within 10 ° of swing plane
* **Timing:** Foot contact to ball contact
* **Typical Range:** 60-95%
## Description
On plane efficiency measures the percentage of the swing path that stays within 10 degrees of the optimal swing plane, indicating swing consistency and efficiency.
## Use Cases
* Swing consistency
* Swing plane efficiency
# Peak Arm Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/peak-arm-angular-velocity
Max angular velocity of the lead upper arm segment during the swing. This represents the peak power generation from the arms.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_arm_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Max lead upper arm angular velocity
* **Optimal Direction:** Higher is better
## Description
Peak arm angular velocity measures the maximum rotational speed (deg/s) of the lead upper arm during the swing, representing the peak power generation from the upper arm segment.
The timing of peak arm angular velocity determines kinematic sequence in part.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 797 – 879 °/s | 608 | 662 | 728 | 797 | 879 |
| High School | 911 – 1097 °/s | 608 | 675 | 740 | 911 | 1097 |
| College | 915 – 1140 °/s | 559 | 647 | 743 | 915 | 1140 |
| Professional | 957 – 1160 °/s | 592 | 680 | 822 | 957 | 1160 |
| Broad (All Levels) | 876 – 1060 °/s | 592 | 663 | 749 | 876 | 1060 |
## Use Cases
* Upper body power analysis
* Arm mechanics assessment
* Kinematic Sequence Order
# Interventions
* [Med Ball Side Toss](https://youtube.com/shorts/Hr7KeI6V5Ik?si=sj2a0lUgO_hoyxEF)
* Focus Area: Rotational Power
# Peak Pelvis Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/peak-pelvis-angular-velocity
Max angular velocity of the pelvis segment during the swing. This represents power generation from the lower body.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_pelvis_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum pelvis angular velocity
* **Optimal Direction:** Higher is better
## Description
Peak pelvis angular velocity measures the maximum rotational speed of the pelvis during the swing, representing the peak power generation from the lower body.
The timing of peak pelvis angular velocity determines kinematic sequence in part.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 517 – 541 °/s | 408 | 448 | 480 | 517 | 541 |
| High School | 526 – 566 °/s | 412 | 461 | 494 | 526 | 566 |
| College | 527 – 552 °/s | 416 | 471 | 509 | 527 | 552 |
| Professional | 524 – 565 °/s | 384 | 438 | 481 | 524 | 565 |
| Broad (All Levels) | 525 – 553 °/s | 402 | 452 | 490 | 525 | 553 |
## Use Cases
* Lower body power analysis
* Pelvis mechanics assessment
* Kinematic Sequence Order
# Interventions
* [Med Ball Side Toss](https://youtube.com/shorts/Hr7KeI6V5Ik?si=sj2a0lUgO_hoyxEF)
* Focus Area: Rotational Power
* [Step-Behind Med Ball Throws](https://youtube.com/shorts/OSL0OZSCGi4?si=D1QmjR5akcCN6McU)
* Focus Area: Pelvis Velocity
* [Med Ball Scoop Toss](https://youtube.com/shorts/O5cscjGQrVo?si=NAfk_BwJKLEjQsKF)
* Focus Area: Pelvis Velocity, Trunk Velocity
# Peak Trunk Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/peak-trunk-angular-velocity
Max angular velocity of the trunk segment during the swing. This represents the peak power generation from the core.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_trunk_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum trunk angular velocity
* **Phase:** Core power generation
* **Optimal Direction:** Higher is better
## Description
Peak trunk angular velocity measures the maximum rotational speed of the trunk during the swing, representing the peak power generation from the core segment.
The timing of peak trunk angular velocity determines kinematic sequence in part.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 697 – 768 °/s | 558 | 601 | 656 | 697 | 768 |
| High School | 738 – 796 °/s | 587 | 624 | 666 | 738 | 796 |
| College | 680 – 738 °/s | 532 | 593 | 631 | 680 | 738 |
| Professional | 636 – 700 °/s | 475 | 524 | 580 | 636 | 700 |
| Broad (All Levels) | 694 – 769 °/s | 527 | 582 | 637 | 694 | 769 |
## Use Cases
* Core power analysis
* Trunk mechanics assessment
* Kinematic Sequence Order
# Interventions
* [Med Ball Side Toss](https://youtube.com/shorts/Hr7KeI6V5Ik?si=sj2a0lUgO_hoyxEF)
* Focus Area: Rotational Power
* [Offset Rotation Drill](https://youtu.be/Divh5BtngPg?si=yewnOU5_Sz_w2KCm)
* Focus Area: Trunk Velocity
* [Med Ball Scoop Toss](https://youtube.com/shorts/O5cscjGQrVo?si=NAfk_BwJKLEjQsKF)
* Focus Area: Pelvis Velocity, Trunk Velocity
# Pelvis Acceleration Time
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/pelvis-acceleration-time
Time from pelvis initiation (start of rotation, also known as launch event) to peak pelvis angular velocity. This measures the acceleration phase of the pelvis during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds
* **Column Name:** pelvis\_acceleration\_time
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Peak pelvis velocity time - Pelvis initiation time
* **Typical Range:** 0.22 – 0.62 s
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Pelvis acceleration time measures the duration of the pelvis acceleration phase from the start of rotation (launch) to peak angular velocity, indicating the time period for lower body power generation.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 0.38 – 0.65 s | 0.27 | 0.38 | 0.49 | 0.65 | 1.47 |
| High School | 0.31 – 0.61 s | 0.20 | 0.31 | 0.45 | 0.61 | 1.52 |
| College | 0.18 – 0.60 s | 0.17 | 0.18 | 0.37 | 0.60 | 0.86 |
| Professional | 0.18 – 0.54 s | 0.15 | 0.18 | 0.23 | 0.54 | 0.75 |
| Broad (All Levels) | 0.22 – 0.62 s | 0.17 | 0.22 | 0.42 | 0.62 | 0.89 |
## Use Cases
* Acceleration phase analysis
* Power generation efficiency
* Lower body mechanics assessment
# Pelvis Deceleration Time
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/pelvis-deceleration-time
Time from peak pelvis angular velocity to pelvis termination (end of rotation). This measures the deceleration phase of the pelvis during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds
* **Column Name:** pelvis\_deceleration\_time
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Pelvis termination time - Peak pelvis velocity time
* **Typical Range:** 0.34 – 0.68 s
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Pelvis deceleration time measures the duration of the pelvis deceleration phase from peak angular velocity to the end of rotation, indicating the control and efficiency of lower body mechanics.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 0.21 – 0.72 s | 0.17 | 0.21 | 0.57 | 0.72 | 1.10 |
| High School | 0.41 – 0.74 s | 0.16 | 0.41 | 0.49 | 0.74 | 1.10 |
| College | 0.34 – 0.65 s | 0.15 | 0.34 | 0.48 | 0.65 | 0.83 |
| Professional | 0.35 – 0.57 s | 0.14 | 0.35 | 0.46 | 0.57 | 0.80 |
| Broad (All Levels) | 0.34 – 0.68 s | 0.16 | 0.34 | 0.50 | 0.68 | 0.99 |
## Use Cases
* Deceleration phase analysis
* Control assessment
* Lower body mechanics evaluation
# Pelvis Global Rotation
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/pelvis-global-rotation
Instantaneous measurement of pelvis transverse plane rotation relative to the global coordinate system. This is a time series metric that tracks pelvis rotation throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `pelvis_global_rotation`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Plane:** Transverse plane
* **Reference:** Global coordinate system
## Description
Pelvis global rotation tracks the amount of rotation of the pelvis relative to the global coordinate system throughout the swing, providing insight into pelvis rotation patterns and power generation.
## Use Cases
* Pelvis rotation analysis
* Rotation tracking
# Pelvis Global Tilt
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/pelvis-global-tilt
Amount of pelvis frontal plane side-to-side tilt relative to the global coordinate system. This is a time series metric that tracks pelvis lateral tilt throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `pelvis_global_tilt`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Plane:** Frontal plane
* **Reference:** Global coordinate system
## Description
Pelvis global tilt tracks the amount of side-to-side tilt of the pelvis relative to the global coordinate system throughout the swing, providing insight into pelvis posture and balance.
## Use Cases
* Pelvis lateral posture analysis
* Tilt tracking
# Pelvis to Trunk Speed Up
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/pelvis-to-trunk-speed-up
Ratio (multiplication factor) of speed increase from pelvis to trunk. This measures the efficiency of power transfer from the lower body to the trunk.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio
* **Column Name:** `pelvis_to_trunk_velocity_speedup`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Peak trunk velocity / Peak pelvis velocity
* **Optimal Range:** 1.25-1.75
* **Optimal Direction:** Higher is better
## Description
Pelvis to trunk speed up measures the multiplication factor of velocity increase from the pelvis to the trunk peak angular velocities.
This metric broadly indicates the efficiency of power transfer from the lower body to the core.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 1.45 – 1.57 | 1.19 | 1.27 | 1.35 | 1.45 | 1.57 |
| High School | 1.49 – 1.63 | 1.20 | 1.29 | 1.39 | 1.49 | 1.63 |
| College | 1.36 – 1.50 | 1.14 | 1.19 | 1.29 | 1.36 | 1.50 |
| Professional | 1.35 – 1.48 | 1.05 | 1.12 | 1.19 | 1.35 | 1.48 |
| Broad (All Levels) | 1.44 – 1.57 | 1.12 | 1.20 | 1.32 | 1.44 | 1.57 |
## Use Cases
* Power transfer analysis
* Kinetic chain efficiency
# Rear Arm Connection
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/rear-arm-connection
Average distance between the rear elbow and mid-torso (halfway between mid-shoulder and mid-hip joint centers) between launch and ball contact events.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `rear_arm_connection`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Average distance from rear elbow to mid-torso
* **Timing:** Launch to ball contact events
* **Typical Range:** 8.9 – 15.7 in (0.225 – 0.399 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Rear arm connection measures the average distance between the rear elbow and the mid-torso during the swing.
This metric indicates the relative connection and efficiency of the rear arm position to the torso during the acceleration phase.
Maintaining a tight connection between rear arm and torso improves power transfer.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 7.2 – 9.6 in | 6.3 | 7.2 | 8.4 | 9.6 | 11.6 |
| High School | 8.9 – 11.7 in | 7.6 | 8.9 | 9.9 | 11.7 | 15.0 |
| College | 12.2 – 17.1 in | 10.2 | 12.2 | 14.3 | 17.1 | 18.9 |
| Professional | 14.7 – 18.5 in | 13.0 | 14.7 | 16.3 | 18.5 | 20.6 |
| Broad (All Levels) | 8.9 – 15.7 in | 7.2 | 8.9 | 11.7 | 15.7 | 18.7 |
## Use Cases
* Arm connection analysis
* Swing efficiency assessment
* Power transfer evaluation
# Relative Hand Position - Away from Body
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-away-from-body
Distance along the axis forward away from the body (+) between mid-shoulders and the average of the two wrists at the foot contact event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `relative_hand_position_away_from_body`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Lateral distance from mid-shoulders to average wrist position
* **Direction:** Away from body (+)
* **Timing:** At foot contact event
* **Typical Range:** 3.3 – 7.1 in (0.083 – 0.180 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Relative hand position away from body measures the fore/aft position of the hands relative to the shoulders at foot contact, indicating pre-swing hand positioning.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 2.4 – 4.7 in | 1.2 | 2.4 | 3.6 | 4.7 | 5.5 |
| High School | 3.0 – 5.6 in | 2.0 | 3.0 | 4.5 | 5.6 | 6.6 |
| College | 4.9 – 8.1 in | 3.3 | 4.9 | 6.3 | 8.1 | 9.4 |
| Professional | 5.8 – 9.0 in | 3.4 | 5.8 | 7.8 | 9.0 | 11.0 |
| Broad (All Levels) | 3.3 – 7.1 in | 1.9 | 3.3 | 4.9 | 7.1 | 9.1 |
## Use Cases
* Swing setup assessment
* Hand position evaluation
# Relative Hand Position - Towards Pitcher
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-towards-pitcher
Distance along the axis towards the pitcher (+) or away (-) between mid-shoulders and the average of the two wrists at the foot contact event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `relative_hand_position_towards_pitcher`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Distance from mid-shoulders to average wrist position
* **Direction:** Negative values (-) indicate the wrists are further from the pitcher than the neck (mid shoulders)
* **Timing:** At foot contact event
* **Typical Range:** -8.7 – -4.2 in (-0.221 – -0.107 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Relative hand position towards pitcher measures the forward-backward position of the hands relative to the shoulders at foot contact, indicating hand placement and swing setup.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :---: | :---: | :--: | :--: | :--: |
| Youth | -6.4 – -3.4 in | -7.5 | -6.4 | -5.2 | -3.4 | -2.5 |
| High School | -7.2 – -4.2 in | -8.7 | -7.2 | -5.9 | -4.2 | -2.8 |
| College | -10.2 – -5.0 in | -11.4 | -10.2 | -7.6 | -5.0 | -2.8 |
| Professional | -11.6 – -6.3 in | -13.3 | -11.6 | -9.0 | -6.3 | -2.8 |
| Broad (All Levels) | -8.7 – -4.2 in | -11.2 | -8.7 | -6.3 | -4.2 | -2.6 |
## Use Cases
* Hand placement analysis
* Swing setup assessment
* Position evaluation
* Technique optimization
# Relative Hand Position - Up
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/relative-hand-position-up
Distance along the up axis (+) between mid-shoulders and the average of the two wrists at the foot contact event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `relative_hand_position_up`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Vertical distance from mid-shoulders to average wrist position
* **Direction:** Above (+) or below (-)
* **Timing:** At foot contact event
* **Typical Range:** 1.9 – 5.6 in (0.049 – 0.143 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Relative hand position up measures the vertical position of the hands relative to the shoulders at foot contact, indicating hand height and swing setup.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 1.7 – 3.7 in | 0.6 | 1.7 | 2.6 | 3.7 | 4.6 |
| High School | 1.7 – 4.1 in | 0.2 | 1.7 | 2.8 | 4.1 | 5.9 |
| College | 2.4 – 5.8 in | 0.3 | 2.4 | 4.5 | 5.8 | 7.4 |
| Professional | 4.0 – 8.2 in | 0.8 | 4.0 | 6.2 | 8.2 | 9.5 |
| Broad (All Levels) | 1.9 – 5.6 in | 0.4 | 1.9 | 3.5 | 5.6 | 7.8 |
## Use Cases
* Hand height analysis
* Swing setup assessment
# Scap Load at Launch
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/scap-load-at-launch
Amount of rear shoulder flexion (+) or extension (-) at launch event. Flexion/Extension translates to horizontal adduction (+) and abduction (-), respectively.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `rear_scap_load_at_launch`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Rear shoulder flexion/extension at launch
* **Positive:** Flexion (horizontal adduction)
* **Negative:** Extension (horizontal abduction)
* **Typical Range:** -8 – 19 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Scap load at launch measures the amount of rear shoulder flexion or extension at the launch event, indicating the loading and preparation of the rear shoulder for power generation.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | -4 – 18 ° | -16 | -4 | 6 | 18 | 28 |
| High School | -6 – 23 ° | -18 | -6 | 10 | 23 | 33 |
| College | -8 – 16 ° | -28 | -8 | 4 | 16 | 32 |
| Professional | -16 – 16 ° | -31 | -16 | 0 | 16 | 29 |
| Broad (All Levels) | -8 – 19 ° | -25 | -8 | 5 | 19 | 31 |
## Use Cases
* Rear shoulder loading analysis
* Scapular mechanics assessment
# Shoulder Rotation Plane Flexion
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-flexion
Amount of trunk flexion required to reach the average plane of rotation of the shoulder joint centers. This measures the trunk posture for optimal swing mechanics.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `shoulder_rotation_plane_flexion`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Trunk flexion for shoulder plane alignment
* **Direction:** positive indicates leaning forward towards home plate
* **Typical Range:** 30 – 39 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Shoulder rotation plane flexion measures the amount of trunk flexion needed to align with the optimal plane of shoulder rotation, indicating trunk posture for efficient shoulder mechanics.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 26 – 35 ° | 22 | 26 | 31 | 35 | 39 |
| High School | 29 – 38 ° | 26 | 29 | 34 | 38 | 45 |
| College | 34 – 41 ° | 31 | 34 | 38 | 41 | 44 |
| Professional | 34 – 41 ° | 30 | 34 | 38 | 41 | 44 |
| Broad (All Levels) | 30 – 39 ° | 26 | 30 | 34 | 39 | 43 |
## Use Cases
* Trunk posture analysis
* Shoulder mechanics assessment
* Plane alignment evaluation
* Technique optimization
# Shoulder Rotation Plane Tilt
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/shoulder-rotation-plane-tilt
Amount of trunk tilt (+ = tilting towards the pitcher) to reach the average plane of rotation of the shoulders. This measures the lateral (side-side) trunk posture for optimal swing mechanics.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `shoulder_rotation_plane_tilt`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Trunk tilt for shoulder plane alignment
* **Direction:** Positive indicates tilting forward towards pitcher
* **Typical Range:** -2 – 12 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Shoulder rotation plane tilt measures the amount of lateral trunk tilt needed to align with the optimal plane of shoulder rotation, indicating lateral trunk posture for efficient shoulder mechanics.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | -5 – 11 ° | -12 | -5 | 2 | 11 | 16 |
| High School | -8 – 6 ° | -13 | -8 | 0 | 6 | 15 |
| College | 2 – 14 ° | -7 | 2 | 7 | 14 | 21 |
| Professional | 2 – 16 ° | -2 | 2 | 8 | 16 | 21 |
| Broad (All Levels) | -2 – 12 ° | -11 | -2 | 4 | 12 | 19 |
## Use Cases
* Lateral trunk posture analysis
* Shoulder mechanics assessment
* Plane alignment evaluation
* Technique optimization
# Stride Length
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/stride-length
Distance between the lead ankle at foot contact and the rear ankle at max foot raise event. This measures the stride length used during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `stride_length`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Distance between lead ankle (foot contact) and rear ankle (max foot raise)
* **Typical Range:** 15.5 – 32.7 in (0.394 – 0.832 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Stride length measures the distance covered by the stride during the swing, providing insight into stride mechanics and balance.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 12.9 – 16.7 in | 11.7 | 12.9 | 15.1 | 16.7 | 20.7 |
| High School | 15.3 – 20.6 in | 13.9 | 15.3 | 17.1 | 20.6 | 29.9 |
| College | 23.5 – 33.4 in | 21.1 | 23.5 | 28.3 | 33.4 | 37.3 |
| Professional | 31.5 – 38.6 in | 27.8 | 31.5 | 35.1 | 38.6 | 40.7 |
| Broad (All Levels) | 15.5 – 32.7 in | 13.0 | 15.5 | 21.7 | 32.7 | 37.4 |
## Use Cases
* Stride analysis
* Balance assessment
# Sway
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/sway
Binary indicator of excessive lateral movement of the pelvis just prior to swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `sway`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Threshold:** 8 cm (\~3 in) lateral movement
* **Measurement:** Pelvis position difference around max knee raise
## Description
Sway indicates excessive lateral movement of the pelvis during the swing, which can compromise balance and power generation.
Sway is determined by the difference in farthest forward and backward pelvis position (forward = towards the pitcher) between initiation (start of any movement) and max knee raise event.
Lateral movement distance threshold for sway fault is 8 cm (\~3 in)
Sway is a method of measuring pre-swing sway movement, which can be used in combination with [Sway Leg](/biomechanics/activities/baseball/hitting/metrics/sway-leg),
measured by rear leg alignment.
## Use Cases
* Balance analysis
* Movement efficiency assessment
* Stability evaluation
## Interventions
* [Step Back Drill](https://youtube.com/shorts/jwdxvnplEaw?si=cL8tgwA3NF6zSbA_)
* Focus Area: Back Hip Loading, Limited Separation
# Sway Leg
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/sway-leg
Binary indicator of excessive lateral movement, determined by rear ankle and knee joint centers.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `sway_leg`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Rear knee position relative to ankle
* **Fault Condition:** Knee passes behind ankle (away from pitcher)
## Description
Sway leg indicates excessive lateral movement in the lower body, specifically when the rear knee passes behind the ankle (further from pitcher), compromising the base of support and power generation.
Sway leg is a different method of measuring pre-swing sway movement, which can be used in combination with normal [Sway](/biomechanics/activities/baseball/hitting/metrics/sway),
measured by lateral pelvis motion.
## Use Cases
* Lower body balance analysis
* Leg stability assessment
* Base of support evaluation
## Interventions
* [Step Back Drill](https://youtube.com/shorts/jwdxvnplEaw?si=cL8tgwA3NF6zSbA_)
* Focus Area: Back Hip Loading, Limited Separation
# Sweet Spot Fore Aft Position At Contact
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/sweet-spot-fore-aft-position-at-contact
Fore/aft position (closer to/further from the pitcher) of the bat sweet spot relative to the pelvis (mid point of the hip joint centers) at ball contact. This measures the bat position at impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `sweet_spot_fore_aft_position_at_contact`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Distance from pelvis to sweet spot
* **Direction:** Positive indicates closer to the pitcher, negative indicates further away from the pitcher relative to the pelvis
* **Timing:** At ball contact
* **Typical Range:** -0.2 to +0.4 meters
## Description
Sweet spot fore aft position at contact measures the forward-backward position of the bat's sweet spot relative to the pelvis at the moment of ball contact, indicating bat placement and timing.
## Use Cases
* Bat placement analysis
* Contact position assessment
* Timing evaluation
* Technique optimization
# Swing Path Angle
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/swing-path-angle
Plane angle of the bat swing path relative to horizontal in the 0.04 s leading up to ball contact. This measures the final approach angle of the bat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `swing_path_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Vertical angle of swing path
* **Timing:** the 0.04 s leading up to ball contact
* **Typical Range:** 5° to 40°
## Description
Swing path angle measures the vertical angle of the bat's path in the final 0.04 seconds before ball contact, indicating the final approach angle and swing plane.
## Use Cases
* Final approach analysis
* Swing path assessment
* Bat position assessment
# Time to Ball Contact
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/time-to-ball-contact
Duration between initiation and ball contact events. This measures the total swing time from start to contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s)
* **Column Name:** `time_to_ball_contact`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Ball contact time - Initiation time
* **Typical Range:** 0.75 – 1.02 s
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Time to ball contact measures the total duration of the swing from initiation to ball contact, providing insight into swing timing and rhythm.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 0.76 – 1.02 s | 0.59 | 0.76 | 0.85 | 1.02 | 1.15 |
| High School | 0.78 – 1.00 s | 0.53 | 0.78 | 0.89 | 1.00 | 1.14 |
| College | 0.70 – 1.03 s | 0.60 | 0.70 | 0.93 | 1.03 | 1.14 |
| Professional | 0.74 – 1.04 s | 0.59 | 0.74 | 0.91 | 1.04 | 1.26 |
| Broad (All Levels) | 0.75 – 1.02 s | 0.58 | 0.75 | 0.89 | 1.02 | 1.16 |
## Use Cases
* Swing timing analysis
* Rhythm assessment
# Time to Launch
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/time-to-launch
Duration between initiation and pelvis velocity initiation (launch) events. This measures the time from swing start to the beginning of power generation.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s)
* **Column Name:** `time_to_launch`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Pelvis initiation time - Initiation time
* **Typical Range:** 0.16 – 0.51 s
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Time to launch measures the duration from swing initiation to the start of pelvis velocity initiation (launch event), indicating the preparation phase before power generation begins.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 0.14 – 0.41 s | 0.00 | 0.14 | 0.23 | 0.41 | 0.57 |
| High School | 0.17 – 0.48 s | 0.00 | 0.17 | 0.29 | 0.48 | 0.65 |
| College | 0.18 – 0.58 s | 0.00 | 0.18 | 0.35 | 0.58 | 0.77 |
| Professional | 0.18 – 0.67 s | 0.10 | 0.18 | 0.45 | 0.67 | 0.79 |
| Broad (All Levels) | 0.16 – 0.51 s | 0.00 | 0.16 | 0.29 | 0.51 | 0.72 |
## Use Cases
* Preparation phase analysis
* Timing assessment
# Trunk Center of Mass Position X
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/trunk-center-of-mass-x
Trunk center of mass X position - for use with keypoint positions. This is a time series metric that tracks the trunk's forward/backward position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `trunk_center_of_mass_x`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Direction:** Forward/Backward
## Description
Trunk center of mass X position tracks the forward-backward position of the trunk's center of mass throughout the swing, providing insight into trunk movement patterns.
## Use Cases
* Trunk movement analysis
* Position tracking
# Trunk Center of Mass Position Y
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/trunk-center-of-mass-y
Trunk center of mass Y position (up/down) - for use with keypoint positions. This is a time series metric that tracks the trunk's vertical position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `trunk_center_of_mass_y`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Direction:** Vertical (up/down)
## Description
Trunk center of mass Y position tracks the vertical position of the trunk's center of mass throughout the swing, providing insight into trunk movement patterns and stability.
## Use Cases
* Trunk vertical movement analysis
* Position tracking
# Trunk Center of Mass Position Z
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/trunk-center-of-mass-z
Trunk center of mass Z position - for use with keypoint positions. This is a time series metric that tracks the trunk's lateral position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `trunk_center_of_mass_z`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Direction:** Lateral (side-to-side)
## Description
Trunk center of mass Z position tracks the lateral position of the trunk's center of mass throughout the swing, providing insight into trunk movement patterns and balance.
## Use Cases
* Trunk lateral movement analysis
* Position tracking
# Trunk Coil
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/trunk-coil
Max rotation angle that the trunk turns away from the pitcher. This measures the loading of the trunk during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_coil`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum trunk rotation away from pitcher between [max foot raise](/biomechanics/activities/baseball/hitting/events/max-foot-raise.mdx) and [foot contact](/biomechanics/activities/baseball/hitting/events/foot-contact.mdx) events
* **Reference:** 0° = neutrally square to the pitcher, shoulders in line with the pitch
* **Typical Range:** 24 – 41 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Trunk coil measures the maximum rotation angle of the trunk away from the pitcher, indicating the loading and preparation of the core for power generation.
Neutrally square towards the pitcher (where the shoulders are in line with the pitch) would be 0 deg.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 28 – 45 ° | 18 | 28 | 35 | 45 | 53 |
| High School | 24 – 42 ° | 17 | 24 | 33 | 42 | 49 |
| College | 26 – 39 ° | 17 | 26 | 31 | 39 | 45 |
| Professional | 22 – 35 ° | 12 | 22 | 27 | 35 | 39 |
| Broad (All Levels) | 24 – 41 ° | 16 | 24 | 31 | 41 | 48 |
## Use Cases
* Core preparation assessment
* Rotation evaluation
## Interventions
* [Coil Drill](https://www.youtube.com/shorts/XcvnswS7stw)
* Focus Area: Back Hip Loading
* [Hook'Em Drill](https://youtu.be/IyCE0hey7-I)
* Focus Area: Back Hip Loading, Limited Separation
# Trunk Global Flexion
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/trunk-global-flexion
Amount of trunk sagittal plane flexion relative to the global coordinate system. This is a time series metric that tracks trunk flexion throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_global_flexion`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Plane:** Sagittal plane
* **Reference:** Global coordinate system
## Description
Trunk global flexion tracks the amount of forward-backward flexion of the trunk relative to the global coordinate system throughout the swing, providing insight into trunk posture and movement.
## Use Cases
* Trunk posture analysis
# Trunk Global Rotation
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/trunk-global-rotation
Amount of trunk transverse plane rotation relative to the global coordinate system. This is a time series metric that tracks trunk rotation throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_global_rotation`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Plane:** Transverse plane
* **Reference:** Global coordinate system
## Description
Trunk global rotation tracks the amount of rotation of the trunk relative to the global coordinate system throughout the swing, providing insight into trunk rotation patterns and power generation.
## Use Cases
* Trunk rotation analysis
# Trunk Global Tilt
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/trunk-global-tilt
Amount of trunk frontal plane side-to-side tilt relative to the global coordinate system. This is a time series metric that tracks trunk lateral tilt throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_global_tilt`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Plane:** Frontal plane
* **Reference:** Global coordinate system
## Description
Trunk global tilt tracks the amount of side-to-side tilt of the trunk relative to the global coordinate system throughout the swing, providing insight into trunk posture and balance.
## Use Cases
* Trunk lateral posture analysis
* Tilt tracking
# Trunk Tilt at Launch
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/trunk-tilt-at-launch
Amount of side-to-side trunk tilt at launch event (pelvis velocity initiation). Positive values indicate tilting towards the pitcher and vice versa.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_tilt_at_launch`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Side-to-side trunk tilt
* **Timing:** At launch event
* **Typical Range:** 5 – 13 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Trunk tilt at launch measures the side-to-side tilt of the trunk at the moment of pelvis velocity initiation, indicating trunk posture and balance at the start of power generation.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 5 – 14 ° | 3 | 5 | 9 | 14 | 16 |
| High School | 5 – 14 ° | 1 | 5 | 10 | 14 | 18 |
| College | 7 – 14 ° | 3 | 7 | 10 | 14 | 16 |
| Professional | 4 – 12 ° | 0 | 4 | 9 | 12 | 14 |
| Broad (All Levels) | 5 – 13 ° | 1 | 5 | 9 | 13 | 16 |
## Use Cases
* Trunk posture analysis
* Launch position evaluation
# Trunk to Arm Speed Up
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/trunk-to-arm-speed-up
Ratio (multiplication factor) of speed increase from trunk to arm. This measures the efficiency of power transfer from the core to the upper body.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio
* **Column Name:** `trunk_to_arm_velocity_speedup`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Peak arm angular velocity / Peak trunk angular velocity
* **Optimal Range:** 1.2-1.8
* **Optimal Direction:** Higher is better
## Description
Trunk to arm speed up measures the multiplication factor of velocity increase from the trunk to the arm, indicating the efficiency of power transfer through the kinetic chain.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 1.20 – 1.32 | 0.94 | 1.03 | 1.12 | 1.20 | 1.32 |
| High School | 1.34 – 1.49 | 0.96 | 1.03 | 1.12 | 1.34 | 1.49 |
| College | 1.39 – 1.76 | 0.91 | 1.00 | 1.19 | 1.39 | 1.76 |
| Professional | 1.60 – 1.92 | 1.02 | 1.20 | 1.40 | 1.60 | 1.92 |
| Broad (All Levels) | 1.39 – 1.65 | 0.95 | 1.06 | 1.17 | 1.39 | 1.65 |
## Use Cases
* Power transfer analysis
* Kinetic chain efficiency
# Vertical Pelvis Hike
Source: https://docs.uplift.ai/biomechanics/activities/baseball/hitting/metrics/vertical-pelvis-hike
Binary indicator of excessive vertical pelvis movement, determined if the pelvis keypoint finishes the swing (at ball contact) higher than where it started (at launch event).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `vertical_pelvis_hike`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Pelvis height at ball contact vs launch
* **Fault Condition:** Pelvis higher at ball contact than at launch
## Description
Vertical pelvis hike indicates excessive upward movement of the pelvis during the swing, which can compromise balance and power transfer efficiency.
## Use Cases
* Pelvis stability analysis
* Vertical movement assessment
* Technique correction
# Baseball: Pitching
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching
Biomechanical analysis of baseball pitching
Evaluate pitching mechanics to improve consistency, maximize energy transfer to the ball, and reduce risk for injury.
Uplift offers dozens of events and metrics to track baseball pitching across movement flags, peak segment angular velocities, and more.
![Example image of a man doing a pitch, front view]()
## Dimensions
Required Inputs for processing:
* **handedness:** the handedness of the pitcher \['left', 'right']
## Variables
Output variables from pitching analysis.
### Normative Ranges
See [Baseball Pitching Norms](/biomechanics/activities/baseball/pitching/baseball-pitching-norms) for the full 5th–95th percentile reference tables by competition level (Youth, High School, College, Pro).
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
Automated events break down the pitch into phases or periods of interest. Many metrics occur at specific events.
| Event | Short Description | Column Name |
| ----------------------------------------------------------------------------------------------------- | ------------------------------------------- | ---------------------------- |
| [Initiation](/biomechanics/activities/baseball/pitching/events/initiation) | Start of the pitch. | `initiation_frame` |
| [Max Knee Raise](/biomechanics/activities/baseball/pitching/events/max-knee-raise) | Maximum lead knee height. | `max_knee_raise_frame` |
| [Low Hand](/biomechanics/activities/baseball/pitching/events/low-hand) | Lowest point of the throwing hand. | `low_hand_frame` |
| [Foot Contact](/biomechanics/activities/baseball/pitching/events/foot-contact) | Front foot contacts the ground. | `foot_contact_frame` |
| [Twist](/biomechanics/activities/baseball/pitching/events/twist) | Maximum rotation of pelvis, trunk, and arm. | `twist_frame` |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/pitching/events/peak-pelvis-ang-vel) | Instant of pelvis peak angular velocity. | `peak_pelvis_velocity_frame` |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/pitching/events/peak-trunk-ang-vel) | Instant of trunk peak angular velocity. | `peak_trunk_velocity_frame` |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/pitching/events/peak-arm-ang-vel) | Instant of upper arm peak angular velocity. | `peak_arm_velocity_frame` |
| [Release](/biomechanics/activities/baseball/pitching/events/release) | Estimated timing of ball release. | `ball_release_frame` |
| [Wrist Below Hips](/biomechanics/activities/baseball/pitching/events/wrist-below-hips) | Wrist drops below hip height. | `wrist_below_hips_frame` |
### Kinematic Sequence Metrics
Assess sequencing and speeds for pitch delivery.
| Metric | Units | Short Description | Column Name |
| --------------------------------------------------------------------------------------------------------------- | ----- | ------------------------------------------------------------------------------- | ---------------------------------- |
| [Kinematic Sequence](/biomechanics/activities/baseball/pitching/metrics/kinematic-sequence-order) | N/A | Order of peak segment angular velocities. Correct sequence is pelvis-trunk-arm. | `kinematic_sequence_order` |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-pelvis-angular-velocity) | deg/s | Max rotational speed of the pelvis. | `peak_pelvis_angular_velocity` |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-trunk-angular-velocity) | deg/s | Max rotational speed of the trunk. | `peak_trunk_angular_velocity` |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-arm-angular-velocity) | deg/s | Max rotational speed of the upper arm. | `peak_arm_angular_velocity` |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/pitching/metrics/trunk-to-arm-speed-up) | ratio | Speed increase ratio from trunk to arm. | `trunk_to_arm_velocity_speedup` |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/pitching/metrics/pelvis-to-trunk-speed-up) | ratio | Speed increase ratio from pelvis to trunk. | `pelvis_to_trunk_velocity_speedup` |
### Movement Flag Metrics
Movement flags identify poor or suboptimal mechanics for timing and body positioning during the pitch.
| Metric | Short Description | Column Name |
| ----------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------- | ----------------------- |
| [Elbow Hike](/biomechanics/activities/baseball/pitching/metrics/elbow-hike) | Elbow is above the shoulder at foot contact. | `elbow_hike` |
| [Arm Drag](/biomechanics/activities/baseball/pitching/metrics/arm-drag) | Elbow is above the wrist at foot contact (late arm motion). | `arm_drag` |
| [Forearm Flyout](/biomechanics/activities/baseball/pitching/metrics/forearm-flyout) | Elbow angle \<75° at foot contact and \<20° at release. | `forearm_flyout` |
| [Sway](/biomechanics/activities/baseball/pitching/metrics/sway) | Front knee, head, or body COM crosses behind the rear leg at max knee raise. | `sway` |
| [Hanging Back](/biomechanics/activities/baseball/pitching/metrics/hanging-back) | Pitcher moves backward after max front knee raise. | `hanging_back` |
| [Closing Front/Back](/biomechanics/activities/baseball/pitching/metrics/closing-front-or-back) | Trunk tilts more than 20° relative to pelvis between max knee raise and foot contact. | `closing_front_or_back` |
| [Flying Open](/biomechanics/activities/baseball/pitching/metrics/flying-open) | Trunk angular velocity peaks before foot contact with X-factor near 0° at foot contact. | `flying_open` |
| [Late Rise](/biomechanics/activities/baseball/pitching/metrics/late-rise) | Wrist is below the elbow at foot contact (delayed wrist flip). | `late_rise` |
| [Getting Out In Front](/biomechanics/activities/baseball/pitching/metrics/getting-out-in-front) | Trunk forward rotation exceeds -20° at foot contact. | `getting_out_in_front` |
| [Knee Collapse](/biomechanics/activities/baseball/pitching/metrics/knee-collapse) | Front knee bends more than 20° between foot contact and release. | `knee_collapse` |
| [High Hand](/biomechanics/activities/baseball/pitching/metrics/high-hand) | Wrist does not descend within 10 cm (\~4 in) of elbow height during the cocking phase. | `high_hand` |
| [Early Release](/biomechanics/activities/baseball/pitching/metrics/early-release) | Wrist is behind the lead toe at release. | `early_release` |
### Linear Metrics & More
Show distances, positions, and speeds relevant to pitching.
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------------------- | ----------- | ------------------------------------------------------------------------------------------------- | ------------------------------------ |
| [Stride Length](/biomechanics/activities/baseball/pitching/metrics/stride-length) | % of height | Stride length as % of athlete height (rear foot at max knee raise to front foot at foot contact). | `stride_length` |
| [Max Trunk COM Velocity](/biomechanics/activities/baseball/pitching/metrics/max-trunk-com-velocity) | m/s | Peak linear speed of the trunk center of mass. | `max_trunk_com_velocity` |
| [Wrist Position to Lead Toe](/biomechanics/activities/baseball/pitching/metrics/wrist-fore-aft-lead-toe-at-release) | m | Wrist fore/aft position relative to lead toe at release (+ = in front). | `wrist_fore_aft_lead_toe_at_release` |
| [Wrist Height at Release](/biomechanics/activities/baseball/pitching/metrics/wrist-height-at-release) | m | Wrist height above mound level at release. | `wrist_height_at_release` |
| [Handedness](/biomechanics/activities/baseball/pitching/metrics/handedness) | N/A | Pitcher handedness \['right' or 'left']. | `handedness` |
| [Time to Release](/biomechanics/activities/baseball/pitching/metrics/time-to-release) | s | Duration from initiation to ball release. | `time_to_release` |
### Angular Metrics
These metrics describe joint angles and segment angles relative to global or home plate.
| Metric | Units | Short Description | Column Name |
| --------------------------------------------------------------------------------------------------------------------------- | ----- | ------------------------------------------------------------------------------- | ------------------------------------ |
| [Max X Factor](/biomechanics/activities/baseball/pitching/metrics/max-x-factor) | deg | Max hip-shoulder separation before the acceleration phase. | `max_x_factor` |
| [Hip Raise Angle](/biomechanics/activities/baseball/pitching/metrics/hip-raise-angle) | deg | Max lead hip flexion at max knee raise. | `hip_raise_angle` |
| [Max Layback Angle](/biomechanics/activities/baseball/pitching/metrics/max-layback-angle) | deg | Maximum trunk extension angle. | `max_layback_angle` |
| [Arm Slot Angle](/biomechanics/activities/baseball/pitching/metrics/arm-slot-angle) | deg | Arm abduction angle at release relative to vertical. | `arm_slot_angle` |
| [Arm Slot Type](/biomechanics/activities/baseball/pitching/metrics/arm-slot-type) | N/A | Classification of arm slot angle. | `arm_slot_type` |
| [Trunk Lateral Tilt at Foot Contact](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-foot-contact) | deg | Lateral trunk tilt at foot contact. | `trunk_lateral_tilt_at_foot_contact` |
| [Trunk Lateral Tilt at Release](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-ball-release) | deg | Lateral trunk tilt at release. | `trunk_lateral_tilt_at_ball_release` |
| [Trunk Forward Tilt at Release](/biomechanics/activities/baseball/pitching/metrics/trunk-forward-tilt-at-ball-release) | deg | Forward trunk tilt at release. | `trunk_forward_tilt_at_ball_release` |
| [Trunk Angle to Plate Coil](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-coil) | deg | Max trunk rotation away from home plate prior to delivery (0° = facing plate). | `trunk_angle_to_plate_coil` |
| [Trunk Angle to Plate Foot Contact](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-foot-contact) | deg | Trunk rotation angle relative to home plate at foot contact. | `trunk_angle_to_plate_foot_contact` |
| [Trunk Angle to Plate Release](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-release) | deg | Trunk rotation angle relative to home plate at release. | `trunk_angle_to_plate_release` |
| [Pelvis Angle to Plate Coil](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-coil) | deg | Max pelvis rotation away from home plate prior to delivery (0° = facing plate). | `pelvis_angle_to_plate_coil` |
| [Pelvis Angle to Plate Foot Contact](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-foot-contact) | deg | Pelvis rotation angle relative to home plate at foot contact. | `pelvis_angle_to_plate_foot_contact` |
| [Pelvis Angle to Plate Release](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-release) | deg | Pelvis rotation angle relative to home plate at release. | `pelvis_angle_to_plate_release` |
## Notes
* Kinematic data typically captured at 240Hz for Baseball Pitching
* All boolean variables (true/false = 1/0) return -1 if metric unable to be calculated.
# Baseball Pitching: Normative Ranges
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/baseball-pitching-norms
Full percentile reference tables (5th–95th) for baseball pitching metrics, broken out by competition level.
This page collects the complete normative reference tables for baseball pitching — the same underlying data shown as 10th/25th/50th/75th/90th percentile summaries on individual [metric pages](/biomechanics/activities/baseball/pitching), extended here to the full 5th–95th percentile range for each competition level. See [Normative Ranges](/biomechanics/normative-ranges) for how to interpret these tables.
Each competition-level dataset was built by pooling all valid pitching sessions per athlete, selecting the single session closest to that athlete's overall average across all metrics, then re-analyzing with the latest biomechanical analysis software and removing sessions that failed Uplift's quality assurance tests.
## Youth Sample
Reference dataset built from 206 unique youth athletes performing a pitch in 2025.
### Kinematic Sequence – Peak Segment Angular Velocities
Prefer higher velocities for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| --------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-pelvis-angular-velocity) | 289 | 330 | 370 | 428 | 463 | 523 | 553 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-trunk-angular-velocity) | 475 | 557 | 627 | 686 | 726 | 773 | 788 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-arm-angular-velocity) | 730 | 947 | 1050 | 1192 | 1255 | 1331 | 1422 | deg/s |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/pitching/metrics/pelvis-to-trunk-speed-up) | 1.22 | 1.29 | 1.43 | 1.57 | 1.75 | 2.02 | 2.29 | ratio |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/pitching/metrics/trunk-to-arm-speed-up) | 1.23 | 1.41 | 1.57 | 1.72 | 1.89 | 2.10 | 2.27 | ratio |
| [Max Trunk COM Velocity](/biomechanics/activities/baseball/pitching/metrics/max-trunk-com-velocity) | 1.37 | 1.39 | 1.49 | 1.65 | 1.89 | 2.38 | 2.74 | m/s |
### Distance and Time
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------- | :---: | :---: | :---: | :---: | :--: | :--: | :--: | -------- |
| [Stride Length](/biomechanics/activities/baseball/pitching/metrics/stride-length) | 0.66 | 0.70 | 0.74 | 0.80 | 0.87 | 0.96 | 1.02 | % height |
| [Time to Release](/biomechanics/activities/baseball/pitching/metrics/time-to-release) | 0.92 | 1.00 | 1.07 | 1.21 | 1.33 | 1.46 | 1.65 | s |
| [Wrist Position to Lead Toe](/biomechanics/activities/baseball/pitching/metrics/wrist-fore-aft-lead-toe-at-release) | -0.30 | -0.22 | -0.10 | -0.03 | 0.01 | 0.06 | 0.08 | m |
| [Wrist Height at Release](/biomechanics/activities/baseball/pitching/metrics/wrist-height-at-release) | 0.75 | 0.80 | 0.86 | 0.95 | 1.01 | 1.10 | 1.13 | m |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ----------------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/baseball/pitching/metrics/max-x-factor) | 9 | 11 | 17 | 23 | 29 | 32 | 38 | deg |
| [Hip Raise Angle](/biomechanics/activities/baseball/pitching/metrics/hip-raise-angle) | 32 | 51 | 72 | 98 | 111 | 126 | 136 | deg |
| [Arm Slot Angle](/biomechanics/activities/baseball/pitching/metrics/arm-slot-angle) | 10 | 23 | 36 | 50 | 58 | 70 | 75 | deg |
| [Max Layback Angle](/biomechanics/activities/baseball/pitching/metrics/max-layback-angle) | 0 | 0 | 124 | 141 | 172 | 195 | 207 | deg |
| [Trunk Angle to Plate (Coil)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-coil) | 88 | 103 | 112 | 123 | 131 | 140 | 145 | deg |
| [Trunk Angle to Plate (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-foot-contact) | 56 | 72 | 87 | 101 | 115 | 126 | 127 | deg |
| [Trunk Angle to Plate (Release)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-release) | -32 | -23 | -18 | -12 | -3 | 5 | 17 | deg |
| [Pelvis Angle to Plate (Coil)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-coil) | 98 | 103 | 111 | 117 | 126 | 136 | 144 | deg |
| [Pelvis Angle to Plate (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-foot-contact) | 55 | 62 | 73 | 84 | 95 | 105 | 106 | deg |
| [Pelvis Angle to Plate (Release)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-release) | -6 | 1 | 13 | 19 | 27 | 36 | 41 | deg |
| [Trunk Lateral Tilt (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-foot-contact) | -12 | -11 | -8 | -5 | -2 | 1 | 3 | deg |
| [Trunk Lateral Tilt at Release](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-ball-release) | 3 | 5 | 10 | 16 | 23 | 28 | 30 | deg |
| [Trunk Forward Tilt (Release)](/biomechanics/activities/baseball/pitching/metrics/trunk-forward-tilt-at-ball-release) | 7 | 14 | 19 | 25 | 28 | 33 | 36 | deg |
## High School Sample
Reference dataset built from 226 unique high school athletes performing a pitch in 2025.
### Kinematic Sequence – Peak Segment Angular Velocities
Prefer higher velocities for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| --------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-pelvis-angular-velocity) | 284 | 335 | 399 | 440 | 505 | 573 | 589 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-trunk-angular-velocity) | 565 | 588 | 636 | 695 | 757 | 786 | 806 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-arm-angular-velocity) | 886 | 1076 | 1166 | 1257 | 1332 | 1445 | 1482 | deg/s |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/pitching/metrics/pelvis-to-trunk-speed-up) | 1.10 | 1.21 | 1.39 | 1.56 | 1.75 | 1.97 | 2.16 | ratio |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/pitching/metrics/trunk-to-arm-speed-up) | 1.41 | 1.50 | 1.64 | 1.82 | 1.92 | 2.12 | 2.30 | ratio |
| [Max Trunk COM Velocity](/biomechanics/activities/baseball/pitching/metrics/max-trunk-com-velocity) | 1.59 | 1.64 | 1.83 | 2.17 | 2.62 | 2.93 | 3.65 | m/s |
### Distance and Time
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------- | :---: | :---: | :---: | :---: | :---: | :--: | :--: | -------- |
| [Stride Length](/biomechanics/activities/baseball/pitching/metrics/stride-length) | 0.71 | 0.75 | 0.82 | 0.92 | 1.04 | 1.08 | 1.13 | % height |
| [Time to Release](/biomechanics/activities/baseball/pitching/metrics/time-to-release) | 1.08 | 1.12 | 1.20 | 1.28 | 1.39 | 1.53 | 2.90 | s |
| [Wrist Position to Lead Toe](/biomechanics/activities/baseball/pitching/metrics/wrist-fore-aft-lead-toe-at-release) | -0.31 | -0.23 | -0.13 | -0.06 | -0.01 | 0.08 | 0.13 | m |
| [Wrist Height at Release](/biomechanics/activities/baseball/pitching/metrics/wrist-height-at-release) | 0.83 | 0.89 | 0.99 | 1.08 | 1.14 | 1.21 | 1.26 | m |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ----------------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/baseball/pitching/metrics/max-x-factor) | 12 | 15 | 19 | 26 | 31 | 36 | 39 | deg |
| [Hip Raise Angle](/biomechanics/activities/baseball/pitching/metrics/hip-raise-angle) | 62 | 82 | 99 | 112 | 124 | 134 | 136 | deg |
| [Arm Slot Angle](/biomechanics/activities/baseball/pitching/metrics/arm-slot-angle) | 25 | 29 | 41 | 50 | 60 | 69 | 78 | deg |
| [Max Layback Angle](/biomechanics/activities/baseball/pitching/metrics/max-layback-angle) | 0 | 0 | 111 | 126 | 164 | 185 | 203 | deg |
| [Trunk Angle to Plate (Coil)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-coil) | 99 | 107 | 117 | 125 | 133 | 143 | 146 | deg |
| [Trunk Angle to Plate (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-foot-contact) | 39 | 59 | 75 | 90 | 107 | 120 | 126 | deg |
| [Trunk Angle to Plate (Release)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-release) | -28 | -23 | -16 | -11 | -5 | -1 | 2 | deg |
| [Pelvis Angle to Plate (Coil)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-coil) | 101 | 104 | 112 | 120 | 129 | 138 | 143 | deg |
| [Pelvis Angle to Plate (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-foot-contact) | 51 | 55 | 64 | 71 | 86 | 100 | 110 | deg |
| [Pelvis Angle to Plate (Release)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-release) | -7 | 1 | 11 | 17 | 24 | 31 | 35 | deg |
| [Trunk Lateral Tilt (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-foot-contact) | -11 | -10 | -7 | -3 | 0 | 8 | 12 | deg |
| [Trunk Lateral Tilt at Release](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-ball-release) | 2 | 4 | 10 | 15 | 21 | 25 | 30 | deg |
| [Trunk Forward Tilt (Release)](/biomechanics/activities/baseball/pitching/metrics/trunk-forward-tilt-at-ball-release) | 9 | 14 | 20 | 27 | 32 | 36 | 38 | deg |
## College Sample
Reference dataset built from 167 unique collegiate athletes performing a pitch in 2025.
### Kinematic Sequence – Peak Segment Angular Velocities
Prefer higher velocities for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| --------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-pelvis-angular-velocity) | 316 | 348 | 407 | 458 | 534 | 575 | 589 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-trunk-angular-velocity) | 594 | 622 | 671 | 742 | 804 | 848 | 886 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-arm-angular-velocity) | 1031 | 1192 | 1288 | 1363 | 1472 | 1595 | 1630 | deg/s |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/pitching/metrics/pelvis-to-trunk-speed-up) | 1.17 | 1.29 | 1.45 | 1.58 | 1.77 | 2.04 | 2.20 | ratio |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/pitching/metrics/trunk-to-arm-speed-up) | 1.45 | 1.57 | 1.71 | 1.86 | 2.02 | 2.23 | 2.37 | ratio |
| [Max Trunk COM Velocity](/biomechanics/activities/baseball/pitching/metrics/max-trunk-com-velocity) | 2.07 | 2.14 | 2.41 | 2.69 | 3.00 | 3.32 | 3.72 | m/s |
### Distance and Time
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------- | :---: | :---: | :---: | :---: | :---: | :--: | :--: | -------- |
| [Stride Length](/biomechanics/activities/baseball/pitching/metrics/stride-length) | 0.86 | 0.88 | 0.93 | 1.01 | 1.06 | 1.12 | 1.16 | % height |
| [Time to Release](/biomechanics/activities/baseball/pitching/metrics/time-to-release) | 1.03 | 1.07 | 1.11 | 1.23 | 1.31 | 1.40 | 1.52 | s |
| [Wrist Position to Lead Toe](/biomechanics/activities/baseball/pitching/metrics/wrist-fore-aft-lead-toe-at-release) | -0.44 | -0.32 | -0.19 | -0.11 | -0.02 | 0.06 | 0.09 | m |
| [Wrist Height at Release](/biomechanics/activities/baseball/pitching/metrics/wrist-height-at-release) | 0.81 | 0.88 | 0.96 | 1.07 | 1.20 | 1.35 | 1.48 | m |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ----------------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/baseball/pitching/metrics/max-x-factor) | 12 | 14 | 22 | 29 | 35 | 39 | 41 | deg |
| [Hip Raise Angle](/biomechanics/activities/baseball/pitching/metrics/hip-raise-angle) | 78 | 98 | 110 | 123 | 131 | 136 | 140 | deg |
| [Arm Slot Angle](/biomechanics/activities/baseball/pitching/metrics/arm-slot-angle) | 32 | 34 | 41 | 55 | 71 | 88 | 97 | deg |
| [Max Layback Angle](/biomechanics/activities/baseball/pitching/metrics/max-layback-angle) | 97 | 107 | 115 | 128 | 141 | 173 | 180 | deg |
| [Trunk Angle to Plate (Coil)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-coil) | 106 | 111 | 118 | 126 | 133 | 139 | 142 | deg |
| [Trunk Angle to Plate (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-foot-contact) | 53 | 59 | 69 | 81 | 95 | 106 | 109 | deg |
| [Trunk Angle to Plate (Release)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-release) | -25 | -22 | -15 | -11 | -6 | 2 | 4 | deg |
| [Pelvis Angle to Plate (Coil)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-coil) | 102 | 105 | 110 | 119 | 128 | 138 | 140 | deg |
| [Pelvis Angle to Plate (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-foot-contact) | 45 | 48 | 54 | 65 | 76 | 84 | 89 | deg |
| [Pelvis Angle to Plate (Release)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-release) | -7 | 0 | 10 | 19 | 25 | 32 | 35 | deg |
| [Trunk Lateral Tilt (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-foot-contact) | -10 | -8 | -4 | 1 | 4 | 8 | 10 | deg |
| [Trunk Lateral Tilt at Release](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-ball-release) | -5 | 3 | 8 | 15 | 21 | 26 | 27 | deg |
| [Trunk Forward Tilt (Release)](/biomechanics/activities/baseball/pitching/metrics/trunk-forward-tilt-at-ball-release) | 15 | 18 | 25 | 29 | 34 | 39 | 42 | deg |
## Professional Sample
Reference dataset built from 155 unique professional athletes performing a pitch in 2025.
### Kinematic Sequence – Peak Segment Angular Velocities
Prefer higher velocities for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| --------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-pelvis-angular-velocity) | 276 | 307 | 363 | 441 | 519 | 651 | 741 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-trunk-angular-velocity) | 463 | 523 | 628 | 699 | 783 | 838 | 866 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-arm-angular-velocity) | 880 | 1123 | 1274 | 1372 | 1478 | 1625 | 1689 | deg/s |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/pitching/metrics/pelvis-to-trunk-speed-up) | 1.02 | 1.14 | 1.41 | 1.58 | 1.84 | 2.13 | 2.63 | ratio |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/pitching/metrics/trunk-to-arm-speed-up) | 1.32 | 1.64 | 1.75 | 1.97 | 2.13 | 2.60 | 2.73 | ratio |
| [Max Trunk COM Velocity](/biomechanics/activities/baseball/pitching/metrics/max-trunk-com-velocity) | 2.32 | 2.72 | 2.99 | 3.40 | 3.79 | 5.82 | 5.91 | m/s |
### Distance and Time
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------- | :---: | :---: | :---: | :---: | :--: | :--: | :--: | -------- |
| [Stride Length](/biomechanics/activities/baseball/pitching/metrics/stride-length) | 0.70 | 0.85 | 0.94 | 1.10 | 1.21 | 1.35 | 1.44 | % height |
| [Time to Release](/biomechanics/activities/baseball/pitching/metrics/time-to-release) | 0.23 | 0.55 | 0.97 | 1.18 | 1.30 | 1.43 | 1.79 | s |
| [Wrist Position to Lead Toe](/biomechanics/activities/baseball/pitching/metrics/wrist-fore-aft-lead-toe-at-release) | -0.37 | -0.25 | -0.16 | -0.04 | 0.07 | 0.23 | 0.30 | m |
| [Wrist Height at Release](/biomechanics/activities/baseball/pitching/metrics/wrist-height-at-release) | 0.89 | 1.03 | 1.13 | 1.28 | 1.48 | 1.91 | 2.00 | m |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ----------------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/baseball/pitching/metrics/max-x-factor) | 7 | 10 | 14 | 20 | 26 | 34 | 37 | deg |
| [Hip Raise Angle](/biomechanics/activities/baseball/pitching/metrics/hip-raise-angle) | 24 | 41 | 53 | 91 | 127 | 138 | 141 | deg |
| [Arm Slot Angle](/biomechanics/activities/baseball/pitching/metrics/arm-slot-angle) | 17 | 30 | 38 | 52 | 61 | 84 | 124 | deg |
| [Max Layback Angle](/biomechanics/activities/baseball/pitching/metrics/max-layback-angle) | 0 | 0 | 114 | 140 | 153 | 181 | 198 | deg |
| [Trunk Angle to Plate (Coil)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-coil) | 72 | 86 | 100 | 110 | 119 | 135 | 146 | deg |
| [Trunk Angle to Plate (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-foot-contact) | 20 | 27 | 51 | 70 | 82 | 95 | 98 | deg |
| [Trunk Angle to Plate (Release)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-release) | -27 | -25 | -17 | -11 | -5 | 0 | 10 | deg |
| [Pelvis Angle to Plate (Coil)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-coil) | 63 | 81 | 94 | 104 | 124 | 132 | 142 | deg |
| [Pelvis Angle to Plate (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-foot-contact) | 32 | 37 | 46 | 62 | 75 | 82 | 90 | deg |
| [Pelvis Angle to Plate (Release)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-release) | -11 | -4 | 8 | 15 | 27 | 37 | 42 | deg |
| [Trunk Lateral Tilt (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-foot-contact) | -12 | -10 | -4 | 5 | 11 | 16 | 18 | deg |
| [Trunk Lateral Tilt at Release](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-ball-release) | -9 | -2 | 5 | 13 | 18 | 22 | 26 | deg |
| [Trunk Forward Tilt (Release)](/biomechanics/activities/baseball/pitching/metrics/trunk-forward-tilt-at-ball-release) | 12 | 13 | 18 | 27 | 34 | 42 | 48 | deg |
## Broad Sample (All Levels)
Reference dataset built from 754 unique athletes performing a pitch in 2025, pooled across all competition levels, from the 2026 Q1 dataset.
### Kinematic Sequence – Peak Segment Angular Velocities
Prefer higher velocities for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| --------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-pelvis-angular-velocity) | 285 | 329 | 382 | 437 | 499 | 573 | 603 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-trunk-angular-velocity) | 519 | 574 | 639 | 700 | 764 | 819 | 846 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/baseball/pitching/metrics/peak-arm-angular-velocity) | 887 | 1002 | 1160 | 1271 | 1382 | 1498 | 1598 | deg/s |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/baseball/pitching/metrics/pelvis-to-trunk-speed-up) | 1.13 | 1.23 | 1.41 | 1.57 | 1.76 | 2.03 | 2.27 | ratio |
| [Trunk to Arm Speed Up](/biomechanics/activities/baseball/pitching/metrics/trunk-to-arm-speed-up) | 1.28 | 1.48 | 1.64 | 1.82 | 1.99 | 2.21 | 2.43 | ratio |
| [Max Trunk COM Velocity](/biomechanics/activities/baseball/pitching/metrics/max-trunk-com-velocity) | 1.45 | 1.52 | 1.76 | 2.35 | 2.90 | 3.58 | 4.65 | m/s |
### Distance and Time
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------- | :----: | :----: | :----: | :----: | :---: | :---: | :---: | -------- |
| [Stride Length](/biomechanics/activities/baseball/pitching/metrics/stride-length) | 0.683 | 0.729 | 0.808 | 0.923 | 1.046 | 1.127 | 1.190 | % height |
| [Time to Release](/biomechanics/activities/baseball/pitching/metrics/time-to-release) | 0.91 | 1.02 | 1.12 | 1.24 | 1.35 | 1.48 | 2.16 | s |
| [Wrist Position to Lead Toe](/biomechanics/activities/baseball/pitching/metrics/wrist-fore-aft-lead-toe-at-release) | -0.365 | -0.273 | -0.153 | -0.059 | 0.008 | 0.081 | 0.120 | m |
| [Wrist Height at Release](/biomechanics/activities/baseball/pitching/metrics/wrist-height-at-release) | 0.797 | 0.837 | 0.942 | 1.045 | 1.164 | 1.336 | 1.494 | m |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ----------------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/baseball/pitching/metrics/max-x-factor) | 9 | 13 | 18 | 25 | 31 | 36 | 40 | deg |
| [Hip Raise Angle](/biomechanics/activities/baseball/pitching/metrics/hip-raise-angle) | 42 | 57 | 89 | 110 | 125 | 134 | 139 | deg |
| [Arm Slot Angle](/biomechanics/activities/baseball/pitching/metrics/arm-slot-angle) | 21 | 29 | 39 | 51 | 63 | 75 | 85 | deg |
| [Max Layback Angle](/biomechanics/activities/baseball/pitching/metrics/max-layback-angle) | 0 | 0 | 116 | 132 | 157 | 189 | 202 | deg |
| [Trunk Angle to Plate (Coil)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-coil) | 90 | 102 | 112 | 123 | 132 | 140 | 145 | deg |
| [Trunk Angle to Plate (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-foot-contact) | 40 | 53 | 71 | 88 | 105 | 116 | 126 | deg |
| [Trunk Angle to Plate (Release)](/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-release) | -28 | -23 | -17 | -11 | -5 | 2 | 6 | deg |
| [Pelvis Angle to Plate (Coil)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-coil) | 89 | 100 | 109 | 118 | 128 | 137 | 143 | deg |
| [Pelvis Angle to Plate (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-foot-contact) | 38 | 49 | 61 | 72 | 86 | 97 | 105 | deg |
| [Pelvis Angle to Plate (Release)](/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-release) | -7 | 0 | 11 | 18 | 25 | 34 | 38 | deg |
| [Trunk Lateral Tilt (Foot Contact)](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-foot-contact) | -11 | -10 | -7 | -3 | 3 | 9 | 13 | deg |
| [Trunk Lateral Tilt at Release](/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-ball-release) | -1 | 4 | 9 | 15 | 21 | 26 | 28 | deg |
| [Trunk Forward Tilt (Release)](/biomechanics/activities/baseball/pitching/metrics/trunk-forward-tilt-at-ball-release) | 10 | 14 | 20 | 27 | 32 | 37 | 41 | deg |
# Foot Contact
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/events/foot-contact
When the lead foot contacts the ground and begins accepting weight.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `foot_contact_frame`
* **Required for QA:** True
* **Measurement:** Front foot ground contact
## Description
Foot contact marks the moment when the front foot makes contact with the ground and begins accepting weight.
Identified using a combination of position and velocity of the ankle and toe keypoints.
This is a critical time point for sequencing the pitch as well as body position metrics
## Use Cases
* Stride time analysis
* Pitch sequence and order
* Posture and body position
# Initiation
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/events/initiation
Initial movement beginning the baseball pitch.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `initiation_frame`
* **Required for QA:** False
* **Measurement:** Start of the baseball pitch
## Description
Initiation represents the very beginning of the pitching sequence when the pitcher starts lead leg movement before the raise and stride.
## Use Cases
* Pitch timing analysis
* Event timing comparisons - time to release
# Low Hand
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/events/low-hand
The low point of the throwing hand between max knee raise and release.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `low_hand_frame`
* **Required for QA:** False
* **Measurement:** Low point of the throwing wrist joint center between max knee raise and release
## Description
Low hand marks the instant when the throwing hand reaches its low point after max knee raise and before ball release.
This event is mainly helpful in identifying other events, giving a reference point for the throwing arm.
## Use Cases
* Event identification for other events
# Max Knee Raise
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/events/max-knee-raise
The maximum height of the knee during the pitch.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `max_knee_raise_frame`
* **Required for QA:** True
* **Measurement:** Maximum height of the knee during the pitch
## Description
Max knee raise marks the peak of the leg lift phase during the pitching motion, when the lead knee reaches its highest point.
If knee height is inconclusive, ankle height may be used instead.
## Use Cases
* Leg lift phase analysis
* Timing assessment
* Balance evaluation
# Peak Arm Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/events/peak-arm-ang-vel
The instant of upper arm peak angular velocity.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_arm_velocity_frame`
* **Required for QA:** False
* **Measurement:** Peak angular velocity (deg/s) of upper arm segment
## Description
This event identifies the moment when the upper arm reaches its maximum angular velocity during the pitch, representing the peak of the arm kinetic energy.
## Use Cases
* Upper body mechanics assessment
* Peak velocity timing
* Pitch sequence evaluation
# Peak Pelvis Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/events/peak-pelvis-ang-vel
The instant of pelvis peak angular velocity.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_pelvis_velocity_frame`
* **Required for QA:** False
* **Measurement:** Peak angular velocity (deg/s) of pelvis segment
## Description
This event identifies the moment when the pelvis reaches its maximum angular velocity during the pitch, representing the peak of the lower body kinetic energy.
## Use Cases
* Lower body mechanics assessment
* Peak velocity timing
* Pitch sequence evaluation
# Peak Trunk Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/events/peak-trunk-ang-vel
The instant of trunk peak angular velocity.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_trunk_velocity_frame`
* **Required for QA:** False
* **Measurement:** Peak angular velocity of trunk segment
## Description
This event identifies the moment when the trunk reaches its maximum angular velocity during the pitch, representing the peak of the trunk kinetic energy.
## Use Cases
* Core mechanics assessment
* Peak velocity timing
* Pitch sequence evaluation
# Release
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/events/release
The estimated time of ball release during the pitch.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `ball_release_frame`
* **Required for QA:** True
* **Measurement:** Estimated timing of ball release
## Description
Release marks the estimated instant when the ball is released from the pitcher's hand, representing the end of the acceleration phase.
Detected via one of 3 methods:
1. peak wrist velocity in the horizontal axis
2. peak wrist height
3. peak elbow extension angle
## Use Cases
* Arm slot angle
* Pitch completion & timing
# Twist
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/events/twist
The average timing of segment angular velocities.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `twist_frame`
* **Required for QA:** True
* **Measurement:** Average of the maximum rotation velocity time for the pelvis, trunk, and arm
## Description
Twist marks the average timing of peak segment angular velocities (pelvis, trunk, and arm) during the pitching motion.
This is a broad representation of the pitch, used to help determine if a pitch was recorded.
## Use Cases
* Pitch detection
# Wrist Below Hips
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/events/wrist-below-hips
The fist low point of the wrist below the hips after ball release.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `wrist_below_hips_frame`
* **Required for QA:** False
* **Measurement:** Low point in wrist position after release
## Description
Wrist below hips is identified as the low point of the wrist after ball release.
The wrist must be below the level of the hips to qualify.
This event marks the end of the pitch delivery.
## Use Cases
* Detecting the end of pitch
# Arm Drag
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/arm-drag
Binary indicator of delayed arm motion, occurs if the elbow is above the wrist at foot contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `arm_drag`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Elbow height relative to wrist at foot contact
## Description
Arm drag is a binary indicator that flags late arm motion during the pitch. It occurs when the elbow is positioned above the wrist at foot contact, indicating delayed arm acceleration.
## Use Cases
* Timing of arm position
* Mechanics evaluation
## Corrective Drills
### 1. Connection Ball Drill
Place a small foam ball (or rolled-up sock) between the throwing elbow and the ribcage. Go through a slow-motion pitch focusing on breaking the hands early enough that the ball stays in place through the stride phase. Dropping the ball signals that the arm is staying back too long relative to lower-body movement. Perform 15–20 repetitions.
[Search YouTube: baseball pitching connection ball drill arm drag](https://www.youtube.com/results?search_query=baseball+pitching+connection+ball+drill+arm+drag+late+arm)
### 2. Rocker Drill
Start in a balanced stance, rock the weight back (as in a normal windup), and break the hands early — driving the throwing arm up and back in sync with the lower-body stride. The goal is to have the wrist above the elbow by the time the front foot lands. Perform 20 repetitions, focusing on earlier hand separation.
[Search YouTube: baseball pitching rocker drill arm timing](https://www.youtube.com/results?search_query=baseball+pitching+rocker+drill+arm+timing+hand+break)
### 3. Hip-Load to Arm-Path Sync Drill
From a balanced one-leg stance, deliberately initiate the arm path (hands break and arm swings back) at the same moment as the hip starts driving toward the plate. Exaggerating the early arm trigger teaches the body that the arm should be "loaded and ready" well before foot contact. Throw at 50–60% effort into a net for 3 sets of 8–10 reps.
[Search YouTube: baseball pitching hip load arm sync drill late arm fix](https://www.youtube.com/results?search_query=baseball+pitching+hip+load+arm+sync+drill+late+arm+fix)
# Arm Slot Angle
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/arm-slot-angle
Abduction angle of the arm at ball release compared to vertical.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `arm_slot_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Abduction angle of arm (shoulder to wrist) at ball release
* **Reference:** Vertical (adducted) = 0°
* **Typical Range:** 39 – 63 °
* **Optimal Direction:** N/A — depends on pitching style
## Description
Arm slot angle measures the abduction angle of the arm (from shoulder to wrist) at ball release compared to vertical (adducted, 0°).
Sidearm and submarine throwers have larger arm slot angles than overhand throwers.
A perfectly side-arm release has an arm slot angle of 90°.
Uplift's arm slot categories broadly follow an article from Graeme Lehman: Do Different Arm Slots = Different Mechanics?
[https://treadathletics.com/arm-slot-differences/](https://treadathletics.com/arm-slot-differences/)
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 36 – 58 ° | 23 | 36 | 50 | 58 | 70 |
| High School | 41 – 60 ° | 29 | 41 | 50 | 60 | 69 |
| College | 41 – 71 ° | 34 | 41 | 55 | 71 | 88 |
| Professional | 38 – 61 ° | 30 | 38 | 52 | 61 | 84 |
| Broad (All Levels) | 39 – 63 ° | 29 | 39 | 51 | 63 | 75 |
## Use Cases
* Arm slot classification
* Release angle assessment
* Pitch consistency tracking
# Arm Slot Type
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/arm-slot-type
Broad classification of arm slot angle.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `arm_slot_type`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
## Description
Arm slot type classifies the arm slot angle into categories based on ranges broadly adopted from Tread Athletics, Graeme Lehman: Do Different Arm Slots = Different Mechanics?
[https://treadathletics.com/arm-slot-differences/](https://treadathletics.com/arm-slot-differences/)
The classifications are:
* overhand (0-45°)
* three-quarter (45-65°)
* sidearm (65-115°)
* submarine (115-180°)
With 0° as vertical and 90° as horizontal.
## Use Cases
* Arm slot classification
* Pitching style identification
* Pitch consistency tracking
# Closing Front/Back
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/closing-front-or-back
Binary indicator of excessive trunk tilt during the pitch.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `closing_front_or_back`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Side-to-side trunk angle relative to pelvis
* **Threshold:** Deviation > 20° from vertical between max knee raise and foot contact
## Description
Closing front/back is a binary indicator that flags excessive trunk tilt during the stride phase of the pitch.
It occurs when the pitcher's side-to-side trunk angle relative to pelvis deviates more than 20 degrees from vertical between max knee raise and foot contact events.
Closing the front or back is an indicator of off axis alignment between the pelvis and trunk segments.
## Use Cases
* Posture evaluation
## Corrective Drills
### 1. Dowel Rod Lateral Tilt Check
Place a dowel rod across the shoulders (behind the neck, resting on both shoulders). Perform the stride phase in slow motion and monitor whether the rod stays level or tilts more than slightly. A coach or video from the front can confirm if excessive side-to-side tilt occurs. Perform 15–20 slow-motion reps, correcting tilt each time.
[Search YouTube: baseball pitching dowel rod shoulder level tilt drill](https://www.youtube.com/results?search_query=baseball+pitching+dowel+rod+shoulder+level+lateral+tilt+drill)
### 2. Hip-Shoulder Stack Drill
Stand in front of a mirror and perform the stride with a focus on keeping the trunk stacked directly over the pelvis in the lateral plane. Cue "nose over belly button" or "keep the shoulders level" to prevent the trunk from dipping toward the front or back. Practice 20 reps at walk-through speed before moving to full-effort throwing.
[Search YouTube: baseball pitching hip shoulder posture alignment drill trunk tilt](https://www.youtube.com/results?search_query=baseball+pitching+hip+shoulder+posture+alignment+drill+trunk+tilt)
### 3. Resistance Band Posture Drill
Anchor a light band at hip height to one side. Perform the stride and delivery while the band provides a lateral pull — this forces the pitcher to actively stabilize the trunk in the frontal plane against the resistance, building the core strength needed to prevent excessive tilt. Perform 3 sets of 8–10 reps on each side.
[Search YouTube: baseball pitching resistance band core stability trunk posture drill](https://www.youtube.com/results?search_query=baseball+pitching+resistance+band+core+stability+trunk+posture+drill)
# Early Release
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/early-release
Binary indicator of early ball release - indicated by wrist fore/aft position to lead toe. If wrist is behind toe at release, then it's early.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `early_release`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Wrist fore/aft position relative to lead toe at release
* **Threshold:** Wrist behind toe at release
## Description
Early release is a binary indicator that flags premature ball release during the pitch.
It occurs when the wrist is positioned behind the lead toe at the instant of ball release.
## Use Cases
* Release point assessment
* Mechanics evaluation
## Corrective Drills
### 1. Extension and Follow-Through Drill
Throw into a net from 20–30 feet while focusing entirely on reaching the throwing hand as far toward the target as possible after release. The cue is "shake hands with the catcher" — the wrist and hand should extend well past the lead toe at the release point. Perform 25–30 repetitions at 60–70% effort, prioritizing extension over velocity.
[Search YouTube: baseball pitching extension follow through drill release point](https://www.youtube.com/results?search_query=baseball+pitching+extension+follow+through+drill+release+point)
### 2. Target Release Point Drill
Place a piece of tape on the ground in front of the lead toe. The goal is to feel (or confirm via video) that the ball is released in front of that mark. If the ball releases behind the tape, the pitcher is releasing early. Throw at reduced effort from the mound or a flat surface, 3 sets of 10 reps, self-correcting after each throw.
[Search YouTube: baseball pitching release point drill target early release fix](https://www.youtube.com/results?search_query=baseball+pitching+release+point+drill+target+early+release+fix)
### 3. Step-Through Throwing Drill
From a balanced position, stride and plant normally, but immediately after ball release, drive the back foot through and plant it in front. This enforced follow-through commitment teaches the body to delay release until the trunk and arm are fully extended over the lead leg. Perform 20 reps into a net at 60% effort.
[Search YouTube: baseball pitching step through throwing drill follow through](https://www.youtube.com/results?search_query=baseball+pitching+step+through+throwing+drill+follow+through+release)
# Elbow Hike
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/elbow-hike
Binary indicator if elbow is above shoulder at foot contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `elbow_hike`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Elbow position relative to shoulder at foot contact
* **Threshold:** Elbow above shoulder
## Description
Elbow hike is a binary indicator that flags when the throwing elbow is positioned above the same-side shoulder at foot contact, which indicates improper arm positioning during the pitch.
## Use Cases
* Arm position assessment
* Mechanics evaluation
* Injury risk identification
## Corrective Drills
### 1. Wall Arm Path Drill
Stand arm's length from a wall with the throwing shoulder facing it. Slowly go through the arm path from the glove break to foot contact, keeping the elbow at or below shoulder height throughout. The wall provides immediate tactile feedback if the elbow rises too high. Perform 3 sets of 10 slow repetitions before bullpen sessions.
[Search YouTube: wall arm path pitching drill elbow](https://www.youtube.com/results?search_query=baseball+pitching+wall+arm+path+drill+elbow+position)
### 2. Towel Drill with Low-Elbow Cue
Use a standard towel drill setup (towel held at the base of the fingers, throw toward a target). Focus on keeping the elbow at or below the shoulder plane during the arm path before launch. Have a coach or mirror confirm elbow position at the moment the front foot contacts the ground. Perform 20–30 repetitions.
[Search YouTube: baseball pitching towel drill arm path mechanics](https://www.youtube.com/results?search_query=baseball+pitching+towel+drill+arm+path+elbow+mechanics)
### 3. Mirror/Video Pause Drill
Throw at half-speed into a net while recording from the front or side. Pause the video at foot contact and check elbow height relative to the shoulder. Repeat and self-correct until the elbow stays at or below the shoulder at foot contact. This builds proprioceptive awareness of proper arm positioning.
[Search YouTube: baseball pitching video analysis arm path elbow position](https://www.youtube.com/results?search_query=baseball+pitching+video+analysis+arm+path+elbow+position+foot+contact)
# Flying Open
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/flying-open
Binary indicator of early trunk rotation.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `flying_open`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Trunk angular velocity peak timing and X-factor at foot contact
* **Threshold:** Trunk angular velocity peaks before foot contact AND X-factor within 5° of neutral (0°) at foot contact
## Description
Flying open is a binary indicator that flags early trunk rotation during the pitch.
It occurs when the trunk angular velocity is peaking before foot contact and the X-factor (hip-shoulder separation) is within 5 degrees of 0 at foot contact.
## Use Cases
* Timing assessment
* Rotation sequencing evaluation
## Corrective Drills
### 1. Stay-Closed Stride Drill
Perform slow-motion stride reps with an emphasis on keeping the front shoulder and hip closed (pointed toward the catcher) until the front foot lands. Place a bat or cone along the glove-side hip as a visual guide — the front of the body should stay "behind" the bat until foot contact. Perform 20 reps, then integrate into full throws at 60% effort.
[Search YouTube: baseball pitching stay closed stride drill flying open fix](https://www.youtube.com/results?search_query=baseball+pitching+stay+closed+stride+drill+flying+open+fix)
### 2. Glove-Side Pull Drill
Attach a light resistance band to the glove wrist, anchored on the glove-side. During the stride, the glove hand is pulled outward and then tucked back to the chest only after foot contact. This forces the front side to stay closed longer and delays trunk rotation until the lower body has landed. Perform 3 sets of 10 reps.
[Search YouTube: baseball pitching glove side pull drill stay closed front shoulder](https://www.youtube.com/results?search_query=baseball+pitching+glove+side+pull+drill+stay+closed+front+shoulder)
### 3. Hip-Shoulder Separation Overload Drill
Deliberately exaggerate the hip-shoulder separation: drive the hips hard toward the plate first, then consciously hold the trunk and shoulders back until the foot lands. This "over-teaches" the proper sequencing by making the pitcher feel the difference between hip rotation and trunk rotation. Start with walk-through reps, then build to full effort. Perform 15–20 reps.
[Search YouTube: baseball pitching hip shoulder separation drill overload sequencing](https://www.youtube.com/results?search_query=baseball+pitching+hip+shoulder+separation+drill+overload+sequencing)
# Forearm Flyout
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/forearm-flyout
Binary indicator of excessive elbow extension prior to ball release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `forearm_flyout`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Elbow angle at foot contact and ball release
* **Threshold:** Elbow angle \< 75° at foot contact AND \< 20° at ball release (where full extension = 0°)
## Description
Forearm flyout is a binary indicator that flags excessive elbow extension prior to ball release.
It occurs when the elbow angle is less than 75 degrees at foot contact and less than 20 degrees at ball release.
Elbow angle is measured with full extension = 0°, thus lower joint angles are more extended.
## Use Cases
* Elbow mechanics assessment
* Injury risk evaluation
* Mechanics correction
## Corrective Drills
### 1. Short-Arm Throwing Drill
Remove the full arm swing and throw from a "cocked" position (elbow bent \~90°, upper arm at shoulder height) using only forearm and wrist. This reinforces maintaining elbow flexion through the acceleration phase and prevents the forearm from extending prematurely. Throw at 50% effort from 30–40 feet for 20–25 repetitions.
[Search YouTube: baseball pitching short arm throwing drill elbow flexion](https://www.youtube.com/results?search_query=baseball+pitching+short+arm+throwing+drill+elbow+flexion)
### 2. Wrist Wrap Drill
Using a lightweight resistance band looped around the wrist and anchored behind the pitcher, throw at reduced intensity. The band provides resistance that encourages the forearm to stay flexed (elbow bent) rather than flying out into early extension. Perform 3 sets of 10 repetitions.
[Search YouTube: baseball pitching resistance band wrist elbow drill forearm flyout](https://www.youtube.com/results?search_query=baseball+pitching+resistance+band+wrist+elbow+drill+forearm+flyout)
### 3. Arm Path Slot Drill
Have the pitcher throw into a net from 15 feet with an emphasis on keeping the elbow at 90° flexion until the hand passes the ear. A coach standing to the glove-hand side watches for the elbow straightening too early. Use video feedback at foot contact and at ball release to confirm the elbow angle stays above 75° at foot contact.
[Search YouTube: baseball pitching arm path slot drill elbow angle forearm flyout](https://www.youtube.com/results?search_query=baseball+pitching+arm+path+slot+drill+elbow+angle+forearm+flyout)
# Getting Out In Front
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/getting-out-in-front
Binary indicator of early trunk forward flexion at foot contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `getting_out_in_front`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Trunk forward flexion angle at foot contact
* **Threshold:** >20° of forward flexion at foot contact
## Description
Getting out in front is a binary indicator that flags early trunk forward rotation during the pitch.
It occurs when the trunk forward flexion angle is greater than 20 degrees at foot contact.
## Use Cases
* Trunk position assessment
## Corrective Drills
### 1. Tall Posting Drill
At the moment of foot contact, actively cue "stay tall" — the trunk should be upright (or slightly tilted back) rather than already flexing forward over the lead leg. Practice this in slow-motion reps by holding the "foot contact" position for 2–3 seconds, confirming trunk is vertical before continuing the throw. Perform 20 reps.
[Search YouTube: baseball pitching stay tall trunk posture drill foot contact](https://www.youtube.com/results?search_query=baseball+pitching+stay+tall+trunk+posture+drill+foot+contact)
### 2. Wall Brace Drill
Stand with the back to a wall about 1–2 feet away. Perform the delivery and monitor whether the upper back touches the wall at foot contact (which would confirm the trunk is leaning back, not forward). If the back doesn't contact the wall, the pitcher is getting out front too early. Use as a diagnostic and corrective tool for 15 reps.
[Search YouTube: baseball pitching wall brace drill trunk forward tilt fix](https://www.youtube.com/results?search_query=baseball+pitching+wall+brace+drill+trunk+forward+tilt+fix)
### 3. Front-Side Brace Throw
Throw at 60–70% effort while actively trying to "brace" the front leg and keep the chest pointing upward at foot contact, only allowing forward trunk tilt after the ball is released. This teaches the pitcher to separate the timing of foot contact (still upright) from trunk flexion (post-contact). Perform 3 sets of 8–10 reps into a net.
[Search YouTube: baseball pitching front side brace throw trunk tilt timing](https://www.youtube.com/results?search_query=baseball+pitching+front+side+brace+throw+trunk+tilt+timing)
# Handedness
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/handedness
Handedness of the athlete ('right' or 'left') as input parameter.
## Technical Details
* **Variable Type:** Dimension
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `handedness`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Values:** 'right' or 'left'
## Description
Handedness specifies which side the athlete throws from (right-handed or left-handed).
This is a required input parameter that affects the interpretation of all other pitching metrics.
## Use Cases
* Throwing side identification
* Data analysis
# Hanging Back
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/hanging-back
Binary indicator if the pitcher initially moves backwards (away from the plate) directly after max front knee raise.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `hanging_back`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Initial movement direction after max front knee raise
* **Threshold:** Backwards movement (away from plate)
## Description
Hanging back is a binary indicator that flags when the pitcher initially moves backwards (away from the plate) between initiation and max knee raise events.
This is an indication of delayed forward momentum.
## Use Cases
* Momentum analysis
* Forward drive assessment
## Corrective Drills
### 1. Tall-and-Fall Drill
Start in a balanced, upright stance on the back foot. Initiate motion by simply "falling" forward toward the plate — resist the urge to shift backward first. The front knee rises as the body falls, so momentum is always directed toward the target. Perform 15–20 reps, throwing into a net at 60% effort.
[Search YouTube: baseball pitching tall and fall drill forward momentum](https://www.youtube.com/results?search_query=baseball+pitching+tall+and+fall+drill+forward+momentum)
### 2. Hip Drive Step Drill
From the windup start position, use a resistance band looped around the hips and anchored behind the pitcher. The band encourages early forward hip drive immediately after initiation and penalizes any backward movement by increasing band resistance. Throw at reduced effort for 3 sets of 10 reps.
[Search YouTube: baseball pitching hip drive band drill forward momentum](https://www.youtube.com/results?search_query=baseball+pitching+hip+drive+resistance+band+drill+forward+momentum)
### 3. Step-Behind Momentum Drill
Begin in the stretch position (no full windup). On a coach's signal, step directly toward the plate and fire — this eliminates the leg-kick delay and trains the body to generate forward momentum from the first movement. Once comfortable, gradually reintroduce the knee raise while maintaining the forward directional intent. Perform 20 repetitions.
[Search YouTube: baseball pitching momentum drill forward drive step](https://www.youtube.com/results?search_query=baseball+pitching+momentum+drill+forward+drive+step+hanging+back)
# High Hand
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/high-hand
Binary indicator of whether sufficient forearm layback occurs.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `high_hand`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Wrist to elbow vertical distance during cocking phase
* **Threshold:** Wrist height not within 10 cm (\~4 in) of elbow height
## Description
High hand is a binary indicator that flags insufficient forearm layback during the cocking phase.
It occurs when the wrist joint center height does not get within 10 cm (\~4 in) of the elbow joint center vertical position during the cocking phase.
## Use Cases
* Forearm layback assessment
* Arm mechanics evaluation
## Corrective Drills
### 1. Forearm Bounce Drill
From a stationary set position (no stride), externally rotate the upper arm so it is at shoulder height, then let the forearm "drop back" (lay back) passively by gravity and the momentum of the throw. Practice this "drop and fire" motion repeatedly to ingrain the feeling of the wrist falling below and then driving back up through the elbow plane. Perform 20–30 reps.
[Search YouTube: baseball pitching forearm layback bounce drill cocking phase](https://www.youtube.com/results?search_query=baseball+pitching+forearm+layback+bounce+drill+cocking+phase)
### 2. Wrist-Below-Elbow Cocking Drill
During slow-motion walk-throughs, pause at the top of the cocking phase and confirm the wrist has dropped to or below elbow height. A partner or video frame check is used to verify correct position. The drill makes the pitcher consciously feel and seek the low-wrist, high-elbow position before progressing to full speed. Perform 15 reps.
[Search YouTube: baseball pitching wrist below elbow cocking position drill layback](https://www.youtube.com/results?search_query=baseball+pitching+wrist+below+elbow+cocking+position+drill+layback)
### 3. Towel Layback Drill
Grip a small towel at the base of the fingers and perform throwing motion at reduced effort toward a target. Focus specifically on the cocking phase: allow the wrist to fall well below the elbow (layback) before snapping forward. The towel reduces the incentive to "muscle" through the throw and allows the pitcher to feel the elastic layback position. Perform 20–25 reps.
[Search YouTube: baseball pitching towel drill forearm layback high hand fix](https://www.youtube.com/results?search_query=baseball+pitching+towel+drill+forearm+layback+high+hand+fix)
# Hip Raise Angle
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/hip-raise-angle
Maximum flexion angle of the lead hip prior to the pitch.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `hip_raise_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum flexion angle of lead hip
* **Timing:** Should occur at max knee raise event
* **Typical Range:** 89 – 125 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Hip raise angle measures the maximum flexion angle of the lead hip prior to the pitch.\
This should occur at (or very close to) the max knee raise event.
Tracking hip raise angle is important for consistency and stability.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 72 – 111 ° | 51 | 72 | 98 | 111 | 126 |
| High School | 99 – 124 ° | 82 | 99 | 112 | 124 | 134 |
| College | 110 – 131 ° | 98 | 110 | 123 | 131 | 136 |
| Professional | 53 – 127 ° | 41 | 53 | 91 | 127 | 138 |
| Broad (All Levels) | 89 – 125 ° | 57 | 89 | 110 | 125 | 134 |
## Use Cases
* Lower body mechanics evaluation
* Consistency and stability assessment
# Kinematic Sequence
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/kinematic-sequence-order
Sequence of peak angular velocities during the pitch.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `kinematic_sequence_order`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Correct Sequence:** pelvis-trunk-arm
## Description
Kinematic sequence describes the order of peak angular velocities during the pitch. The correct sequence is pelvis-trunk-arm, indicating proper energy transfer from the lower body through the core to the arm.
## Use Cases
* Sequencing analysis
* Power generation assessment
* Mechanics evaluation
# Knee Collapse
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/knee-collapse
Binary indicator of front knee bends excessively during the acceleration phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `knee_collapse`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Front knee flexion
* **Threshold:** flexing >20° between foot contact and ball release
## Description
Knee collapse is a binary indicator that flags excessive front knee bending during the pitch.
It occurs when the front knee bends more than 20 degrees between foot contact and ball release.
The 20° threshold accounts for the initial knee angle at foot contact.
In other words, if the knee is flexed 15° at foot contact, then surpassing 35° would indicate knee collapse.
## References
1. [https://www.onbaseu.com/articles/Coaching/collapsing\_lead\_knee\_one\_of\_the\_most\_significant\_power\_killers\_in\_pitching](https://www.onbaseu.com/articles/Coaching/collapsing_lead_knee_one_of_the_most_significant_power_killers_in_pitching)
2. [https://floridabaseballarmory.com/lead-leg-blocking-is-corruptive-it-has-to-go/](https://floridabaseballarmory.com/lead-leg-blocking-is-corruptive-it-has-to-go/)
3. [https://www.integratedperformanceteam.com/blog/pitching-mechanical-faults-lead-leg-block](https://www.integratedperformanceteam.com/blog/pitching-mechanical-faults-lead-leg-block)
4. [https://treadathletics.com/back-leg-mechanics/](https://treadathletics.com/back-leg-mechanics/)
## Use Cases
* Lower body mechanics assessment
* Stability evaluation
## Corrective Drills
### 1. Front Leg Isometric Block Drill
After foot contact, hold the front leg at its landing angle for 3–5 seconds before completing the throw — do not allow the knee to flex further. This builds the quad and hip strength needed to resist collapse and creates proprioceptive awareness of what a "braced" front leg feels like. Perform 15–20 reps at walk-through speed.
[Search YouTube: baseball pitching front leg isometric block drill knee collapse](https://www.youtube.com/results?search_query=baseball+pitching+front+leg+isometric+block+drill+knee+collapse)
### 2. Step-and-Land Stability Drill
Step toward the plate and land on the front foot, then freeze — do not collapse the knee. Hold the position for 3 seconds, checking that the knee stays stacked over the foot. Gradually add an arm throw once the landing position is consistently stable. Perform 3 sets of 10 reps.
[Search YouTube: baseball pitching step land stability drill lead leg block](https://www.youtube.com/results?search_query=baseball+pitching+step+land+stability+drill+lead+leg+block)
### 3. Band-Resisted Front Leg Drive
Attach a resistance band to the back of the lead knee, anchored behind the pitcher. As the pitcher strides and lands, the band pulls the knee backward (into flexion), requiring the pitcher to actively extend and brace the lead leg against the resistance. This directly trains the strength and motor pattern needed to block knee collapse. Perform 3 sets of 8–10 reps.
[Search YouTube: baseball pitching band resisted front leg drive knee collapse fix](https://www.youtube.com/results?search_query=baseball+pitching+band+resisted+front+leg+drive+knee+collapse+fix)
# Late Rise
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/late-rise
Binary indicator of delayed wrist elevation (flip up), occurring if wrist is below elbow at foot contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `late_rise`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Wrist position relative to elbow at foot contact
* **Threshold:** Wrist below elbow
## Description
Late rise is a binary indicator that flags delayed wrist elevation (flip up) during the pitch. It occurs when the wrist is positioned below the elbow at foot contact.
## Use Cases
* Timing assessment
* Arm position evaluation
## Corrective Drills
### 1. Early Arm Circle Drill
Break the hands early (before the peak of the knee raise) and complete a full, deliberate arm circle so the throwing hand is already working upward — wrist above the elbow — by the time the foot contacts the ground. Throw at 50% effort into a net for 20 repetitions, focusing entirely on early wrist elevation.
[Search YouTube: baseball pitching early arm circle drill wrist elevation late rise](https://www.youtube.com/results?search_query=baseball+pitching+early+arm+circle+drill+wrist+elevation+late+rise)
### 2. Glove-Hand Mirror Drill
Focus on the glove hand and throwing hand staying synchronized: as the glove arm rises toward the target, the throwing hand should "flip up" simultaneously so both wrists are rising at the same rate. This symmetric timing cue helps break the habit of keeping the throwing wrist low late into the stride. Perform 15–20 walk-through reps.
[Search YouTube: baseball pitching glove arm sync drill arm path timing](https://www.youtube.com/results?search_query=baseball+pitching+glove+arm+sync+drill+arm+path+timing+wrist)
### 3. High-Arm Towel Drill
Use a towel drill where the specific cue is to have the towel/throwing hand at ear level (wrist above elbow) before the front foot lands. A coach or video confirms the wrist position at the foot-contact frame. Perform 3 sets of 10 reps with a deliberate pause at foot contact in slow motion before building to full speed.
[Search YouTube: baseball pitching towel drill high arm wrist above elbow](https://www.youtube.com/results?search_query=baseball+pitching+towel+drill+high+arm+wrist+above+elbow+cocking)
# Max Layback Angle
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/max-layback-angle
Maximum forearm layback angle (relative to horizontal forward) during the pitch.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `max_layback_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Angle of the forearm relative to forward horizontal
* **Typical Range:** 116 – 157 °
* **Optimal Direction:** Higher is better
## Description
Max layback angle measures the forearm angle relative to the horizontal plane during the pitch.
Larger amounts of layback (closer to 180 degrees) indicate greater amount of shoulder external rotation, providing more time & range for forearm action.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 172 – 195 ° | 0 | 124 | 141 | 172 | 195 |
| High School | 164 – 185 ° | 0 | 111 | 126 | 164 | 185 |
| College | 141 – 173 ° | 107 | 115 | 128 | 141 | 173 |
| Professional | 153 – 181 ° | 0 | 114 | 140 | 153 | 181 |
| Broad (All Levels) | 157 – 189 ° | 0 | 116 | 132 | 157 | 189 |
## Use Cases
* Forearm position assessment
* Arm mechanics evaluation
# Max Trunk COM Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/max-trunk-com-velocity
Maximum linear velocity of the trunk center of mass during the pitch.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** m/s
* **Column Name:** `max_trunk_com_velocity`
* **Aggregation:** mean
* **Precision:** 3
* **Measurement:** Maximum linear velocity of trunk center of mass
* **Typical Range:** 1.755 – 2.896 m/s
* **Optimal Direction:** Higher is better
## Description
Max trunk COM velocity measures the maximum linear velocity of the trunk center of mass during the pitch.
This indicates the peak forward velocity of the trunk segment as we assume the max velocity will be oriented towards home plate.
Increasing trunk linear velocity (with all else held constant) will increase pitch speed.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :---: | :---: | :---: | :---: | :---: |
| Youth | 1.886 – 2.382 m/s | 1.387 | 1.489 | 1.646 | 1.886 | 2.382 |
| High School | 2.624 – 2.926 m/s | 1.636 | 1.826 | 2.166 | 2.624 | 2.926 |
| College | 3.001 – 3.321 m/s | 2.142 | 2.406 | 2.690 | 3.001 | 3.321 |
| Professional | 3.785 – 5.816 m/s | 2.717 | 2.989 | 3.404 | 3.785 | 5.816 |
| Broad (All Levels) | 2.896 – 3.583 m/s | 1.517 | 1.755 | 2.351 | 2.896 | 3.583 |
## Use Cases
* Trunk velocity assessment
* Power generation analysis
# Max X Factor
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/max-x-factor
Maximum amount of hip-shoulder separation before acceleration phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** Degrees
* **Column Name:** `max_x_factor`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum rotational difference (separation) between hips and shoulders
* **Typical Range:** 18 – 31 °
* **Optimal Direction:** Higher is better
## Description
Max X Factor marks the amount of maximum separation between the hips and shoulders before the acceleration phase begins.
Hip shoulder separation is the rotational difference (twisting, transverse axis) between the hips (pelvis) and shoulders (trunk).
Max X factor indicates the maximum amount for pre-load range of motion prior to pitch delivery.
Increasing X factor provides more time and space for accelerating the ball.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 29 – 32 ° | 11 | 17 | 23 | 29 | 32 |
| High School | 31 – 36 ° | 15 | 19 | 26 | 31 | 36 |
| College | 35 – 39 ° | 14 | 22 | 29 | 35 | 39 |
| Professional | 26 – 34 ° | 10 | 14 | 20 | 26 | 34 |
| Broad (All Levels) | 31 – 36 ° | 13 | 18 | 25 | 31 | 36 |
## Use Cases
* Core loading assessment
# Peak Arm Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/peak-arm-angular-velocity
Maximum angular velocity (twist speed) of the upper arm segment during the pitch.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_arm_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum angular velocity of upper arm segment
* **Typical Range:** 1160 – 1382 °/s
* **Optimal Direction:** Higher is better
## Description
Peak arm angular velocity measures the maximum angular velocity (twist speed) of the upper arm segment during the pitch, indicating the peak rotational speed of the arm.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 1255 – 1331 °/s | 947 | 1050 | 1192 | 1255 | 1331 |
| High School | 1332 – 1445 °/s | 1076 | 1166 | 1257 | 1332 | 1445 |
| College | 1472 – 1595 °/s | 1192 | 1288 | 1363 | 1472 | 1595 |
| Professional | 1478 – 1625 °/s | 1123 | 1274 | 1372 | 1478 | 1625 |
| Broad (All Levels) | 1382 – 1498 °/s | 1002 | 1160 | 1271 | 1382 | 1498 |
## Use Cases
* Arm power assessment
* Kinematic sequence analysis
# Peak Pelvis Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/peak-pelvis-angular-velocity
Maximum angular velocity (twist speed) of the pelvis segment during the pitch.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_pelvis_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum angular velocity of pelvis segment
* **Typical Range:** 382 – 499 °/s
* **Optimal Direction:** Higher is better
## Description
Peak pelvis angular velocity measures the maximum angular velocity (twist speed) of the pelvis segment during the pitch, indicating the peak rotational speed of the lower body.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 463 – 523 °/s | 330 | 370 | 428 | 463 | 523 |
| High School | 505 – 573 °/s | 335 | 399 | 440 | 505 | 573 |
| College | 534 – 575 °/s | 348 | 407 | 458 | 534 | 575 |
| Professional | 519 – 651 °/s | 307 | 363 | 441 | 519 | 651 |
| Broad (All Levels) | 499 – 573 °/s | 329 | 382 | 437 | 499 | 573 |
## Use Cases
* Lower body power assessment
* Kinematic sequence analysis
# Peak Trunk Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/peak-trunk-angular-velocity
Maximum angular velocity (twist speed) of the trunk segment during the pitch.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_trunk_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum angular velocity of trunk segment
* **Typical Range:** 639 – 764 °/s
* **Optimal Direction:** Higher is better
## Description
Peak trunk angular velocity measures the maximum angular velocity (twist speed) of the trunk segment during the pitch, indicating the peak rotational speed of the core.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 726 – 773 °/s | 557 | 627 | 686 | 726 | 773 |
| High School | 757 – 786 °/s | 588 | 636 | 695 | 757 | 786 |
| College | 804 – 848 °/s | 622 | 671 | 742 | 804 | 848 |
| Professional | 783 – 838 °/s | 523 | 628 | 699 | 783 | 838 |
| Broad (All Levels) | 764 – 819 °/s | 574 | 639 | 700 | 764 | 819 |
## Use Cases
* Core power assessment
* Kinematic sequence analysis
# Pelvis Angle to Plate Coil
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-coil
Max pelvis rotation angle away from home plate.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `pelvis_angle_to_plate_coil`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum pelvis rotation (twist) angle away from home plate prior to delivery
* **Reference:** 0° = facing home plate
* **Typical Range:** 109 – 128 °
* **Optimal Direction:** Higher is better
## Description
Pelvis angle to plate coil measures the maximum pelvis rotation angle away from home plate prior to delivery, where facing home plate is 0 degrees.
This represents the coil or loading phase of the pelvis.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 126 – 136 ° | 103 | 111 | 117 | 126 | 136 |
| High School | 129 – 138 ° | 104 | 112 | 120 | 129 | 138 |
| College | 128 – 138 ° | 105 | 110 | 119 | 128 | 138 |
| Professional | 124 – 132 ° | 81 | 94 | 104 | 124 | 132 |
| Broad (All Levels) | 128 – 137 ° | 100 | 109 | 118 | 128 | 137 |
## Use Cases
* Rotation analysis
* Mechanics evaluation
# Pelvis Angle to Plate Foot Contact
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-foot-contact
Pelvis rotation angle relative to home plate at foot contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `pelvis_angle_to_plate_foot_contact`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Pelvis rotation (twist or transverse) angle
* **Reference:** 0° = facing home plate
* **Timing:** At foot contact event
* **Typical Range:** 61 – 86 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Pelvis angle to plate foot contact measures the pelvis rotation angle relative to home plate at the instant of lead foot contact, where facing home plate is 0 degrees.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 73 – 95 ° | 62 | 73 | 84 | 95 | 105 |
| High School | 64 – 86 ° | 55 | 64 | 71 | 86 | 100 |
| College | 54 – 76 ° | 48 | 54 | 65 | 76 | 84 |
| Professional | 46 – 75 ° | 37 | 46 | 62 | 75 | 82 |
| Broad (All Levels) | 61 – 86 ° | 49 | 61 | 72 | 86 | 97 |
## Use Cases
* Pelvis position assessment
* Timing evaluation
# Pelvis Angle to Plate Release
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/pelvis-angle-to-plate-release
Pelvis rotation angle relative to home plate at ball release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `pelvis_angle_to_plate_release`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Pelvis rotation (twist or transverse) angle at ball release
* **Reference:** 0° = facing home plate
* **Timing:** At ball release event
* **Typical Range:** 11 – 25 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Pelvis angle to plate release measures the pelvis rotation angle relative to home plate at the instant of ball release, where facing home plate is 0 degrees.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 13 – 27 ° | 1 | 13 | 19 | 27 | 36 |
| High School | 11 – 24 ° | 1 | 11 | 17 | 24 | 31 |
| College | 10 – 25 ° | 0 | 10 | 19 | 25 | 32 |
| Professional | 8 – 27 ° | -4 | 8 | 15 | 27 | 37 |
| Broad (All Levels) | 11 – 25 ° | 0 | 11 | 18 | 25 | 34 |
## Use Cases
* Pelvis position assessment at release
* Timing evaluation
# Pelvis to Trunk Speed Up
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/pelvis-to-trunk-speed-up
Ratio (multiplication factor) of speed increase from pelvis to trunk.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio
* **Column Name:** `pelvis_to_trunk_velocity_speedup`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Peak trunk velocity / Peak pelvis velocity
* **Optimal Range:** 1.5+
* **Typical Range:** 1.41 – 1.76
* **Optimal Direction:** Higher is better
## Description
Pelvis to trunk speed up measures the multiplication factor of velocity increase from the pelvis to the trunk peak angular velocities.
This metric broadly indicates the efficiency of power transfer from the lower body to the core.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 1.75 – 2.02 | 1.29 | 1.43 | 1.57 | 1.75 | 2.02 |
| High School | 1.75 – 1.97 | 1.21 | 1.39 | 1.56 | 1.75 | 1.97 |
| College | 1.77 – 2.04 | 1.29 | 1.45 | 1.57 | 1.77 | 2.04 |
| Professional | 1.84 – 2.13 | 1.14 | 1.41 | 1.57 | 1.84 | 2.13 |
| Broad (All Levels) | 1.76 – 2.03 | 1.23 | 1.41 | 1.57 | 1.76 | 2.03 |
## Use Cases
* Power transfer analysis
* Kinetic chain efficiency
# Stride Length
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/stride-length
Length of stride as percentage of athlete height.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** % of height
* **Column Name:** `stride_length`
* **Aggregation:** mean
* **Precision:** 0
* **Calculation:** Distance between rear foot at max knee raise and front foot at foot contact, normalized by height
* **Typical Range:** 81 – 105 %
* **Optimal Direction:** Higher is better
## Description
Stride length measures the length of the stride as a percentage of the athlete's height.
It is calculated as the distance between the rear foot position at max knee raise and the front foot position at foot contact, normalized by the athlete's height.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 87 – 96 % | 69 | 74 | 80 | 87 | 96 |
| High School | 104 – 108 % | 75 | 82 | 92 | 104 | 108 |
| College | 106 – 112 % | 88 | 93 | 101 | 106 | 112 |
| Professional | 121 – 135 % | 85 | 94 | 110 | 121 | 135 |
| Broad (All Levels) | 105 – 113 % | 73 | 81 | 92 | 105 | 113 |
## Use Cases
* Stride analysis
* Mechanics evaluation
# Sway
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/sway
Binary indicator of excessive forwards/backwards motion of the body around the max knee raise event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `sway`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Position of front knee, head midpoint, or body center of mass relative to back leg
* **Threshold:** 15 cm (\~6 in) of forward/backward movement in the 0.4 s around max knee raise event
## Description
Sway is a binary indicator that flags excessive backwards body motion (away from home plate) around max knee raise.
Occurs if the pelvis keypoint (center of the hips) moves backwards more than 15 cm (\~6 in)
## Use Cases
* Balance analysis
* Movement efficiency assessment
* Stability evaluation
## Corrective Drills
### 1. Balance Beam Knee Raise
Stand on a 2×4 or balance beam oriented toward the plate. Perform the leg lift and hold at max knee raise for 2–3 seconds without wobbling forward or backward. This isolates the balance component and makes any sway immediately apparent through loss of footing. Perform 3 sets of 10 reps.
[Search YouTube: baseball pitching balance drill knee raise sway fix](https://www.youtube.com/results?search_query=baseball+pitching+balance+drill+knee+raise+sway+fix)
### 2. Dowel Rod Posture Check
Hold a dowel or PVC pipe vertically against the back (touching head, upper back, and tailbone). Perform slow-motion pitching reps and monitor whether the dowel stays vertical through the knee raise. Swaying backward will cause the rod to tilt, giving instant tactile feedback. Perform 15–20 reps.
[Search YouTube: baseball pitching dowel rod posture drill balance](https://www.youtube.com/results?search_query=baseball+pitching+dowel+rod+posture+drill+balance+mechanics)
### 3. Hip Hinge Load Drill
Rather than initiating with a backward weight shift, practice loading directly into the back hip by hinging (pushing the back hip out laterally) while keeping the pelvis centered over the back foot. This trains forward-neutral momentum from initiation to max knee raise without the backward sway. Perform 20 reps before bullpen or live throwing.
[Search YouTube: baseball pitching hip hinge load drill balance sway](https://www.youtube.com/results?search_query=baseball+pitching+hip+hinge+load+drill+balance+sway+fix)
# Time to Release
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/time-to-release
Time from initiation to ball release. This measures the total duration of the pitching motion.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s)
* **Column Name:** `time_to_release`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Ball release time - Initiation time
* **Typical Range:** 1.12 – 1.35 s
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Time to release measures the total duration of the pitching motion from initiation to ball release, indicating the overall timing of the pitch from first movement to release.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 1.07 – 1.33 s | 1.00 | 1.07 | 1.21 | 1.33 | 1.46 |
| High School | 1.20 – 1.39 s | 1.12 | 1.20 | 1.28 | 1.39 | 1.53 |
| College | 1.11 – 1.31 s | 1.07 | 1.11 | 1.23 | 1.31 | 1.40 |
| Professional | 0.97 – 1.30 s | 0.55 | 0.97 | 1.18 | 1.30 | 1.43 |
| Broad (All Levels) | 1.12 – 1.35 s | 1.02 | 1.12 | 1.24 | 1.35 | 1.48 |
## Use Cases
* Pitch timing analysis
# Trunk Angle to Plate Coil
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-coil
Maximum trunk rotation angle away from home plate.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_angle_to_plate_coil`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum trunk rotation away from home plate prior to delivery
* **Reference:** 0° = facing home plate
* **Typical Range:** 112 – 132 °
* **Optimal Direction:** Higher is better
## Description
Trunk angle to plate coil measures the maximum trunk rotation angle away from home plate prior to delivery, where facing home plate is 0 degrees.
This represents the coil or loading phase of the trunk.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 131 – 140 ° | 103 | 112 | 123 | 131 | 140 |
| High School | 133 – 143 ° | 107 | 117 | 125 | 133 | 143 |
| College | 133 – 139 ° | 111 | 118 | 126 | 133 | 139 |
| Professional | 119 – 135 ° | 86 | 100 | 110 | 119 | 135 |
| Broad (All Levels) | 132 – 140 ° | 102 | 112 | 123 | 132 | 140 |
## Use Cases
* Trunk loading assessment
* Rotation analysis
# Trunk Angle to Plate Foot Contact
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-foot-contact
Trunk rotation angle relative to home plate at foot contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_angle_to_plate_foot_contact`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Trunk rotation (twist or transverse) angle at foot contact
* **Reference:** 0° = facing home plate
* **Timing:** At foot contact event
* **Typical Range:** 71 – 105 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Trunk angle to plate foot contact measures the trunk rotation angle relative to home plate at the instant of lead foot contact, where facing home plate is 0 degrees.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 87 – 115 ° | 72 | 87 | 101 | 115 | 126 |
| High School | 75 – 107 ° | 59 | 75 | 90 | 107 | 120 |
| College | 69 – 95 ° | 59 | 69 | 81 | 95 | 106 |
| Professional | 51 – 82 ° | 27 | 51 | 70 | 82 | 95 |
| Broad (All Levels) | 71 – 105 ° | 53 | 71 | 88 | 105 | 116 |
## Use Cases
* Trunk position assessment at foot contact
* Timing evaluation
# Trunk Angle to Plate Release
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/trunk-angle-to-plate-release
Trunk rotation angle relative to home plate at ball release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_angle_to_plate_release`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Trunk rotation (twist or transverse) angle at ball release
* **Reference:** 0° = facing home plate
* **Timing:** At ball release event
* **Typical Range:** -17 – -5 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Trunk angle to plate release measures the trunk rotation angle relative to home plate at the instant of ball release, where facing home plate is 0 degrees.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | -18 – -3 ° | -23 | -18 | -12 | -3 | 5 |
| High School | -16 – -5 ° | -23 | -16 | -11 | -5 | -1 |
| College | -15 – -6 ° | -22 | -15 | -11 | -6 | 2 |
| Professional | -17 – -5 ° | -25 | -17 | -11 | -5 | 0 |
| Broad (All Levels) | -17 – -5 ° | -23 | -17 | -11 | -5 | 2 |
## Use Cases
* Trunk position assessment at release
* Rotation evaluation
# Trunk Forward Tilt (Release)
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/trunk-forward-tilt-at-ball-release
Forward trunk tilt at ball release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_forward_tilt_at_ball_release`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Sagittal plane trunk angle relative to the global coordinate system
* **Timing:** At ball release event
* **Typical Range:** 20 – 32 °
* **Optimal Direction:** Higher is better
## Description
Trunk forward tilt at ball release measures the forward lean of the trunk at the instant of ball release during the pitch.
This is an indicator of body position at a critical point in time, useful for measuring proper positioning and consistency.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 28 – 33 ° | 14 | 19 | 25 | 28 | 33 |
| High School | 32 – 36 ° | 14 | 20 | 27 | 32 | 36 |
| College | 34 – 39 ° | 18 | 25 | 29 | 34 | 39 |
| Professional | 34 – 42 ° | 13 | 18 | 27 | 34 | 42 |
| Broad (All Levels) | 32 – 37 ° | 14 | 20 | 27 | 32 | 37 |
## Use Cases
* Trunk position assessment at release
* Posture evaluation
# Trunk Lateral Tilt at Release
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-ball-release
Lateral (left/right) trunk tilt at ball release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_lateral_tilt_at_ball_release`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Frontal plane trunk angle relative to the global coordinate system
* **Timing:** At ball release event
* **Typical Range:** 9 – 21 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Trunk lateral tilt at ball release measures the side-to-side (left/right) tilt of the trunk at the instant of ball release during the pitch.
This is an indicator of body position at a critical point in time, useful for measuring proper positioning and consistency.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 10 – 23 ° | 5 | 10 | 16 | 23 | 28 |
| High School | 10 – 21 ° | 4 | 10 | 15 | 21 | 25 |
| College | 8 – 21 ° | 3 | 8 | 15 | 21 | 26 |
| Professional | 5 – 18 ° | -2 | 5 | 13 | 18 | 22 |
| Broad (All Levels) | 9 – 21 ° | 4 | 9 | 15 | 21 | 26 |
## Use Cases
* Trunk alignment assessment at release
* Posture evaluation
# Trunk Lateral Tilt (Foot Contact)
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/trunk-lateral-tilt-at-foot-contact
Lateral (left-right) trunk tilt at foot contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_lateral_tilt_at_foot_contact`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Frontal plane trunk angle relative to the global coordinate system
* **Timing:** At foot contact event
* **Typical Range:** -7 – 3 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Trunk lateral tilt at foot contact measures the side-to-side (left/right) tilt of the trunk at the instant of front foot contact during the pitch.
This is an indicator of body position at a critical point in time, useful for measuring proper positioning and consistency.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | -8 – -2 ° | -11 | -8 | -5 | -2 | 1 |
| High School | -7 – 0 ° | -10 | -7 | -3 | 0 | 8 |
| College | -4 – 4 ° | -8 | -4 | 1 | 4 | 8 |
| Professional | -4 – 11 ° | -10 | -4 | 5 | 11 | 16 |
| Broad (All Levels) | -7 – 3 ° | -10 | -7 | -3 | 3 | 9 |
## Use Cases
* Trunk alignment assessment at foot contact
* Posture evaluation
# Trunk to Arm Speed Up
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/trunk-to-arm-speed-up
Ratio (multiplication factor) of speed increase from trunk to arm.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio
* **Column Name:** `trunk_to_arm_velocity_speedup`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Peak arm angular velocity / Peak trunk angular velocity
* **Optimal Range:** 1.7+
* **Typical Range:** 1.64 – 1.99
* **Optimal Direction:** Higher is better
## Description
Trunk to arm speed up measures the multiplication factor of velocity increase from the trunk to the arm, indicating the efficiency of power transfer through the kinetic chain.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 1.89 – 2.10 | 1.41 | 1.57 | 1.72 | 1.89 | 2.10 |
| High School | 1.92 – 2.12 | 1.50 | 1.64 | 1.82 | 1.92 | 2.12 |
| College | 2.02 – 2.23 | 1.57 | 1.71 | 1.86 | 2.02 | 2.23 |
| Professional | 2.13 – 2.60 | 1.64 | 1.75 | 1.97 | 2.13 | 2.60 |
| Broad (All Levels) | 1.99 – 2.21 | 1.48 | 1.64 | 1.82 | 1.99 | 2.21 |
## Use Cases
* Power transfer analysis
* Kinetic chain efficiency
# Wrist Position to Lead Toe
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/wrist-fore-aft-lead-toe-at-release
Wrist fore/aft position relative to the lead toe at release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `wrist_fore_aft_lead_toe_at_release`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Wrist fore/aft position relative to lead toe at release
* **Reference:** Positive = in front of toe, Negative = behind toe
* **Timing:** At ball release event
* **Typical Range:** -6.0 – 0.3 in (-0.153 – 0.008 m)
* **Optimal Direction:** Higher is better
## Description
Wrist position to lead toe measures the fore/aft position of the wrist relative to the lead toe at the instant of ball release.
Positive values indicate the wrist is in front of the toe, while negative values indicate it is behind.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :---: | :--: | :--: | :--: | :--: |
| Youth | 0.3 – 2.4 in | -8.7 | -3.8 | -1.3 | 0.3 | 2.4 |
| High School | -0.4 – 3.2 in | -8.9 | -5.1 | -2.4 | -0.4 | 3.2 |
| College | -0.7 – 2.2 in | -12.6 | -7.4 | -4.4 | -0.7 | 2.2 |
| Professional | 2.6 – 9.1 in | -9.8 | -6.2 | -1.4 | 2.6 | 9.1 |
| Broad (All Levels) | -6.0 – 3.2 in | -10.7 | -6.0 | -2.3 | 0.3 | 3.2 |
## Use Cases
* Release position assessment
* Mechanics analysis
# Wrist Height at Release
Source: https://docs.uplift.ai/biomechanics/activities/baseball/pitching/metrics/wrist-height-at-release
Wrist height above the mound at release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `wrist_height_at_release`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Wrist vertical position at release
* **Reference:** Relative to rear toe height at pitch start (estimating mound height)
* **Timing:** At ball release event
* **Typical Range:** 37.1 – 45.8 in (0.942 – 1.164 m)
* **Optimal Direction:** Higher is better
## Description
Wrist height at release measures the vertical position of the wrist at the instant of ball release, relative to the rear toe height at the start of the pitch (used as a proxy for mound level).
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 39.6 – 43.5 in | 31.5 | 33.9 | 37.3 | 39.6 | 43.5 |
| High School | 44.9 – 47.8 in | 35.0 | 38.9 | 42.5 | 44.9 | 47.8 |
| College | 47.1 – 53.1 in | 34.6 | 37.8 | 42.0 | 47.1 | 53.1 |
| Professional | 58.1 – 75.0 in | 40.6 | 44.4 | 50.4 | 58.1 | 75.0 |
| Broad (All Levels) | 45.8 – 52.6 in | 33.0 | 37.1 | 41.1 | 45.8 | 52.6 |
## Use Cases
* Release height assessment
# Basketball: Free Throw
Source: https://docs.uplift.ai/biomechanics/activities/basketball/free_throw
Biomechanical analysis of basketball free throw movements, including events, phases, and discrete metrics.
## Overview
The free throw (foul shot) is an uncontested shot taken from the free throw line after certain fouls. The shooter stands behind the line, receives the ball from the official, and may use a self-paced routine before releasing the ball.
Because the context is standardized (no defender, fixed distance and target), the free throw is often used to assess shooting technique and consistency under low time pressure.
Successful free throw mechanics typically include a repeatable pre-shot routine, consistent lower-body contribution (leg drive and balance), aligned shooting arm (elbow under the ball, wrist snap), and a stable release and follow-through.
Variability in timing, posture, or release from one attempt to the next is associated with lower accuracy.
Biomechanical analysis of the free throw can focus on routine consistency, alignment and sequencing from legs through release, release angle and backspin, and between-shot variability.
## Dimensions
Required inputs for processing are not yet defined. When supported, typical dimensions may include:
* **handedness:** the handedness of the shooter \['left', 'right']
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Data Type | Acronym | Description |
| ------ | --------- | ------- | ----------- |
### Discrete Metrics
| Metric | Data Type | Units | Description |
| ------ | --------- | ----- | ----------- |
| | | | |
## Notes
* Events and metrics are placeholders; definitions will be added in a future update.
# Basketball: Jump Shot
Source: https://docs.uplift.ai/biomechanics/activities/basketball/jump_shot
Biomechanical analysis of basketball jump shot movements, including events, phases, and discrete metrics.
## Overview
The jump shot is a fundamental shooting technique in basketball in which the player releases the ball at the peak of a vertical jump (or on the way up), using the legs to generate force and the arms and wrists to control release angle, backspin, and trajectory. It is the primary scoring weapon from mid-range and beyond the arc. Effective jump shots rely on consistent lower-body drive (knee and hip extension), a stable core, aligned shooting elbow and wrist, and a repeatable release point and follow-through. Variants include the set shot (minimal jump), pull-up (off the dribble), and catch-and-shoot; mechanics may differ with distance, defensive pressure, and shot type.
Biomechanical analysis of the jump shot can address timing of the jump and release, alignment of the shooting side (shoulder–elbow–wrist–ball), lower- and upper-body sequencing, and consistency of release and follow-through. Events and discrete metrics for the jump shot are not yet defined in this documentation and will be added when available.
## Dimensions
Required inputs for processing are not yet defined. When supported, typical dimensions may include:
* **handedness:** the handedness of the shooter \['left', 'right']
* **shot type or context:** e.g., catch-and-shoot, pull-up, if applicable
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Data Type | Acronym | Description |
| ------ | --------- | ------- | ----------- |
| | | | |
### Discrete Metrics
| Metric | Data Type | Units | Description |
| ------ | --------- | ----- | ----------- |
| | | | |
## Notes
* Events and metrics are placeholders; definitions will be added in a future update.
# Basketball: Layup
Source: https://docs.uplift.ai/biomechanics/activities/basketball/layup
Biomechanical analysis of basketball layup movements, including events, phases, and discrete metrics.
## Overview
The layup is a close-range shot in which the player drives toward the basket and releases the ball off the backboard (or directly through the rim), typically with one hand, after one or more steps.
It is a fundamental finishing move and is performed from various angles (e.g., right-hand layup from the right side, left-hand from the left) and with different footwork (e.g., one-step, two-step, Euro step).
Key biomechanical elements include approach speed and angle, takeoff from one or both feet, body control and protection of the ball, release hand and timing relative to peak height or descent, and use of the backboard for angle and spin. Layups can be contested, so arm extension, body positioning, and release height are often analyzed for success and injury risk.
Biomechanical analysis of the layup can address approach and plant, takeoff and flight, release timing and hand placement, and landing.
## Dimensions
Required inputs for processing are not yet defined. When supported, typical dimensions may include:
* **handedness:** the handedness of the player \['left', 'right']
* **layup hand or side:** e.g., right-hand vs left-hand layup, if applicable
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Data Type | Acronym | Description |
| ------ | --------- | ------- | ----------- |
### Phases and Stages
| Phase | Start | End |
| ----- | ----- | --- |
| | | |
### Discrete Metrics
| Metric | Data Type | Units | Description |
| ------ | --------- | ----- | ----------- |
| | | | |
## Detailed Documentation
### Events
### Metrics
## Notes
* Events and metrics are placeholders; definitions will be added in a future update.
# Running
Source: https://docs.uplift.ai/biomechanics/activities/gait/running
Biomechanical analysis of running gait, including stride patterns, ground contact phases, and joint kinematics.
## Overview
Running gait analysis evaluates the biomechanics of running motion, including stride patterns, ground contact phases, and joint kinematics during the running cycle.
![Example image of a man doing a running, top view]()
![Example image of a man doing a running, front view]()
![Example image of a man doing a running, quarter view]()
![Example image of a man doing a running, side view]()
## Instructions
Run at a consistent, natural pace on a flat surface or treadmill.
Maintain normal running form without consciously altering your stride.
Multiple consecutive strides will be captured and analyzed.
## Variables
Output Variables for running gait analysis:
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Data Type | Description |
| ----------------- | --------- | ------------------------------------------------------- |
| Right Heel Strike | Int | when the right heel contacts the ground |
| Right Toe Off | Int | when the right toe leaves the ground |
| Left Heel Strike | Int | when the left heel contacts the ground |
| Left Toe Off | Int | when the left toe leaves the ground |
| Right Mid Stance | Int | the instant of maximum right knee flexion during stance |
| Left Mid Stance | Int | the instant of maximum left knee flexion during stance |
| Right Mid Swing | Int | the instant of maximum right knee flexion during swing |
| Left Mid Swing | Int | the instant of maximum left knee flexion during swing |
### Phases and Stages of Gait
| Phase | Stage | Start | End | Event or Phase |
| ------------ | --------------- | ----------------- | ----------------- | -------------- |
| Right Stance | Initial Contact | Right Heel Strike | Right Mid Stance | Phase |
| Right Stance | Terminal Stance | Right Mid Stance | Right Toe Off | Phase |
| Right Swing | Initial Swing | Right Toe Off | Right Mid Swing | Phase |
| Right Swing | Terminal Swing | Right Mid Swing | Left Heel Strike | Phase |
| Left Stance | Initial Contact | Left Heel Strike | Left Mid Stance | Phase |
| Left Stance | Terminal Stance | Left Mid Stance | Left Toe Off | Phase |
| Left Swing | Initial Swing | Left Toe Off | Left Mid Swing | Phase |
| Left Swing | Terminal Swing | Left Mid Swing | Right Heel Strike | Phase |
### Discrete Metrics
| Metric | Data Type | Units | Description |
| ------------------------------ | --------- | --------- | --------------------------------------------------------- |
| Step Length | Float | meters | Distance between heel strikes |
| Step Width | Float | meters | Lateral distance between feet |
| Stride Length | Float | meters | Distance between same foot heel strikes |
| Cadence | Float | steps/min | Number of steps per minute |
| Walking Speed | Float | m/s | Average walking speed |
| Step Time | Float | seconds | Time between heel strikes |
| Stride Time | Float | seconds | Time between same foot heel strikes |
| Stance Time | Float | seconds | Time foot is in contact with ground |
| Swing Time | Float | seconds | Time foot is not in contact with ground |
| Double Support Time | Float | seconds | Time both feet are in contact with ground |
| Single Support Time | Float | seconds | Time only one foot is in contact with ground |
| Knee Flexion | Float | degrees | Maximum knee flexion during gait cycle |
| Hip Flexion | Float | degrees | Maximum hip flexion during gait cycle |
| Ankle Dorsiflexion | Float | degrees | Maximum ankle dorsiflexion during gait cycle |
| Ground Reaction Force | Float | N | Maximum ground reaction force |
| Joint Angles at Peak Force | Float | degrees | Joint angles at instant of peak ground reaction force |
| Joint Velocities at Peak Force | Float | degrees/s | Joint velocities at instant of peak ground reaction force |
| Symmetry Index | Float | % | Comparison of left and right side parameters |
## Notes
* Kinematic data typically captured at 240Hz for Running Analysis
# Gait: Walking
Source: https://docs.uplift.ai/biomechanics/activities/gait/walking
Biomechanical analysis of walking gait, including stride patterns, ground contact phases, and joint kinematics.
## Overview
Walking gait analysis evaluates the biomechanics of walking motion, including stride patterns, ground contact phases, and joint kinematics during the walking cycle.
![Example image of a man doing a gait walking]()
## Dimensions
Required Inputs for processing:
* **surface:** the type of ground on which the person walks \['treadmill', 'other']
## Instructions
Walk at a comfortable, natural pace on a flat surface or treadmill.
Maintain normal walking form without consciously altering your gait.
Multiple consecutive strides will be captured and analyzed.
## Variables
Output Variables for gait analysis:
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Event | Description | Column Name |
| ----------------- | ------------------------------------------------- | ----------- |
| Right Foot Strike | when the right foot initially contacts the ground | - |
| Right Foot Off | when the right foot leaves the ground | - |
| Left Foot Strike | when the left foot contacts the ground | - |
| Left Foot Off | when the left toe leaves the ground | - |
### Phases and Stages of Gait Walking
| Phase | Start | End | Description |
| ----------------------- | -------------------- | -------------------- | ----------------------------------------------------------------------------------------------------------- |
| Stance | Foot Strike | Foot Off | the period between foot strike and foot off, when the foot is in contact with the ground |
| Swing | Foot Off | Foot Strike | the period between foot off and foot strike, when the foot is not in contact with the ground |
| Leading Double Support | Foot Strike | Opposite Foot Off | when both feet are in contact with the ground and the step side is in early stance (just after foot strike) |
| Single Limb Support | Opposite Foot Off | Opposite Foot Strike | when only one foot is in contact with the ground |
| Trailing Double Support | Opposite Foot Strike | Foot Off | when both feet are in contact with the ground and the step side is in late stance (just before foot off) |
### Discrete Metrics
| Metric | Data Type | Units | Description |
| ------------------------------- | --------- | ------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| Percent Gait Cycle Left | Float | % | Relative percent of the gait cycle (left foot strike to left foot strike) |
| Percent Gait Cycle Right | Float | % | Relative percent of the gait cycle (right foot strike to right foot strike) |
| Side | String | N/A | Side of the Gait Cycle \['left', 'right'] |
| Side Gait Cycle Number | Int | number | Gait cycle index for the trial. Left and Right gait cycles are counted separately |
| Opposite Foot Off Percent | Float | % | Relative % of the gait cycle at which the opposite foot off event occurs |
| Opposite Foot Strike Percent | Float | % | Relative % of the gait cycle at which the opposite foot strike event occurs |
| Stance Percent | Float | % | Relative % duration of the gait cycle for stance phase |
| Swing Percent | Float | % | Relative % duration of the gait cycle for swing phase |
| Stride Duration | Float | seconds | Time between same-side heel strikes |
| Walking Speed | Float | m/s | Average walking speed for the gait cycle |
| Stride Length | Float | meters | Distance between same foot heel strikes |
| Step Width | Float | meters | Side-side distance between feet |
| Step Length | Float | meters | Distance travelled between contralateral heel strikes |
| Ankle Push Off Range of Motion | Float | Degrees | The functional amount of ankle extension used during push off, range of motion from peak flexion during stance to extension angle at foot off event. Does not consider follow through extension when the foot is no longer in contact with the ground. |
| Knee Absorption Range of Motion | Float | Degrees | The functional amount of knee flexion used during weight acceptance, range of motion from foot strike event until peak flexion angle in the first half of stance phase. |
| Foot Progression Angle | Float | Degrees | The outward rotation of the foot (transverse plane) relative to the direction of walking. |
## Notes
* Kinematic data typically captured at 120Hz for Walking Analysis
# Golf: Swing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing
Data-driven golf swing analysis that reveals the posture, timing, and sequencing faults holding back consistency and power, so golfers and coaches know exactly what to work on.
![Example image of a golf swing]()
A repeatable swing is what separates consistent ball-striking from a round full of surprises.
Uplift breaks the swing down frame-by-frame using the [P Classification System](https://www.thediygolfer.com/swing-positions), tracking how the pelvis, trunk, and arms sequence power from Address through Finish.
Surfacing faults like sway, early extension, or a reverse spine angle turns a vague "something feels off" into specific, coachable fixes.
Quantifying tempo and rotational power over time can track subtle and long-term changes in efficiency and consistency.
## Dimensions
Required Inputs for processing:
* **handedness:** the handedness of the athlete \['left', 'right']
## Variables
Output variables from golf swing analysis.
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
Identify specific time points during the swing, anchored to the P Classification System used by golf instructors worldwide (P1 Address through P10 Finish), plus supporting events used to detect them.
| Event | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------- | ------------------------------------ |
| [P1 Address](/biomechanics/activities/golf/swing/events/p1-address) | Static setup position immediately before the swing begins. | `p1_address_frame` |
| [P2 Takeaway](/biomechanics/activities/golf/swing/events/p2-takeaway) | Start of the swing; trunk has rotated more than 20° from Address. | `p2_takeaway_frame` |
| [P3 Mid Backswing](/biomechanics/activities/golf/swing/events/p3-mid-backswing) | Hands rise above the elbows on the way to the top of the backswing. | `p3_mid_backswing_frame` |
| [P4 Top of Swing](/biomechanics/activities/golf/swing/events/p4-top-of-swing) | Highest hand position of the backswing, just before the downswing transition. | `p4_top_of_swing_frame` |
| [P5 Transition](/biomechanics/activities/golf/swing/events/p5-transition) | Swing changes direction from backswing to downswing. | `p5_transition_frame` |
| [P6 Pre-Impact](/biomechanics/activities/golf/swing/events/p6-pre-impact) | Moment just before impact; lead wrist closest to the trail hip. | `p6_pre_impact_frame` |
| [P7 Impact](/biomechanics/activities/golf/swing/events/p7-impact) | The moment of ball contact — "the moment of truth." | `p7_impact_frame` |
| [P8 Release](/biomechanics/activities/golf/swing/events/p8-release) | Moment just after impact; continued rotation through the shot. | `p8_release_frame` |
| [P9 Follow Through](/biomechanics/activities/golf/swing/events/p9-follow-through) | Hands rise back above the elbows after impact. | `p9_follow_through_frame` |
| [P10 Finish](/biomechanics/activities/golf/swing/events/p10-finish) | Final, balanced finish position of the swing. | `p10_finish_frame` |
| [Max X-Factor](/biomechanics/activities/golf/swing/events/max-x-factor) | Frame of maximum hip-shoulder separation during the swing. | `max_x_factor_frame` |
| [X-Factor Zero Crossing](/biomechanics/activities/golf/swing/events/x-factor-zero-crossing) | Hip-shoulder separation returns to zero after its steepest rise. | `x_factor_zero_crossing_frame` |
| [Min X-Factor](/biomechanics/activities/golf/swing/events/min-x-factor) | Frame of minimum hip-shoulder separation, used to bound Low Hands. | \`\` |
| [Low Hands](/biomechanics/activities/golf/swing/events/low-hands) | Lowest hand position during the downswing. | \`\` |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/golf/swing/events/peak-pelvis-angular-velocity) | Instant of pelvis peak rotational velocity. | `peak_pelvis_angular_velocity_frame` |
| [Peak Trunk Angular Velocity](/biomechanics/activities/golf/swing/events/peak-trunk-angular-velocity) | Instant of trunk peak rotational velocity. | `peak_trunk_angular_velocity_frame` |
| [Peak Arm Angular Velocity](/biomechanics/activities/golf/swing/events/peak-arm-angular-velocity) | Instant of lead arm peak rotational velocity. | `peak_arm_angular_velocity_frame` |
### Movement Flags
Identify poor or suboptimal mechanics and posture faults during the swing.
| Metric | Short Description | Column Name |
| ------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------- | --------------------- |
| [Loss of Posture](/biomechanics/activities/golf/swing/flags/loss-of-posture) | Mid-shoulder or mid-pelvis position shifts more than 10 cm from Address. | `loss_of_posture` |
| [Early Extension](/biomechanics/activities/golf/swing/flags/early-extension) | Pelvis moves toward the ball by more than 10 cm during the swing. | `early_extension` |
| [Reverse Spine Angle](/biomechanics/activities/golf/swing/flags/reverse-spine-angle) | Mid-shoulder moves in front of mid-pelvis by more than 5 cm during the backswing. | `reverse_spine_angle` |
| [Sway](/biomechanics/activities/golf/swing/flags/sway) | Pelvis shifts laterally away from the target by more than 10 cm. | `sway` |
| [Chicken Wing](/biomechanics/activities/golf/swing/flags/chicken-wing) | Lead elbow bends more than 20° at impact. | `chicken_wing` |
| [Hang Back](/biomechanics/activities/golf/swing/flags/hang-back) | Pelvis stays more than 5 cm behind its Address position at Impact. | `hang_back` |
| [Slide](/biomechanics/activities/golf/swing/flags/slide) | Lead knee or hip shifts more than 5 cm toward the target during the downswing. | `slide` |
### Kinematic Sequence
Order and magnitude of pelvis, trunk, and lead-arm peak rotational velocity during the downswing.
| Metric | Units | Short Description | Column Name |
| ---------------------------------------------------------------------------------------- | ----- | ------------------------------------------------------------------------------- | ------------------------------ |
| [Kinematic Sequence](/biomechanics/activities/golf/swing/metrics/kinematic-sequence) | N/A | Order of peak segment angular velocities. Optimal sequence is pelvis-trunk-arm. | `kinematic_sequence` |
| [Peak Pelvis Velocity](/biomechanics/activities/golf/swing/metrics/peak-pelvis-velocity) | deg/s | Max rotational speed of the pelvis during the downswing. | `peak_pelvis_angular_velocity` |
| [Peak Trunk Velocity](/biomechanics/activities/golf/swing/metrics/peak-trunk-velocity) | deg/s | Max rotational speed of the trunk during the downswing. | `peak_trunk_angular_velocity` |
| [Peak Arm Velocity](/biomechanics/activities/golf/swing/metrics/peak-arm-velocity) | deg/s | Max rotational speed of the lead arm during the downswing. | `peak_arm_angular_velocity` |
### X-Factor & Timing
Hip-shoulder separation and swing timing metrics.
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------ | ----- | ---------------------------------------------------------------- | ----------------------------- |
| [Pre-Load Max X-Factor](/biomechanics/activities/golf/swing/metrics/pre-load-max-x-factor) | deg | Max hip-shoulder separation between Address and Impact. | `pre_load_max_x_factor` |
| [Follow-Through Max X-Factor](/biomechanics/activities/golf/swing/metrics/follow-through-max-x-factor) | deg | Max hip-shoulder separation between Impact and Finish. | `follow_through_max_x_factor` |
| [Upswing Duration](/biomechanics/activities/golf/swing/metrics/upswing-duration) | s | Duration from Takeaway to Top of Swing. | `upswing_duration` |
| [Downswing Duration](/biomechanics/activities/golf/swing/metrics/downswing-duration) | s | Duration from Top of Swing to Impact. | `downswing_duration` |
| [Dynamic Tempo Ratio](/biomechanics/activities/golf/swing/metrics/dynamic-tempo-ratio) | ratio | Ratio of downswing duration to upswing duration. | `dynamic_tempo_ratio` |
| [Pelvis Sway Range](/biomechanics/activities/golf/swing/metrics/pelvis-sway-range) | m | Range of lateral pelvis displacement between Address and Impact. | `pelvis_sway_range` |
### Shoulder Angles at Key Events
Lead and trail shoulder flexion and tilt relative to the trunk, sampled at Address, Top of Swing, and Impact.
| Metric | Units | Short Description | Column Name |
| ---------------------------------------------------------------------------------------------------------------------------------- | ----- | ---------------------------------------------------------------------- | ------------------------------ |
| [Lead Shoulder Flexion at P1 Address](/biomechanics/activities/golf/swing/metrics/lead-shoulder-flexion-at-p1-address) | deg | Lead shoulder flexion angle relative to the trunk at P1 Address. | `lead_shoulder_flexion_at_p1` |
| [Lead Shoulder Flexion at P4 Top of Swing](/biomechanics/activities/golf/swing/metrics/lead-shoulder-flexion-at-p4-top-of-swing) | deg | Lead shoulder flexion angle relative to the trunk at P4 Top of Swing. | `lead_shoulder_flexion_at_p4` |
| [Lead Shoulder Flexion at P7 Impact](/biomechanics/activities/golf/swing/metrics/lead-shoulder-flexion-at-p7-impact) | deg | Lead shoulder flexion angle relative to the trunk at P7 Impact. | `lead_shoulder_flexion_at_p7` |
| [Lead Shoulder Tilt at P1 Address](/biomechanics/activities/golf/swing/metrics/lead-shoulder-tilt-at-p1-address) | deg | Lead shoulder tilt angle relative to the trunk at P1 Address. | `lead_shoulder_tilt_at_p1` |
| [Lead Shoulder Tilt at P4 Top of Swing](/biomechanics/activities/golf/swing/metrics/lead-shoulder-tilt-at-p4-top-of-swing) | deg | Lead shoulder tilt angle relative to the trunk at P4 Top of Swing. | `lead_shoulder_tilt_at_p4` |
| [Lead Shoulder Tilt at P7 Impact](/biomechanics/activities/golf/swing/metrics/lead-shoulder-tilt-at-p7-impact) | deg | Lead shoulder tilt angle relative to the trunk at P7 Impact. | `lead_shoulder_tilt_at_p7` |
| [Trail Shoulder Flexion at P1 Address](/biomechanics/activities/golf/swing/metrics/trail-shoulder-flexion-at-p1-address) | deg | Trail shoulder flexion angle relative to the trunk at P1 Address. | `trail_shoulder_flexion_at_p1` |
| [Trail Shoulder Flexion at P4 Top of Swing](/biomechanics/activities/golf/swing/metrics/trail-shoulder-flexion-at-p4-top-of-swing) | deg | Trail shoulder flexion angle relative to the trunk at P4 Top of Swing. | `trail_shoulder_flexion_at_p4` |
| [Trail Shoulder Flexion at P7 Impact](/biomechanics/activities/golf/swing/metrics/trail-shoulder-flexion-at-p7-impact) | deg | Trail shoulder flexion angle relative to the trunk at P7 Impact. | `trail_shoulder_flexion_at_p7` |
| [Trail Shoulder Tilt at P1 Address](/biomechanics/activities/golf/swing/metrics/trail-shoulder-tilt-at-p1-address) | deg | Trail shoulder tilt angle relative to the trunk at P1 Address. | `trail_shoulder_tilt_at_p1` |
| [Trail Shoulder Tilt at P4 Top of Swing](/biomechanics/activities/golf/swing/metrics/trail-shoulder-tilt-at-p4-top-of-swing) | deg | Trail shoulder tilt angle relative to the trunk at P4 Top of Swing. | `trail_shoulder_tilt_at_p4` |
| [Trail Shoulder Tilt at P7 Impact](/biomechanics/activities/golf/swing/metrics/trail-shoulder-tilt-at-p7-impact) | deg | Trail shoulder tilt angle relative to the trunk at P7 Impact. | `trail_shoulder_tilt_at_p7` |
### Global Trunk & Pelvis Angles at Key Events
Trunk and pelvis flexion, tilt, and rotation relative to the global (ground) reference frame, sampled at Address, Top of Swing, and Impact.
| Metric | Units | Short Description | Column Name |
| ---------------------------------------------------------------------------------------------------------------------------------- | ----- | ---------------------------------------------------------------------- | ------------------------------ |
| [Global Trunk Flexion at P1 Address](/biomechanics/activities/golf/swing/metrics/global-trunk-flexion-at-p1-address) | deg | Trunk flexion angle relative to the global frame at P1 Address. | `global_trunk_flexion_at_p1` |
| [Global Trunk Tilt at P1 Address](/biomechanics/activities/golf/swing/metrics/global-trunk-tilt-at-p1-address) | deg | Trunk tilt angle relative to the global frame at P1 Address. | `global_trunk_tilt_at_p1` |
| [Global Pelvis Tilt at P1 Address](/biomechanics/activities/golf/swing/metrics/global-pelvis-tilt-at-p1-address) | deg | Pelvis tilt angle relative to the global frame at P1 Address. | `global_pelvis_tilt_at_p1` |
| [Global Trunk Flexion at P4 Top of Swing](/biomechanics/activities/golf/swing/metrics/global-trunk-flexion-at-p4-top-of-swing) | deg | Trunk flexion angle relative to the global frame at P4 Top of Swing. | `global_trunk_flexion_at_p4` |
| [Global Trunk Tilt at P4 Top of Swing](/biomechanics/activities/golf/swing/metrics/global-trunk-tilt-at-p4-top-of-swing) | deg | Trunk tilt angle relative to the global frame at P4 Top of Swing. | `global_trunk_tilt_at_p4` |
| [Global Trunk Rotation at P4 Top of Swing](/biomechanics/activities/golf/swing/metrics/global-trunk-rotation-at-p4-top-of-swing) | deg | Trunk rotation angle relative to the global frame at P4 Top of Swing. | `global_trunk_rotation_at_p4` |
| [Global Pelvis Tilt at P4 Top of Swing](/biomechanics/activities/golf/swing/metrics/global-pelvis-tilt-at-p4-top-of-swing) | deg | Pelvis tilt angle relative to the global frame at P4 Top of Swing. | `global_pelvis_tilt_at_p4` |
| [Global Pelvis Rotation at P4 Top of Swing](/biomechanics/activities/golf/swing/metrics/global-pelvis-rotation-at-p4-top-of-swing) | deg | Pelvis rotation angle relative to the global frame at P4 Top of Swing. | `global_pelvis_rotation_at_p4` |
| [Global Trunk Flexion at P7 Impact](/biomechanics/activities/golf/swing/metrics/global-trunk-flexion-at-p7-impact) | deg | Trunk flexion angle relative to the global frame at P7 Impact. | `global_trunk_flexion_at_p7` |
| [Global Trunk Tilt at P7 Impact](/biomechanics/activities/golf/swing/metrics/global-trunk-tilt-at-p7-impact) | deg | Trunk tilt angle relative to the global frame at P7 Impact. | `global_trunk_tilt_at_p7` |
| [Global Trunk Rotation at P7 Impact](/biomechanics/activities/golf/swing/metrics/global-trunk-rotation-at-p7-impact) | deg | Trunk rotation angle relative to the global frame at P7 Impact. | `global_trunk_rotation_at_p7` |
| [Global Pelvis Tilt at P7 Impact](/biomechanics/activities/golf/swing/metrics/global-pelvis-tilt-at-p7-impact) | deg | Pelvis tilt angle relative to the global frame at P7 Impact. | `global_pelvis_tilt_at_p7` |
| [Global Pelvis Rotation at P7 Impact](/biomechanics/activities/golf/swing/metrics/global-pelvis-rotation-at-p7-impact) | deg | Pelvis rotation angle relative to the global frame at P7 Impact. | `global_pelvis_rotation_at_p7` |
## Notes
* Kinematic data typically captured at 240Hz for Golf Swing
* All boolean variables (true/false = 1/0) return -1 if metric unable to be calculated.
# Low Hands
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/low-hands
The lowest hand position during the downswing, marking the driving point between the top of the backswing and impact.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** \`\`
* **Required for QA:** False
* **Measurement:** Minimum average wrist height between Top of Swing and Min X-Factor
* **Timing:** Between P4 Top of Swing and P7 Impact
## Description
Low Hands identifies the lowest vertical hand position during the downswing, occurring between the top of the backswing and Min X-Factor. It is used internally to detect P1 Address and P9 Follow Through.
## Use Cases
* P1 Address detection boundary
* P9 Follow Through detection boundary
# Max X-Factor
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/max-x-factor
The frame of maximum hip-shoulder separation (X-Factor) angle reached during the swing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `max_x_factor_frame`
* **Required for QA:** False
* **Measurement:** Frame of maximum trunk-relative-to-pelvis rotation angle (direction depends on handedness)
* **Timing:** Typically occurs during the downswing, after Top of Swing
## Description
Max X-Factor identifies the frame where hip-shoulder separation (X-Factor) reaches its largest magnitude during the swing, reflecting peak torso coil relative to the pelvis.
## Use Cases
* X-Factor magnitude analysis
* Power generation assessment
# Min X-Factor
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/min-x-factor
The frame of minimum hip-shoulder separation (X-Factor) angle, used to bound the search window for the Low Hands event.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** \`\`
* **Required for QA:** False
* **Measurement:** Frame of minimum trunk-relative-to-pelvis rotation angle (direction depends on handedness)
* **Timing:** After Top of Swing
## Description
Min X-Factor identifies the frame where hip-shoulder separation reaches its smallest (or most negative) value after the top of the backswing. It is used internally to bound the search window for the Low Hands event.
## Use Cases
* Low Hands detection boundary
# P1 Address
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/p1-address
Static setup position immediately before the swing begins, identified as roughly 0.3 seconds before the hands start rising toward the top of the backswing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `p1_address_frame`
* **Required for QA:** False
* **Measurement:** 0.3 s before the onset of the hands rising toward the Low Hands / Top of Swing peak
* **Timing:** First event in the P Classification System, before P2 Takeaway
## Description
P1 Address marks the golfer's setup position before any swing motion begins. It is located by working backward 0.3 seconds from the point where the hands start to rise toward the top of the backswing, capturing the static stance and grip position used as the reference posture for angle-at-event metrics.
## Use Cases
* Swing timing analysis
* Setup and posture assessment
* Reference posture for angle-at-event metrics
# P10 Finish
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/p10-finish
The final, balanced finish position of the swing, identified as the frame of maximum hand height after Low Hands.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `p10_finish_frame`
* **Required for QA:** False
* **Measurement:** Maximum average wrist height occurring after the Low Hands event
* **Timing:** Final event in the P Classification System
* **Legacy Name:** Finish
## Description
P10 Finish marks the final, balanced finish position of the golf swing, identified as the frame of maximum hand height after the Low Hands event.
Also exposed under the legacy column name Finish.
## Use Cases
* Full-swing duration bounds
* Follow-Through Max X-Factor window end
# P2 Takeaway
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/p2-takeaway
Start of the golf swing, identified as the first frame where hip-shoulder separation (X-Factor) has moved more than 20 degrees from the Address position.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `p2_takeaway_frame`
* **Required for QA:** False
* **Measurement:** First frame where the X-Factor angle differs from its Address value by more than 20°
* **Timing:** Between P1 Address and P4 Top of Swing
## Description
P2 Takeaway marks the beginning of the backswing, when the golfer starts rotating the club and body away from the ball. It is detected as the first meaningful (greater than 20°) change in hip-shoulder separation (X-Factor) relative to the Address position.
## Use Cases
* Backswing timing
* Upswing Duration calculation
* Sequencing analysis
# P3 Mid Backswing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/p3-mid-backswing
Midpoint of the backswing, identified as the first frame between Address and Top of Swing where the hands rise above the elbows.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `p3_mid_backswing_frame`
* **Required for QA:** False
* **Measurement:** First frame where average wrist height exceeds average elbow height
* **Timing:** Between P2 Takeaway and P4 Top of Swing
## Description
P3 Mid Backswing captures the point during the backswing when the arms and hips are actively rotating toward the top of the swing, identified as the first frame where the hands rise above elbow height.
## Use Cases
* Backswing plane analysis
* Arm and body sequencing checks
# P4 Top of Swing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/p4-top-of-swing
The highest hand position of the backswing and the moment just before the downswing transition begins.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `p4_top_of_swing_frame`
* **Required for QA:** False
* **Measurement:** Peak hand height occurring before the X-Factor Zero Crossing event
* **Timing:** Between P3 Mid Backswing and P5 Transition
* **Legacy Name:** Top Backswing
## Description
P4 Top of Swing marks the highest point of the backswing, immediately before the club changes direction into the downswing.
It is found as the frame of peak hand height occurring before the X-Factor Zero Crossing event.
This event is also used as the reference for Upswing Duration, Downswing Duration, and several angle-at-event metrics.
Also exposed under the legacy column name Top Backswing.
## Use Cases
* Backswing completion
* Upswing / Downswing Duration split point
* Kinematic sequence and angle-at-event reference
# P5 Transition
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/p5-transition
The change of direction from backswing to downswing, identified from the trailing edge of the hand-height peak near the top of the swing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `p5_transition_frame`
* **Required for QA:** False
* **Measurement:** Trailing-edge width boundary of the hand-height peak located between Address and Low Hands
* **Timing:** Between P4 Top of Swing and P6 Pre-Impact
## Description
P5 Transition marks the moment the swing changes direction from backswing to downswing. It is identified from the trailing edge of the hand-height peak found between Address and Low Hands.
## Use Cases
* Transition timing
* Reverse Spine Angle detection window boundary
# P6 Pre-Impact
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/p6-pre-impact
The moment just before impact, identified as the frame where the lead wrist is closest to the trail hip.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `p6_pre_impact_frame`
* **Required for QA:** False
* **Measurement:** Minimum distance between the lead wrist and trail hip, searched between Top of Swing and Finish
* **Timing:** Between P5 Transition and P7 Impact
## Description
P6 Pre-Impact approximates the moment just before the club strikes the ball, identified as the frame where the lead wrist is closest to the trail hip.
## Use Cases
* Impact approach timing
* Downswing mechanics analysis
# P7 Impact
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/p7-impact
The moment of ball contact, the 'moment of truth' that determines where the ball goes. Also exposed under the legacy column name Ball Contact.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `p7_impact_frame`
* **Required for QA:** False
* **Measurement:** Minimum distance between the lead wrist and lead hip, searched between Top of Swing and Finish
* **Timing:** Between P6 Pre-Impact and P8 Release
* **Legacy Name:** Ball Contact
## Description
P7 Impact approximates the instant the club strikes the ball, identified as the frame where the lead wrist is closest to the lead hip. It is the primary reference event for Downswing Duration, Follow-Through Max X-Factor, and the angle-at-impact metrics.
## Use Cases
* Downswing Duration calculation
* Follow-Through Max X-Factor window start
* Angle-at-impact metrics
# P8 Release
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/p8-release
The moment just after impact, identified as the temporal midpoint between Impact and Follow Through.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `p8_release_frame`
* **Required for QA:** False
* **Measurement:** Midpoint in time between P7 Impact and P9 Follow Through
* **Timing:** Between P7 Impact and P9 Follow Through
## Description
P8 Release marks the moment just after impact as the golfer continues rotating through the shot. It is computed as the temporal midpoint between Impact and Follow Through, and bounds the search window for the peak segment angular velocity events.
## Use Cases
* Peak angular velocity search window
* Post-impact mechanics analysis
# P9 Follow Through
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/p9-follow-through
Continued rotation after the strike, identified as the first frame after Low Hands where the hands rise back above the elbows. Also exposed under the legacy column name Follow Through.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `p9_follow_through_frame`
* **Required for QA:** False
* **Measurement:** First frame after Low Hands where average wrist height exceeds average elbow height
* **Timing:** Between P8 Release and P10 Finish
* **Legacy Name:** Follow Through
## Description
P9 Follow Through captures the continued rotation of the body after ball contact, identified as the first frame after Low Hands where the hands rise back above elbow height.
## Use Cases
* Follow-through mechanics analysis
* Finish approach timing
# Peak Arm Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/peak-arm-angular-velocity
The instant the lead arm reaches its maximum rotational velocity during the downswing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_arm_angular_velocity_frame`
* **Required for QA:** False
* **Measurement:** Frame of maximum lead-shoulder angular velocity about the twist axis, searched between Top of Swing and Release
* **Timing:** Between P4 Top of Swing and P8 Release
## Description
This event identifies the moment when the lead arm reaches its maximum angular velocity during the downswing, representing the final link in the kinematic chain before impact.
## Use Cases
* Kinematic Sequence order
* Peak Arm Velocity metric
# Peak Pelvis Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/peak-pelvis-angular-velocity
The instant the pelvis reaches its maximum rotational (twist) velocity during the downswing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_pelvis_angular_velocity_frame`
* **Required for QA:** False
* **Measurement:** Frame of maximum pelvis angular velocity about the twist axis, searched between Top of Swing and Release
* **Timing:** Between P4 Top of Swing and P8 Release
## Description
This event identifies the moment when the pelvis reaches its maximum angular velocity during the downswing, representing peak lower-body rotational power.
## Use Cases
* Kinematic Sequence order
* Peak Pelvis Velocity metric
# Peak Trunk Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/peak-trunk-angular-velocity
The instant the trunk reaches its maximum rotational (twist) velocity during the downswing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_trunk_angular_velocity_frame`
* **Required for QA:** False
* **Measurement:** Frame of maximum trunk angular velocity about the twist axis, searched between Top of Swing and Release
* **Timing:** Between P4 Top of Swing and P8 Release
## Description
This event identifies the moment when the trunk reaches its maximum angular velocity during the downswing, representing peak torso rotational power.
## Use Cases
* Kinematic Sequence order
* Peak Trunk Velocity metric
# X-Factor Zero Crossing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/events/x-factor-zero-crossing
The instant the hip-shoulder separation (X-Factor) angle crosses zero following its steepest rise, used to locate the Top of Swing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `x_factor_zero_crossing_frame`
* **Required for QA:** False
* **Measurement:** Zero crossing of the X-Factor angle nearest the point of its steepest rate of change
* **Timing:** Used internally to identify P4 Top of Swing
## Description
X-Factor Zero Crossing marks the instant hip and shoulder rotation have no separation, following the steepest rise in the X-Factor signal — the point where the shoulders are stacked directly on top of the hips. It is used internally to bound the search for the Top of Swing event.
## Use Cases
* Top of Swing detection
# Chicken Wing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/flags/chicken-wing
Binary indicator of a 'chicken wing' fault — the lead elbow bends more than 20 degrees at impact instead of staying extended.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `chicken_wing`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Lead elbow flexion angle at P7 Impact
* **Threshold:** Lead elbow flexion exceeds 20°
## Description
Chicken Wing flags a lead arm fault where the lead elbow bends significantly at impact instead of staying extended, which typically results in inconsistent contact and reduced clubhead speed.
## Use Cases
* Lead arm mechanics coaching
* Contact consistency analysis
# Early Extension
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/flags/early-extension
Binary indicator of early extension — the pelvis moves toward the ball (target line) by more than 10 cm during the swing, a common power-and-consistency fault.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `early_extension`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Derived from the Loss of Posture Pelvis direction component
* **Threshold:** Mid-pelvis position moves more than 10 cm (0.1 m) toward the ball (Z-axis) between P1 Address and P7 Impact
## Description
Early Extension flags a golfer whose pelvis thrusts toward the ball during the downswing rather than continuing to rotate in place. It is derived from the [Loss of Posture](/biomechanics/activities/golf/swing/flags/loss-of-posture) pelvis-direction breakdown, specifically when the flagged displacement occurs along the Z-axis (toward the ball).
## Use Cases
* Posture fault detection
* Power leak identification
* Injury risk screening
# Hang Back
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/flags/hang-back
Binary indicator of a 'hang back' fault — the golfer's weight stays on the trail side, with the pelvis more than 5 cm behind its Address position at Impact instead of shifting toward the target.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `hang_back`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Mid-pelvis X position at P1 Address vs. P7 Impact
* **Threshold:** Pelvis X position at Impact is more than 5 cm (0.05 m) behind its Address value
## Description
Hang Back flags a golfer who fails to shift weight toward the target during the downswing, leaving the pelvis behind its Address position at Impact. This weight-transfer fault typically reduces power and can produce inconsistent, thin contact.
## Use Cases
* Weight transfer analysis
* Power and contact consistency coaching
# Loss of Posture
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/flags/loss-of-posture
Binary indicator if the golfer loses spine posture during the swing, flagged when the mid-shoulder or mid-pelvis position shifts more than 10 cm (~4 in) from its Address position between Address and Impact.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `loss_of_posture`
* **Related Column Names:** `loss_of_posture_shoulder`, `loss_of_posture_pelvis`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Mid-shoulder and mid-pelvis 3D position between P1 Address and P7 Impact
* **Threshold:** Mid-shoulder or mid-pelvis position moves more than 10 cm (0.1 m) from its Address value, in any axis
## Description
Loss of Posture flags when the golfer's spine angle changes significantly during the swing, identified by excessive displacement of the mid-shoulder or mid-pelvis position relative to Address. Related outputs break this down further: Loss of Posture Shoulder and Loss of Posture Pelvis report the shoulder- and pelvis-specific components, and Loss of Posture Shoulder Direction / Loss of Posture Pelvis Direction report which axes triggered the flag. Early Extension and Reverse Spine Angle are related, more specific posture faults.
## Use Cases
* Posture fault detection
* Swing consistency coaching
* Injury risk screening
# Reverse Spine Angle
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/flags/reverse-spine-angle
Binary indicator of a reverse spine angle — the trunk tilts toward the target during the backswing instead of away from it, identified when the mid-shoulder position moves in front of the mid-pelvis position by more than 5 cm.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `reverse_spine_angle`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Mid-shoulder X position vs. mid-pelvis X position, between P1 Address and P5 Transition
* **Threshold:** Mid-shoulder X position exceeds mid-pelvis X position by more than 5 cm (0.05 m) at any point during the backswing
## Description
Reverse Spine Angle flags a backswing fault where the upper body tilts toward the target instead of away from it, identified when the mid-shoulder position moves ahead of the mid-pelvis position (along the swing direction) by more than 5 cm between Address and Transition.
## Use Cases
* Posture fault detection
* Backswing mechanics coaching
* Injury risk screening
# Slide
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/flags/slide
Binary indicator of a 'slide' fault — the lead knee or hip shifts laterally toward the target by more than 5 cm during the downswing instead of rotating around a stable base.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `slide`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Lead knee and lead hip X position, between P1 Address and P7 Impact
* **Threshold:** Lead knee or lead hip X position exceeds its Address value by more than 5 cm (0.05 m) at any point
## Description
Slide flags a lower body fault where the lead knee or hip shifts laterally toward the target during the downswing rather than rotating around a stable base, which can rob the swing of rotational power.
## Use Cases
* Lower body stability analysis
* Swing consistency coaching
# Sway
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/flags/sway
Binary indicator of a sway fault — the pelvis shifts laterally away from the target by more than 10 cm between Address and Impact instead of rotating in place.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `sway`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Mid-pelvis X position, between P1 Address and P7 Impact
* **Threshold:** Pelvis X position drops more than 10 cm (0.1 m) below its Address value at any point
## Description
Sway flags a golfer whose pelvis shifts laterally away from the target during the backswing rather than rotating around a stable base. The magnitude of the lateral shift is reported separately by the [Pelvis Sway Range](/biomechanics/activities/golf/swing/metrics/pelvis-sway-range) metric.
## Use Cases
* Lower body stability analysis
* Swing consistency coaching
# Downswing Duration
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/downswing-duration
Duration from Top of Swing (P4) to Impact (P7).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s)
* **Column Name:** `downswing_duration`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** (P7 Impact frame − P4 Top of Swing frame) / fps
* **Optimal Direction:** N/A
## Description
Downswing Duration measures the time from the top of the backswing to impact. It is used together with Upswing Duration to compute the Dynamic Tempo Ratio.
## Use Cases
* Tempo analysis
* Dynamic Tempo Ratio input
# Dynamic Tempo Ratio
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/dynamic-tempo-ratio
Ratio of Downswing Duration to Upswing Duration.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio
* **Column Name:** `dynamic_tempo_ratio`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Downswing Duration / Upswing Duration
* **Optimal Direction:** N/A
## Description
Dynamic Tempo Ratio compares the time spent in the downswing to the time spent in the backswing. Golf instruction commonly references a ratio around 3:1 for tour-level swings, though the optimal value varies by golfer.
## Use Cases
* Swing tempo assessment
* Backswing/downswing balance
# Follow-Through Max X-Factor
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/follow-through-max-x-factor
Maximum hip-shoulder separation (X-Factor) reached between Impact and Finish — the release of separation after contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `follow_through_max_x_factor`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Maximum absolute X-Factor angle between P7 Impact and P10 Finish
## Description
Follow-Through Max X-Factor measures the largest hip-shoulder separation reached after impact, reflecting how the torso continues to rotate relative to the pelvis through the finish.
## Use Cases
* Follow-through mechanics analysis
# Global Pelvis Rotation at P4 Top of Swing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-pelvis-rotation-at-p4-top-of-swing
Pelvis rotation angle relative to its own position at Address, measured in the global reference frame, at P4 Top of Swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_pelvis_rotation_at_p4`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Pelvis rotation angle in the global reference frame, sampled at the P4 Top of Swing event
## Description
Global Pelvis Rotation at P4 Top of Swing reports the pelvis rotation angle relative to its own position at Address, measured in the global reference frame, sampled at the P4 Top of Swing event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P4 Top of Swing position analysis
# Global Pelvis Rotation at P7 Impact
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-pelvis-rotation-at-p7-impact
Pelvis rotation angle relative to its own position at Address, measured in the global reference frame, at P7 Impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_pelvis_rotation_at_p7`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Pelvis rotation angle in the global reference frame, sampled at the P7 Impact event
## Description
Global Pelvis Rotation at P7 Impact reports the pelvis rotation angle relative to its own position at Address, measured in the global reference frame, sampled at the P7 Impact event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P7 Impact position analysis
# Global Pelvis Tilt at P1 Address
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-pelvis-tilt-at-p1-address
Pelvis side-to-side tilt angle relative to the global reference frame, at P1 Address.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_pelvis_tilt_at_p1`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Pelvis tilt angle in the global reference frame, sampled at the P1 Address event
## Description
Global Pelvis Tilt at P1 Address reports the pelvis side-to-side tilt angle relative to the global reference frame, sampled at the P1 Address event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P1 Address position analysis
# Global Pelvis Tilt at P4 Top of Swing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-pelvis-tilt-at-p4-top-of-swing
Pelvis side-to-side tilt angle relative to the global reference frame, at P4 Top of Swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_pelvis_tilt_at_p4`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Pelvis tilt angle in the global reference frame, sampled at the P4 Top of Swing event
## Description
Global Pelvis Tilt at P4 Top of Swing reports the pelvis side-to-side tilt angle relative to the global reference frame, sampled at the P4 Top of Swing event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P4 Top of Swing position analysis
# Global Pelvis Tilt at P7 Impact
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-pelvis-tilt-at-p7-impact
Pelvis side-to-side tilt angle relative to the global reference frame, at P7 Impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_pelvis_tilt_at_p7`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Pelvis tilt angle in the global reference frame, sampled at the P7 Impact event
## Description
Global Pelvis Tilt at P7 Impact reports the pelvis side-to-side tilt angle relative to the global reference frame, sampled at the P7 Impact event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P7 Impact position analysis
# Global Trunk Flexion at P1 Address
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-trunk-flexion-at-p1-address
Trunk forward/backward flexion angle relative to the global (vertical) reference frame, at P1 Address.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_trunk_flexion_at_p1`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trunk flexion angle in the global reference frame, sampled at the P1 Address event
## Description
Global Trunk Flexion at P1 Address reports the trunk forward/backward flexion angle relative to the global (vertical) reference frame, sampled at the P1 Address event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P1 Address position analysis
# Global Trunk Flexion at P4 Top of Swing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-trunk-flexion-at-p4-top-of-swing
Trunk forward/backward flexion angle relative to the global (vertical) reference frame, at P4 Top of Swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_trunk_flexion_at_p4`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trunk flexion angle in the global reference frame, sampled at the P4 Top of Swing event
## Description
Global Trunk Flexion at P4 Top of Swing reports the trunk forward/backward flexion angle relative to the global (vertical) reference frame, sampled at the P4 Top of Swing event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P4 Top of Swing position analysis
# Global Trunk Flexion at P7 Impact
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-trunk-flexion-at-p7-impact
Trunk forward/backward flexion angle relative to the global (vertical) reference frame, at P7 Impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_trunk_flexion_at_p7`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trunk flexion angle in the global reference frame, sampled at the P7 Impact event
## Description
Global Trunk Flexion at P7 Impact reports the trunk forward/backward flexion angle relative to the global (vertical) reference frame, sampled at the P7 Impact event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P7 Impact position analysis
# Global Trunk Rotation at P4 Top of Swing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-trunk-rotation-at-p4-top-of-swing
Trunk rotation angle relative to its own position at Address, measured in the global reference frame, at P4 Top of Swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_trunk_rotation_at_p4`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trunk rotation angle in the global reference frame, sampled at the P4 Top of Swing event
## Description
Global Trunk Rotation at P4 Top of Swing reports the trunk rotation angle relative to its own position at Address, measured in the global reference frame, sampled at the P4 Top of Swing event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P4 Top of Swing position analysis
# Global Trunk Rotation at P7 Impact
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-trunk-rotation-at-p7-impact
Trunk rotation angle relative to its own position at Address, measured in the global reference frame, at P7 Impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_trunk_rotation_at_p7`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trunk rotation angle in the global reference frame, sampled at the P7 Impact event
## Description
Global Trunk Rotation at P7 Impact reports the trunk rotation angle relative to its own position at Address, measured in the global reference frame, sampled at the P7 Impact event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P7 Impact position analysis
# Global Trunk Tilt at P1 Address
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-trunk-tilt-at-p1-address
Trunk side-to-side tilt angle relative to the global reference frame, at P1 Address.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_trunk_tilt_at_p1`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trunk tilt angle in the global reference frame, sampled at the P1 Address event
## Description
Global Trunk Tilt at P1 Address reports the trunk side-to-side tilt angle relative to the global reference frame, sampled at the P1 Address event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P1 Address position analysis
# Global Trunk Tilt at P4 Top of Swing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-trunk-tilt-at-p4-top-of-swing
Trunk side-to-side tilt angle relative to the global reference frame, at P4 Top of Swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_trunk_tilt_at_p4`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trunk tilt angle in the global reference frame, sampled at the P4 Top of Swing event
## Description
Global Trunk Tilt at P4 Top of Swing reports the trunk side-to-side tilt angle relative to the global reference frame, sampled at the P4 Top of Swing event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P4 Top of Swing position analysis
# Global Trunk Tilt at P7 Impact
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/global-trunk-tilt-at-p7-impact
Trunk side-to-side tilt angle relative to the global reference frame, at P7 Impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `global_trunk_tilt_at_p7`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trunk tilt angle in the global reference frame, sampled at the P7 Impact event
## Description
Global Trunk Tilt at P7 Impact reports the trunk side-to-side tilt angle relative to the global reference frame, sampled at the P7 Impact event. Global angles are expressed relative to the ground/vertical reference frame rather than a body-relative axis, making them comparable across different camera setups.
## Use Cases
* Global posture assessment
* P7 Impact position analysis
# Kinematic Sequence
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/kinematic-sequence
Order of peak angular velocity timing among the pelvis, trunk, and arm during the downswing. The optimal sequence is Pelvis-Trunk-Arm.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `kinematic_sequence`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Optimal Sequence:** Pelvis-Trunk-Arm
* **Measurement:** Chronological order of the Peak Pelvis, Peak Trunk, and Peak Arm Angular Velocity events
## Description
Kinematic Sequence tracks the timing order of peak angular velocities across the pelvis, trunk, and lead arm during the downswing. The optimal sequence is Pelvis-Trunk-Arm, reflecting efficient energy transfer up the kinetic chain from the ground through the club.
## Use Cases
* Kinetic chain analysis
* Sequencing evaluation
* Power transfer assessment
# Lead Shoulder Flexion at P1 Address
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/lead-shoulder-flexion-at-p1-address
Lead shoulder forward/backward raise angle relative to the trunk at P1 Address.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `lead_shoulder_flexion_at_p1`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Lead shoulder flexion angle relative to the trunk, sampled at the P1 Address event
## Description
Lead Shoulder Flexion at P1 Address reports the forward/backward raise angle of the lead shoulder relative to the trunk, sampled at the P1 Address event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P1 Address position analysis
# Lead Shoulder Flexion at P4 Top of Swing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/lead-shoulder-flexion-at-p4-top-of-swing
Lead shoulder forward/backward raise angle relative to the trunk at P4 Top of Swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `lead_shoulder_flexion_at_p4`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Lead shoulder flexion angle relative to the trunk, sampled at the P4 Top of Swing event
## Description
Lead Shoulder Flexion at P4 Top of Swing reports the forward/backward raise angle of the lead shoulder relative to the trunk, sampled at the P4 Top of Swing event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P4 Top of Swing position analysis
# Lead Shoulder Flexion at P7 Impact
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/lead-shoulder-flexion-at-p7-impact
Lead shoulder forward/backward raise angle relative to the trunk at P7 Impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `lead_shoulder_flexion_at_p7`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Lead shoulder flexion angle relative to the trunk, sampled at the P7 Impact event
## Description
Lead Shoulder Flexion at P7 Impact reports the forward/backward raise angle of the lead shoulder relative to the trunk, sampled at the P7 Impact event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P7 Impact position analysis
# Lead Shoulder Tilt at P1 Address
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/lead-shoulder-tilt-at-p1-address
Lead shoulder up/down tilt angle relative to the trunk at P1 Address.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `lead_shoulder_tilt_at_p1`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Lead shoulder tilt angle relative to the trunk, sampled at the P1 Address event
## Description
Lead Shoulder Tilt at P1 Address reports the up/down tilt angle of the lead shoulder relative to the trunk, sampled at the P1 Address event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P1 Address position analysis
# Lead Shoulder Tilt at P4 Top of Swing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/lead-shoulder-tilt-at-p4-top-of-swing
Lead shoulder up/down tilt angle relative to the trunk at P4 Top of Swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `lead_shoulder_tilt_at_p4`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Lead shoulder tilt angle relative to the trunk, sampled at the P4 Top of Swing event
## Description
Lead Shoulder Tilt at P4 Top of Swing reports the up/down tilt angle of the lead shoulder relative to the trunk, sampled at the P4 Top of Swing event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P4 Top of Swing position analysis
# Lead Shoulder Tilt at P7 Impact
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/lead-shoulder-tilt-at-p7-impact
Lead shoulder up/down tilt angle relative to the trunk at P7 Impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `lead_shoulder_tilt_at_p7`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Lead shoulder tilt angle relative to the trunk, sampled at the P7 Impact event
## Description
Lead Shoulder Tilt at P7 Impact reports the up/down tilt angle of the lead shoulder relative to the trunk, sampled at the P7 Impact event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P7 Impact position analysis
# Peak Arm Velocity
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/peak-arm-velocity
Maximum rotational velocity of the lead arm during the downswing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_arm_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Lead shoulder angular velocity about the twist axis at the Peak Arm Angular Velocity event
## Description
Peak Arm Velocity measures the maximum rotational speed of the lead arm during the downswing, representing the final link in the kinetic chain before impact.
## Use Cases
* Arm speed analysis
* Kinematic Sequence input
# Peak Pelvis Velocity
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/peak-pelvis-velocity
Maximum rotational (twist) velocity of the pelvis during the downswing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_pelvis_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Pelvis angular velocity about the twist axis at the Peak Pelvis Angular Velocity event
## Description
Peak Pelvis Velocity measures the maximum rotational speed of the pelvis during the downswing, representing the lower body's contribution to the kinetic chain.
## Use Cases
* Lower body power analysis
* Kinematic Sequence input
# Peak Trunk Velocity
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/peak-trunk-velocity
Maximum rotational (twist) velocity of the trunk during the downswing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_trunk_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Trunk angular velocity about the twist axis at the Peak Trunk Angular Velocity event
## Description
Peak Trunk Velocity measures the maximum rotational speed of the trunk during the downswing, representing the torso's contribution to the kinetic chain.
## Use Cases
* Torso power analysis
* Kinematic Sequence input
# Pelvis Sway Range
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/pelvis-sway-range
Range of lateral pelvis displacement between Address and Impact, reported alongside the Sway flag.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** m
* **Column Name:** `pelvis_sway_range`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Lower is better
* **Measurement:** Max pelvis X position − min pelvis X position, between P1 Address and P7 Impact
## Description
Pelvis Sway Range reports the total lateral range of pelvis motion between Address and Impact, providing magnitude context for the [Sway](/biomechanics/activities/golf/swing/flags/sway) movement flag.
## Use Cases
* Sway magnitude context
* Lower body stability analysis
# Pre-Load Max X-Factor
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/pre-load-max-x-factor
Maximum hip-shoulder separation (X-Factor) reached between Address and Impact — the backswing 'load'.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `pre_load_max_x_factor`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum absolute X-Factor angle between P1 Address and P7 Impact
## Description
Pre-Load Max X-Factor measures the largest hip-shoulder separation reached during the backswing and downswing prior to impact, reflecting how much torso coil the golfer loads before releasing the club.
## Use Cases
* Power loading assessment
* Backswing coil analysis
# Trail Shoulder Flexion at P1 Address
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/trail-shoulder-flexion-at-p1-address
Trail shoulder forward/backward raise angle relative to the trunk at P1 Address.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `trail_shoulder_flexion_at_p1`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trail shoulder flexion angle relative to the trunk, sampled at the P1 Address event
## Description
Trail Shoulder Flexion at P1 Address reports the forward/backward raise angle of the trail shoulder relative to the trunk, sampled at the P1 Address event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P1 Address position analysis
# Trail Shoulder Flexion at P4 Top of Swing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/trail-shoulder-flexion-at-p4-top-of-swing
Trail shoulder forward/backward raise angle relative to the trunk at P4 Top of Swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `trail_shoulder_flexion_at_p4`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trail shoulder flexion angle relative to the trunk, sampled at the P4 Top of Swing event
## Description
Trail Shoulder Flexion at P4 Top of Swing reports the forward/backward raise angle of the trail shoulder relative to the trunk, sampled at the P4 Top of Swing event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P4 Top of Swing position analysis
# Trail Shoulder Flexion at P7 Impact
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/trail-shoulder-flexion-at-p7-impact
Trail shoulder forward/backward raise angle relative to the trunk at P7 Impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `trail_shoulder_flexion_at_p7`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trail shoulder flexion angle relative to the trunk, sampled at the P7 Impact event
## Description
Trail Shoulder Flexion at P7 Impact reports the forward/backward raise angle of the trail shoulder relative to the trunk, sampled at the P7 Impact event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P7 Impact position analysis
# Trail Shoulder Tilt at P1 Address
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/trail-shoulder-tilt-at-p1-address
Trail shoulder up/down tilt angle relative to the trunk at P1 Address.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `trail_shoulder_tilt_at_p1`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trail shoulder tilt angle relative to the trunk, sampled at the P1 Address event
## Description
Trail Shoulder Tilt at P1 Address reports the up/down tilt angle of the trail shoulder relative to the trunk, sampled at the P1 Address event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P1 Address position analysis
# Trail Shoulder Tilt at P4 Top of Swing
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/trail-shoulder-tilt-at-p4-top-of-swing
Trail shoulder up/down tilt angle relative to the trunk at P4 Top of Swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `trail_shoulder_tilt_at_p4`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trail shoulder tilt angle relative to the trunk, sampled at the P4 Top of Swing event
## Description
Trail Shoulder Tilt at P4 Top of Swing reports the up/down tilt angle of the trail shoulder relative to the trunk, sampled at the P4 Top of Swing event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P4 Top of Swing position analysis
# Trail Shoulder Tilt at P7 Impact
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/trail-shoulder-tilt-at-p7-impact
Trail shoulder up/down tilt angle relative to the trunk at P7 Impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `trail_shoulder_tilt_at_p7`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Trail shoulder tilt angle relative to the trunk, sampled at the P7 Impact event
## Description
Trail Shoulder Tilt at P7 Impact reports the up/down tilt angle of the trail shoulder relative to the trunk, sampled at the P7 Impact event. It is used to characterize upper-body posture and arm position at key points in the swing.
## Use Cases
* Upper body posture assessment
* P7 Impact position analysis
# Upswing Duration
Source: https://docs.uplift.ai/biomechanics/activities/golf/swing/metrics/upswing-duration
Duration from Takeaway (P2) to Top of Swing (P4).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s)
* **Column Name:** `upswing_duration`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** (P4 Top of Swing frame − P2 Takeaway frame) / fps
* **Optimal Direction:** N/A
## Description
Upswing Duration measures the time spent in the backswing, from Takeaway to the Top of Swing. It is used together with Downswing Duration to compute the Dynamic Tempo Ratio.
## Use Cases
* Tempo analysis
* Dynamic Tempo Ratio input
# Broad Jump
Source: https://docs.uplift.ai/biomechanics/activities/jump/broad
Biomechanical analysis of broad jump movements, including events, phases, and discrete metrics.
## Overview
The broad jump is a horizontal jumping movement assessment that evaluates an athlete's ability to generate horizontal power and maintain stability during landing. This movement is commonly used in athletic assessment and training as it provides valuable information about horizontal power, landing mechanics, and lower extremity function.
## Instructions
Stand with feet shoulder-width apart. Swing arms back while bending the knees, then jump forward as far as possible. Land on both feet and absorb the landing with a soft bend at the hips and knees. Use the specified arm position (arm-swing or hands-on-hips) consistently for the trial.
## Dimensions
Required inputs for processing:
* **Arm Position**: \['arm-swing','hands-on-hips']
## Phases of the Jump
| Phase | Start | End |
| ------------------ | -------------- | -------------- |
| Jumping | Initiation | Takeoff |
| Jumping Eccentric | Initiation | Bottom |
| Jumping Concentric | Bottom | Takeoff |
| Landing | Landing | Termination |
| Landing Eccentric | Landing | Landing Bottom |
| Landing Concentric | Landing Bottom | Termination |
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Event | Description | Column Name |
| --------------------------------------------------------------------- | ------------------------------------------------------------------------- | ----------- |
| [Initiation](/biomechanics/activities/jump/events/initiation) | the start of the jump - when the person begins to move downward | \`\` |
| [Bottom](/biomechanics/activities/jump/events/bottom) | the lowest point of the pelvis before the jump | \`\` |
| [Takeoff](/biomechanics/activities/jump/events/takeoff) | the instant of leaving the ground | \`\` |
| [Peak Height](/biomechanics/activities/jump/events/peak-height) | the instant when maximum height reached | \`\` |
| [Landing](/biomechanics/activities/jump/events/landing) | the instant of ground contact | \`\` |
| [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom) | the lowest point of the pelvis after the jump | \`\` |
| [Termination](/biomechanics/activities/jump/events/termination) | end of the movement - when the person returns to normal standing position | \`\` |
### Distance Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------- | ------ | ---------------------------------------- | ----------- |
| [Jump Height](/biomechanics/activities/jump/metrics/jump-height) | meters | Maximum height reached during the jump | \`\` |
| [Right Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at bottom position | \`\` |
| [Left Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at bottom position | \`\` |
| [Right Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing | \`\` |
| [Left Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing | \`\` |
| [Right Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing bottom | \`\` |
| [Left Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing bottom | \`\` |
| [Right Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum right knee valgus during landing | \`\` |
| [Left Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum left knee valgus during landing | \`\` |
| [Right Displacement](/biomechanics/activities/jump/metrics/right-displacement) | meters | Lateral displacement during landing | \`\` |
| [Forward Displacement](/biomechanics/activities/jump/metrics/forward-displacement) | meters | Forward displacement during landing | \`\` |
### Movement Flags and Other Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------------------------- | ------- | ---------------------------------------------------------------------------- | ----------- |
| [Knees Track](/biomechanics/activities/jump/metrics/knees-track) | binary | Binary indicator if knees track properly (1=yes, 0=no) | \`\` |
| [Hips Feet Stationary](/biomechanics/activities/jump/metrics/hips-feet-stationary) | binary | Binary indicator if hips and feet remain stationary | \`\` |
| [High Jump Height](/biomechanics/activities/jump/metrics/high-jump-height) | binary | Binary indicator if jump height exceeds 14 inches (\~0.36 m) | \`\` |
| [Stiff Knee Landing](/biomechanics/activities/jump/metrics/stiff-knee-landing) | binary | Binary indicator of stiff knee landing | \`\` |
| [Flight Time](/biomechanics/activities/jump/metrics/flight-time) | seconds | Time from takeoff to landing | \`\` |
| [RSI Mod](/biomechanics/activities/jump/metrics/reactive-strength-index-modified) | N/A | Reactive Strength Index Modified | \`\` |
| [Eccentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during eccentric phase (0=hip dominant, 1=knee dominant) | \`\` |
| [Concentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during concentric phase (0=hip dominant, 1=knee dominant) | \`\` |
| [Landing Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during landing phase (0=hip dominant, 1=knee dominant) | \`\` |
| [Landing Stiffness Index](/biomechanics/activities/jump/metrics/landing-stiffness-index) | N/A | Index of landing stiffness | \`\` |
| [Landing Stiffness Index Level](/biomechanics/activities/jump/metrics/landing-stiffness-index-level) | N/A | Classification of landing stiffness | \`\` |
| [Eccentric Velocity](/biomechanics/activities/jump/metrics/eccentric-velocity) | m/s | Average velocity during eccentric phase | \`\` |
| [Kinematic Sequence](/biomechanics/activities/jump/metrics/kinematic-sequence) | N/A | Sequence of peak velocities during the jump | \`\` |
| [Kinematic Sequence Array](/biomechanics/activities/jump/metrics/kinematic-sequence-array) | N/A | Array representation of kinematic sequence | \`\` |
### Joint Angles
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------------ | ------- | ------------------------------------------ | ----------- |
| [Left Peak Hip Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum left hip flexion during takeoff | \`\` |
| [Right Peak Hip Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum right hip flexion during takeoff | \`\` |
| [Left Peak Knee Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum left knee flexion during takeoff | \`\` |
| [Right Peak Knee Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum right knee flexion during takeoff | \`\` |
| [Left Peak Ankle Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum left ankle flexion during takeoff | \`\` |
| [Right Peak Ankle Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum right ankle flexion during takeoff | \`\` |
| [Left Peak Hip Flexion Landing](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum left hip flexion during landing | \`\` |
| [Right Peak Hip Flexion Landing](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum right hip flexion during landing | \`\` |
| [Left Peak Knee Flexion Landing](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum left knee flexion during landing | \`\` |
| [Right Peak Knee Flexion Landing](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum right knee flexion during landing | \`\` |
| [Left Peak Ankle Flexion Landing](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum left ankle flexion during landing | \`\` |
| [Right Peak Ankle Flexion Landing](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum right ankle flexion during landing | \`\` |
### Joint Velocities
| Metric | Units | Description | Column Name |
| -------------------------------------------------------------------------------------------------------------------------------------------------- | --------- | ---------------------------------------------------------------------- | ----------- |
| [Left Peak Hip Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip flexion velocity during eccentric phase | \`\` |
| [Right Peak Hip Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip flexion velocity during eccentric phase | \`\` |
| [Left Peak Knee Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee flexion velocity during eccentric phase | \`\` |
| [Right Peak Knee Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee flexion velocity during eccentric phase | \`\` |
| [Left Peak Ankle Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle flexion velocity during eccentric phase | \`\` |
| [Right Peak Ankle Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle flexion velocity during eccentric phase | \`\` |
| [Left Peak Shoulder Flexion Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-shoulder-flexion-velocity-takeoff-concentric) | degrees/s | Maximum left shoulder flexion velocity during concentric phase | \`\` |
| [Right Peak Shoulder Flexion Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-shoulder-flexion-velocity-takeoff-concentric) | degrees/s | Maximum right shoulder flexion velocity during concentric phase | \`\` |
| [Left Peak Hip Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip extension velocity during concentric phase | \`\` |
| [Right Peak Hip Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip extension velocity during concentric phase | \`\` |
| [Left Peak Knee Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee extension velocity during concentric phase | \`\` |
| [Right Peak Knee Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee extension velocity during concentric phase | \`\` |
| [Left Peak Ankle Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle extension velocity during concentric phase | \`\` |
| [Right Peak Ankle Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle extension velocity during concentric phase | \`\` |
| [Left Peak Hip Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip flexion velocity during landing eccentric phase | \`\` |
| [Right Peak Hip Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip flexion velocity during landing eccentric phase | \`\` |
| [Left Peak Knee Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee flexion velocity during landing eccentric phase | \`\` |
| [Right Peak Knee Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee flexion velocity during landing eccentric phase | \`\` |
| [Left Peak Ankle Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle flexion velocity during landing eccentric phase | \`\` |
| [Right Peak Ankle Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle flexion velocity during landing eccentric phase | \`\` |
| [Left Peak Hip Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip extension velocity during landing concentric phase | \`\` |
| [Right Peak Hip Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip extension velocity during landing concentric phase | \`\` |
| [Left Peak Knee Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee extension velocity during landing concentric phase | \`\` |
| [Right Peak Knee Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee extension velocity during landing concentric phase | \`\` |
| [Left Peak Ankle Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle extension velocity during landing concentric phase | \`\` |
| [Right Peak Ankle Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle extension velocity during landing concentric phase | \`\` |
### Linear Velocities
| Metric | Units | Description | Column Name |
| ----------------------------------------------------------------------------------------------- | ----- | --------------------------------------------------------------- | ----------- |
| [Takeoff Velocity](/biomechanics/activities/jump/metrics/takeoff-velocity) | m/s | Vertical velocity at takeoff | \`\` |
| [Peak COM Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during eccentric phase | \`\` |
| [Peak COM Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during concentric phase | \`\` |
| [Peak COM Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing eccentric phase | \`\` |
| [Peak COM Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing concentric phase | \`\` |
## Notes
* Kinematic data typically captured at 120Hz for Jumping
# Jump: Countermovement
Source: https://docs.uplift.ai/biomechanics/activities/jump/countermovement
Biomechanical analysis of countermovement jump movements, including events, phases, and discrete metrics.
## Overview
The countermovement jump is a fundamental movement assessment that involves a rapid downward movement (countermovement) followed immediately by an explosive upward jump. This movement is commonly used in athletic assessment and training as it provides valuable information about an athlete's explosive power, neuromuscular coordination, and lower extremity function.
## Instructions
Stand with feet roughly shoulder-width apart.
Quickly dip down (countermovement) by bending at the hips and knees, then immediately jump as high as possible.
Land softly on both feet.
Use the specified arm position (arm-swing or hands-on-hips) consistently for the trial.
## Example Videos
## Dimensions
Required inputs for processing:
* **Arm Position**: \['arm-swing','hands-on-hips']
## Phases of the Jump
| Phase | Start | End |
| ------------------ | -------------- | -------------- |
| Jumping | Initiation | Takeoff |
| Jumping Eccentric | Initiation | Bottom |
| Jumping Concentric | Bottom | Takeoff |
| Landing | Landing | Termination |
| Landing Eccentric | Landing | Landing Bottom |
| Landing Concentric | Landing Bottom | Termination |
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Event | Description | Column Name |
| --------------------------------------------------------------------- | ------------------------------------------------------------------------- | ------------------------- |
| [Initiation](/biomechanics/activities/jump/events/initiation) | the start of the jump - when the person begins to move downward | `jump_initiation_frame` |
| [Bottom](/biomechanics/activities/jump/events/bottom) | the lowest point of the pelvis before the jump | `bottom_of_jump_frame` |
| [Takeoff](/biomechanics/activities/jump/events/takeoff) | the instant of leaving the ground | `takeoff_frame` |
| [Peak Height](/biomechanics/activities/jump/events/peak-height) | the instant when maximum height reached | \`\` |
| [Landing](/biomechanics/activities/jump/events/landing) | the instant of ground contact | `jump_landing_frame` |
| [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom) | the lowest point of the pelvis after the jump | `bottom_of_landing_frame` |
| [Termination](/biomechanics/activities/jump/events/termination) | end of the movement - when the person returns to normal standing position | `jump_termination_frame` |
### Distance Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------- | ------ | ---------------------------------------- | ------------------------------------- |
| [Jump Height](/biomechanics/activities/jump/metrics/jump-height) | meters | Maximum height reached during the jump | `jump_height` |
| [Right Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at bottom position | `right_knee_valgus_at_bottom` |
| [Left Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at bottom position | `left_knee_valgus_at_bottom` |
| [Right Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing | `right_knee_valgus_at_landing` |
| [Left Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing | `left_knee_valgus_at_landing` |
| [Right Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing bottom | `right_knee_valgus_at_landing_bottom` |
| [Left Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing bottom | `left_knee_valgus_at_landing_bottom` |
| [Right Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum right knee valgus during landing | `right_knee_valgus_full_landing` |
| [Left Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum left knee valgus during landing | `left_knee_valgus_full_landing` |
| [Right Displacement](/biomechanics/activities/jump/metrics/right-displacement) | meters | Lateral displacement during landing | \`\` |
| [Forward Displacement](/biomechanics/activities/jump/metrics/forward-displacement) | meters | Forward displacement during landing | \`\` |
### Movement Flags and Other Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------------------------- | ------- | ---------------------------------------------------------------------------------------------------- | ---------------------------------- |
| [Knees Track](/biomechanics/activities/jump/metrics/knees-track) | binary | Binary indicator if knees track properly (1=yes, 0=no) | `knees_track` |
| [Hips Feet Stationary](/biomechanics/activities/jump/metrics/hips-feet-stationary) | binary | Binary indicator if hips and feet refrain from twisting inwards or outwards during the takeoff phase | `hips_feet_stationary` |
| [High Jump Height](/biomechanics/activities/jump/metrics/high-jump-height) | binary | Binary indicator if jump height exceeds 14 inches (\~0.36 m) | \`\` |
| [Stiff Knee Landing](/biomechanics/activities/jump/metrics/stiff-knee-landing) | binary | Binary indicator of stiff knee landing | `stiff_knee_landing` |
| [Flight Time](/biomechanics/activities/jump/metrics/flight-time) | seconds | Time from takeoff to landing | `jump_flight_time` |
| [RSI Mod](/biomechanics/activities/jump/metrics/reactive-strength-index-modified) | N/A | Reactive Strength Index Modified | `reactive_strength_index_modified` |
| [Eccentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during eccentric phase (0=hip dominant, 1=knee dominant) | `eccentric_hip_knee_dominance` |
| [Concentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during concentric phase (0=hip dominant, 1=knee dominant) | `concentric_hip_knee_dominance` |
| [Landing Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during landing phase (0=hip dominant, 1=knee dominant) | `landing_hip_knee_dominance` |
| [Landing Stiffness Index](/biomechanics/activities/jump/metrics/landing-stiffness-index) | N/A | Index of landing stiffness | \`\` |
| [Landing Stiffness Index Level](/biomechanics/activities/jump/metrics/landing-stiffness-index-level) | N/A | Classification of landing stiffness | \`\` |
| [Kinematic Sequence](/biomechanics/activities/jump/metrics/kinematic-sequence) | N/A | Sequence of peak velocities during the jump | \`\` |
| [Kinematic Sequence Array](/biomechanics/activities/jump/metrics/kinematic-sequence-array) | N/A | Array representation of kinematic sequence | \`\` |
### Joint Angles
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------------------- | ------- | ---------------------------------------------------------------------------- | ---------------------------------------- |
| [Left Peak Hip Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum left hip flexion during takeoff | `jumping_left_hip_peak_flexion_angle` |
| [Right Peak Hip Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum right hip flexion during takeoff | `jumping_right_hip_peak_flexion_angle` |
| [Left Peak Knee Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum left knee flexion during takeoff | `jumping_left_knee_peak_flexion_angle` |
| [Right Peak Knee Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum right knee flexion during takeoff | `jumping_right_knee_peak_flexion_angle` |
| [Left Peak Ankle Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum left ankle flexion during takeoff | `jumping_left_ankle_peak_flexion_angle` |
| [Right Peak Ankle Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum right ankle flexion during takeoff | `jumping_right_ankle_peak_flexion_angle` |
| [Left Peak Hip Flexion Landing](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum left hip flexion during landing | `landing_left_hip_peak_flexion_angle` |
| [Right Peak Hip Flexion Landing](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum right hip flexion during landing | `landing_right_hip_peak_flexion_angle` |
| [Left Peak Knee Flexion Landing](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum left knee flexion during landing | `landing_left_knee_peak_flexion_angle` |
| [Right Peak Knee Flexion Landing](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum right knee flexion during landing | `landing_right_knee_peak_flexion_angle` |
| [Left Peak Ankle Flexion Landing](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum left ankle flexion during landing | `landing_left_ankle_peak_flexion_angle` |
| [Right Peak Ankle Flexion Landing](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum right ankle flexion during landing | `landing_right_ankle_peak_flexion_angle` |
| [Left Thigh Sagittal Angle WRT Global](/biomechanics/activities/jump/metrics/thigh-angle-global) | deg | Sagittal angle of the thigh compared to global coordinate system | `left_thigh_angle_global_sagittal` |
| [Left Thigh Frontal Angle WRT Global](/biomechanics/activities/jump/metrics/thigh-angle-global) | deg | Frontal angle of the thigh compared to global coordinate system | `left_thigh_angle_global_frontal` |
| [Left Thigh Twist Angle WRT Global](/biomechanics/activities/jump/metrics/thigh-angle-global) | deg | Twist angle of the thigh compared to global coordinate system | `left_thigh_angle_global_twist` |
| [Left Shank Sagittal Angle WRT Global](/biomechanics/activities/jump/metrics/shank-angle-global) | deg | Sagittal angle of the shank (lower leg) compared to global coordinate system | `left_shank_angle_global_sagittal` |
| [Left Shank Frontal Angle WRT Global](/biomechanics/activities/jump/metrics/shank-angle-global) | deg | Frontal angle of the shank (lower leg) compared to global coordinate system | `left_shank_angle_global_frontal` |
| [Left Shank Twist Angle WRT Global](/biomechanics/activities/jump/metrics/shank-angle-global) | deg | Twist angle of the shank (lower leg) compared to global coordinate system | `left_shank_angle_global_twist` |
| [Right Thigh Sagittal Angle WRT Global](/biomechanics/activities/jump/metrics/thigh-angle-global) | deg | Sagittal angle of the thigh compared to global coordinate system | `right_thigh_angle_global_sagittal` |
| [Right Thigh Frontal Angle WRT Global](/biomechanics/activities/jump/metrics/thigh-angle-global) | deg | Frontal angle of the thigh compared to global coordinate system | `right_thigh_angle_global_frontal` |
| [Right Thigh Twist Angle WRT Global](/biomechanics/activities/jump/metrics/thigh-angle-global) | deg | Twist angle of the thigh compared to global coordinate system | `right_thigh_angle_global_twist` |
| [Right Shank Sagittal Angle WRT Global](/biomechanics/activities/jump/metrics/shank-angle-global) | deg | Sagittal angle of the shank (lower leg) compared to global coordinate system | `right_shank_angle_global_sagittal` |
| [Right Shank Frontal Angle WRT Global](/biomechanics/activities/jump/metrics/shank-angle-global) | deg | Frontal angle of the shank (lower leg) compared to global coordinate system | `right_shank_angle_global_frontal` |
| [Right Shank Twist Angle WRT Global](/biomechanics/activities/jump/metrics/shank-angle-global) | deg | Twist angle of the shank (lower leg) compared to global coordinate system | `right_shank_angle_global_twist` |
### Joint Velocities
| Metric | Units | Description | Column Name |
| -------------------------------------------------------------------------------------------------------------------------------------------------- | --------- | ---------------------------------------------------------------------- | --------------------------------------------- |
| [Left Peak Hip Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip flexion velocity during eccentric phase | \`\` |
| [Right Peak Hip Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip flexion velocity during eccentric phase | \`\` |
| [Left Peak Knee Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee flexion velocity during eccentric phase | \`\` |
| [Right Peak Knee Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee flexion velocity during eccentric phase | \`\` |
| [Left Peak Ankle Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle flexion velocity during eccentric phase | \`\` |
| [Right Peak Ankle Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle flexion velocity during eccentric phase | \`\` |
| [Left Peak Shoulder Flexion Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-shoulder-flexion-velocity-takeoff-concentric) | degrees/s | Maximum left shoulder flexion velocity during concentric phase | \`\` |
| [Right Peak Shoulder Flexion Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-shoulder-flexion-velocity-takeoff-concentric) | degrees/s | Maximum right shoulder flexion velocity during concentric phase | \`\` |
| [Left Peak Hip Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip extension velocity during concentric phase | `jumping_left_hip_peak_extension_velocity` |
| [Right Peak Hip Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip extension velocity during concentric phase | `jumping_right_hip_peak_extension_velocity` |
| [Left Peak Knee Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee extension velocity during concentric phase | `jumping_left_knee_peak_extension_velocity` |
| [Right Peak Knee Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee extension velocity during concentric phase | `jumping_right_knee_peak_extension_velocity` |
| [Left Peak Ankle Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle extension velocity during concentric phase | `jumping_left_ankle_peak_extension_velocity` |
| [Right Peak Ankle Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle extension velocity during concentric phase | `jumping_right_ankle_peak_extension_velocity` |
| [Left Peak Hip Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip flexion velocity during landing eccentric phase | `landing_left_hip_peak_flexion_velocity` |
| [Right Peak Hip Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip flexion velocity during landing eccentric phase | `landing_right_hip_peak_flexion_velocity` |
| [Left Peak Knee Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee flexion velocity during landing eccentric phase | `landing_left_knee_peak_flexion_velocity` |
| [Right Peak Knee Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee flexion velocity during landing eccentric phase | `landing_right_knee_peak_flexion_velocity` |
| [Left Peak Ankle Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle flexion velocity during landing eccentric phase | `landing_left_ankle_peak_flexion_velocity` |
| [Right Peak Ankle Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle flexion velocity during landing eccentric phase | `landing_right_ankle_peak_flexion_velocity` |
| [Left Peak Hip Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip extension velocity during landing concentric phase | \`\` |
| [Right Peak Hip Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip extension velocity during landing concentric phase | \`\` |
| [Left Peak Knee Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee extension velocity during landing concentric phase | \`\` |
| [Right Peak Knee Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee extension velocity during landing concentric phase | \`\` |
| [Left Peak Ankle Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle extension velocity during landing concentric phase | \`\` |
| [Right Peak Ankle Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle extension velocity during landing concentric phase | \`\` |
### Linear Velocities
| Metric | Units | Description | Column Name |
| ----------------------------------------------------------------------------------------------- | ----- | --------------------------------------------------------------- | --------------------------- |
| [Takeoff Velocity](/biomechanics/activities/jump/metrics/takeoff-velocity) | m/s | Vertical velocity at takeoff | `takeoff_velocity` |
| [Eccentric Velocity](/biomechanics/activities/jump/metrics/eccentric-velocity) | m/s | Average velocity during eccentric phase | \`\` |
| [Peak COM Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during eccentric phase | \`\` |
| [Peak COM Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during concentric phase | `jumping_com_peak_velocity` |
| [Peak COM Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing eccentric phase | `landing_com_peak_velocity` |
| [Peak COM Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing concentric phase | \`\` |
## Notes
* Kinematic data typically captured at 120Hz for Jumping
# Drop Vertical Jump
Source: https://docs.uplift.ai/biomechanics/activities/jump/drop_vertical
Biomechanical analysis of drop vertical jump movements, including events, phases, and discrete metrics.
## Overview
The drop vertical jump is a plyometric movement assessment that involves dropping from a platform and immediately performing a maximal vertical jump upon landing. This movement is commonly used in athletic assessment and training as it provides valuable information about reactive strength, neuromuscular coordination, and lower extremity function.
## Instructions
Step off the box or platform (do not jump off). Upon landing with both feet, immediately perform a maximal vertical jump. Land softly. Use the specified arm position (arm-swing or hands-on-hips) consistently for the trial.
## Dimensions
Required inputs for processing:
* **Arm Position**: \['arm-swing','hands-on-hips']
## Phases of the Jump
| Phase | Start | End |
| ------------------ | -------------- | -------------- |
| Jumping | Initiation | Takeoff |
| Jumping Eccentric | Initiation | Bottom |
| Jumping Concentric | Bottom | Takeoff |
| Landing | Landing | Termination |
| Landing Eccentric | Landing | Landing Bottom |
| Landing Concentric | Landing Bottom | Termination |
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Event | Description | Column Name |
| --------------------------------------------------------------------- | ------------------------------------------------------------------------- | ----------------------- |
| [Initiation](/biomechanics/activities/jump/events/initiation) | the start of the jump - when the person begins to move downward | `jump_initiation_frame` |
| [Bottom](/biomechanics/activities/jump/events/bottom) | the lowest point of the pelvis before the jump | `bottom_of_jump_frame` |
| [Takeoff](/biomechanics/activities/jump/events/takeoff) | the instant of leaving the ground | `takeoff_frame` |
| [Peak Height](/biomechanics/activities/jump/events/peak-height) | the instant when maximum height reached | \`\` |
| [Landing](/biomechanics/activities/jump/events/landing) | the instant of ground contact | `jump_landing_frame` |
| [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom) | the lowest point of the pelvis after the jump | \`\` |
| [Termination](/biomechanics/activities/jump/events/termination) | end of the movement - when the person returns to normal standing position | \`\` |
### Distance Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------- | ------ | ---------------------------------------- | ------------------------------------- |
| [Jump Height](/biomechanics/activities/jump/metrics/jump-height) | meters | Maximum height reached during the jump | `jump_height` |
| [Right Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at bottom position | `right_knee_valgus_at_bottom` |
| [Left Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at bottom position | `left_knee_valgus_at_bottom` |
| [Right Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing | `right_knee_valgus_at_landing` |
| [Left Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing | `left_knee_valgus_at_landing` |
| [Right Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing bottom | `right_knee_valgus_at_landing_bottom` |
| [Left Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing bottom | `left_knee_valgus_at_landing_bottom` |
| [Right Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum right knee valgus during landing | \`\` |
| [Left Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum left knee valgus during landing | \`\` |
| [Right Displacement](/biomechanics/activities/jump/metrics/right-displacement) | meters | Lateral displacement during landing | \`\` |
| [Forward Displacement](/biomechanics/activities/jump/metrics/forward-displacement) | meters | Forward displacement during landing | \`\` |
### Movement Flags and Other Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------------------------- | ------- | ---------------------------------------------------------------------------- | ---------------------------------- |
| [Knees Track](/biomechanics/activities/jump/metrics/knees-track) | binary | Binary indicator if knees track properly (1=yes, 0=no) | \`\` |
| [Hips Feet Stationary](/biomechanics/activities/jump/metrics/hips-feet-stationary) | binary | Binary indicator if hips and feet remain stationary | \`\` |
| [High Jump Height](/biomechanics/activities/jump/metrics/high-jump-height) | binary | Binary indicator if jump height exceeds 14 inches (\~0.36 m) | \`\` |
| [Stiff Knee Landing](/biomechanics/activities/jump/metrics/stiff-knee-landing) | binary | Binary indicator of stiff knee landing | \`\` |
| [Flight Time](/biomechanics/activities/jump/metrics/flight-time) | seconds | Time from takeoff to landing | \`\` |
| [RSI Mod](/biomechanics/activities/jump/metrics/reactive-strength-index-modified) | N/A | Reactive Strength Index Modified | `reactive_strength_index_modified` |
| [Eccentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during eccentric phase (0=hip dominant, 1=knee dominant) | `eccentric_hip_knee_dominance` |
| [Concentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during concentric phase (0=hip dominant, 1=knee dominant) | `concentric_hip_knee_dominance` |
| [Landing Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during landing phase (0=hip dominant, 1=knee dominant) | `landing_hip_knee_dominance` |
| [Landing Stiffness Index](/biomechanics/activities/jump/metrics/landing-stiffness-index) | N/A | Index of landing stiffness | \`\` |
| [Landing Stiffness Index Level](/biomechanics/activities/jump/metrics/landing-stiffness-index-level) | N/A | Classification of landing stiffness | \`\` |
| [Eccentric Velocity](/biomechanics/activities/jump/metrics/eccentric-velocity) | m/s | Average velocity during eccentric phase | \`\` |
| [Kinematic Sequence](/biomechanics/activities/jump/metrics/kinematic-sequence) | N/A | Sequence of peak velocities during the jump | \`\` |
| [Kinematic Sequence Array](/biomechanics/activities/jump/metrics/kinematic-sequence-array) | N/A | Array representation of kinematic sequence | \`\` |
### Joint Angles
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------------ | ------- | ------------------------------------------ | ---------------------------------------- |
| [Left Peak Hip Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum left hip flexion during takeoff | `jumping_left_hip_peak_flexion_angle` |
| [Right Peak Hip Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum right hip flexion during takeoff | `jumping_right_hip_peak_flexion_angle` |
| [Left Peak Knee Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum left knee flexion during takeoff | `jumping_left_knee_peak_flexion_angle` |
| [Right Peak Knee Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum right knee flexion during takeoff | `jumping_right_knee_peak_flexion_angle` |
| [Left Peak Ankle Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum left ankle flexion during takeoff | `jumping_left_ankle_peak_flexion_angle` |
| [Right Peak Ankle Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum right ankle flexion during takeoff | `jumping_right_ankle_peak_flexion_angle` |
| [Left Peak Hip Flexion Landing](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum left hip flexion during landing | `landing_left_hip_peak_flexion_angle` |
| [Right Peak Hip Flexion Landing](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum right hip flexion during landing | `landing_right_hip_peak_flexion_angle` |
| [Left Peak Knee Flexion Landing](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum left knee flexion during landing | `landing_left_knee_peak_flexion_angle` |
| [Right Peak Knee Flexion Landing](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum right knee flexion during landing | `landing_right_knee_peak_flexion_angle` |
| [Left Peak Ankle Flexion Landing](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum left ankle flexion during landing | `landing_left_ankle_peak_flexion_angle` |
| [Right Peak Ankle Flexion Landing](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum right ankle flexion during landing | `landing_right_ankle_peak_flexion_angle` |
### Joint Velocities
| Metric | Units | Description | Column Name |
| -------------------------------------------------------------------------------------------------------------------------------------------------- | --------- | ---------------------------------------------------------------------- | --------------------------------------------- |
| [Left Peak Hip Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip flexion velocity during eccentric phase | \`\` |
| [Right Peak Hip Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip flexion velocity during eccentric phase | \`\` |
| [Left Peak Knee Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee flexion velocity during eccentric phase | \`\` |
| [Right Peak Knee Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee flexion velocity during eccentric phase | \`\` |
| [Left Peak Ankle Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle flexion velocity during eccentric phase | \`\` |
| [Right Peak Ankle Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle flexion velocity during eccentric phase | \`\` |
| [Left Peak Shoulder Flexion Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-shoulder-flexion-velocity-takeoff-concentric) | degrees/s | Maximum left shoulder flexion velocity during concentric phase | \`\` |
| [Right Peak Shoulder Flexion Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-shoulder-flexion-velocity-takeoff-concentric) | degrees/s | Maximum right shoulder flexion velocity during concentric phase | \`\` |
| [Left Peak Hip Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip extension velocity during concentric phase | `jumping_left_hip_peak_extension_velocity` |
| [Right Peak Hip Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip extension velocity during concentric phase | `jumping_right_hip_peak_extension_velocity` |
| [Left Peak Knee Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee extension velocity during concentric phase | `jumping_left_knee_peak_extension_velocity` |
| [Right Peak Knee Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee extension velocity during concentric phase | `jumping_right_knee_peak_extension_velocity` |
| [Left Peak Ankle Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle extension velocity during concentric phase | `jumping_left_ankle_peak_extension_velocity` |
| [Right Peak Ankle Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle extension velocity during concentric phase | `jumping_right_ankle_peak_extension_velocity` |
| [Left Peak Hip Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip flexion velocity during landing eccentric phase | `landing_left_hip_peak_flexion_velocity` |
| [Right Peak Hip Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip flexion velocity during landing eccentric phase | `landing_right_hip_peak_flexion_velocity` |
| [Left Peak Knee Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee flexion velocity during landing eccentric phase | `landing_left_knee_peak_flexion_velocity` |
| [Right Peak Knee Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee flexion velocity during landing eccentric phase | `landing_right_knee_peak_flexion_velocity` |
| [Left Peak Ankle Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle flexion velocity during landing eccentric phase | `landing_left_ankle_peak_flexion_velocity` |
| [Right Peak Ankle Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle flexion velocity during landing eccentric phase | `landing_right_ankle_peak_flexion_velocity` |
| [Peak COM Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing eccentric phase | `landing_com_peak_velocity` |
| [Left Peak Hip Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip extension velocity during landing concentric phase | \`\` |
| [Right Peak Hip Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip extension velocity during landing concentric phase | \`\` |
| [Left Peak Knee Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee extension velocity during landing concentric phase | \`\` |
| [Right Peak Knee Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee extension velocity during landing concentric phase | \`\` |
| [Left Peak Ankle Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle extension velocity during landing concentric phase | \`\` |
| [Right Peak Ankle Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle extension velocity during landing concentric phase | \`\` |
### Linear Velocities
| Metric | Units | Description | Column Name |
| ----------------------------------------------------------------------------------------------- | ----- | --------------------------------------------------------------- | --------------------------- |
| [Takeoff Velocity](/biomechanics/activities/jump/metrics/takeoff-velocity) | m/s | Vertical velocity at takeoff | `takeoff_velocity` |
| [Peak COM Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during eccentric phase | \`\` |
| [Peak COM Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during concentric phase | `jumping_com_peak_velocity` |
| [Peak COM Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing eccentric phase | `landing_com_peak_velocity` |
| [Peak COM Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing concentric phase | \`\` |
## Notes
* Kinematic data typically captured at 120Hz for Jumping
# Bottom
Source: https://docs.uplift.ai/biomechanics/activities/jump/events/bottom
The lowest point of the pelvis before the jump.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `bottom_of_jump_frame`
* **Required for QA:** False
* **Measurement:** Lowest pelvis height during the jumping eccentric phase
## Description
Bottom marks the instant when the pelvis reaches its lowest point during the downward (eccentric) phase of the jump, immediately before the concentric push.
This event separates the jumping eccentric phase from the jumping concentric phase.
## Use Cases
* Eccentric vs. concentric phase definition
* Joint angle metrics at bottom (e.g., hip, knee, ankle flexion)
* Knee valgus at bottom
# Initiation
Source: https://docs.uplift.ai/biomechanics/activities/jump/events/initiation
The start of the jump—when the person begins to move downward.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `jump_initiation_frame`
* **Required for QA:** False
* **Measurement:** Start of the jump movement
## Description
Initiation represents the very beginning of the jump when the athlete begins the downward movement (e.g., countermovement or drop). This event is used to define the start of the jumping phase and for calculating phase durations.
## Use Cases
* Jump phase timing analysis
* Eccentric phase duration (initiation to bottom)
* Time to takeoff
# Landing
Source: https://docs.uplift.ai/biomechanics/activities/jump/events/landing
The instant of ground contact after the jump.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `jump_landing_frame`
* **Required for QA:** True
* **Measurement:** First frame of ground contact after flight
## Description
Landing marks the instant when the athlete makes contact with the ground after the flight phase. This event defines the start of the landing phase and is used for landing mechanics and stiffness metrics.
## Use Cases
* Landing phase start
* Flight time (takeoff to landing)
* Knee valgus at landing
* Joint angles at landing
# Landing Bottom
Source: https://docs.uplift.ai/biomechanics/activities/jump/events/landing-bottom
The lowest point of the pelvis after the jump (deepest landing absorption).
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `bottom_of_landing_frame`
* **Required for QA:** False
* **Measurement:** Lowest pelvis height during the landing eccentric phase
## Description
Landing bottom marks the instant when the pelvis reaches its lowest point during the landing absorption (eccentric) phase. This event separates landing eccentric from landing concentric (stand-up) phase.
## Use Cases
* Landing eccentric vs. concentric phase definition
* Landing stiffness and absorption metrics
* Knee valgus at landing bottom
# Peak Height
Source: https://docs.uplift.ai/biomechanics/activities/jump/events/peak-height
The instant when maximum height is reached during the jump.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** \`\`
* **Required for QA:** False
* **Measurement:** Frame at which mid-pelvis keypoint (center of hips) reaches maximum vertical position
## Description
Peak height marks the instant during the flight phase when the athlete's center of mass (mid-pelvis keypoint) reaches its maximum vertical position.
This event occurs between takeoff and landing.
## Use Cases
* Jump height validation
* Asymmetric analysis (time to peak)
* Flight phase segmentation
# Takeoff
Source: https://docs.uplift.ai/biomechanics/activities/jump/events/takeoff
The instant of leaving the ground.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `takeoff_frame`
* **Required for QA:** True
* **Measurement:** Last frame of ground contact before flight
## Description
Takeoff marks the instant when the athlete leaves the ground, ending the jumping concentric phase and beginning the flight phase. Detected using loss of foot contact or vertical velocity threshold.
## Use Cases
* Flight time calculation (takeoff to landing)
* Takeoff velocity and jump height
* Concentric phase duration (bottom to takeoff)
# Termination
Source: https://docs.uplift.ai/biomechanics/activities/jump/events/termination
End of the movement—when the person returns to normal standing position.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `jump_termination_frame`
* **Required for QA:** False
* **Measurement:** End of the jump trial (return to standing)
## Description
Termination marks the end of the jump movement when the athlete has completed the landing and returned to a stable standing position. This event closes the landing phase and the full trial.
## Use Cases
* Landing phase duration (landing to termination)
* Trial length and data trimming
* Balance and stability assessment
# Eccentric Velocity
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/eccentric-velocity
Average velocity during the jumping eccentric (downward) phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** m/s
* **Column Name:** (varies by jump type)
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Higher is better
* **Calculation:** Average center of mass velocity (e.g., vertical) from initiation to bottom
## Description
Eccentric velocity is the average velocity of the center of mass during the downward (eccentric) phase of the jump, from initiation to bottom. It reflects how quickly the athlete loads before the concentric push.
## Use Cases
* Countermovement depth and speed
* Stretch-shortening cycle assessment
* Consistency of loading phase
# Flight Time
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/flight-time
Time from takeoff to landing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s)
* **Column Name:** `jump_flight_time`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Higher is better
* **Calculation:** Landing time − Takeoff time
## Description
Flight time is the duration the athlete spends in the air from the instant of takeoff to the instant of landing. It is used to estimate jump height and is a direct measure of hang time.
## Use Cases
* Jump height estimation (when force plate not available)
* Consistency and variability of jump performance
* Reactive strength (e.g., with drop jump)
# Forward Displacement
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/forward-displacement
Forward displacement during landing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** (varies by jump type)
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Lower is better
* **Measurement:** Forward displacement of the body or center of mass between takeoff and landing
* **Direction:** forward positive (+), backward negative (-)
## Description
Forward displacement measures how far the athlete travels forward during the jump.
In vertical or broad jumps it reflects horizontal drift and landing position consistency.
## Use Cases
* Landing consistency and control
* Broad jump and horizontal jump assessment
* Balance and stability
# High Jump Height
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/high-jump-height
Binary indicator if jump height exceeds 14 inches.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = yes (≥14 in), 0 = no
* **Column Name:** (varies by jump type)
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Threshold:** 14 inches (\~0.36 m)
## Description
High jump height is a binary metric that flags whether the athlete's jump height meets or exceeds 14 inches. It is used as a performance pass/fail or screening threshold in some protocols.
## Use Cases
* Performance screening and standards
* Grouping by performance level
* Return-to-play or readiness criteria
# Hip Knee Dominance
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/hip-knee-dominance
Ratio of hip vs. knee contribution (0 = hip dominant, 1 = knee dominant) during a given phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio (0–1)
* **Column Name:** Varies by phase and jump type (see Events/Phases)
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Relative contribution of hip vs. knee motion during the specified phase
## Events / Phases
This metric can be reported at different events or phases depending on jump type:
* **Eccentric (jumping):** From [Initiation](/biomechanics/activities/jump/events/initiation) to [Bottom](/biomechanics/activities/jump/events/bottom).
* Column examples:
* `eccentric_hip_knee_dominance` (bilateral);
* `right_eccentric_hip_knee_dominance`, `left_eccentric_hip_knee_dominance` (single-leg).
* **Concentric (jumping):** From [Bottom](/biomechanics/activities/jump/events/bottom) to [Takeoff](/biomechanics/activities/jump/events/takeoff).
* Column examples:
* `concentric_hip_knee_dominance` (bilateral);
* `right_concentric_hip_knee_dominance`, `left_concentric_hip_knee_dominance` (single-leg).
* **Landing:** From [Landing](/biomechanics/activities/jump/events/landing) to [Termination](/biomechanics/activities/jump/events/termination).
* Column example:
* `landing_hip_knee_dominance`
## Description
Hip knee dominance describes how much the athlete uses the hip versus the knee during a given phase.
A value of 0 indicates hip-dominant strategy; 1 indicates knee-dominant.
Single-leg jump types may report left/right-specific columns for eccentric and concentric phases; landing is often a single value.
The phase (eccentric, concentric, or landing) determines which column name applies.
## Use Cases
* Movement strategy and injury risk (e.g., knee-dominant loading)
* Coaching and technique feedback
* Bilateral or single-leg comparison across phases
# Hips Feet Stationary
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/hips-feet-stationary
Binary indicator of whether the legs refrain from rotating in or out during the jump.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = yes, 0 = no
* **Column Name:** `hips_feet_stationary`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Assessment of whether hips and feet stay within acceptable position during or after landing
## Description
Hips feet stationary is a binary indicator that the athlete's hips and feet remained facing forward during the jump.
There should be no rotation inwards or outwards during the jumping motion. This metric reflects lower limb stability.
## Use Cases
* Landing stability and balance
* Screening for injury risk
# Jump Height
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/jump-height
Maximum height reached during the jump.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `jump_height`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum vertical displacement of center of mass (or equivalent) during the jump
## Description
Jump height is the maximum height reached during the jump, typically derived from flight time or from the peak vertical position of the center of mass. It is a primary performance outcome for vertical jump assessments.
## Use Cases
* Vertical jump performance
* Power and explosiveness assessment
* Pre/post intervention comparison
# Kinematic Sequence
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/kinematic-sequence
Sequence of peak joint angular velocities during the jump.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `kinematic_sequence`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Order in which segments (e.g., hip-knee-ankle) reach peak angular velocity during the jump
## Description
Kinematic sequence describes the order of peak angular velocities across lower extremity segments (and optionally trunk/arms) during the jump.
An efficient sequence typically progresses from proximal to distal (e.g., hip → knee → ankle), supporting energy transfer and jump height.
## Use Cases
* Technique and sequencing quality
* Comparison with optimal sequence
* Training and coaching feedback
# Kinematic Sequence Array
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/kinematic-sequence-array
Array representation of the sequence of peak segment angular velocities during the jump.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Array
* **Units:** N/A
* **Column Name:** `kinematic_sequence_array`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Ordered array of segment identifiers (e.g., hip, knee, ankle) by time of peak angular velocity
## Description
Kinematic sequence array is the array (or list) form of the kinematic sequence, representing the order in which segments reach peak angular velocity during the jump. It is used for programmatic analysis and comparison with the categorical kinematic sequence metric.
## Use Cases
* Programmatic analysis of sequencing
* Custom thresholds and scoring
* Export and downstream processing
# Knee Valgus
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/knee-valgus
Medial (inward) knee displacement at a specific event or over a phase during the jump.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** Varies by event/phase (see Events/Phases)
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Lower is better
* **Measurement:** Medial displacement of the knee
* **Direction:** outward positive (+), inward negative (-)
## Events / Phases
This metric can be reported at different events or phases depending on jump type:
* **At Bottom:** At the [Bottom](/biomechanics/activities/jump/events/bottom) event (lowest pelvis before the jump).
* Column examples: `right_knee_valgus_at_bottom`, `left_knee_valgus_at_bottom`.
* **At Landing:** At the [Landing](/biomechanics/activities/jump/events/landing) event (first ground contact after flight).
* Column examples: `right_knee_valgus_at_landing`, `left_knee_valgus_at_landing`.
* **At Landing Bottom:** At the [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom) event (deepest absorption after landing).
* Column examples: `right_knee_valgus_at_landing_bottom`, `left_knee_valgus_at_landing_bottom`.
* **Landing Full (max during landing phase):** Maximum valgus from [Landing](/biomechanics/activities/jump/events/landing) to [Termination](/biomechanics/activities/jump/events/termination).
* Column examples: `right_knee_valgus_full_landing`, `left_knee_valgus_full_landing`.
## Description
Knee valgus measures the amount of medial (inward) knee motion at or between specific time points during the jump.
Excessive knee valgus motion (lower than 0.05 m or about 2 inches) is associated with increased injury risk and suboptimal loading.
Knee valgus is reported separately for left and right in bilateral jumps; single-leg jumps may report one side.
The event or phase determines which column name applies.
## Use Cases
* Injury risk screening
* Movement quality and knee control
* Bilateral comparison
* Landing mechanics and ACL risk
# Knees Track
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/knees-track
Binary indicator of whether the knees track properly over the toes during the jump
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = yes *correct*, 0 = no *incorrect*
* **Column Name:** `knees_track`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Measurement:** knee-to-ankle separation ratio: the relative distance between knees and ankles
* Distance threshold: 85% - the the knee-knee distance drops below 85% of the ankle-ankle distance, then the knees do not track
## Description
Knees track is a binary flag indicating whether the knees track properly over the toes during the jump and landing.
Poor tracking (e.g., knee valgus or inward knee motion) is associated with injury risk.
Knees track is determined using the knee to ankle separation ratio, measuring the relative distances between both knees and both ankles.
If the knee-to-knee distance crosses below 85% of the ankle-to-ankle distance, then the knees do not track, flagging suboptimal jumping mechanics.
## Use Cases
* Movement quality and injury risk screening
* Coaching feedback
* Landing mechanics assessment
# Landing Stiffness Index
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/landing-stiffness-index
Index of landing stiffness during the landing phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** N/A (index)
* **Column Name:** (varies by implementation)
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Stiffness or compliance of the lower extremity during landing absorption
## Description
Landing stiffness index quantifies how stiff or compliant the athlete's landing is.
Higher stiffness may indicate a stiffer, less shock-absorbing strategy; lower stiffness (more compliance) typically reflects greater absorption through joint motion.
May be reported with a companion classification (e.g., landing stiffness index level).
## Use Cases
* Landing strategy and injury risk
* Impact absorption assessment
* Screening and intervention feedback
# Landing Stiffness Index Level
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/landing-stiffness-index-level
Classification or level of landing stiffness (e.g., stiff, moderate, compliant).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Categorical
* **Units:** N/A
* **Column Name:** (varies by implementation)
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** Derived from landing stiffness index; categorical label for stiffness level
## Description
Landing stiffness index level is a categorical classification of landing stiffness (e.g., stiff, moderate, compliant) based on the landing stiffness index.
It provides an interpretable category for screening or reporting, compared to the numeric output from [Landing Stiffness Index](/biomechanics/activities/jump/metrics/landing-stiffness-index).
## Use Cases
* Landing strategy classification
* Screening and reporting
* Grouping athletes by landing style
# Peak Ankle Angle
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/peak-ankle-angle
Maximum ankle flexion (dorsiflexion) angle at a given phase or event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees
* **Column Name:** Varies by phase and type; see Events/Phases
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum ankle flexion angle during the specified phase,
## Events / Phases
* **During Takeoff:** Maximum ankle flexion during the jumping phase (initiation to [Takeoff](/biomechanics/activities/jump/events/takeoff)).
* Column examples: `jumping_left_ankle_peak_flexion_angle`, `jumping_right_ankle_peak_flexion_angle` (bilateral); `jumping_ankle_peak_flexion_angle` (single-leg).
* **During Landing:** Maximum ankle flexion during the landing absorption phase ([Landing](/biomechanics/activities/jump/events/landing) to [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom)).
* Column examples: `landing_left_ankle_peak_flexion_angle`, `landing_right_ankle_peak_flexion_angle` (bilateral); `landing_ankle_peak_flexion_angle` (single-leg).
## Description
Peak ankle flexion refers to the maximum ankle dorsiflexion angle during takeoff or landing.
It reflects ankle range of motion, loading, and absorption, and can also help identify side-side asymmetries.
The side and phase determines which column name applies.
## Use Cases
* Ankle contribution and stiffness
* Landing absorption and technique
* Lower extremity sequencing and ROM
# Peak Ankle Velocity
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/peak-ankle-velocity
Maximum ankle angular velocity (flexion or extension).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/s
* **Column Name:** Varies by phase (see Events/Phases); left/right in bilateral, single value in single-leg
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum rate of ankle extension (plantarflexion) during the specified concentric phase
## Events / Phases
This metric can be reported during the following concentric (push/stand-up) phases:
* **Takeoff Concentric:** From [Bottom](/biomechanics/activities/jump/events/bottom) to [Takeoff](/biomechanics/activities/jump/events/takeoff).
* Column examples: `jumping_left_ankle_peak_extension_velocity`, `jumping_right_ankle_peak_extension_velocity` (bilateral); `jumping_ankle_peak_extension_velocity` (single-leg).
* **Landing Concentric:** From [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom) to [Termination](/biomechanics/activities/jump/events/termination).
* Column names vary by implementation; typically left/right in bilateral.
## Description
Peak ankle velocity is the maximum angular velocity of ankle dorsiflexion (flexion) or plantarflexion (extension) during a specific phase of the jump.
It reflects ankle power and contribution to the kinematic sequence.
The phase, direction, and side determines which column name applies.
## Use Cases
* Ankle power and contribution to jump or stand-up
* Distal segment timing in kinematic sequence
* Technique and power assessment
# Peak COM Velocity
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/peak-com-velocity
Maximum center of mass velocity during a specified phase of the jump or landing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** m/s
* **Column Name:** Varies by phase (see Events/Phases)
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum vertical component of center of mass velocity during the specified phase
## Events / Phases
This metric can be reported during the following phases:
* **Takeoff Eccentric:** From [Initiation](/biomechanics/activities/jump/events/initiation) to [Bottom](/biomechanics/activities/jump/events/bottom). Maximum COM velocity during the downward (loading) phase.
* **Takeoff Concentric:** From [Bottom](/biomechanics/activities/jump/events/bottom) to [Takeoff](/biomechanics/activities/jump/events/takeoff).
* Column example: `jumping_com_peak_velocity`. Reflects push-phase effectiveness and correlates with jump height.
* **Landing Eccentric:** From [Landing](/biomechanics/activities/jump/events/landing) to [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom).
* Column example: `landing_com_peak_velocity`. Reflects how fast the body is moving downward during absorption.
* **Landing Concentric:** From [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom) to [Termination](/biomechanics/activities/jump/events/termination). Maximum COM velocity during the stand-up (recovery) phase. Column names vary by implementation.
## Description
Peak COM velocity is the center of mass maximum vertical velocity during a given phase—either the eccentric or concentric portion of the jump or landing.
It is used to assess loading speed, push effectiveness, and landing absorption or recovery. The phase determines which column name applies.
## Use Cases
* Countermovement depth and speed (takeoff eccentric)
* Concentric phase performance and jump height (takeoff concentric)
* Landing absorption and stiffness (landing eccentric)
* Landing recovery (landing concentric)
# Peak Hip Flexion
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/peak-hip-angle
Maximum hip flexion angle at a given phase or event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees
* **Column Name:** Varies by phase and side; see Events/Phases
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum hip flexion angle during the specified phase
## Events / Phases
* **At Takeoff:** Maximum hip flexion during the jumping phase ([Initiation](/biomechanics/activities/jump/events/initiation) to [Takeoff](/biomechanics/activities/jump/events/takeoff)).
* Column examples: `jumping_left_hip_peak_flexion_angle`, `jumping_right_hip_peak_flexion_angle` (bilateral); `jumping_hip_peak_flexion_angle` (single-leg).
* **At Landing:** Maximum hip flexion during the landing absorption phase ([Landing](/biomechanics/activities/jump/events/landing) to [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom)).
* Column examples: `landing_left_hip_peak_flexion_angle`, `landing_right_hip_peak_flexion_angle` (bilateral); `landing_hip_peak_flexion_angle` (single-leg).
## Description
Peak hip flexion refers to the maximum hip flexion angle during takeoff or landing.
It reflects loading depth, technique, and absorption at the hip.
The side and phase determines which column name applies.
## Use Cases
* Hip contribution to jump and landing
* Technique and range of motion
* Bilateral or single-leg comparison
# Peak Hip Extension Velocity
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/peak-hip-velocity
Maximum hip extension angular velocity during a concentric phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/s
* **Column Name:** Varies by phase (see Events/Phases); left/right in bilateral, single value in single-leg
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum rate of hip extension during the specified concentric phase
## Events / Phases
This metric can be reported during the following concentric phases:
* **Takeoff Concentric:** From [Bottom](/biomechanics/activities/jump/events/bottom) to [Takeoff](/biomechanics/activities/jump/events/takeoff).
* Maximum hip extension velocity during the propulsive jumping phase.
* Column examples: `jumping_left_hip_peak_extension_velocity`, `jumping_right_hip_peak_extension_velocity` (bilateral); `jumping_hip_peak_extension_velocity` (single-leg).
* **Landing Concentric:** From [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom) to [Termination](/biomechanics/activities/jump/events/termination).
* Maximum hip extension velocity during the return to stand after landing.
* Column names vary by implementation; left/right in bilateral.
## Description
Peak hip extension velocity is the maximum angular velocity of hip extension during a concentric phase—either the push phase of the jump (takeoff concentric) or the stand-up phase after landing (landing concentric).
It is a key contributor to jump performance and reflects hip power. The phase determines which column name applies.
## Use Cases
* Hip power and contribution to jump or stand-up
* Kinematic sequence (proximal-to-distal)
* Bilateral or single-leg comparison
# Peak Knee Flexion
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/peak-knee-angle
Maximum knee flexion angle over a given phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees
* **Column Name:** Varies by phase and side; see Events/Phases
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum knee flexion angle or maximum knee flexion velocity during the specified phase
## Events / Phases
* **At Takeoff:** Maximum knee flexion during the jumping phase ([Initiation](/biomechanics/activities/jump/events/initiation) to [Takeoff](/biomechanics/activities/jump/events/takeoff)). Column examples: `jumping_left_knee_peak_flexion_angle`, `jumping_right_knee_peak_flexion_angle` (bilateral); `jumping_knee_peak_flexion_angle` (single-leg).
* **At Landing:** Maximum knee flexion during the landing absorption phase ([Landing](/biomechanics/activities/jump/events/landing) to [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom)). Column examples: `landing_left_knee_peak_flexion_angle`, `landing_right_knee_peak_flexion_angle` (bilateral); `landing_knee_peak_flexion_angle` (single-leg).
## Description
Peak knee flexion can refer to the maximum knee flexion angle during takeoff or landing.
It indicates loading depth and absorption; adequate landing flexion is associated with softer landings and lower injury risk.
The side or phase determines which column name applies.
## Use Cases
* Knee contribution and loading depth
* Landing quality and stiff-knee-landing assessment
* ACL and knee injury risk screening
# Peak Knee Extension Velocity
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/peak-knee-velocity
Maximum knee angular velocity, either flexion or extension depending on the phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/s
* **Column Name:** Varies by phase (see Events/Phases); left/right in bilateral, single value in single-leg
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum rate of change of knee angle during the specified concentric phase
## Events / Phases
This metric can be reported during the following concentric phases:
* **Takeoff Concentric:** From [Bottom](/biomechanics/activities/jump/events/bottom) to [Takeoff](/biomechanics/activities/jump/events/takeoff).
* Maximum knee extension velocity during the propulsive jumping phase.
* Column examples: `jumping_left_knee_peak_extension_velocity`, `jumping_right_knee_peak_extension_velocity` (bilateral); `jumping_knee_peak_extension_velocity` (single-leg).
* **Landing Concentric:** From [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom) to [Termination](/biomechanics/activities/jump/events/termination).
* Maximum knee extension velocity during the stand-up phase.
* Column names vary by implementation; left/right in bilateral.
## Description
Peak knee extension velocity is the maximum angular velocity of knee extension during a concentric phase—either the push phase of the jump (takeoff concentric) or the stand-up phase after landing (landing concentric).
It reflects knee power and contribution to takeoff or recovery.
The phase determines which column name applies.
## Use Cases
* Knee power and contribution to jump or stand-up
* Kinematic sequence and timing
* Technique and training assessment
# Peak Shoulder Flexion Velocity Takeoff Concentric
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/peak-shoulder-flexion-velocity-takeoff-concentric
Maximum shoulder flexion velocity during the concentric (push) phase of the jump.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/s
* **Column Name:** (varies by jump type; left/right in bilateral)
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum rate of change of shoulder flexion angle during bottom to takeoff (arm swing)
## Description
Peak shoulder flexion velocity takeoff concentric quantifies the amount of arm swing one uses for a jump.
It specifically measures the maximum angular velocity of shoulder flexion during the concentric (push) phase.
It contributes to jump height and reflects upper body coordination.
Bilateral jumps may report left and right separately.
## Use Cases
* Arm swing contribution to jump height
* Upper-lower body coordination
* Technique and training feedback
# Reactive Strength Index Modified (RSI Mod)
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/reactive-strength-index-modified
Measures ratio of jump height to ground contact time or drop height.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** N/A (ratio)
* **Column Name:** `reactive_strength_index_modified`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Higher is better
* **Measurement:** Jump height divided by appropriate time or drop metric (definition may vary by jump type)
## Description
Reactive Strength Index Modified is a measure of reactive strength and stretch-shortening cycle utilization.
The exact formula may vary by jump type but generally relates jump height to contact time (countermovement jump) or drop height (drop vertical jump).
## Use Cases
* Reactive strength assessment
* Plyometric capacity
* Drop jump and countermovement jump evaluation
# Right Displacement
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/right-displacement
Lateral (side-to-side) displacement during landing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** (varies by jump type)
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Lower is better
* **Measurement:** Lateral displacement of the body (mid pelvis keypoint) between takeoff and landing
* **Direction:** right positive (+), left negative (-)
## Description
Right displacement (or lateral displacement) quantifies how far the athlete moves sideways (left-right) during the jump.
Excessive lateral displacement can indicate reduced control or balance and is relevant for single-leg and bilateral landings.
## Use Cases
* Landing stability and control
* Balance assessment
* Screening for excessive drift
# Shank Angle WRT Global
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/shank-angle-global
Angle of the shank (lower leg) segment relative to the global coordinate system, in a given plane.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees
* **Column Name:** Varies by plane (see Axes Orientation); left/right reported separately
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Shank segment angle in the specified plane (sagittal, frontal, or twist) relative to global reference
## Axes Orientation
This metric is reported for the shank segment in three planes. Column names follow the pattern `left_shank_angle_global_*`, `right_shank_angle_global_*`. The **plane** (and side) determines which column applies:
* **Sagittal:** Anterior–posterior or forward-backward angles, like a somersault
* Column examples: `left_shank_angle_global_sagittal`, `right_shank_angle_global_sagittal`.
* **Frontal:** Medial–lateral or side-side angles, like a cartwheel
* Column examples: `left_shank_angle_global_frontal`, `right_shank_angle_global_frontal`.
* **Twist (transverse):** Twisting rotation like a tornado
* Column examples: `left_shank_angle_global_twist`, `right_shank_angle_global_twist`.
## Description
Shank angle WRT (with respect to) global describes the orientation of the shank (lower leg) segment in the global coordinate system.
Sagittal, frontal, and twist components are reported separately.
Used in some jump types (e.g., countermovement) for segment orientation and research.
The plane (sagittal, frontal, twist) determines which column name applies.
## Use Cases
* Segment orientation and technique
* Bilateral comparison
* Research and detailed kinematics
# Stiff Knee Landing
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/stiff-knee-landing
Binary indicator of stiff knee landing (reduced knee flexion during landing absorption).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = stiff landing present, 0 = no
* **Column Name:** `stiff_knee_landing`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Measurement:** Indicator of insufficient knee flexion during landing absorption
* **Threshold:** under 30 deg for bilateral jumps, under 20 deg for single leg jumps
## Description
Stiff knee landing is a binary flag indicating that the athlete landed with relatively stiff knees.
Stiff landings increase impact forces and are associated with higher injury risk compared to softer landings that use more knee flexion for absorption.
## Use Cases
* Landing technique and injury risk screening
* Coaching feedback for “soft” landings
* ACL and lower extremity injury prevention
# Takeoff Velocity
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/takeoff-velocity
Vertical velocity at takeoff.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** m/s
* **Column Name:** `takeoff_velocity`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Higher is better
* **Measurement:** Vertical component of center of mass velocity at the takeoff event
## Description
Takeoff velocity is the vertical velocity of the center of mass at the instant of takeoff. It directly relates to jump height and reflects the impulse generated during the concentric phase.
## Use Cases
* Jump performance and impulse assessment
* Comparison with jump height (consistency check)
* Force–velocity profiling
# Thigh Angle WRT Global
Source: https://docs.uplift.ai/biomechanics/activities/jump/metrics/thigh-angle-global
Angle of the thigh segment relative to the global coordinate system, in a given plane.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees
* **Column Name:** Varies by plane (see Axes Orientation); left/right reported separately
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Thigh segment angle in the specified plane (sagittal, frontal, or twist) relative to global reference
## Axes Orientation
This metric is reported for the thigh segment in three planes.
Column names follow the pattern `left_thigh_angle_global_*`, `right_thigh_angle_global_*`.
The **plane** (and side) determines which column applies:
* **Sagittal:** Anterior–posterior or forward-backward angles, like a somersault
* Column examples: `left_thigh_angle_global_sagittal`, `right_thigh_angle_global_sagittal`.
* **Frontal:** Medial–lateral or side-side angles, like a cartwheel
* Column examples: `left_thigh_angle_global_frontal`, `right_thigh_angle_global_frontal`.
* **Twist (transverse):** Twisting rotation like a tornado
* Column examples: `left_thigh_angle_global_twist`, `right_thigh_angle_global_twist`.
## Description
Thigh angle WRT (with respect to) global describes the orientation of the thigh segment in the global coordinate system.
Sagittal, frontal, and twist components are reported separately.
Used in some jump types (e.g., countermovement) for segment orientation and research.
The plane (sagittal, frontal, twist) determines which column name applies.
## Use Cases
* Segment orientation and technique
* Bilateral comparison
* Research and detailed kinematics
# Single Leg Jump
Source: https://docs.uplift.ai/biomechanics/activities/jump/single_leg
Biomechanical analysis of single leg jump movements, including events, phases, and discrete metrics.
## Overview
The single leg jump is a unilateral movement assessment that evaluates an athlete's ability to generate power and maintain stability on one leg. This movement provides valuable information about lower extremity strength, balance, and neuromuscular control.
![Example image of a man doing a single leg jump, bottom position]()
## Instructions
Stand on one leg (the stance leg as specified by footedness). Dip slightly by bending the stance knee and hip, then jump as high as possible off that leg. Land on the same leg and absorb the landing. Use the specified arm position (arm-swing or hands-on-hips) consistently. Repeat on the other leg when both sides are assessed.
## Dimensions
Required inputs for processing:
* **Arm Position**: \['arm-swing','hands-on-hips']
* **Footedness**: \['left','right']
## Phases of the Jump
| Phase | Start | End |
| ------------------ | -------------- | -------------- |
| Jumping | Initiation | Takeoff |
| Jumping Eccentric | Initiation | Bottom |
| Jumping Concentric | Bottom | Takeoff |
| Landing | Landing | Termination |
| Landing Eccentric | Landing | Landing Bottom |
| Landing Concentric | Landing Bottom | Termination |
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Event | Description | Column Name |
| --------------------------------------------------------------------- | ------------------------------------------------------------------------- | ----------------------- |
| [Initiation](/biomechanics/activities/jump/events/initiation) | the start of the jump - when the person begins to move downward | `jump_initiation_frame` |
| [Bottom](/biomechanics/activities/jump/events/bottom) | the lowest point of the pelvis before the jump | `bottom_of_jump_frame` |
| [Takeoff](/biomechanics/activities/jump/events/takeoff) | the instant of leaving the ground | `takeoff_frame` |
| [Peak Height](/biomechanics/activities/jump/events/peak-height) | the instant when maximum height reached | \`\` |
| [Landing](/biomechanics/activities/jump/events/landing) | the instant of ground contact | `jump_landing_frame` |
| [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom) | the lowest point of the pelvis after the jump | \`\` |
| [Termination](/biomechanics/activities/jump/events/termination) | end of the movement - when the person returns to normal standing position | \`\` |
### Distance Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------- | ------ | ---------------------------------------- | ------------------------------------- |
| [Jump Height](/biomechanics/activities/jump/metrics/jump-height) | meters | Maximum height reached during the jump | `jump_height` |
| [Right Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at bottom position | `right_knee_valgus_at_bottom` |
| [Left Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at bottom position | `left_knee_valgus_at_bottom` |
| [Right Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing | `right_knee_valgus_at_landing` |
| [Left Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing | `left_knee_valgus_at_landing` |
| [Right Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing bottom | `right_knee_valgus_at_landing_bottom` |
| [Left Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing bottom | `left_knee_valgus_at_landing_bottom` |
| [Right Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum right knee valgus during landing | \`\` |
| [Left Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum left knee valgus during landing | \`\` |
| [Right Displacement](/biomechanics/activities/jump/metrics/right-displacement) | meters | Lateral displacement during landing | \`\` |
| [Forward Displacement](/biomechanics/activities/jump/metrics/forward-displacement) | meters | Forward displacement during landing | \`\` |
### Movement Flags and Other Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------------------------- | ------- | ---------------------------------------------------------------------------------- | ------------------------------------- |
| [Knees Track](/biomechanics/activities/jump/metrics/knees-track) | binary | Binary indicator if knees track properly (1=yes, 0=no) | \`\` |
| [Hips Feet Stationary](/biomechanics/activities/jump/metrics/hips-feet-stationary) | binary | Binary indicator if hips and feet remain stationary | \`\` |
| [High Jump Height](/biomechanics/activities/jump/metrics/high-jump-height) | binary | Binary indicator if jump height exceeds 14 inches (\~0.36 m) | \`\` |
| [Stiff Knee Landing](/biomechanics/activities/jump/metrics/stiff-knee-landing) | binary | Binary indicator of stiff knee landing | \`\` |
| [Flight Time](/biomechanics/activities/jump/metrics/flight-time) | seconds | Time from takeoff to landing | \`\` |
| [RSI Mod](/biomechanics/activities/jump/metrics/reactive-strength-index-modified) | N/A | Reactive Strength Index Modified | `reactive_strength_index_modified` |
| [Right Eccentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Right hip-knee dominance during eccentric phase (0=hip dominant, 1=knee dominant) | `right_eccentric_hip_knee_dominance` |
| [Left Eccentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Left hip-knee dominance during eccentric phase (0=hip dominant, 1=knee dominant) | `left_eccentric_hip_knee_dominance` |
| [Right Concentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Right hip-knee dominance during concentric phase (0=hip dominant, 1=knee dominant) | `right_concentric_hip_knee_dominance` |
| [Left Concentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Left hip-knee dominance during concentric phase (0=hip dominant, 1=knee dominant) | `left_concentric_hip_knee_dominance` |
| [Landing Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during landing phase (0=hip dominant, 1=knee dominant) | `landing_hip_knee_dominance` |
| [Landing Stiffness Index](/biomechanics/activities/jump/metrics/landing-stiffness-index) | N/A | Index of landing stiffness | \`\` |
| [Landing Stiffness Index Level](/biomechanics/activities/jump/metrics/landing-stiffness-index-level) | N/A | Classification of landing stiffness | \`\` |
| [Eccentric Velocity](/biomechanics/activities/jump/metrics/eccentric-velocity) | m/s | Average velocity during eccentric phase | \`\` |
| [Kinematic Sequence](/biomechanics/activities/jump/metrics/kinematic-sequence) | N/A | Sequence of peak velocities during the jump | \`\` |
| [Kinematic Sequence Array](/biomechanics/activities/jump/metrics/kinematic-sequence-array) | N/A | Array representation of kinematic sequence | \`\` |
### Joint Angles
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------ | ------- | ------------------------------------ | ---------------------------------- |
| [Peak Hip Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum hip flexion during takeoff | `jumping_hip_peak_flexion_angle` |
| [Peak Knee Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum knee flexion during takeoff | `jumping_knee_peak_flexion_angle` |
| [Peak Ankle Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum ankle flexion during takeoff | `jumping_ankle_peak_flexion_angle` |
| [Peak Hip Flexion Landing](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum hip flexion during landing | `landing_hip_peak_flexion_angle` |
| [Peak Knee Flexion Landing](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum knee flexion during landing | `landing_knee_peak_flexion_angle` |
| [Peak Ankle Flexion Landing](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum ankle flexion during landing | `landing_ankle_peak_flexion_angle` |
### Joint Velocities
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------------------------------- | --------- | ------------------------------------------------------------- | --------------------------------------- |
| [Peak Hip Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum hip extension velocity during concentric phase | `jumping_hip_peak_extension_velocity` |
| [Peak Knee Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum knee extension velocity during concentric phase | `jumping_knee_peak_extension_velocity` |
| [Peak Ankle Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum ankle extension velocity during concentric phase | `jumping_ankle_peak_extension_velocity` |
| [Peak Hip Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum hip flexion velocity during landing eccentric phase | `landing_hip_peak_flexion_velocity` |
| [Peak Knee Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum knee flexion velocity during landing eccentric phase | `landing_knee_peak_flexion_velocity` |
| [Peak Ankle Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum ankle flexion velocity during landing eccentric phase | `landing_ankle_peak_flexion_velocity` |
### Linear Velocities
| Metric | Units | Description | Column Name |
| ----------------------------------------------------------------------------------------------- | ----- | -------------------------------------------------------------- | --------------------------- |
| [Takeoff Velocity](/biomechanics/activities/jump/metrics/takeoff-velocity) | m/s | Vertical velocity at takeoff | `takeoff_velocity` |
| [Peak COM Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during concentric phase | `jumping_com_peak_velocity` |
| [Peak COM Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing eccentric phase | `landing_com_peak_velocity` |
## Notes
* Kinematic data typically captured at 120Hz for Jumping
# Single Leg Broad Jump
Source: https://docs.uplift.ai/biomechanics/activities/jump/single_leg_broad
Biomechanical analysis of single leg broad jump movements, including events, phases, and discrete metrics.
## Overview
The single leg broad jump is a unilateral horizontal jumping movement assessment that evaluates an athlete's ability to generate horizontal power and maintain stability on one leg during landing. This movement is commonly used in athletic assessment and training as it provides valuable information about unilateral horizontal power, balance, and lower extremity function.
## Instructions
Stand on one leg (the stance leg as specified by footedness). Dip slightly, then jump forward as far as possible off that leg. Land on the same leg and absorb the landing with a soft bend at the hip and knee. Use the specified arm position (arm-swing or hands-on-hips) consistently. Repeat on the other leg when both sides are assessed.
## Dimensions
Required inputs for processing:
* **Arm Position**: \['arm-swing','hands-on-hips']
* **Footedness**: \['left','right']
## Phases of the Jump
| Phase | Start | End |
| ------------------ | -------------- | -------------- |
| Jumping | Initiation | Takeoff |
| Jumping Eccentric | Initiation | Bottom |
| Jumping Concentric | Bottom | Takeoff |
| Landing | Landing | Termination |
| Landing Eccentric | Landing | Landing Bottom |
| Landing Concentric | Landing Bottom | Termination |
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Event | Description | Column Name |
| --------------------------------------------------------------------- | ------------------------------------------------------------------------- | ----------- |
| [Initiation](/biomechanics/activities/jump/events/initiation) | the start of the jump - when the person begins to move downward | \`\` |
| [Bottom](/biomechanics/activities/jump/events/bottom) | the lowest point of the pelvis before the jump | \`\` |
| [Takeoff](/biomechanics/activities/jump/events/takeoff) | the instant of leaving the ground | \`\` |
| [Peak Height](/biomechanics/activities/jump/events/peak-height) | the instant when maximum height reached | \`\` |
| [Landing](/biomechanics/activities/jump/events/landing) | the instant of ground contact | \`\` |
| [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom) | the lowest point of the pelvis after the jump | \`\` |
| [Termination](/biomechanics/activities/jump/events/termination) | end of the movement - when the person returns to normal standing position | \`\` |
### Distance Metrics
| Metric | Units | Description | Column Name |
| ----------------------------------------------------------------------------------------- | ------- | ---------------------------------------------------------------------------- | ----------- |
| [Jump Height](/biomechanics/activities/jump/metrics/jump-height) | meters | Maximum height reached during the jump | \`\` |
| [Flight Time](/biomechanics/activities/jump/metrics/flight-time) | seconds | Time from takeoff to landing | \`\` |
| [Takeoff Velocity](/biomechanics/activities/jump/metrics/takeoff-velocity) | m/s | Vertical velocity at takeoff | \`\` |
| [RSI Mod](/biomechanics/activities/jump/metrics/reactive-strength-index-modified) | N/A | Reactive Strength Index Modified | \`\` |
| [Right Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at bottom position | \`\` |
| [Left Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at bottom position | \`\` |
| [Right Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing | \`\` |
| [Left Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing | \`\` |
| [Right Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing bottom | \`\` |
| [Left Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing bottom | \`\` |
| [Right Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum right knee valgus during landing | \`\` |
| [Left Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum left knee valgus during landing | \`\` |
| [Eccentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during eccentric phase (0=hip dominant, 1=knee dominant) | \`\` |
| [Concentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during concentric phase (0=hip dominant, 1=knee dominant) | \`\` |
| [Landing Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during landing phase (0=hip dominant, 1=knee dominant) | \`\` |
| [Right Displacement](/biomechanics/activities/jump/metrics/right-displacement) | meters | Lateral displacement during landing | \`\` |
| [Forward Displacement](/biomechanics/activities/jump/metrics/forward-displacement) | meters | Forward displacement during landing | \`\` |
### Movement Flags and Other Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------------------------- | ------- | ---------------------------------------------------------------------------- | ----------- |
| [Knees Track](/biomechanics/activities/jump/metrics/knees-track) | binary | Binary indicator if knees track properly (1=yes, 0=no) | \`\` |
| [Hips Feet Stationary](/biomechanics/activities/jump/metrics/hips-feet-stationary) | binary | Binary indicator if hips and feet remain stationary | \`\` |
| [High Jump Height](/biomechanics/activities/jump/metrics/high-jump-height) | binary | Binary indicator if jump height exceeds 14 inches (\~0.36 m) | \`\` |
| [Stiff Knee Landing](/biomechanics/activities/jump/metrics/stiff-knee-landing) | binary | Binary indicator of stiff knee landing | \`\` |
| [Flight Time](/biomechanics/activities/jump/metrics/flight-time) | seconds | Time from takeoff to landing | \`\` |
| [RSI Mod](/biomechanics/activities/jump/metrics/reactive-strength-index-modified) | N/A | Reactive Strength Index Modified | \`\` |
| [Eccentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during eccentric phase (0=hip dominant, 1=knee dominant) | \`\` |
| [Concentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during concentric phase (0=hip dominant, 1=knee dominant) | \`\` |
| [Landing Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during landing phase (0=hip dominant, 1=knee dominant) | \`\` |
| [Landing Stiffness Index](/biomechanics/activities/jump/metrics/landing-stiffness-index) | N/A | Index of landing stiffness | \`\` |
| [Landing Stiffness Index Level](/biomechanics/activities/jump/metrics/landing-stiffness-index-level) | N/A | Classification of landing stiffness | \`\` |
| [Eccentric Velocity](/biomechanics/activities/jump/metrics/eccentric-velocity) | m/s | Average velocity during eccentric phase | \`\` |
| [Kinematic Sequence](/biomechanics/activities/jump/metrics/kinematic-sequence) | N/A | Sequence of peak velocities during the jump | \`\` |
| [Kinematic Sequence Array](/biomechanics/activities/jump/metrics/kinematic-sequence-array) | N/A | Array representation of kinematic sequence | \`\` |
### Joint Angles
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------------ | ------- | ------------------------------------------ | ----------- |
| [Left Peak Hip Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum left hip flexion during takeoff | \`\` |
| [Right Peak Hip Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum right hip flexion during takeoff | \`\` |
| [Left Peak Knee Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum left knee flexion during takeoff | \`\` |
| [Right Peak Knee Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum right knee flexion during takeoff | \`\` |
| [Left Peak Ankle Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum left ankle flexion during takeoff | \`\` |
| [Right Peak Ankle Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum right ankle flexion during takeoff | \`\` |
| [Left Peak Hip Flexion Landing](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum left hip flexion during landing | \`\` |
| [Right Peak Hip Flexion Landing](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum right hip flexion during landing | \`\` |
| [Left Peak Knee Flexion Landing](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum left knee flexion during landing | \`\` |
| [Right Peak Knee Flexion Landing](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum right knee flexion during landing | \`\` |
| [Left Peak Ankle Flexion Landing](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum left ankle flexion during landing | \`\` |
| [Right Peak Ankle Flexion Landing](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum right ankle flexion during landing | \`\` |
### Joint Velocities
| Metric | Units | Description | Column Name |
| -------------------------------------------------------------------------------------------------------------------------------------------------- | --------- | ---------------------------------------------------------------------- | ----------- |
| [Left Peak Hip Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip flexion velocity during eccentric phase | \`\` |
| [Right Peak Hip Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip flexion velocity during eccentric phase | \`\` |
| [Left Peak Knee Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee flexion velocity during eccentric phase | \`\` |
| [Right Peak Knee Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee flexion velocity during eccentric phase | \`\` |
| [Left Peak Ankle Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle flexion velocity during eccentric phase | \`\` |
| [Right Peak Ankle Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle flexion velocity during eccentric phase | \`\` |
| [Peak COM Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during eccentric phase | \`\` |
| [Left Peak Shoulder Flexion Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-shoulder-flexion-velocity-takeoff-concentric) | degrees/s | Maximum left shoulder flexion velocity during concentric phase | \`\` |
| [Right Peak Shoulder Flexion Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-shoulder-flexion-velocity-takeoff-concentric) | degrees/s | Maximum right shoulder flexion velocity during concentric phase | \`\` |
| [Left Peak Hip Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip extension velocity during concentric phase | \`\` |
| [Right Peak Hip Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip extension velocity during concentric phase | \`\` |
| [Left Peak Knee Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee extension velocity during concentric phase | \`\` |
| [Right Peak Knee Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee extension velocity during concentric phase | \`\` |
| [Left Peak Ankle Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle extension velocity during concentric phase | \`\` |
| [Right Peak Ankle Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle extension velocity during concentric phase | \`\` |
| [Peak COM Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during concentric phase | \`\` |
| [Left Peak Hip Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip flexion velocity during landing eccentric phase | \`\` |
| [Right Peak Hip Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip flexion velocity during landing eccentric phase | \`\` |
| [Left Peak Knee Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee flexion velocity during landing eccentric phase | \`\` |
| [Right Peak Knee Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee flexion velocity during landing eccentric phase | \`\` |
| [Left Peak Ankle Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle flexion velocity during landing eccentric phase | \`\` |
| [Right Peak Ankle Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle flexion velocity during landing eccentric phase | \`\` |
| [Peak COM Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing eccentric phase | \`\` |
| [Left Peak Hip Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip extension velocity during landing concentric phase | \`\` |
| [Right Peak Hip Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip extension velocity during landing concentric phase | \`\` |
| [Left Peak Knee Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee extension velocity during landing concentric phase | \`\` |
| [Right Peak Knee Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee extension velocity during landing concentric phase | \`\` |
| [Left Peak Ankle Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle extension velocity during landing concentric phase | \`\` |
| [Right Peak Ankle Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle extension velocity during landing concentric phase | \`\` |
### Linear Velocities
| Metric | Units | Description | Column Name |
| ----------------------------------------------------------------------------------------------- | ----- | --------------------------------------------------------------- | ----------- |
| [Takeoff Velocity](/biomechanics/activities/jump/metrics/takeoff-velocity) | m/s | Vertical velocity at takeoff | \`\` |
| [Peak COM Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during eccentric phase | \`\` |
| [Peak COM Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during concentric phase | \`\` |
| [Peak COM Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing eccentric phase | \`\` |
| [Peak COM Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing concentric phase | \`\` |
## Notes
* Kinematic data typically captured at 120Hz for Jumping
# Squat Jump
Source: https://docs.uplift.ai/biomechanics/activities/jump/squat
Biomechanical analysis of squat jump movements, including events, phases, and discrete metrics.
## Overview
The squat jump is a fundamental movement assessment that involves jumping from a static squat position without a countermovement. This movement is commonly used in athletic assessment and training as it provides valuable information about an athlete's explosive power and lower extremity function.
![Example image of a man doing a squat jump, bottom position]()
## Instructions
Start in a squat position with knees bent (typically to about 90°). Hold briefly without moving, then jump as high as possible without any preliminary dip. Land softly on both feet. Use the specified arm position (arm-swing or hands-on-hips) consistently for the trial.
## Dimensions
Required inputs for processing:
* **Arm Position**: \['arm-swing','hands-on-hips']
## Phases of the Jump
| Phase | Start | End |
| ------------------ | -------------- | -------------- |
| Jumping | Initiation | Takeoff |
| Jumping Eccentric | Initiation | Bottom |
| Jumping Concentric | Bottom | Takeoff |
| Landing | Landing | Termination |
| Landing Eccentric | Landing | Landing Bottom |
| Landing Concentric | Landing Bottom | Termination |
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Event | Description | Column Name |
| --------------------------------------------------------------------- | ------------------------------------------------------------------------- | ----------------------- |
| [Initiation](/biomechanics/activities/jump/events/initiation) | the start of the jump - when the person begins to move downward | `jump_initiation_frame` |
| [Bottom](/biomechanics/activities/jump/events/bottom) | the lowest point of the pelvis before the jump | \`\` |
| [Takeoff](/biomechanics/activities/jump/events/takeoff) | the instant of leaving the ground | `takeoff_frame` |
| [Peak Height](/biomechanics/activities/jump/events/peak-height) | the instant when maximum height reached | \`\` |
| [Landing](/biomechanics/activities/jump/events/landing) | the instant of ground contact | `jump_landing_frame` |
| [Landing Bottom](/biomechanics/activities/jump/events/landing-bottom) | the lowest point of the pelvis after the jump | \`\` |
| [Termination](/biomechanics/activities/jump/events/termination) | end of the movement - when the person returns to normal standing position | \`\` |
### Distance Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------- | ------ | ---------------------------------------- | ------------------------------------- |
| [Jump Height](/biomechanics/activities/jump/metrics/jump-height) | meters | Maximum height reached during the jump | `jump_height` |
| [Right Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at bottom position | `right_knee_valgus_at_landing` |
| [Left Valgus Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at bottom position | `left_knee_valgus_at_landing` |
| [Right Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing | \`\` |
| [Left Valgus Landing](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing | \`\` |
| [Right Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Right knee valgus at landing bottom | `right_knee_valgus_at_landing_bottom` |
| [Left Valgus Landing Bottom](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Left knee valgus at landing bottom | `left_knee_valgus_at_landing_bottom` |
| [Right Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum right knee valgus during landing | \`\` |
| [Left Valgus Landing Full](/biomechanics/activities/jump/metrics/knee-valgus) | meters | Maximum left knee valgus during landing | \`\` |
| [Right Displacement](/biomechanics/activities/jump/metrics/right-displacement) | meters | Lateral displacement during landing | \`\` |
| [Forward Displacement](/biomechanics/activities/jump/metrics/forward-displacement) | meters | Forward displacement during landing | \`\` |
### Movement Flags and Other Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------------------------- | ------- | ---------------------------------------------------------------------------- | ------------------------------- |
| [Knees Track](/biomechanics/activities/jump/metrics/knees-track) | binary | Binary indicator if knees track properly (1=yes, 0=no) | \`\` |
| [Hips Feet Stationary](/biomechanics/activities/jump/metrics/hips-feet-stationary) | binary | Binary indicator if hips and feet remain stationary | \`\` |
| [High Jump Height](/biomechanics/activities/jump/metrics/high-jump-height) | binary | Binary indicator if jump height exceeds 14 inches (\~0.36 m) | \`\` |
| [Stiff Knee Landing](/biomechanics/activities/jump/metrics/stiff-knee-landing) | binary | Binary indicator of stiff knee landing | \`\` |
| [Flight Time](/biomechanics/activities/jump/metrics/flight-time) | seconds | Time from takeoff to landing | \`\` |
| [RSI Mod](/biomechanics/activities/jump/metrics/reactive-strength-index-modified) | N/A | Reactive Strength Index Modified | \`\` |
| [Eccentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during eccentric phase (0=hip dominant, 1=knee dominant) | \`\` |
| [Concentric Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during concentric phase (0=hip dominant, 1=knee dominant) | `concentric_hip_knee_dominance` |
| [Landing Hip Knee Dominance](/biomechanics/activities/jump/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during landing phase (0=hip dominant, 1=knee dominant) | `landing_hip_knee_dominance` |
| [Landing Stiffness Index](/biomechanics/activities/jump/metrics/landing-stiffness-index) | N/A | Index of landing stiffness | \`\` |
| [Landing Stiffness Index Level](/biomechanics/activities/jump/metrics/landing-stiffness-index-level) | N/A | Classification of landing stiffness | \`\` |
| [Kinematic Sequence](/biomechanics/activities/jump/metrics/kinematic-sequence) | N/A | Sequence of peak velocities during the jump | \`\` |
| [Kinematic Sequence Array](/biomechanics/activities/jump/metrics/kinematic-sequence-array) | N/A | Array representation of kinematic sequence | \`\` |
### Joint Angles
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------------ | ------- | ------------------------------------------ | ---------------------------------------- |
| [Left Peak Hip Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum left hip flexion during takeoff | `jumping_left_hip_peak_flexion_angle` |
| [Right Peak Hip Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum right hip flexion during takeoff | `jumping_right_hip_peak_flexion_angle` |
| [Left Peak Knee Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum left knee flexion during takeoff | `jumping_left_knee_peak_flexion_angle` |
| [Right Peak Knee Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum right knee flexion during takeoff | `jumping_right_knee_peak_flexion_angle` |
| [Left Peak Ankle Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum left ankle flexion during takeoff | `jumping_left_ankle_peak_flexion_angle` |
| [Right Peak Ankle Flexion Takeoff](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum right ankle flexion during takeoff | `jumping_right_ankle_peak_flexion_angle` |
| [Left Peak Hip Flexion Landing](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum left hip flexion during landing | `landing_left_hip_peak_flexion_angle` |
| [Right Peak Hip Flexion Landing](/biomechanics/activities/jump/metrics/peak-hip-angle) | degrees | Maximum right hip flexion during landing | `landing_right_hip_peak_flexion_angle` |
| [Left Peak Knee Flexion Landing](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum left knee flexion during landing | `landing_left_knee_peak_flexion_angle` |
| [Right Peak Knee Flexion Landing](/biomechanics/activities/jump/metrics/peak-knee-angle) | degrees | Maximum right knee flexion during landing | `landing_right_knee_peak_flexion_angle` |
| [Left Peak Ankle Flexion Landing](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum left ankle flexion during landing | `landing_left_ankle_peak_flexion_angle` |
| [Right Peak Ankle Flexion Landing](/biomechanics/activities/jump/metrics/peak-ankle-angle) | degrees | Maximum right ankle flexion during landing | `landing_right_ankle_peak_flexion_angle` |
### Joint Velocities
| Metric | Units | Description | Column Name |
| -------------------------------------------------------------------------------------------------------------------------------------------------- | --------- | ---------------------------------------------------------------------- | --------------------------------------------- |
| [Left Peak Hip Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip flexion velocity during eccentric phase | \`\` |
| [Right Peak Hip Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip flexion velocity during eccentric phase | \`\` |
| [Left Peak Knee Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee flexion velocity during eccentric phase | \`\` |
| [Right Peak Knee Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee flexion velocity during eccentric phase | \`\` |
| [Left Peak Ankle Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle flexion velocity during eccentric phase | \`\` |
| [Right Peak Ankle Flexion Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle flexion velocity during eccentric phase | \`\` |
| [Left Peak Shoulder Flexion Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-shoulder-flexion-velocity-takeoff-concentric) | degrees/s | Maximum left shoulder flexion velocity during concentric phase | \`\` |
| [Right Peak Shoulder Flexion Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-shoulder-flexion-velocity-takeoff-concentric) | degrees/s | Maximum right shoulder flexion velocity during concentric phase | \`\` |
| [Left Peak Hip Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip extension velocity during concentric phase | `jumping_left_hip_peak_extension_velocity` |
| [Right Peak Hip Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip extension velocity during concentric phase | `jumping_right_hip_peak_extension_velocity` |
| [Left Peak Knee Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee extension velocity during concentric phase | `jumping_left_knee_peak_extension_velocity` |
| [Right Peak Knee Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee extension velocity during concentric phase | `jumping_right_knee_peak_extension_velocity` |
| [Left Peak Ankle Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle extension velocity during concentric phase | `jumping_left_ankle_peak_extension_velocity` |
| [Right Peak Ankle Extension Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle extension velocity during concentric phase | `jumping_right_ankle_peak_extension_velocity` |
| [Left Peak Hip Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip flexion velocity during landing eccentric phase | `landing_left_hip_peak_flexion_velocity` |
| [Right Peak Hip Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip flexion velocity during landing eccentric phase | `landing_right_hip_peak_flexion_velocity` |
| [Left Peak Knee Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee flexion velocity during landing eccentric phase | `landing_left_knee_peak_flexion_velocity` |
| [Right Peak Knee Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee flexion velocity during landing eccentric phase | `landing_right_knee_peak_flexion_velocity` |
| [Left Peak Ankle Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle flexion velocity during landing eccentric phase | `landing_left_ankle_peak_flexion_velocity` |
| [Right Peak Ankle Flexion Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle flexion velocity during landing eccentric phase | `landing_right_ankle_peak_flexion_velocity` |
| [Left Peak Hip Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum left hip extension velocity during landing concentric phase | \`\` |
| [Right Peak Hip Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-hip-velocity) | degrees/s | Maximum right hip extension velocity during landing concentric phase | \`\` |
| [Left Peak Knee Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum left knee extension velocity during landing concentric phase | \`\` |
| [Right Peak Knee Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-knee-velocity) | degrees/s | Maximum right knee extension velocity during landing concentric phase | \`\` |
| [Left Peak Ankle Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum left ankle extension velocity during landing concentric phase | \`\` |
| [Right Peak Ankle Extension Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-ankle-velocity) | degrees/s | Maximum right ankle extension velocity during landing concentric phase | \`\` |
### Linear Velocities
| Metric | Units | Description | Column Name |
| ----------------------------------------------------------------------------------------------- | ----- | --------------------------------------------------------------- | --------------------------- |
| [Takeoff Velocity](/biomechanics/activities/jump/metrics/takeoff-velocity) | m/s | Vertical velocity at takeoff | `takeoff_velocity` |
| [Eccentric Velocity](/biomechanics/activities/jump/metrics/eccentric-velocity) | m/s | Average velocity during eccentric phase | \`\` |
| [Peak COM Velocity Takeoff Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during eccentric phase | \`\` |
| [Peak COM Velocity Takeoff Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during concentric phase | `jumping_com_peak_velocity` |
| [Peak COM Velocity Landing Eccentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing eccentric phase | `landing_com_peak_velocity` |
| [Peak COM Velocity Landing Concentric](/biomechanics/activities/jump/metrics/peak-com-velocity) | m/s | Maximum center of mass velocity during landing concentric phase | \`\` |
## Notes
* Kinematic data typically captured at 120Hz for Jumping
# Bottom
Source: https://docs.uplift.ai/biomechanics/activities/lunge/events/bottom
The instant of maximum lunge depth, when the pelvis reaches its lowest point.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `lunge_forward_bottom_frame`
* **Required for QA:** True
* **Measurement:** Frame at which the pelvis reaches its peak vertical height (lowest COM position)
## Description
Bottom marks the instant when the pelvis reaches its lowest point during the forward lunge, corresponding to the peak of the vertical pelvis trajectory. This event separates the eccentric (descent) phase from the concentric (ascent/recovery) phase and is the reference frame for bottom-of-lunge metrics such as knee valgus and stance geometry.
## Use Cases
* Eccentric vs. concentric phase definition
* Joint angle metrics at bottom (e.g., knee valgus, hip/knee/ankle flexion)
* Stance length and width measurement
# End
Source: https://docs.uplift.ai/biomechanics/activities/lunge/events/end
The end of the forward lunge, when the athlete returns to the starting position.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `lunge_forward_end_frame`
* **Required for QA:** True
* **Measurement:** Frame at which the lunge movement concludes, detected as the right interpolated base of the pelvis vertical trajectory peak
## Description
End marks the completion of the forward lunge when the athlete has returned to the starting stance position.
It is detected from the pelvis vertical position waveform as the interpolated right boundary (right\_ips) of the peak prominence, and defines the end of the concentric (recovery) phase.
## Use Cases
* Lunge phase timing and duration
* Concentric phase definition (Bottom to End)
* Total rep duration
* Bounds for joint angle range-of-motion metrics
# Initiation
Source: https://docs.uplift.ai/biomechanics/activities/lunge/events/initiation
The start of the forward lunge, when the athlete begins stepping forward.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `lunge_forward_initiation_frame`
* **Required for QA:** True
* **Measurement:** Frame at which the lunge movement begins, detected as the left interpolated base of the pelvis vertical trajectory peak
## Description
Initiation marks the start of the forward lunge when the athlete begins to step forward and descend.
It is detected from the pelvis vertical position waveform as the interpolated left boundary (left\_ips) of the peak prominence, and separates the preparation phase from the loading (descent) phase.
## Use Cases
* Lunge phase timing and duration
* Eccentric phase definition (Initiation to Bottom)
* Total rep duration
# Forward Lunge
Source: https://docs.uplift.ai/biomechanics/activities/lunge/forward
Biomechanical analysis of forward lunge movements, including events, phases, and discrete metrics.
## Overview
The forward lunge is a fundamental movement assessment that evaluates an athlete's ability to perform a stepping motion with proper form and stability.
This movement is commonly used in athletic assessment and training as it provides valuable information about lower extremity strength, balance, and movement patterns.
![Example image of a man doing a forward lunge]()
## Instructions
Stand with feet hip-width apart in a neutral stance.
Step forward with one leg, lowering the back knee toward the ground while keeping the trunk upright.
Drop down as far as possible, being careful to not slam your rear knee into the ground.
Push back through the front foot to return to the starting position.
Perform at a natural, controlled pace without pausing at the bottom.
## Dimensions
Required inputs for processing:
* **Footedness**: \['right', 'left'] — indicates the lead (stepping) leg
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Description | Column Name |
| -------------------------------------------------------------- | --------------------------------------------------------------- | -------------------------------- |
| [Initiation](/biomechanics/activities/lunge/events/initiation) | The start of the lunge when the athlete begins stepping forward | `lunge_forward_initiation_frame` |
| [Bottom](/biomechanics/activities/lunge/events/bottom) | The instant of maximum lunge depth (lowest pelvis position) | `lunge_forward_bottom_frame` |
| [End](/biomechanics/activities/lunge/events/end) | The end of the movement when the athlete returns to standing | `lunge_forward_end_frame` |
### Phases
| Phase | Start | End |
| ------------------- | -------------------------------------------------------------- | ------------------------------------------------------ |
| Eccentric (Descent) | [Initiation](/biomechanics/activities/lunge/events/initiation) | [Bottom](/biomechanics/activities/lunge/events/bottom) |
| Concentric (Ascent) | [Bottom](/biomechanics/activities/lunge/events/bottom) | [End](/biomechanics/activities/lunge/events/end) |
### Knee Metrics
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------- | ------ | ------------------------------------------------- | ----------------------------------- |
| [Right Valgus Bottom](/biomechanics/activities/lunge/metrics/knee-valgus) | meters | Right knee medial displacement at bottom position | `lunge_forward_right_valgus_bottom` |
| [Left Valgus Bottom](/biomechanics/activities/lunge/metrics/knee-valgus) | meters | Left knee medial displacement at bottom position | `lunge_forward_left_valgus_bottom` |
### Movement Strategy Metrics
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------------------ | ----- | ---------------------------------------------------------------- | --------------------------------------------------- |
| [Right Eccentric Hip-Knee Dominance](/biomechanics/activities/lunge/metrics/hip-knee-dominance) | ratio | Right lead leg hip-knee dominance during descent (0=hip, 1=knee) | `lunge_forward_right_eccentric_hip_knee_dominance` |
| [Left Eccentric Hip-Knee Dominance](/biomechanics/activities/lunge/metrics/hip-knee-dominance) | ratio | Left lead leg hip-knee dominance during descent (0=hip, 1=knee) | `lunge_forward_left_eccentric_hip_knee_dominance` |
| [Right Concentric Hip-Knee Dominance](/biomechanics/activities/lunge/metrics/hip-knee-dominance) | ratio | Right lead leg hip-knee dominance during ascent (0=hip, 1=knee) | `lunge_forward_right_concentric_hip_knee_dominance` |
| [Left Concentric Hip-Knee Dominance](/biomechanics/activities/lunge/metrics/hip-knee-dominance) | ratio | Left lead leg hip-knee dominance during ascent (0=hip, 1=knee) | `lunge_forward_left_concentric_hip_knee_dominance` |
### Trunk and Joint Angle Metrics
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------- | ------- | ------------------------------------------------- | --------------------------------------------- |
| [Max Right Trunk Lean](/biomechanics/activities/lunge/metrics/trunk-lean) | degrees | Maximum rightward lateral trunk lean during lunge | `lunge_forward_max_right_trunk_lean` |
| [Max Left Trunk Lean](/biomechanics/activities/lunge/metrics/trunk-lean) | degrees | Maximum leftward lateral trunk lean during lunge | `lunge_forward_max_left_trunk_lean` |
| [Max Right Hip Flexion Angle](/biomechanics/activities/lunge/metrics/hip-flexion) | degrees | Maximum right hip flexion angle during lunge | `lunge_forward_max_right_hip_flexion_angle` |
| [Max Left Hip Flexion Angle](/biomechanics/activities/lunge/metrics/hip-flexion) | degrees | Maximum left hip flexion angle during lunge | `lunge_forward_max_left_hip_flexion_angle` |
| [Max Right Knee Flexion Angle](/biomechanics/activities/lunge/metrics/knee-flexion) | degrees | Maximum right knee flexion angle during lunge | `lunge_forward_max_right_knee_flexion_angle` |
| [Max Left Knee Flexion Angle](/biomechanics/activities/lunge/metrics/knee-flexion) | degrees | Maximum left knee flexion angle during lunge | `lunge_forward_max_left_knee_flexion_angle` |
| [Max Right Ankle Flexion Angle](/biomechanics/activities/lunge/metrics/ankle-flexion) | degrees | Maximum right ankle dorsiflexion during lunge | `lunge_forward_max_right_ankle_flexion_angle` |
| [Max Left Ankle Flexion Angle](/biomechanics/activities/lunge/metrics/ankle-flexion) | degrees | Maximum left ankle dorsiflexion during lunge | `lunge_forward_max_left_ankle_flexion_angle` |
### Distance Metrics
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------- | ------ | ---------------------------------------------------- | ----------------------------- |
| [Lunge Depth](/biomechanics/activities/lunge/metrics/lunge-depth) | meters | Vertical pelvis displacement from baseline to bottom | `lunge_forward_lunge_depth` |
| [Stance Length](/biomechanics/activities/lunge/metrics/stance-dimensions) | meters | Anterior–posterior distance between feet at bottom | `lunge_forward_stance_length` |
| [Stance Width](/biomechanics/activities/lunge/metrics/stance-dimensions) | meters | Medial–lateral distance between feet at bottom | `lunge_forward_stance_width` |
## Notes
* Kinematic data typically captured at 60 Hz for lunging
* Lead leg metrics (valgus, hip-knee dominance) are reported for the stepping leg only; the non-lead side is set to NaN
* Trunk and joint angle metrics are computed over the full lunge window (Initiation to End)
* Stance dimensions are measured at the Bottom event, normalized to pelvis orientation
# Max Ankle Flexion Angle
Source: https://docs.uplift.ai/biomechanics/activities/lunge/metrics/ankle-flexion
Maximum dorsiflexion angle of the right or left ankle during the forward lunge.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `lunge_forward_max_right_ankle_flexion_angle`, `lunge_forward_max_left_ankle_flexion_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum ankle dorsiflexion from [Initiation](/biomechanics/activities/lunge/events/initiation) to [End](/biomechanics/activities/lunge/events/end)
## Description
Max ankle flexion angle is the peak dorsiflexion achieved at each ankle during the lunge.
The 90° offset normalizes the angle so that 0° represents neutral (perpendicular shank–foot alignment).
Greater dorsiflexion reflects better ankle mobility, which supports deeper and more controlled lunge positions.
Both sides are reported regardless of footedness.
## Use Cases
* Ankle dorsiflexion mobility assessment
* Bilateral ankle mobility comparison
* Identifying ankle restrictions limiting lunge depth or form
# Max Hip Flexion Angle
Source: https://docs.uplift.ai/biomechanics/activities/lunge/metrics/hip-flexion
Maximum hip flexion angle of the right or left hip during the forward lunge.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `lunge_forward_max_right_hip_flexion_angle`, `lunge_forward_max_left_hip_flexion_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum hip flexion angle from [Initiation](/biomechanics/activities/lunge/events/initiation) to [End](/biomechanics/activities/lunge/events/end)
## Description
Max hip flexion angle is the greatest hip flexion achieved by each leg during the lunge.
The front (lead) leg typically shows larger hip flexion as it bears load in the deep position, while the rear leg stays neutral or extends slightly.
Both sides are reported regardless of footedness.
## Use Cases
* Hip range of motion assessment
* Bilateral hip mobility comparison
* Loading strategy and lunge depth analysis
# Hip Knee Dominance
Source: https://docs.uplift.ai/biomechanics/activities/lunge/metrics/hip-knee-dominance
Ratio of hip vs. knee contribution (0 = hip dominant, 1 = knee dominant) during eccentric or concentric phase of the forward lunge.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio (0–1)
* **Column Name:** Varies by phase and footedness (see Events / Phases)
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Relative contribution of hip vs. knee flexion motion during the specified phase, computed via vector coding of the lead leg's hip and knee angles
## Events / Phases
* **Eccentric:** From [Initiation](/biomechanics/activities/lunge/events/initiation) to [Bottom](/biomechanics/activities/lunge/events/bottom).
* Column names: `lunge_forward_right_eccentric_hip_knee_dominance` (right footedness), `lunge_forward_left_eccentric_hip_knee_dominance` (left footedness). Non-lead side is NaN.
* **Concentric:** From [Bottom](/biomechanics/activities/lunge/events/bottom) to [End](/biomechanics/activities/lunge/events/end).
* Column names: `lunge_forward_right_concentric_hip_knee_dominance` (right footedness), `lunge_forward_left_concentric_hip_knee_dominance` (left footedness). Non-lead side is NaN.
## Description
Hip knee dominance describes how much the athlete uses the hip versus the knee joint during the descent or ascent of the forward lunge.
A value of 0 indicates a hip-dominant strategy; 1 indicates a knee-dominant strategy.
Only the lead (stepping) leg is computed based on footedness.
The ratio is determined by the relative amount of range of motion used at the hip and knee joints.
## Use Cases
* Movement strategy assessment and coaching feedback
* Injury risk screening (e.g., excessive knee-dominant loading)
* Comparison of eccentric vs. concentric loading strategies
# Max Knee Flexion Angle
Source: https://docs.uplift.ai/biomechanics/activities/lunge/metrics/knee-flexion
Maximum knee flexion angle of the right or left knee during the forward lunge.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `lunge_forward_max_right_knee_flexion_angle`, `lunge_forward_max_left_knee_flexion_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum knee flexion angle from [Initiation](/biomechanics/activities/lunge/events/initiation) to [End](/biomechanics/activities/lunge/events/end)
## Description
Max knee flexion angle is the greatest knee flexion achieved by each leg during the lunge movement. The lead knee typically reaches its maximum flexion near the [Bottom](/biomechanics/activities/lunge/events/bottom) event. Both sides are reported regardless of footedness.
## Use Cases
* Knee range of motion assessment
* Bilateral knee mobility comparison
* Lunge depth and movement quality analysis
# Knee Valgus
Source: https://docs.uplift.ai/biomechanics/activities/lunge/metrics/knee-valgus
Medial knee displacement (valgus) of the lead leg at the bottom of the forward lunge.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `lunge_forward_right_valgus_bottom`, `lunge_forward_left_valgus_bottom`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Lower is better
* **Measurement:** Orthogonal distance of the knee joint center from the hip–foot plane at the [Bottom](/biomechanics/activities/lunge/events/bottom) event
* **Direction:** outward positive (+, varus), inward negative (−, valgus)
## Events / Phases
* **At Bottom:** Measured at the [Bottom](/biomechanics/activities/lunge/events/bottom) event for the lead (stepping) leg.
* Column names: `lunge_forward_right_valgus_bottom` (right footedness), `lunge_forward_left_valgus_bottom` (left footedness). The non-lead leg is set to NaN.
## Description
Knee valgus measures the medial (inward) displacement of the knee joint center relative to the plane defined by the hip and foot at the deepest point of the lunge.
Negative values indicate valgus (knee caving in); positive values indicate varus (knee pushing out).
Only the lead leg is computed based on the movement's reported footedness.
## Use Cases
* Injury risk screening for the lead knee
* Movement quality and knee control during single-leg loading
* Rehabilitation and return-to-sport assessment
# Lunge Depth
Source: https://docs.uplift.ai/biomechanics/activities/lunge/metrics/lunge-depth
Vertical displacement of the pelvis during the forward lunge, reflecting range of motion depth.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `lunge_forward_lunge_depth`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Higher is better
* **Measurement:** Difference between the average pelvis height outside the lunge (before [Initiation](/biomechanics/activities/lunge/events/initiation) and after [End](/biomechanics/activities/lunge/events/end)) and the minimum pelvis height during the lunge
## Description
Lunge depth is the vertical drop of the pelvis from the standing baseline to the lowest position during the forward lunge.
A greater depth indicates a deeper, more demanding lunge.
The baseline is computed as the average pelvis height in frames outside the lunge window (before and after the lunge) to account for subject height variation.
## Use Cases
* Range of motion assessment
* Movement quality and consistency
* Comparison across athletes or over time
# Stance Length and Width
Source: https://docs.uplift.ai/biomechanics/activities/lunge/metrics/stance-dimensions
Anterior–posterior (length) and medial–lateral (width) distance between the feet at the bottom of the forward lunge.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `lunge_forward_stance_length`, `lunge_forward_stance_width`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Higher is better
* **Measurement:** Distance between mid-toe markers at the [Bottom](/biomechanics/activities/lunge/events/bottom) event, normalized to pelvis orientation
## Description
Stance length is the anterior–posterior (fore–aft) distance between the front and rear feet at the bottom of the lunge, measured after rotating the coordinate frame to align with the pelvis orientation.
Stance width is the medial–lateral (side-to-side) distance between the feet at the same instant.
Together, these describe the step geometry adopted by the athlete.
## Use Cases
* Step length and width consistency assessment
* Identification of overly narrow or asymmetric stances
* Comparison across athletes, sessions, or fatigue conditions
# Max Trunk Lean
Source: https://docs.uplift.ai/biomechanics/activities/lunge/metrics/trunk-lean
Maximum lateral trunk lean to the right or left during the forward lunge.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `lunge_forward_max_right_trunk_lean`, `lunge_forward_max_left_trunk_lean`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Measurement:** Maximum frontal-plane trunk angle relative to the pelvis from [Initiation](/biomechanics/activities/lunge/events/initiation) to [End](/biomechanics/activities/lunge/events/end)
## Events / Phases
* Measured from [Initiation](/biomechanics/activities/lunge/events/initiation) to [End](/biomechanics/activities/lunge/events/end).
* `lunge_forward_max_right_trunk_lean`: maximum positive trunk lateral angle (lean toward right)
* `lunge_forward_max_left_trunk_lean`: maximum magnitude of negative trunk lateral angle (lean toward left)
## Description
Max trunk lean captures the greatest lateral deviation of the trunk relative to the pelvis during the lunge movement.
Excessive lateral lean can indicate compensatory strategies related to hip mobility limitations, weakness, or balance deficits.
Reported separately for rightward and leftward lean.
## Use Cases
* Balance and stability assessment during single-leg loading
* Identifying lateral compensation strategies
* Coaching and movement quality feedback
# Side Lunge
Source: https://docs.uplift.ai/biomechanics/activities/lunge/side
Biomechanical analysis of side lunge movements, including events, phases, and discrete metrics.
## Overview
The side lunge is a lateral movement assessment that evaluates an athlete's ability to step to the side with proper form, stability, and lower extremity control.
This movement provides valuable information about hip abductor and adductor strength, lateral knee stability, and frontal-plane movement patterns.
![Example image of a man doing a side lunge]()
## Instructions
Stand with feet hip-width apart in a neutral stance.
Step laterally with one leg, shifting your weight onto the stepping leg and lowering into a lateral squat while keeping the trunk upright and the opposite leg straight.
Drop down as far as possible while maintaining heel contact on the stepping foot.
Push back through the stepping foot to return to the starting position.
Perform at a natural, controlled pace without pausing at the bottom.
## Dimensions
Required inputs for processing:
* **Footedness**: \['right', 'left'] — indicates the stepping leg and direction
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Event | Short Description | Column Name |
| -------------------------------------------------------------- | -------------------------------------------------------------- | ----------------------------- |
| [Initiation](/biomechanics/activities/lunge/events/initiation) | Start of the lunge when the athlete begins stepping laterally. | `lunge_side_initiation_frame` |
| [Bottom](/biomechanics/activities/lunge/events/bottom) | Instant of maximum lunge depth (lowest pelvis position). | `lunge_side_bottom_frame` |
| [End](/biomechanics/activities/lunge/events/end) | End of the movement when the athlete returns to standing. | `lunge_side_end_frame` |
### Phases
| Phase | Start | End |
| ------------------- | -------------------------------------------------------------- | ------------------------------------------------------ |
| Eccentric (Descent) | [Initiation](/biomechanics/activities/lunge/events/initiation) | [Bottom](/biomechanics/activities/lunge/events/bottom) |
| Concentric (Ascent) | [Bottom](/biomechanics/activities/lunge/events/bottom) | [End](/biomechanics/activities/lunge/events/end) |
### Knee Metrics
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------- | ----- | ----------------------------------------- | -------------------------------- |
| [Right Valgus Bottom](/biomechanics/activities/lunge/metrics/knee-valgus) | m | Right knee medial displacement at bottom. | `lunge_side_right_valgus_bottom` |
| [Left Valgus Bottom](/biomechanics/activities/lunge/metrics/knee-valgus) | m | Left knee medial displacement at bottom. | `lunge_side_left_valgus_bottom` |
### Movement Strategy Metrics
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------ | ----- | ----------------------------------------------------------------- | ------------------------------------------------ |
| [Right Eccentric Hip-Knee Dominance](/biomechanics/activities/lunge/metrics/hip-knee-dominance) | ratio | Right lead leg hip-knee dominance during descent (0=hip, 1=knee). | `lunge_side_right_eccentric_hip_knee_dominance` |
| [Left Eccentric Hip-Knee Dominance](/biomechanics/activities/lunge/metrics/hip-knee-dominance) | ratio | Left lead leg hip-knee dominance during descent (0=hip, 1=knee). | `lunge_side_left_eccentric_hip_knee_dominance` |
| [Right Concentric Hip-Knee Dominance](/biomechanics/activities/lunge/metrics/hip-knee-dominance) | ratio | Right lead leg hip-knee dominance during ascent (0=hip, 1=knee). | `lunge_side_right_concentric_hip_knee_dominance` |
| [Left Concentric Hip-Knee Dominance](/biomechanics/activities/lunge/metrics/hip-knee-dominance) | ratio | Left lead leg hip-knee dominance during ascent (0=hip, 1=knee). | `lunge_side_left_concentric_hip_knee_dominance` |
### Trunk and Joint Angle Metrics
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------------------- | ----- | -------------------------------------------------- | ------------------------------------------ |
| [Max Right Trunk Lean](/biomechanics/activities/lunge/metrics/trunk-lean) | deg | Maximum rightward lateral trunk lean during lunge. | `lunge_side_max_right_trunk_lean` |
| [Max Left Trunk Lean](/biomechanics/activities/lunge/metrics/trunk-lean) | deg | Maximum leftward lateral trunk lean during lunge. | `lunge_side_max_left_trunk_lean` |
| [Max Right Hip Flexion Angle](/biomechanics/activities/lunge/metrics/hip-flexion) | deg | Maximum right hip flexion angle during lunge. | `lunge_side_max_right_hip_flexion_angle` |
| [Max Left Hip Flexion Angle](/biomechanics/activities/lunge/metrics/hip-flexion) | deg | Maximum left hip flexion angle during lunge. | `lunge_side_max_left_hip_flexion_angle` |
| [Max Right Knee Flexion Angle](/biomechanics/activities/lunge/metrics/knee-flexion) | deg | Maximum right knee flexion angle during lunge. | `lunge_side_max_right_knee_flexion_angle` |
| [Max Left Knee Flexion Angle](/biomechanics/activities/lunge/metrics/knee-flexion) | deg | Maximum left knee flexion angle during lunge. | `lunge_side_max_left_knee_flexion_angle` |
| [Max Right Ankle Flexion Angle](/biomechanics/activities/lunge/metrics/ankle-flexion) | deg | Maximum right ankle dorsiflexion during lunge. | `lunge_side_max_right_ankle_flexion_angle` |
| [Max Left Ankle Flexion Angle](/biomechanics/activities/lunge/metrics/ankle-flexion) | deg | Maximum left ankle dorsiflexion during lunge. | `lunge_side_max_left_ankle_flexion_angle` |
### Distance Metrics
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------- | ----- | ----------------------------------------------------- | -------------------------- |
| [Lunge Depth](/biomechanics/activities/lunge/metrics/lunge-depth) | m | Vertical pelvis displacement from baseline to bottom. | `lunge_side_lunge_depth` |
| [Stance Length](/biomechanics/activities/lunge/metrics/stance-dimensions) | m | Anterior–posterior distance between feet at bottom. | `lunge_side_stance_length` |
| [Stance Width](/biomechanics/activities/lunge/metrics/stance-dimensions) | m | Medial–lateral distance between feet at bottom. | `lunge_side_stance_width` |
## Notes
* Kinematic data typically captured at 60 Hz for lunges
* Stepping leg metrics (valgus, hip-knee dominance) are reported for the stepping leg only; the non-lead side is set to NaN
* Trunk and joint angle metrics are computed over the full lunge window (Initiation to End)
* Stance width is the primary distance measure for the side lunge; stance length is expected to be near zero
# range_of_motion-ankle_flexion
Source: https://docs.uplift.ai/biomechanics/activities/range_of_motion/ankle_flexion
Biomechanical analysis of ankle dorsiflexion range of motion assessment, including measurement positions and discrete metrics.
## Overview
The ankle dorsiflexion assessment evaluates the range of motion and quality of movement in the ankle joint. This assessment can be performed in either a standing or half-kneel position, and measures the ability to achieve sufficient dorsiflexion while maintaining proper alignment.
## Instructions
**Standing**: With one foot in front of the other, keep your back foot flat on the ground and bend your back knee, pushing your shin towards the ground.
Hold for \~1 second.
**Half-kneeling**: Place one knee on the ground below you and the other leg in front of you with your foot flat on the ground.
Shift your weight forward, pushing your front shin towards the ground and keeping your front foot fully in contact with the ground.
Hold for \~1 second.
## Dimensions
Required inputs for processing:
* **Footedness**: the side *('left', 'right')* of the ankle being tested *(standing: back, half-kneeling: front)*
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Discrete Metrics
| Metric | Units | Description | Column Names |
| ---------------------- | ------- | ------------------------------------------------ | ----------------------------------- |
| AssessmentPosition | - | Assessment position ('standing' or 'half-kneel') | \`\` |
| Footedness | - | Which foot is being tested ('left' or 'right') | \`\` |
| MaxFlexion | Degrees | Maximum dorsiflexion angle | `range_of_motion_max_ankle_flexion` |
| Excursion | Degrees | Total range of motion | \`\` |
| SufficientFlexion | - | Whether flexion is sufficient (≥ 30°) | `sufficient_ankle_flexion` |
| BackKneePassFrontAnkle | - | Whether back knee passes front ankle | \`\` |
## Notes
* Assessment position is determined by knee and hip angles (threshold of 80°)
* Footedness is determined by hip angle patterns
* Sufficient dorsiflexion is defined as ≥ 30°
* Kinematic data typically captured at 30 or 60 Hz for range-of-motion activities
# Cervical Flexion/Extension
Source: https://docs.uplift.ai/biomechanics/activities/range_of_motion/cervical_flexion_extension
Biomechanical analysis of cervical spine flexion and extension range of motion assessment.
## Overview
Cervical flexion/extension evaluates the range of motion and quality of movement in the neck during forward and backward bending. This assessment provides valuable information about cervical spine mobility and function.
## Instructions
From a standing position facing forward, flex the neck bringing your chin close to your chest and hold for \~1 second.
Then extend your neck and look up as far as possible, also holding for \~1 second, before returning to the starting position.
Keep your back straight and shoulders square during the motion.
## Example Videos
## Dimensions
Required inputs for processing:
* **None**
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Discrete Metrics
| Metric | Units | Description | Column Name |
| ----------------------------- | ------- | ---------------------------------------- | ------------------------------------------------------- |
| MaxFlexion | degrees | Maximum cervical flexion (90° offset) | `cervical_peak_flexion` |
| MaxExtension | degrees | Maximum cervical extension (90° offset) | `cervical_peak_extension` |
| FlexionExtensionROM | degrees | Total range of motion | `cervical_flexion_extension_range_of_motion` |
| MaxFlexionSufficient | - | Whether flexion is sufficient (≥ 45°) | `functional_cervical_flexion` |
| MaxExtensionSufficient | - | Whether extension is sufficient (≥ 70°) | `functional_cervical_extension` |
| FlexionExtensionROMSufficient | - | Whether total ROM is sufficient (≥ 115°) | `functional_cervical_flexion_extension_range_of_motion` |
## Notes
* Measurements are based on FreeHeadAngleWRTTrunkXYZ.X with 90° offset
* Sufficient flexion is defined as ≥ 45°
* Sufficient extension is defined as ≥ 70°
* Sufficient total ROM is defined as ≥ 115°
# Cervical Rotation
Source: https://docs.uplift.ai/biomechanics/activities/range_of_motion/cervical_rotation
Biomechanical analysis of cervical spine rotation range of motion assessment.
## Overview
Cervical rotation evaluates the range of motion and quality of movement in the neck during left and right rotation. This assessment provides valuable information about cervical spine mobility and function.
## Instructions
Stand or sit upright with shoulders relaxed and spine in a neutral position. Slowly rotate your head to one side as far as possible without moving your shoulders or trunk. Hold briefly at maximum rotation, then return to center. Repeat on the opposite side.
## Example Videos
### Left
### Right
## Dimensions
Required inputs for processing:
* **Direction**
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Discrete Metrics
| Metric | Units | Description | Column Name |
| -------------------------- | ------- | -------------------------------------------- | ------------------------------------ |
| MaxLeftRotation | degrees | Maximum left rotation angle | `cervical_rotation_left_peak` |
| MaxRightRotation | degrees | Maximum right rotation angle | `cervical_rotation_right_peak` |
| MaxLeftRotationSufficient | - | Whether left rotation is sufficient (≥ 45°) | `cervical_rotation_left_functional` |
| MaxRightRotationSufficient | - | Whether right rotation is sufficient (≥ 45°) | `cervical_rotation_right_functional` |
| FullRotationRangeOfMotion | degrees | Total rotation range of motion | \`\` |
## Notes
* Sufficient rotation is defined as ≥ 45° in each direction
* Measurements are based on HeadAngleWRTTrunkXYZ.Z
* Kinematic data typically captured at 30 or 60 Hz for range-of-motion activities
# SFMA Shoulder Extension
Source: https://docs.uplift.ai/biomechanics/activities/range_of_motion/sfma_shoulder_extension
Biomechanical analysis of SFMA shoulder extension range of motion assessment, including compensations and functional scoring.
## Overview
The SFMA shoulder extension is a standardized movement assessment used in the Selective Functional Movement Assessment (SFMA) protocol to evaluate shoulder extension range of motion and identify potential sources of pain or limitation. This assessment provides valuable information about shoulder mobility and function.
## Instructions
Stand upright with arms at your sides. Reach the testing arm backward as far as possible, keeping the elbow straight and palm facing inward. Avoid rotating the trunk or tilting the pelvis. Hold briefly at maximum extension, then return to the starting position. Repeat on the opposite side.
## Example Videos
### Left
### Right
## Dimensions
Required inputs for processing:
* **Handedness:** the side \['left','right'] performing the movement
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Events
| Event | Description | Column Name |
| --------------- | ----------------------------------------------- | ----------- |
| MaxElbowFlexion | Frame of maximum elbow flexion during extension | \`\` |
## Discrete Metrics
| Metric | Units | Description | Column Name |
| ----------------------- | ------- | ----------------------------------------------- | ------------------------------------------------------ |
| MaxElbowFlexion | Degrees | Maximum elbow flexion angle | \`\` |
| MaxExtensionAngle | Degrees | Maximum shoulder extension angle | `sfma_shoulder_extension_peak_extension_angle` |
| MaxInternalRotation | Degrees | Maximum internal rotation | `sfma_shoulder_extension_peak_internal_rotation_angle` |
| SideBendComp | - | Whether side bend compensation occurred (> 20°) | \`\` |
| WristDeviation | Degrees | Wrist deviation angle | `sfma_shoulder_extension_wrist_deviation` |
| Functional | - | Whether movement is functional | `sfma_shoulder_extension_functional` |
| WristToShoulderDistance | m | Distance from wrist to shoulder | \`\` |
## Notes
* Maximum elbow flexion is detected using peak detection with inverted signal
* The event is used to identify the time point for assessing wrist/fingertip position relative to shoulder
* Functional movement is determined by wrist/fingertip position relative to shoulder
# SFMA Shoulder Flexion
Source: https://docs.uplift.ai/biomechanics/activities/range_of_motion/sfma_shoulder_flexion
Biomechanical analysis of SFMA shoulder flexion range of motion assessment, including compensations and functional scoring.
## Overview
The SFMA shoulder flexion is a standardized movement assessment used in the Selective Functional Movement Assessment (SFMA) protocol to evaluate shoulder flexion range of motion and identify potential sources of pain or limitation. This assessment provides valuable information about shoulder mobility and function.
## Instructions
Stand upright with feet together and arms at your sides. Raise the testing arm forward and overhead as far as possible, keeping the elbow fully extended and thumb pointing up. Avoid arching the lower back or rotating the trunk. Hold briefly at maximum elevation, then return to the starting position. Repeat on the opposite side.
## Example Videos
### Left
### Right
## Dimensions
Required inputs for processing:
* **Handedness:** the side \['left','right'] performing the movement
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Events
| Event | Description | Column Name |
| --------------- | --------------------------------- | ----------- |
| MaxFlexion | Frame of maximum shoulder flexion | \`\` |
| MaxFlexionStart | Frame of movement start | \`\` |
## Discrete Metrics
| Metric | Units | Description | Column Name |
| ----------------------- | ------- | ----------------------------------------------- | ------------------------------------------- |
| MaxFlexionAngle | degrees | Maximum shoulder flexion angle | `sfma_shoulder_flexion_max_flexion_angle` |
| MaxAbductionAngle | degrees | Maximum shoulder abduction angle | `sfma_shoulder_flexion_max_abduction_angle` |
| MaxExternalRotation | degrees | Maximum external rotation | \`\` |
| SideBendComp | - | Whether side bend compensation occurred (> 20°) | \`\` |
| WristDeviation | degrees | Wrist deviation angle | `sfma_shoulder_flexion_wrist_deviation` |
| Functional | - | Whether movement is functional | `sfma_shoulder_flexion_functional` |
| WristToShoulderDistance | m | Distance from wrist to shoulder | \`\` |
## Notes
* Maximum flexion is detected using peak detection with 30° prominence
* If no flexion peak is found, it looks for abduction peaks
* Start event is detected by finding a window of 30 frames where the shoulder flexion difference is less than 0.5 degrees
* Functional movement is determined by wrist/fingertip position relative to shoulder
# Shoulder 90/90
Source: https://docs.uplift.ai/biomechanics/activities/range_of_motion/shoulder_9090
Biomechanical analysis of shoulder 90/90 range of motion assessment for external and internal rotation with compensations.
## Overview
The shoulder 9090 assessment evaluates internal and external rotation range of motion in the shoulder joint with the arm positioned at 90 degrees of abduction and 90 degrees of elbow flexion. This assessment provides valuable information about shoulder mobility and function.
## Instructions
Stand upright and raise the testing arm to 90 degrees of abduction (arm out to the side at shoulder height) with the elbow bent to 90 degrees and forearm pointing forward. From this position, rotate the forearm upward (external rotation) and then downward (internal rotation) as far as possible, keeping the upper arm level. Hold briefly at each end range, then return to neutral. Repeat on the opposite side.
## Example Videos
### Left
### Right
## Dimensions
Required inputs for processing:
* **Handedness:** the side \['left','right'] performing the movement
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Events
| Event | Description | Column Name |
| ----- | ---------------------------------- | ----------- |
| Start | Frame of movement start | |
| MER | Frame of maximum external rotation | |
| MIR | Frame of maximum internal rotation | |
## Discrete Metrics
| Metric | Units | Description | Column Name |
| -------------------------- | ------- | -------------------------------------------------------------------- | -------------------------- |
| MERAngle | degrees | Maximum External Rotation angle | \`\` |
| MIRAngle | degrees | Maximum Internal Rotation angle | \`\` |
| HorizontalAbductionCompMER | - | Horizontal abduction compensation at MER (1 if > 30°, -1 if \< -30°) | \`\` |
| HorizontalAbductionCompMIR | - | Horizontal abduction compensation at MIR (1 if > 30°, -1 if \< -30°) | \`\` |
| SideBendCompMER | - | Side bend compensation at MER (1 if > 20°, -1 if \< -20°) | \`\` |
| SideBendCompMIR | - | Side bend compensation at MIR (1 if > 20°, -1 if \< -20°) | \`\` |
| ElbowHikeCompMER | - | Elbow hike compensation at MER (1 if > 0.05m, -1 if \< -0.05m) | \`\` |
| ElbowHikeCompMIR | - | Elbow hike compensation at MIR (1 if > 0.05m, -1 if \< -0.05m) | \`\` |
| MERFunctional | - | Whether MER is functional (> 90°) | `shoulder_9090_functional` |
## Notes
* MER is detected using peak detection with 30° prominence
* MIR is detected using peak detection with 30° prominence on inverted signal
* Start event is detected by finding a window of 30 frames where the shoulder rotation difference is less than 0.5 degrees
* Functional MER is defined as > 90°
# Shoulder Flexion
Source: https://docs.uplift.ai/biomechanics/activities/range_of_motion/shoulder_flexion
Biomechanical analysis of shoulder flexion and extension range of motion assessment.
## Overview
Shoulder flexion assessment evaluates the range of motion and quality of movement in the shoulder during forward elevation.
## Instructions
Stand upright with arms at your sides. Raise the testing arm forward and overhead as far as possible, keeping the elbow straight and thumb pointing up. Hold briefly at maximum elevation, then lower back to the starting position. Repeat on the opposite side.
## Example Videos
### Left
### Right
## Dimensions
Required inputs for processing:
* **Handedness:** the side \['left','right'] performing the movement
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Discrete Metrics
| Metric | Units | Description | Column Name |
| ------------------- | ------- | --------------------------------------- | --------------------------------------- |
| MaxFlexion | degrees | Maximum shoulder flexion | `shoulder_flexion_max_flexion_angle` |
| MaxExtension | degrees | Maximum shoulder extension | `shoulder_flexion_max_extension_angle` |
| SufficientFlexion | - | Whether flexion is sufficient (≥ 165°) | `shoulder_flexion_functional_flexion` |
| SufficientExtension | - | Whether extension is sufficient (≥ 40°) | `shoulder_flexion_functional_extension` |
## Notes
* Measurements are based on ShoulderAngleWRTTrunkXYZ.X
* Sufficient flexion is defined as ≥ 165°
* Sufficient extension is defined as ≥ 40°
# T-Spine Rotation
Source: https://docs.uplift.ai/biomechanics/activities/range_of_motion/t_spine
Biomechanical analysis of thoracic spine rotation range of motion assessment with compensation detection.
## Overview
T-spine rotation assessment evaluates the range of motion and quality of movement in the thoracic spine during rotation. This assessment provides valuable information about thoracic spine mobility and function.
## Instructions
Kneel or sit upright to minimize lumbar contribution. Cross arms over the chest or place hands behind the head. Rotate the upper body to one side as far as possible, keeping the pelvis stationary and facing forward. Hold briefly at maximum rotation, then return to center. Repeat on the opposite side.
## Example Videos
### Left
### Right
## Dimensions
Required inputs for processing:
* **None**
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Discrete Metrics
| Metric | Units | Description | Column Name |
| ---------------------------- | ------- | --------------------------------------------------- | ----------------------------------------------- |
| Direction | - | The direction of the twist \['left','right] | `t_spine_rotation_direction` |
| Peak Rotation | degrees | Maximum rotation angle, relative to ankles | `t_spine_rotation_peak_trunk_rotation` |
| Functional | - | If both pelvis and trunk rotations > 45° | `t_spine_rotation_functional` |
| Peak Pelvis Rotation | degrees | Maximum pelvis rotation angle, relative to ankles | `t_spine_rotation_peak_pelvis_rotation` |
| Peak Trunk-Pelvis Separation | degrees | Difference between trunk and pelvis rotation angles | `t_spine_rotation_peak_trunk_pelvis_separation` |
## Notes
* Sufficient rotation is defined as ≥ 45°
# Softball: Hitting
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting
Biomechanical analysis of softball hitting movements, including events and metrics for body and bat variables.
Break down the precise timing and sequencing of movements from the pelvis, trunk, and arms, to identify inefficiencies in swing mechanics, improve consistency, and maximize energy transfer from the lower body through the core to the bat.
Uplift offers dozens of events and metrics to track softball hitting for youth to professional athletes.
![Example image of a woman doing a swing, side view]()
## Dimensions
Required Inputs for processing:
* **handedness:** the handedness of the batter \['left', 'right']
## Variables
Output variables from hitting analysis.
### Normative Ranges
See [Softball Hitting Norms](/biomechanics/activities/softball/hitting/softball-hitting-norms) for the full 5th–95th percentile reference tables by competition level (Youth, High School, College, Professional, Broad).
Note: due to relatively low sample size in some subgroups, Softball Hitting Norms are identical for (youth, high school) and (college, pro).
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
Identify specific time points during the hit.
| Event | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------- | ----------------------------------- |
| [Initiation](/biomechanics/activities/softball/hitting/events/initiation) | Lead foot begins to move prior to max knee raise. | `initiation_frame` |
| [Max Foot Raise](/biomechanics/activities/softball/hitting/events/max-foot-raise) | Maximum height of the lead foot. | `max_foot_raise_frame` |
| [Foot Contact](/biomechanics/activities/softball/hitting/events/foot-contact) | Front foot contacts the ground. | `foot_contact_frame` |
| [Pelvis Velocity Initiation (Launch)](/biomechanics/activities/softball/hitting/events/pelvis-velocity-initiation) | Start of pelvis rotation (launch event). | `pelvis_initiation_frame` |
| [Max X Factor](/biomechanics/activities/softball/hitting/events/max-x-factor) | Maximum hip-shoulder separation before the twisting motion. | `max_x_factor_frame` |
| [X Factor Zero Crossing](/biomechanics/activities/softball/hitting/events/x-factor-zero-crossing) | Shoulder-hip separation crosses zero after Max X Factor. | `x_factor_zero_crossing_frame` |
| [Wrist Initiation](/biomechanics/activities/softball/hitting/events/wrist-initiation) | Start of wrist movement during the swing. | `wrist_movement_initiation_frame` |
| [Twist](/biomechanics/activities/softball/hitting/events/twist) | Average timing of peak pelvis, trunk, and arm angular velocities. | `twist_frame` |
| [Peak Pelvis Ang Vel](/biomechanics/activities/softball/hitting/events/peak-pelvis-ang-vel) | Instant of pelvis peak angular velocity. | `peak_pelvis_velocity_frame` |
| [Peak Trunk Ang Vel](/biomechanics/activities/softball/hitting/events/peak-trunk-ang-vel) | Instant of trunk peak angular velocity. | `peak_trunk_velocity_frame` |
| [Peak Arm Ang Vel](/biomechanics/activities/softball/hitting/events/peak-arm-ang-vel) | Instant of lead arm peak angular velocity. | `peak_arm_velocity_frame` |
| [Peak Wrist Angular Velocity](/biomechanics/activities/softball/hitting/events/peak-wrist-angular-velocity) | Instant of maximum wrist angular velocity. | `peak_wrist_angular_velocity_frame` |
| [Ball Contact](/biomechanics/activities/softball/hitting/events/ball-contact) | Estimated timing of ball contact (audio signal primary, swing through secondary). | `ball_contact_frame` |
| [Swing Through](/biomechanics/activities/softball/hitting/events/swing-through) | Rear wrist passes in front of the lead wrist — batter commits to swing. | `swing_through_frame` |
| [Pelvis Velocity Termination](/biomechanics/activities/softball/hitting/events/pelvis-velocity-termination) | First local minimum after peak pelvis velocity. | `pelvis_velocity_termination_frame` |
| [End Twist](/biomechanics/activities/softball/hitting/events/end-twist) | End of twisting motion — X Factor velocity returns to 0 deg/s. | `end_twist_frame` |
### Movement Flags
Find inefficiencies during the hitting motion.
| Metric | Short Description | Column Name |
| ---------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------ | ------------------------------- |
| [Leads With Wrist](/biomechanics/activities/softball/hitting/metrics/leads-with-wrist) | Wrist initiation occurs before pelvis initiation. | `leads_with_wrist` |
| [Sway](/biomechanics/activities/softball/hitting/metrics/sway) | Pelvis drifts backward more than 8 cm (\~3 in) around max knee raise. | `sway` |
| [Sway Leg](/biomechanics/activities/softball/hitting/metrics/sway-leg) | Rear knee passes behind the ankle (away from pitcher). | `sway_leg` |
| [Knee Dominant](/biomechanics/activities/softball/hitting/metrics/knee-dominant) | Rear hip and ankle angles differ \<25° at launch with >15° ankle dorsiflexion. | `knee_dominant_swing` |
| [Vertical Pelvis Hike](/biomechanics/activities/softball/hitting/metrics/vertical-pelvis-hike) | Pelvis finishes higher at ball contact than at launch. | `vertical_pelvis_hike` |
| [Lateral Pelvis Tilt](/biomechanics/activities/softball/hitting/metrics/lateral-pelvis-tilt) | Pelvis tilts upward more than 10 deg during the swing. | `excessive_lateral_pelvis_tilt` |
| [Drifting Forward](/biomechanics/activities/softball/hitting/metrics/drifting-forward) | Pelvis drifts forward more than 15 cm (\~6 in) from launch to ball contact. | `drifting_forward` |
### Kinematic Sequence
Order and magnitude of pelvis, trunk, and upper arm peak rotational velocity (deg/s) during the swing.
| Metric | Units | Short Description | Column Name |
| -------------------------------------------------------------------------------------------------------------- | ----- | ------------------------------------------------------------------------------- | ---------------------------------- |
| [Kinematic Sequence](/biomechanics/activities/softball/hitting/metrics/kinematic-sequence-order) | N/A | Order of peak segment angular velocities. Correct sequence is pelvis-trunk-arm. | `kinematic_sequence_order` |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-pelvis-angular-velocity) | deg/s | Max rotational speed of the pelvis. | `peak_pelvis_angular_velocity` |
| [Peak Trunk Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-trunk-angular-velocity) | deg/s | Max rotational speed of the trunk. | `peak_trunk_angular_velocity` |
| [Peak Arm Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-arm-angular-velocity) | deg/s | Max rotational speed of the lead upper arm. | `peak_arm_angular_velocity` |
| [Trunk to Arm Speed Up](/biomechanics/activities/softball/hitting/metrics/trunk-to-arm-speed-up) | ratio | Speed increase ratio from trunk to arm. | `trunk_to_arm_velocity_speedup` |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/softball/hitting/metrics/pelvis-to-trunk-speed-up) | ratio | Speed increase ratio from pelvis to trunk. | `pelvis_to_trunk_velocity_speedup` |
### Timing & General Metrics
Durations, sequencing info, and general session metadata.
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------ | ----- | ---------------------------------------------------------------- | -------------------------- |
| [Time to Ball Contact](/biomechanics/activities/softball/hitting/metrics/time-to-ball-contact) | s | Duration from initiation to ball contact. | `time_to_ball_contact` |
| [Time to Launch](/biomechanics/activities/softball/hitting/metrics/time-to-launch) | s | Duration from initiation to launch (pelvis velocity initiation). | `time_to_launch` |
| [Pelvis Acceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-acceleration-time) | s | Time from pelvis rotation start to peak pelvis angular velocity. | `pelvis_acceleration_time` |
| [Pelvis Deceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-deceleration-time) | s | Time from peak pelvis angular velocity to end of rotation. | `pelvis_deceleration_time` |
| [Handedness](/biomechanics/activities/softball/hitting/metrics/handedness) | N/A | Batter handedness \['right' or 'left']. | `handedness` |
| [Ball Contact Method](/biomechanics/activities/softball/hitting/metrics/ball-contact-method) | N/A | Detection method: both audio, single audio, or swing through. | `ball_contact_method` |
### Lower Body & Stride
Lower body positions, stride mechanics, and forward movement during the swing.
| Metric | Units | Short Description | Column Name |
| -------------------------------------------------------------------------------------------------------------------- | ----- | ----------------------------------------------------------------------------- | --------------------------------- |
| [Stride Length](/biomechanics/activities/softball/hitting/metrics/stride-length) | m | Lead ankle at foot contact to rear ankle at max foot raise. | `stride_length` |
| [Hip Hinge](/biomechanics/activities/softball/hitting/metrics/hip-hinge) | deg | Max rear hip flexion between max foot raise and foot contact. | `hip_hinge` |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/softball/hitting/metrics/lead-knee-angle-at-ball-contact) | deg | Lead knee flexion at ball contact. | `lead_knee_angle_at_ball_contact` |
| [Drifting Forward Magnitude](/biomechanics/activities/softball/hitting/metrics/drifting-forward-magnitude) | m | Pelvis forward drift from launch to ball contact — see Drifting Forward flag. | `drifting_forward_magnitude` |
### Trunk & X-Factor
Trunk and pelvis rotation angles, coil, and swing plane metrics.
| Metric | Units | Short Description | Column Name |
| -------------------------------------------------------------------------------------------------------------------- | ----- | ----------------------------------------------------------------------------------- | --------------------------------- |
| [Max X Factor](/biomechanics/activities/softball/hitting/metrics/max-x-factor) | deg | Max hip-shoulder separation angle. | `max_x_factor` |
| [Trunk Coil](/biomechanics/activities/softball/hitting/metrics/trunk-coil) | deg | Max trunk rotation away from the pitcher (0 = facing pitcher). | `trunk_coil` |
| [Trunk Tilt at Launch](/biomechanics/activities/softball/hitting/metrics/trunk-tilt-at-launch) | deg | Side-to-side trunk tilt at launch (+ = towards pitcher). | `trunk_tilt_at_launch` |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-flexion) | deg | Trunk flexion to align with the average shoulder rotation plane. | `shoulder_rotation_plane_flexion` |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-tilt) | deg | Trunk tilt to align with the average shoulder rotation plane (+ = towards pitcher). | `shoulder_rotation_plane_tilt` |
### Arm, Hand & Connection
Upper extremity angles, distances, and hand positions relative to the body.
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------------------------------------ | ----- | ---------------------------------------------------------------------------- | ---------------------------------------- |
| [Scap Load at Launch](/biomechanics/activities/softball/hitting/metrics/scap-load-at-launch) | deg | Rear shoulder flexion (+) or extension (-) at launch. | `rear_scap_load_at_launch` |
| [Elbow Flexion at Launch](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-launch) | deg | Rear elbow flexion at launch. | `rear_elbow_flexion_at_launch` |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-ball-contact) | deg | Rear elbow flexion at ball contact. | `rear_elbow_flexion_at_ball_contact` |
| [Rear Arm Connection](/biomechanics/activities/softball/hitting/metrics/rear-arm-connection) | m | Avg distance from rear elbow to mid-torso between launch and ball contact. | `rear_arm_connection` |
| [Inter Elbow Distance at Elbow Slot](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-elbow-slot) | m | Elbow-to-elbow distance at elbow slot. | `inter_elbow_distance_at_elbow_slot` |
| [Inter Elbow Distance at Trunk Peak](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-trunk-peak) | m | Elbow-to-elbow distance at peak trunk angular velocity. | `inter_elbow_distance_at_trunk_peak` |
| [Inter Elbow Distance at Ball Contact](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-ball-contact) | m | Elbow-to-elbow distance at ball contact. | `inter_elbow_distance_at_ball_contact` |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-towards-pitcher) | m | Wrist position relative to mid-shoulders along pitcher axis at foot contact. | `relative_hand_position_towards_pitcher` |
| [Relative Hand Position - Up](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-up) | m | Wrist height relative to mid-shoulders at foot contact. | `relative_hand_position_up` |
| [Relative Hand Position - Away from Body](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-away-from-body) | m | Wrist distance away from mid-shoulders (lateral) at foot contact. | `relative_hand_position_away_from_body` |
| [Linear Stretch](/biomechanics/activities/softball/hitting/metrics/linear-stretch) | m | Lead ankle to wrist center distance along pitch direction at foot contact. | `linear_stretch` |
### Time Series Metrics
Metrics describing motion over the duration of the capture, changing values with every frame.
Use in combination with the keypoints and kinematics from [Generic Outputs](/biomechanics/generic-outputs).
| Metric | Units | Short Description | Column Name |
| ----------------------------------------------------------------------------------------------------------- | ----- | ---------------------------------------------------------- | ----------------------------- |
| [Trunk Center of Mass Position X](/biomechanics/activities/softball/hitting/metrics/trunk-center-of-mass-x) | m | Trunk COM X position. | `trunk_center_of_mass_x` |
| [Trunk Center of Mass Position Y](/biomechanics/activities/softball/hitting/metrics/trunk-center-of-mass-y) | m | Trunk COM Y position (vertical). | `trunk_center_of_mass_y` |
| [Trunk Center of Mass Position Z](/biomechanics/activities/softball/hitting/metrics/trunk-center-of-mass-z) | m | Trunk COM Z position. | `trunk_center_of_mass_z` |
| [Body Center of Mass Position X](/biomechanics/activities/softball/hitting/metrics/body-center-of-mass-x) | m | Whole-body COM X position. | `whole_body_center_of_mass_x` |
| [Body Center of Mass Position Y](/biomechanics/activities/softball/hitting/metrics/body-center-of-mass-y) | m | Whole-body COM Y position (vertical). | `whole_body_center_of_mass_y` |
| [Body Center of Mass Position Z](/biomechanics/activities/softball/hitting/metrics/body-center-of-mass-z) | m | Whole-body COM Z position. | `whole_body_center_of_mass_z` |
| [Trunk Global Flexion](/biomechanics/activities/softball/hitting/metrics/trunk-global-flexion) | deg | Trunk sagittal plane flexion relative to global frame. | `trunk_global_flexion` |
| [Trunk Global Tilt](/biomechanics/activities/softball/hitting/metrics/trunk-global-tilt) | deg | Trunk frontal plane tilt relative to global frame. | `trunk_global_tilt` |
| [Trunk Global Rotation](/biomechanics/activities/softball/hitting/metrics/trunk-global-rotation) | deg | Trunk transverse plane rotation relative to global frame. | `trunk_global_rotation` |
| [Pelvis Global Tilt](/biomechanics/activities/softball/hitting/metrics/pelvis-global-tilt) | deg | Pelvis frontal plane tilt relative to global frame. | `pelvis_global_tilt` |
| [Pelvis Global Rotation](/biomechanics/activities/softball/hitting/metrics/pelvis-global-rotation) | deg | Pelvis transverse plane rotation relative to global frame. | `pelvis_global_rotation` |
### Bat Metrics
Descriptors of bat positions, speeds, and more during the swing.
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------------------------------------ | ----- | ------------------------------------------------------------------------------ | ----------------------------------------- |
| [Attack Angle](/biomechanics/activities/softball/hitting/metrics/attack-angle) | deg | Bat path angle relative to horizontal at contact. | `attack_angle` |
| [On Plane Efficiency](/biomechanics/activities/softball/hitting/metrics/on-plane-efficiency) | % | % of swing path within 10 deg of optimal plane (foot contact to ball contact). | `on_plane_efficiency` |
| [Launch Position](/biomechanics/activities/softball/hitting/metrics/launch-position) | deg | Bat angle relative to spine in the sagittal plane at launch. | `launch_position` |
| [Sweet Spot Fore Aft Position At Contact](/biomechanics/activities/softball/hitting/metrics/sweet-spot-fore-aft-position-at-contact) | m | Fore/aft position of bat sweet spot relative to pelvis at contact. | `sweet_spot_fore_aft_position_at_contact` |
| [Attack Direction](/biomechanics/activities/softball/hitting/metrics/attack-direction) | deg | Horizontal bat angle relative to home plate (indicates hit direction). | `attack_direction` |
| [Swing Path](/biomechanics/activities/softball/hitting/metrics/swing-path-angle) | deg | Vertical bat path angle in the 0.04 s leading up to ball contact. | `swing_path_angle` |
## Notes
* Kinematic data typically captured at 240Hz for Softball Hitting
* All boolean variables (true/false = 1/0) return -1 if metric unable to be calculated.
# Ball Contact
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/ball-contact
The estimated timing of ball contact - determined by audio signal (primary) or swing through event (secondary, if ball contact not detected or detected outside of foot contact and end twist events).
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `ball_contact_frame`
* **Required for QA:** True
* **Primary Detection:** Audio signal analysis
* **Secondary Detection:** Swing through event
* **Validation:** Audio-based ball contact must occur between foot contact and end twist events.
If not, uses swing through event (when the rear wrist passes in front of the lead wrist).
## Description
Ball contact represents the instant when the bat makes contact with the ball.
This is detected primarily through audio analysis, using a model to identify the hit "crack".
The secondary detection method ([Swing Through](/biomechanics/activities/softball/hitting/events/swing-through)) is useful for capturing environment where other athletes are hitting.
Audio-based ball contact detection could pick up other nearby hitters nearby.
## Use Cases
* Largely determines body and bat metrics at ball contact
* Swing sequence completion
* Must occur in correct sequence, otherwise fails QA.
# Elbow Slot
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/elbow-slot
When the rear elbow drops downward in preparation for the arm swing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** TBD
* **Required for QA:** False
* **Detection Method:** Hip shoulder separation (X Factor) velocity returns to 0 deg/s
* **Timing:** Must occur after X Factor zero crossing
## Description
End twist marks the completion of the twisting motion, indicated by when hip shoulder separation
(X Factor) velocity returns to zero, indicating the end of trunk rotation.
## Use Cases
* Arm positioning during the swing
* Transition from body to arm
# End Twist
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/end-twist
Finds the end of the twisting motion: after X Factor zero crossing, when X Factor velocity returns to 0 deg/s. This marks the completion of the twisting motion and swing overall.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `end_twist_frame`
* **Required for QA:** True
* **Detection Method:** Hip shoulder separation (X Factor) velocity returns to 0 deg/s
* **Timing:** Must occur after X Factor zero crossing
## Description
End twist marks the completion of the twisting motion, indicated by when hip shoulder separation
(X Factor) velocity returns to zero, indicating the end of trunk rotation.
## Use Cases
* Twist completion analysis
* Swing sequence timing
# Foot Contact
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/foot-contact
The instant the front foot fully contacts the ground and begins accepting weight.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `foot_contact_frame`
* **Required for QA:** False
* **Detection Method:** Velocity-based analysis
* **Threshold:** 0.2 m/s vertical velocity for 5 consecutive frames
## Description
Foot contact marks the moment when the lead foot fully makes contact with the ground and begins accepting weight.\
Determined by finding the max downward velocity of the lead ankle after max foot raise,
then searching forward for 5 consecutive frames with an ankle vertical velocity below 0.2 m/s."
Foot contact is crucial for timing analysis and is used as a reference point for many other swing event and metrics.
## Use Cases
* Stride timing analysis
* Swing sequence timing
* Balance and stability assessmentS
# Initiation
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/initiation
The initiation event marks when the lead foot begins to move prior to max knee raise. This marks the starting point of the swing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `initiation_frame`
* **Required for QA:** False
* **Measurement:** First detectable movement of lead foot
* **Timing:** Before max knee raise event
## Description
The initiation event represents the very beginning of the swing sequence when the batter starts to move their lead foot.
Identified by the leading 5th percentile height of the max foot raise peak.
## Use Cases
* Swing timing analysis
* Event timing comparisons - time to launch, time to contact
# Max Foot Raise
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/max-foot-raise
The maximum height of the lead foot during the swing. This event marks the peak elevation of the lead foot and is important for analyzing stride mechanics and balance.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `max_foot_raise_frame`
* **Measurement:** Peak vertical position of lead foot
* **Timing:** During swing sequence
## Description
The max foot raise event identifies the instant when the lead foot reaches its highest point during the swing.
This is an important indicator event, helping to break down the swing into events/phases and assisting with detecting other events.
## Use Cases
* Swing Segmentation
* Swing timing evaluation
# Max X Factor
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/max-x-factor
The instant of maximum separation between shoulders and hips before the twisting motion of the swing. This represents the peak loading phase in preparation for the swing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `max_x_factor_frame`
* **Measurement:** Maximum shoulder-hip separation angle (usually negative as its backwards twisting)
* **Phase:** Loading phase before rotation
## Description
The max X factor event identifies the moment of maximum separation between the shoulders and hips, representing the maximum amount of coil before the explosive rotation begins for the swing.
## Use Cases
* Loading phase analysis
* Power generation assessment
* Swing sequence timing
* Energy transfer evaluation
# Peak Arm Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/peak-arm-ang-vel
The instant of lead arm peak angular velocity.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_arm_velocity_frame`
* **Peak Detection Parameters:**
* Minimum height: 250 deg/s
* Minimum prominence: 500 deg/s
* Distance to next peak: 24 frames (0.1 s)
* Minimum width: 0.025 s (6 frames)
## Description
This event identifies the moment when the lead upper arm reaches its maximum angular velocity during the swing, representing the peak of the arm kinetic energy.
## Use Cases
* Arm power analysis
* Upper body mechanics assessment
* Peak velocity timing
* Swing sequence evaluation
# Peak Pelvis Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/peak-pelvis-ang-vel
The instant of pelvis peak angular velocity.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_pelvis_velocity_frame`
* **Peak Detection Parameters:**
* Minimum height: 250 deg/s
* Minimum prominence: 250 deg/s
* Distance to next peak: 24 frames (0.1 s)
* Minimum width: 0.1 s (24 frames)
## Description
This event identifies the moment when the pelvis reaches its maximum angular velocity during the swing, representing the peak of the lower body kinetic energy.
## Use Cases
* Pelvis power analysis
* Lower body mechanics assessment
* Peak velocity timing
* Swing sequence evaluation
# Peak Trunk Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/peak-trunk-ang-vel
The instant of trunk peak angular velocity.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_trunk_velocity_frame`
* **Peak Detection Parameters:**
* Minimum height: 250 deg/s
* Minimum prominence: 250 deg/s
* Distance to next peak: 24 frames (0.1 s)
* Minimum width: 0.1 s (24 frames)
## Description
This event identifies the moment when the trunk reaches its maximum angular velocity during the swing, representing the peak of the trunk kinetic energy.
## Use Cases
* Trunk power analysis
* Core mechanics assessment
* Peak velocity timing
* Swing sequence evaluation
# Peak Wrist Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/peak-wrist-angular-velocity
The instant of maximum wrist angular velocity during the swing. This represents the peak of the final acceleration phase when the wrists generate maximum bat speed.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `peak_wrist_angular_velocity_frame`
* **Measurement:** Maximum wrist angular velocity
* **Phase:** Final acceleration phase
## Description
This event identifies the moment when the wrists reach their maximum angular velocity, representing the peak of the final acceleration phase and maximum bat speed generation.
## Use Cases
* Wrist mechanics analysis
* Bat speed generation assessment
* Final acceleration timing
* Swing sequence evaluation
# Pelvis Velocity Initiation (Launch)
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/pelvis-velocity-initiation
The start of pelvis rotation - also known as launch event. Determined as the leading edge of the pelvis angular velocity waveform. This marks the beginning of the power generation phase.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `pelvis_initiation_frame`
* **Detection Method:** Last local minimum before peak pelvis angular velocity
* **Alternative Name:** Launch event
## Description
The pelvis velocity initiation event marks the beginning of the power generation phase when the pelvis starts rotating.
This is often called the "launch" event and is critical for understanding the kinetic chain sequence.
## Use Cases
* Power generation analysis
* Kinetic chain evaluation
* Swing timing assessment
* Launch position measurements
# Pelvis Velocity Termination
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/pelvis-velocity-termination
The trailing edge of the pelvis angular velocity waveform. This marks the end of the pelvis rotation phase and the completion of lower body power generation.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `pelvis_velocity_termination_frame`
* **Detection Method:** First local minimum after peak pelvis velocity
* **Phase:** End of pelvis rotation
## Description
Pelvis velocity termination marks the end of the pelvis rotation phase when the pelvis angular velocity reaches its first local minimum after peak velocity, indicating completion of lower body power generation.
## Use Cases
* Pelvis rotation analysis
* Power generation completion
* Lower body mechanics assessment
* Swing sequence timing
# Swing Through
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/swing-through
The instant the rear wrist passes in front of the lead wrist, corresponding to a batter committing to a swing (would be a strike). Swing through is used as a backup estimate for ball contact.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `swing_through_frame`
* **Measurement:** Rear wrist passing lead wrist (closer to the pitcher)
* **Significance:** Estimate for ball contact and indicator of swing commitment
## Description
Swing through marks the moment when the rear wrist passes in front of the lead wrist (closer to the pitcher), indicating that the batter has committed to the swing and it would be considered a strike.
## Use Cases
* Swing commitment analysis
* Strike zone assessment
* Swing completion timing
* Decision-making evaluation
# Twist
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/twist
The average timing of peak angular velocities for the pelvis, trunk, and arm. Used to identify the timing of the major twisting motion during the swing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `twist_frame`
* **Calculation:** Average of peak angular velocity events
* **Segments:** Pelvis, trunk, and arm
## Description
The twist event represents the average timing of peak angular velocities across the major body segments (pelvis, trunk, and arm), identifying the core of the twisting motion during the swing.
## Use Cases
* Twist timing analysis
* Segment coordination assessment
* Swing sequence evaluation
* Power transfer analysis
# Wrist Initiation
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/wrist-initiation
The start of the wrist movement during the swing. Finds the last local minimum before peak wrist angular velocity. This marks the beginning of the final acceleration phase.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `wrist_movement_initiation_frame`
* **Detection Method:** Last local minimum before peak wrist angular velocity
* **Phase:** Final acceleration phase
## Description
Wrist initiation marks the beginning of the final acceleration phase when the wrists start moving to generate bat speed. This event is crucial for understanding the complete kinetic chain sequence.
## Use Cases
* Final acceleration analysis
* Kinetic chain evaluation
* Bat speed generation assessment
* Swing sequence timing
# X Factor Zero Crossing
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/events/x-factor-zero-crossing
When the shoulder-hip separation crosses zero after Max X Factor. This marks the transition from loading to acceleration phase as the shoulders catch up to the hips.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `x_factor_zero_crossing_frame`
* **Measurement:** Zero crossing of shoulder-hip separation
* **Timing:** After max X factor event
## Description
The X factor zero crossing event marks the transition from the loading phase to the acceleration phase when the shoulder-hip separation crosses zero, indicating that the torso rotation angle catches up to the pelvis rotation angle.
## Use Cases
* Phase transition analysis
* Acceleration timing assessment
* Swing sequence evaluation
* Power transfer analysis
# Attack Angle
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/attack-angle
Angle relative to forward horizontal that the bat sweet spot moves through in the frames leading up to ball contact. Positive value indicates the bat sweet spot is moving upwards at that angle, vice versa for negative.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `attack_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Bat position relative to the front of home plate
* **Time Period:** 3 frames before ball contact to 1 frame after ball contact
* **Typical Range:** -10° to +30°
## Description
Attack angle measures the vertical angle of the bat's path relative to horizontal, indicating whether the swing is level, uppercut, or chopping.
## Use Cases
* Bat path analysis
* Swing plane assessment
* Contact angle optimization
* Launch angle correlation
# Attack Direction
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/attack-direction
Horizontal plane angle of the bat relative to the front of home plate, generally determines direction (right/left) of the hit.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `attack_direction`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Horizontal angle relative to home plate
* **Reference:** Front of home plate
* **Typical Range:** -45° to +45°
## Description
Attack direction measures the horizontal plane angle of the bat relative to the front of home plate, indicating the intended direction of the hit (right or left field).
Positive angles indicate hitting to the right, negative angles indicate hitting to the left.
## Use Cases
* Hit direction analysis
* Bat angle assessment
* Directional control evaluation
* Technique optimization
# Ball Contact Method
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/ball-contact-method
Ball contact event detection method: [both audio, single audio, swing through]. This indicates how the ball contact event was detected during analysis.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `ball_contact_method`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Values:** 'both audio', 'single audio', 'swing through'
* **Purpose:** Detection method indicator
## Description
Ball contact method indicates the method used to detect the ball contact event, providing information about the reliability and source of ball contact timing.
## Use Cases
* Detection reliability analysis
* Data quality assessment
* Method validation
* Analysis confidence evaluation
# Bat Speed - Angular to Linear
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/bat-speed-angular-to-linear
Converted angular velocity to linear velocity. This measures the bat speed calculated from angular velocity measurements.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** mph
* **Column Name:** TBD
* **Aggregation:** mean
* **Precision:** 1
* **Optimal Direction:** Higher is better
* **Measurement:** Angular velocity converted to linear velocity
* **Typical Range:** 40-90 mph
## Description
Bat speed angular to linear measures the linear velocity of the bat calculated from angular velocity measurements, providing an alternative method for bat speed calculation.
## Use Cases
* Bat speed analysis
* Angular velocity conversion
* Performance comparison
* Speed calculation validation
# Bat Speed - Resultant Sweet Spot
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/bat-speed-resultant-sweet-spot
Linear velocity of bat sweet spot during the swing. This measures the actual bat speed at the optimal contact point.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** mph
* **Column Name:** TBD
* **Aggregation:** mean
* **Precision:** 1
* **Optimal Direction:** Higher is better
* **Measurement:** Linear velocity at sweet spot
* **Typical Range:** 40-90 mph
## Description
Sweet spot bat speed measures the linear velocity of the bat at its optimal contact point (\~6 in from the bat tip), providing insight into swing power and effectiveness.
## Use Cases
* Swing power analysis
* Bat speed assessment
* Performance comparison
* Power optimization
# Body Center of Mass Position X
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/body-center-of-mass-x
Whole body center of mass X position - for use with keypoint positions. This is a time series metric that tracks the body's forward-backward position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `whole_body_center_of_mass_x`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Use:** With keypoint positions
* **Frame Rate:** 240 Hz
* **Direction:** Forward-backward
## Description
Body center of mass X position tracks the forward-backward position of the whole body's center of mass throughout the swing, providing insight into overall body movement patterns.
## Use Cases
* Body movement analysis
* Position tracking
* Overall stability assessment
* Time series analysis
# Body Center of Mass Position Y
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/body-center-of-mass-y
Whole body center of mass Y position (up/down) - for use with keypoint positions. This is a time series metric that tracks the body's vertical position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `whole_body_center_of_mass_y`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Use:** With keypoint positions
* **Frame Rate:** 240 Hz
* **Direction:** Vertical (up/down)
## Description
Body center of mass Y position tracks the vertical position of the whole body's center of mass throughout the swing, providing insight into overall body movement patterns and stability.
## Use Cases
* Body vertical movement analysis
* Position tracking
* Overall stability assessment
* Time series analysis
# Body Center of Mass Position Z
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/body-center-of-mass-z
Whole body center of mass Z position - for use with keypoint positions. This is a time series metric that tracks the body's lateral position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `whole_body_center_of_mass_z`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Use:** With keypoint positions
* **Frame Rate:** 240 Hz
* **Direction:** Lateral (side-to-side)
## Description
Body center of mass Z position tracks the lateral position of the whole body's center of mass throughout the swing, providing insight into overall body movement patterns and balance.
## Use Cases
* Body lateral movement analysis
* Position tracking
* Overall balance assessment
* Time series analysis
# Connection at Impact
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/connection-at-impact
Horizontal plane angle of the bat relative to the batter's torso at the instant of ball contact. This measures the connection between the bat and body at impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** TBD
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Horizontal angle between bat and torso
* **Timing:** At ball contact
## Description
Connection at impact measures the horizontal plane angle between the bat and the batter's torso at the moment of ball contact, indicating proper connection and timing.
## Use Cases
* Impact analysis
* Connection assessment
* Timing evaluation
* Technique optimization
# Drifting Forward
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/drifting-forward
Binary indicator of excessive forward movement, determine by whether the pelvis drifts forward (towards the pitcher) more than 15 cm (~6 in) from launch to ball contact events.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False (1/0)
* **Column Name:** `drifting_forward`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Threshold:** 15 cm (\~6 in) forward movement
* **Timing:** Launch to ball contact events
## Description
Drifting forward indicates excessive forward movement of the pelvis during the swing, which can compromise balance and reduce power generation efficiency.
## Use Cases
* Forward movement analysis
* Balance assessment
* Pelvis stability evaluation
* Technique correction
## Interventions
* [Step Back Drill](https://youtube.com/shorts/jwdxvnplEaw?si=cL8tgwA3NF6zSbA_)
* Focus Area: Back Hip Loading, Limited Separation
* [Controlled Fall Drill](https://www.youtube.com/watch?v=T-juvkH4lQE)
* Focus Area: Stride Controlled
# Drifting Forward Magnitude
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/drifting-forward-magnitude
Distance drifted forward during the swing - see Drifting Forward movement flag. This quantifies the amount of excessive forward movement of the pelvis.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `drifting_forward_magnitude`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Forward distance from launch to ball contact
* **Related Flag:** [Drifting Forward movement flag](/biomechanics/activities/softball/hitting/metrics/drifting-forward)
* **Typical Range:** 0.0 – 1.5 in (0.001 – 0.038 m)
* **Optimal Direction:** Middle — moderate forward movement is biomechanically normal; too little or too much is suboptimal
## Description
Drifting forward magnitude quantifies the actual distance the pelvis moves forward during the swing, providing a continuous measure of the excessive forward movement identified by the Drifting Forward flag.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 0.1 – 1.5 in | -0.6 | 0.1 | 0.7 | 1.5 | 2.9 |
| High School | 0.1 – 1.5 in | -0.6 | 0.1 | 0.7 | 1.5 | 2.9 |
| College | 0.0 – 1.5 in | -0.6 | 0.0 | 0.7 | 1.5 | 2.2 |
| Professional | 0.0 – 1.5 in | -0.6 | 0.0 | 0.7 | 1.5 | 2.2 |
| Broad (All Levels) | 0.0 – 1.5 in | -0.5 | 0.0 | 0.7 | 1.5 | 2.8 |
## Use Cases
* Forward movement quantification
* Balance analysis
* Movement efficiency assessment
* Technique correction
# Elbow Flexion at Ball Contact
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-ball-contact
Amount of rear elbow flexion at ball contact event. This measures the elbow angle at the instant of impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `rear_elbow_flexion_at_ball_contact`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Rear elbow flexion angle
* **Timing:** At ball contact event
* **Typical Range:** 60 – 90 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Elbow flexion at ball contact measures the amount of rear elbow flexion at the moment of ball contact, indicating the arm position and extension during impact.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 60 – 88 ° | 50 | 60 | 74 | 88 | 97 |
| High School | 60 – 88 ° | 50 | 60 | 74 | 88 | 97 |
| College | 56 – 86 ° | 45 | 56 | 72 | 86 | 98 |
| Professional | 56 – 86 ° | 45 | 56 | 72 | 86 | 98 |
| Broad (All Levels) | 57 – 87 ° | 48 | 57 | 72 | 87 | 97 |
## Use Cases
* Impact position analysis
* Rear elbow mechanics assessment
* Contact evaluation
# Elbow Flexion at Launch
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-launch
Amount of rear elbow flexion at launch event. This measures the elbow angle at the start of the power generation phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `rear_elbow_flexion_at_launch`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Rear elbow flexion angle
* **Timing:** At launch event
* **Typical Range:** 115 – 128 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Elbow flexion at launch measures the amount of rear elbow flexion at the launch event, indicating the arm position and loading when starting the power generation phase.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 124 – 132 ° | 117 | 124 | 128 | 132 | 135 |
| High School | 124 – 132 ° | 117 | 124 | 128 | 132 | 135 |
| College | 125 – 135 ° | 118 | 125 | 130 | 135 | 137 |
| Professional | 125 – 135 ° | 118 | 125 | 130 | 135 | 137 |
| Broad (All Levels) | 124 – 133 ° | 117 | 124 | 129 | 133 | 136 |
## Use Cases
* Arm position analysis
* Rear elbow mechanics assessment
* Technique optimization
# Handedness
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/handedness
Handedness of the athlete ['right' or 'left'] as input parameter. This determines the swing side and affects the interpretation of all other metrics.
## Technical Details
* **Variable Type:** Dimension
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `handedness`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Values:** 'right' or 'left'
## Description
Handedness specifies which side the athlete bats from (right-handed or left-handed). This is a required input parameter that affects the interpretation of all other swing metrics.
## Use Cases
* Swing side identification
* Metric interpretation
* Data analysis
# Hip Hinge
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/hip-hinge
Max amount of rear hip flexion between max foot raise and foot contact events.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `hip_hinge`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Max rear hip flexion
* **Timing:** Max foot raise to foot contact
* **Typical Range:** 51 – 64 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Hip hinge measures the maximum amount of rear hip flexion during the stride phase, indicating the loading and preparation of the rear hip for power generation.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 54 – 67 ° | 44 | 54 | 60 | 67 | 73 |
| High School | 54 – 67 ° | 44 | 54 | 60 | 67 | 73 |
| College | 49 – 62 ° | 44 | 49 | 55 | 62 | 69 |
| Professional | 49 – 62 ° | 44 | 49 | 55 | 62 | 69 |
| Broad (All Levels) | 50 – 64 ° | 44 | 50 | 58 | 64 | 71 |
## Use Cases
* Hip loading analysis
* Stride mechanics assessment
# Inter Elbow Distance at Ball Contact
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-ball-contact
Distance between the lead and rear elbows at ball contact event. This measures the separation between elbows at the instant of impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `inter_elbow_distance_at_ball_contact`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Distance between lead and rear elbows
* **Timing:** At ball contact event
* **Typical Range:** 0.24-0.38 meters
## Description
Inter elbow distance at ball contact measures the distance between the lead and rear elbows at the moment of ball contact, indicating the arm separation and positioning during impact.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :---: | :---: | :---: | :---: | :---: |
| Youth | 0.214 – 0.306 m | 0.193 | 0.214 | 0.249 | 0.306 | 0.355 |
| High School | 0.214 – 0.306 m | 0.193 | 0.214 | 0.249 | 0.306 | 0.355 |
| College | 0.259 – 0.372 m | 0.231 | 0.259 | 0.313 | 0.372 | 0.403 |
| Professional | 0.259 – 0.372 m | 0.231 | 0.259 | 0.313 | 0.372 | 0.403 |
| Broad (All Levels) | 0.231 – 0.344 m | 0.203 | 0.231 | 0.282 | 0.344 | 0.391 |
## Use Cases
* Arm positioning
* Transfer of body's rotational power to bat
# Inter Elbow Distance at Elbow Slot
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-elbow-slot
Distance between the lead and rear elbows at the elbow slot event. This measures the separation between elbows during the slot position.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `inter_elbow_distance_at_elbow_slot`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Distance between lead and rear elbows
* **Timing:** At elbow slot event
* **Typical Range:** 0.28-0.41 meters
## Description
Inter elbow distance at elbow slot measures the distance between the lead and rear elbows at the elbow slot event, indicating the arm separation and positioning during the slot phase of the swing.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :---: | :---: | :---: | :---: | :---: |
| Youth | 0.233 – 0.301 m | 0.208 | 0.233 | 0.272 | 0.301 | 0.344 |
| High School | 0.233 – 0.301 m | 0.208 | 0.233 | 0.272 | 0.301 | 0.344 |
| College | 0.295 – 0.388 m | 0.235 | 0.295 | 0.341 | 0.388 | 0.403 |
| Professional | 0.295 – 0.388 m | 0.235 | 0.295 | 0.341 | 0.388 | 0.403 |
| Broad (All Levels) | 0.254 – 0.358 m | 0.218 | 0.254 | 0.302 | 0.358 | 0.395 |
## Use Cases
* Arm positioning
* Transfer of body's rotational power to bat
# Inter Elbow Distance at Trunk Peak
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-trunk-peak
Distance between the lead and rear elbows at the trunk peak angular velocity event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `inter_elbow_distance_at_trunk_peak`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Distance between lead and rear elbows
* **Timing:** At trunk peak angular velocity event
* **Typical Range:** 0.27-0.41 meters
## Description
Inter elbow distance at trunk peak measures the distance between the lead and rear elbows when trunk rotation reaches its peak angular velocity, indicating arm separation during maximum trunk rotation.
## Use Cases
* Arm positioning
* Transfer of body's rotational power to bat
# Kinematic Sequence Order
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/kinematic-sequence-order
Sequence of segment peak angular velocities (twist speed) during the swing. Correct sequencing is pelvis-trunk-arm, representing the optimal kinetic chain transfer.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `kinematic_sequence_order`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Optimal Sequence:** pelvis-trunk-arm
* **Measurement:** Order of peak angular velocities
## Description
Kinematic sequence order tracks the timing sequence of peak angular velocities across body segments. The optimal sequence is pelvis-trunk-arm, ensuring efficient energy transfer through the kinetic chain.
## Use Cases
* Kinetic chain analysis
* Sequencing evaluation
* Power transfer assessment
## Interventions
* [Medicine Ball Rotational Throws - Sequence Focus](https://youtube.com/shorts/9fyhs2aNu3A?si=ajHDFXGhmPK8S0r9)
* Focus Area: Improper Sequencing
# Knee Dominant
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/knee-dominant
Binary indicator if swing is knee-dominant, determined by comparing rear knee flexion with hip and ankle angle at launch event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False (1/0)
* **Column Name:** `knee_dominant_swing`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Timing:** At launch event
## Description
Knee dominant indicates a swing pattern where the lower body mechanics are primarily driven by the knees rather than the hips, which can limit power generation and efficiency.
## Use Cases
* Lower body mechanics analysis
* Power generation assessment
* Hip mobility evaluation
* Technique correction
## Interventions
* [Kershaw Drill](https://youtu.be/r3wazOZE-MQ)
* Focus Area: Back Hip Loading, Front-Side Stability
* [Front Side Block Drill](https://youtube.com/shorts/qhjY_Ao5xjU?si=jfGncV5-jJsoHifS)
* Focus Area: Front Side Stability
# Lateral Pelvis Tilt
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/lateral-pelvis-tilt
Binary indicator of excessive lateral pelvis tilt, determined by whether the pelvis tilts upwards or downwards more than 10 deg during the swing (initiation to ball contact).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False (1/0)
* **Column Name:** `excessive_lateral_pelvis_tilt`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Threshold:** 10 ° tilt (upwards or downwards)
* **Timing:** Initiation to ball contact
## Description
Lateral pelvis tilt indicates excessive side-to-side tilting of the pelvis during the swing, which can compromise balance and power transfer efficiency.
## Use Cases
* Pelvis stability analysis
* Lateral movement assessment
* Balance evaluation
* Technique correction
# Launch Position
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/launch-position
Launch position indicates how the bat is positioned relative to the spine when the swing begins. A proper launch position helps ensure optimal bat path and contact point.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** Degrees (°)
* **Column Name:** `launch_position`
* **Range:** 0° to 180°
* **Calculation:** Sagittal plane (somersault) angle between bat and spine
* **Measurement Point:** At pelvis velocity initiation (launch event)
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
## Interpretation
* **Higher values:** (over 90°) Bat angled downward relative to spine, bat tip is lower
* **Lower values:** (under 90°) Bat angled upward relative to spine, bat tip is higher and bat is closer to being in line with spine.
* **Optimal range:** Typically 30-90° for most hitters, preferably closer to 90°
## Use Cases
* Swing analysis and coaching
* Bat path optimization
* Pre-swing position consistency
# Lead Knee Angle at Ball Contact
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/lead-knee-angle-at-ball-contact
Amount of lead knee flexion at ball contact. This measures the knee angle of the front leg at the instant of impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `lead_knee_angle_at_ball_contact`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Lead knee flexion angle
* **Timing:** At ball contact event
* **Typical Range:** 13 – 28 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Lead knee angle at ball contact measures the amount of flexion in the lead knee at the moment of ball contact, indicating the front leg position and stability during impact.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 11 – 20 ° | 10 | 11 | 15 | 20 | 28 |
| High School | 11 – 20 ° | 10 | 11 | 15 | 20 | 28 |
| College | 9 – 17 ° | 7 | 9 | 12 | 17 | 21 |
| Professional | 9 – 17 ° | 7 | 9 | 12 | 17 | 21 |
| Broad (All Levels) | 10 – 19 ° | 8 | 10 | 13 | 19 | 25 |
## Use Cases
* Front leg stability analysis
* Knee mechanics assessment
* Impact position evaluation
* Balance optimization
# Leads With Wrist
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/leads-with-wrist
Binary indicator if wrist leads the swing: if wrist initiation event occurs before pelvis initiation event. This identifies improper swing sequencing where the upper body initiates before the lower body.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `leads_with_wrist`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Calculation:** Wrist initiation event \< Pelvis initiation event (launch)
* **Optimal Value:** False (pelvis should initiate first)
## Description
This flag indicates whether the wrist initiation occurs before pelvis initiation, which represents improper swing sequencing. In an optimal swing, the pelvis should initiate before the wrists.
## Use Cases
* Swing sequencing analysis
* Technique correction
* Upper body timing assessment
* Kinetic chain evaluation
# Interventions
* [Connection Ball Drill](https://youtube.com/shorts/niIx3NlyJO4?si=O95jAeR_0CKqZ4dc)
* Focus Area: Improper Sequencing
# Linear Stretch
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/linear-stretch
Distance between the lead ankle and center of both wrists along the pitch direction at foot contact. This measures the linear stretch of the body during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `linear_stretch`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Distance from lead ankle to center of wrists
* **Direction:** Along pitch direction
* **Timing:** At foot contact event
* **Typical Range:** 19.3 – 25.7 in (0.491 – 0.653 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Linear stretch measures the distance between the lead ankle and the center of both wrists along the pitch direction at foot contact, indicating the body's linear extension during the swing.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 19.3 – 25.4 in | 16.5 | 19.3 | 22.0 | 25.4 | 27.2 |
| High School | 19.3 – 25.4 in | 16.5 | 19.3 | 22.0 | 25.4 | 27.2 |
| College | 19.9 – 27.3 in | 15.4 | 19.9 | 23.2 | 27.3 | 30.6 |
| Professional | 19.9 – 27.3 in | 15.4 | 19.9 | 23.2 | 27.3 | 30.6 |
| Broad (All Levels) | 19.3 – 25.7 in | 15.3 | 19.3 | 22.3 | 25.7 | 28.8 |
## Use Cases
* Body extension analysis
* Stretch assessment
* Linear mechanics evaluation
# Max X Factor
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/max-x-factor
Max amount of twist hip shoulder separation during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `max_x_factor`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** maximum twist angle difference between shoulders and hips (torso and pelvis)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Max amount of hip shoulder separation (X Factor) during the swing.
Usually occurs as the pelvis begins its rotation, while the torso is relatively stable.
Greater amounts of X Factor may permit greater range of motion through which to rotate for the swing.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 14 – 26 ° | 0 | 14 | 19 | 26 | 36 |
| High School | 14 – 26 ° | 0 | 14 | 19 | 26 | 36 |
| College | 21 – 34 ° | 16 | 21 | 27 | 34 | 38 |
| Professional | 21 – 34 ° | 16 | 21 | 27 | 34 | 38 |
| Broad (All Levels) | 17 – 31 ° | 10 | 17 | 24 | 31 | 37 |
## Use Cases
* Pre-swing loading
* Range of motion assessment
## Interventions
* [Separation Drill](https://www.youtube.com/watch?v=EczxevOOVLY)
* Focus Area: Limited Separation
* [Hook'Em Drill](https://youtu.be/IyCE0hey7-I)
* Focus Area: Back Hip Loading, Limited Separation
# On Plane Efficiency
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/on-plane-efficiency
Percentage of swing (within 10 deg) aligned with swing plane between foot contact and ball contact events. This measures swing consistency and efficiency.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** %
* **Column Name:** `on_plane_efficiency`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Tolerance:** Within 10 ° of swing plane
* **Timing:** Foot contact to ball contact
* **Typical Range:** 60-95%
## Description
On plane efficiency measures the percentage of the swing path that stays within 10 degrees of the optimal swing plane, indicating swing consistency and efficiency.
## Use Cases
* Swing consistency
* Swing plane efficiency
# Peak Arm Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/peak-arm-angular-velocity
Max angular velocity of the lead upper arm segment during the swing. This represents the peak power generation from the arms.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_arm_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Max lead upper arm angular velocity
* **Optimal Direction:** Higher is better
## Description
Peak arm angular velocity measures the maximum rotational speed (deg/s) of the lead upper arm during the swing, representing the peak power generation from the upper arm segment.
The timing of peak arm angular velocity determines kinematic sequence in part.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 805 – 924 °/s | 486 | 577 | 694 | 805 | 924 |
| High School | 805 – 924 °/s | 486 | 577 | 694 | 805 | 924 |
| College | 919 – 1011 °/s | 588 | 684 | 792 | 919 | 1011 |
| Professional | 919 – 1011 °/s | 588 | 684 | 792 | 919 | 1011 |
| Broad (All Levels) | 881 – 996 °/s | 509 | 634 | 743 | 881 | 996 |
## Use Cases
* Upper body power analysis
* Arm mechanics assessment
* Kinematic Sequence Order
# Interventions
* [Med Ball Side Toss](https://youtube.com/shorts/Hr7KeI6V5Ik?si=sj2a0lUgO_hoyxEF)
* Focus Area: Rotational Power
# Peak Pelvis Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/peak-pelvis-angular-velocity
Max angular velocity of the pelvis segment during the swing. This represents power generation from the lower body.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_pelvis_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum pelvis angular velocity
* **Optimal Direction:** Higher is better
## Description
Peak pelvis angular velocity measures the maximum rotational speed of the pelvis during the swing, representing the peak power generation from the lower body.
The timing of peak pelvis angular velocity determines kinematic sequence in part.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 494 – 537 °/s | 384 | 406 | 455 | 494 | 537 |
| High School | 494 – 537 °/s | 384 | 406 | 455 | 494 | 537 |
| College | 543 – 578 °/s | 438 | 472 | 507 | 543 | 578 |
| Professional | 543 – 578 °/s | 438 | 472 | 507 | 543 | 578 |
| Broad (All Levels) | 526 – 564 °/s | 402 | 437 | 485 | 526 | 564 |
## Use Cases
* Lower body power analysis
* Pelvis mechanics assessment
* Kinematic Sequence Order
# Interventions
* [Med Ball Side Toss](https://youtube.com/shorts/Hr7KeI6V5Ik?si=sj2a0lUgO_hoyxEF)
* Focus Area: Rotational Power
* [Step-Behind Med Ball Throws](https://youtube.com/shorts/OSL0OZSCGi4?si=D1QmjR5akcCN6McU)
* Focus Area: Pelvis Velocity
* [Med Ball Scoop Toss](https://youtube.com/shorts/O5cscjGQrVo?si=NAfk_BwJKLEjQsKF)
* Focus Area: Pelvis Velocity, Trunk Velocity
# Peak Trunk Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/peak-trunk-angular-velocity
Max angular velocity of the trunk segment during the swing. This represents the peak power generation from the core.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °/s
* **Column Name:** `peak_trunk_angular_velocity`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum trunk angular velocity
* **Phase:** Core power generation
* **Optimal Direction:** Higher is better
## Description
Peak trunk angular velocity measures the maximum rotational speed of the trunk during the swing, representing the peak power generation from the core segment.
The timing of peak trunk angular velocity determines kinematic sequence in part.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 666 – 715 °/s | 489 | 533 | 582 | 666 | 715 |
| High School | 666 – 715 °/s | 489 | 533 | 582 | 666 | 715 |
| College | 692 – 746 °/s | 553 | 595 | 645 | 692 | 746 |
| Professional | 692 – 746 °/s | 553 | 595 | 645 | 692 | 746 |
| Broad (All Levels) | 683 – 739 °/s | 511 | 563 | 630 | 683 | 739 |
## Use Cases
* Core power analysis
* Trunk mechanics assessment
* Kinematic Sequence Order
# Interventions
* [Med Ball Side Toss](https://youtube.com/shorts/Hr7KeI6V5Ik?si=sj2a0lUgO_hoyxEF)
* Focus Area: Rotational Power
* [Offset Rotation Drill](https://youtu.be/Divh5BtngPg?si=yewnOU5_Sz_w2KCm)
* Focus Area: Trunk Velocity
* [Med Ball Scoop Toss](https://youtube.com/shorts/O5cscjGQrVo?si=NAfk_BwJKLEjQsKF)
* Focus Area: Pelvis Velocity, Trunk Velocity
# Pelvis Acceleration Time
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/pelvis-acceleration-time
Time from pelvis initiation (start of rotation, also known as launch event) to peak pelvis angular velocity. This measures the acceleration phase of the pelvis during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds
* **Column Name:** pelvis\_acceleration\_time
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Peak pelvis velocity time - Pelvis initiation time
* **Typical Range:** 0.22 – 0.62 s
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Pelvis acceleration time measures the duration of the pelvis acceleration phase from the start of rotation (launch) to peak angular velocity, indicating the time period for lower body power generation.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 0.16 – 0.33 s | 0.14 | 0.16 | 0.19 | 0.33 | 0.38 |
| High School | 0.16 – 0.33 s | 0.14 | 0.16 | 0.19 | 0.33 | 0.38 |
| College | 0.17 – 0.30 s | 0.15 | 0.17 | 0.18 | 0.30 | 0.34 |
| Professional | 0.17 – 0.30 s | 0.15 | 0.17 | 0.18 | 0.30 | 0.34 |
| Broad (All Levels) | 0.16 – 0.31 s | 0.15 | 0.16 | 0.18 | 0.31 | 0.36 |
## Use Cases
* Acceleration phase analysis
* Power generation efficiency
* Lower body mechanics assessment
# Pelvis Deceleration Time
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/pelvis-deceleration-time
Time from peak pelvis angular velocity to pelvis termination (end of rotation). This measures the deceleration phase of the pelvis during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds
* **Column Name:** pelvis\_deceleration\_time
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Pelvis termination time - Peak pelvis velocity time
* **Typical Range:** 0.34 – 0.68 s
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Pelvis deceleration time measures the duration of the pelvis deceleration phase from peak angular velocity to the end of rotation, indicating the control and efficiency of lower body mechanics.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 0.17 – 0.42 s | 0.14 | 0.17 | 0.25 | 0.42 | 0.54 |
| High School | 0.17 – 0.42 s | 0.14 | 0.17 | 0.25 | 0.42 | 0.54 |
| College | 0.17 – 0.39 s | 0.16 | 0.17 | 0.20 | 0.39 | 0.51 |
| Professional | 0.17 – 0.39 s | 0.16 | 0.17 | 0.20 | 0.39 | 0.51 |
| Broad (All Levels) | 0.17 – 0.42 s | 0.15 | 0.17 | 0.23 | 0.42 | 0.52 |
## Use Cases
* Deceleration phase analysis
* Control assessment
* Lower body mechanics evaluation
# Pelvis Global Rotation
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/pelvis-global-rotation
Instantaneous measurement of pelvis transverse plane rotation relative to the global coordinate system. This is a time series metric that tracks pelvis rotation throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `pelvis_global_rotation`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Plane:** Transverse plane
* **Reference:** Global coordinate system
## Description
Pelvis global rotation tracks the amount of rotation of the pelvis relative to the global coordinate system throughout the swing, providing insight into pelvis rotation patterns and power generation.
## Use Cases
* Pelvis rotation analysis
* Rotation tracking
# Pelvis Global Tilt
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/pelvis-global-tilt
Amount of pelvis frontal plane side-to-side tilt relative to the global coordinate system. This is a time series metric that tracks pelvis lateral tilt throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `pelvis_global_tilt`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Plane:** Frontal plane
* **Reference:** Global coordinate system
## Description
Pelvis global tilt tracks the amount of side-to-side tilt of the pelvis relative to the global coordinate system throughout the swing, providing insight into pelvis posture and balance.
## Use Cases
* Pelvis lateral posture analysis
* Tilt tracking
# Pelvis to Trunk Speed Up
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/pelvis-to-trunk-speed-up
Ratio (multiplication factor) of speed increase from pelvis to trunk. This measures the efficiency of power transfer from the lower body to the trunk.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio
* **Column Name:** `pelvis_to_trunk_velocity_speedup`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Peak trunk velocity / Peak pelvis velocity
* **Optimal Range:** 1.25-1.75
* **Optimal Direction:** Higher is better
## Description
Pelvis to trunk speed up measures the multiplication factor of velocity increase from the pelvis to the trunk peak angular velocities.
This metric broadly indicates the efficiency of power transfer from the lower body to the core.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 1.42 – 1.48 | 1.13 | 1.23 | 1.33 | 1.42 | 1.48 |
| High School | 1.42 – 1.48 | 1.13 | 1.23 | 1.33 | 1.42 | 1.48 |
| College | 1.34 – 1.42 | 1.12 | 1.18 | 1.28 | 1.34 | 1.42 |
| Professional | 1.34 – 1.42 | 1.12 | 1.18 | 1.28 | 1.34 | 1.42 |
| Broad (All Levels) | 1.39 – 1.48 | 1.12 | 1.20 | 1.30 | 1.39 | 1.48 |
## Use Cases
* Power transfer analysis
* Kinetic chain efficiency
# Rear Arm Connection
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/rear-arm-connection
Average distance between the rear elbow and mid-torso (halfway between mid-shoulder and mid-hip joint centers) between launch and ball contact events.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `rear_arm_connection`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Average distance from rear elbow to mid-torso
* **Timing:** Launch to ball contact events
* **Typical Range:** 11.0 – 14.4 in (0.280 – 0.366 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Rear arm connection measures the average distance between the rear elbow and the mid-torso during the swing.
This metric indicates the relative connection and efficiency of the rear arm position to the torso during the acceleration phase.
Maintaining a tight connection between rear arm and torso improves power transfer.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 10.3 – 12.2 in | 9.5 | 10.3 | 11.1 | 12.2 | 13.5 |
| High School | 10.3 – 12.2 in | 9.5 | 10.3 | 11.1 | 12.2 | 13.5 |
| College | 12.6 – 15.4 in | 11.2 | 12.6 | 14.0 | 15.4 | 16.8 |
| Professional | 12.6 – 15.4 in | 11.2 | 12.6 | 14.0 | 15.4 | 16.8 |
| Broad (All Levels) | 11.0 – 14.4 in | 9.9 | 11.0 | 12.6 | 14.4 | 15.8 |
## Use Cases
* Arm connection analysis
* Swing efficiency assessment
* Power transfer evaluation
# Relative Hand Position - Away from Body
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/relative-hand-position-away-from-body
Distance along the axis forward away from the body (+) between mid-shoulders and the average of the two wrists at the foot contact event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `relative_hand_position_away_from_body`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Lateral distance from mid-shoulders to average wrist position
* **Direction:** Away from body (+)
* **Timing:** At foot contact event
* **Typical Range:** 3.6 – 7.6 in (0.093 – 0.192 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Relative hand position away from body measures the fore/aft position of the hands relative to the shoulders at foot contact, indicating pre-swing hand positioning.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 2.3 – 5.9 in | 0.8 | 2.3 | 4.5 | 5.9 | 7.3 |
| High School | 2.3 – 5.9 in | 0.8 | 2.3 | 4.5 | 5.9 | 7.3 |
| College | 4.7 – 8.5 in | 3.3 | 4.7 | 6.7 | 8.5 | 10.1 |
| Professional | 4.7 – 8.5 in | 3.3 | 4.7 | 6.7 | 8.5 | 10.1 |
| Broad (All Levels) | 3.6 – 7.6 in | 1.4 | 3.6 | 5.6 | 7.6 | 9.2 |
## Use Cases
* Swing setup assessment
* Hand position evaluation
# Relative Hand Position - Towards Pitcher
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/relative-hand-position-towards-pitcher
Distance along the axis towards the pitcher (+) or away (-) between mid-shoulders and the average of the two wrists at the foot contact event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `relative_hand_position_towards_pitcher`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Distance from mid-shoulders to average wrist position
* **Direction:** Negative values (-) indicate the wrists are further from the pitcher than the neck (mid shoulders)
* **Timing:** At foot contact event
* **Typical Range:** -10.1 – -6.1 in (-0.257 – -0.154 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Relative hand position towards pitcher measures the forward-backward position of the hands relative to the shoulders at foot contact, indicating hand placement and swing setup.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :---: | :---: | :--: | :--: | :--: |
| Youth | -9.8 – -6.2 in | -10.8 | -9.8 | -8.0 | -6.2 | -4.2 |
| High School | -9.8 – -6.2 in | -10.8 | -9.8 | -8.0 | -6.2 | -4.2 |
| College | -10.8 – -5.6 in | -12.1 | -10.8 | -8.3 | -5.6 | -2.9 |
| Professional | -10.8 – -5.6 in | -12.1 | -10.8 | -8.3 | -5.6 | -2.9 |
| Broad (All Levels) | -10.1 – -6.1 in | -11.6 | -10.1 | -8.1 | -6.1 | -3.7 |
## Use Cases
* Hand placement analysis
* Swing setup assessment
* Position evaluation
* Technique optimization
# Relative Hand Position - Up
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/relative-hand-position-up
Distance along the up axis (+) between mid-shoulders and the average of the two wrists at the foot contact event.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `relative_hand_position_up`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Vertical distance from mid-shoulders to average wrist position
* **Direction:** Above (+) or below (-)
* **Timing:** At foot contact event
* **Typical Range:** 2.6 – 6.6 in (0.065 – 0.166 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Relative hand position up measures the vertical position of the hands relative to the shoulders at foot contact, indicating hand height and swing setup.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 1.8 – 6.1 in | -0.2 | 1.8 | 4.0 | 6.1 | 7.1 |
| High School | 1.8 – 6.1 in | -0.2 | 1.8 | 4.0 | 6.1 | 7.1 |
| College | 4.0 – 7.3 in | 1.6 | 4.0 | 5.6 | 7.3 | 8.9 |
| Professional | 4.0 – 7.3 in | 1.6 | 4.0 | 5.6 | 7.3 | 8.9 |
| Broad (All Levels) | 2.6 – 6.6 in | 0.3 | 2.6 | 4.7 | 6.6 | 8.0 |
## Use Cases
* Hand height analysis
* Swing setup assessment
# Scap Load at Launch
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/scap-load-at-launch
Amount of rear shoulder flexion (+) or extension (-) at launch event. Flexion/Extension translates to horizontal adduction (+) and abduction (-), respectively.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `rear_scap_load_at_launch`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Rear shoulder flexion/extension at launch
* **Positive:** Flexion (horizontal adduction)
* **Negative:** Extension (horizontal abduction)
* **Typical Range:** -8 – 19 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Scap load at launch measures the amount of rear shoulder flexion or extension at the launch event, indicating the loading and preparation of the rear shoulder for power generation.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | -4 – 21 ° | -11 | -4 | 8 | 21 | 29 |
| High School | -4 – 21 ° | -11 | -4 | 8 | 21 | 29 |
| College | -6 – 16 ° | -19 | -6 | 6 | 16 | 33 |
| Professional | -6 – 16 ° | -19 | -6 | 6 | 16 | 33 |
| Broad (All Levels) | -4 – 19 ° | -15 | -4 | 7 | 19 | 33 |
## Use Cases
* Rear shoulder loading analysis
* Scapular mechanics assessment
# Shoulder Rotation Plane Flexion
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-flexion
Amount of trunk flexion required to reach the average plane of rotation of the shoulder joint centers. This measures the trunk posture for optimal swing mechanics.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `shoulder_rotation_plane_flexion`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Trunk flexion for shoulder plane alignment
* **Direction:** positive indicates leaning forward towards home plate
* **Typical Range:** 30 – 39 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Shoulder rotation plane flexion measures the amount of trunk flexion needed to align with the optimal plane of shoulder rotation, indicating trunk posture for efficient shoulder mechanics.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 27 – 37 ° | 24 | 27 | 33 | 37 | 40 |
| High School | 27 – 37 ° | 24 | 27 | 33 | 37 | 40 |
| College | 29 – 37 ° | 25 | 29 | 33 | 37 | 40 |
| Professional | 29 – 37 ° | 25 | 29 | 33 | 37 | 40 |
| Broad (All Levels) | 28 – 37 ° | 24 | 28 | 33 | 37 | 40 |
## Use Cases
* Trunk posture analysis
* Shoulder mechanics assessment
* Plane alignment evaluation
* Technique optimization
# Shoulder Rotation Plane Tilt
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-tilt
Amount of trunk tilt (+ = tilting towards the pitcher) to reach the average plane of rotation of the shoulders. This measures the lateral (side-side) trunk posture for optimal swing mechanics.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `shoulder_rotation_plane_tilt`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Trunk tilt for shoulder plane alignment
* **Direction:** Positive indicates tilting forward towards pitcher
* **Typical Range:** -2 – 12 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Shoulder rotation plane tilt measures the amount of lateral trunk tilt needed to align with the optimal plane of shoulder rotation, indicating lateral trunk posture for efficient shoulder mechanics.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 3 – 19 ° | -1 | 3 | 12 | 19 | 26 |
| High School | 3 – 19 ° | -1 | 3 | 12 | 19 | 26 |
| College | 3 – 17 ° | -1 | 3 | 9 | 17 | 23 |
| Professional | 3 – 17 ° | -1 | 3 | 9 | 17 | 23 |
| Broad (All Levels) | 3 – 18 ° | -1 | 3 | 11 | 18 | 25 |
## Use Cases
* Lateral trunk posture analysis
* Shoulder mechanics assessment
* Plane alignment evaluation
* Technique optimization
# Stride Length
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/stride-length
Distance between the lead ankle at foot contact and the rear ankle at max foot raise event. This measures the stride length used during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** raw: m, display: in
* **Column Name:** `stride_length`
* **Aggregation:** mean
* **Precision:** 1
* **Measurement:** Distance between lead ankle (foot contact) and rear ankle (max foot raise)
* **Typical Range:** 24.1 – 29.6 in (0.612 – 0.752 m)
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Stride length measures the distance covered by the stride during the swing, providing insight into stride mechanics and balance.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 23.6 – 27.7 in | 20.7 | 23.6 | 25.3 | 27.7 | 29.5 |
| High School | 23.6 – 27.7 in | 20.7 | 23.6 | 25.3 | 27.7 | 29.5 |
| College | 26.1 – 31.6 in | 23.0 | 26.1 | 28.8 | 31.6 | 34.3 |
| Professional | 26.1 – 31.6 in | 23.0 | 26.1 | 28.8 | 31.6 | 34.3 |
| Broad (All Levels) | 24.1 – 29.6 in | 21.6 | 24.1 | 26.9 | 29.6 | 32.6 |
## Use Cases
* Stride analysis
* Balance assessment
# Sway
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/sway
Binary indicator of excessive lateral movement of the pelvis just prior to swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `sway`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Threshold:** 8 cm (\~3 in) lateral movement
* **Measurement:** Pelvis position difference around max knee raise
## Description
Sway indicates excessive lateral movement of the pelvis during the swing, which can compromise balance and power generation.
Sway is determined by the difference in farthest forward and backward pelvis position (forward = towards the pitcher) between initiation (start of any movement) and max knee raise event.
Lateral movement distance threshold for sway fault is 8 cm (\~3 in)
Sway is a method of measuring pre-swing sway movement, which can be used in combination with [Sway Leg](/biomechanics/activities/softball/hitting/metrics/sway-leg),
measured by rear leg alignment.
## Use Cases
* Balance analysis
* Movement efficiency assessment
* Stability evaluation
## Interventions
* [Step Back Drill](https://youtube.com/shorts/jwdxvnplEaw?si=cL8tgwA3NF6zSbA_)
* Focus Area: Back Hip Loading, Limited Separation
# Sway Leg
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/sway-leg
Binary indicator of excessive lateral movement, determined by rear ankle and knee joint centers.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `sway_leg`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Rear knee position relative to ankle
* **Fault Condition:** Knee passes behind ankle (away from pitcher)
## Description
Sway leg indicates excessive lateral movement in the lower body, specifically when the rear knee passes behind the ankle (further from pitcher), compromising the base of support and power generation.
Sway leg is a different method of measuring pre-swing sway movement, which can be used in combination with normal [Sway](/biomechanics/activities/softball/hitting/metrics/sway),
measured by lateral pelvis motion.
## Use Cases
* Lower body balance analysis
* Leg stability assessment
* Base of support evaluation
## Interventions
* [Step Back Drill](https://youtube.com/shorts/jwdxvnplEaw?si=cL8tgwA3NF6zSbA_)
* Focus Area: Back Hip Loading, Limited Separation
# Sweet Spot Fore Aft Position At Contact
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/sweet-spot-fore-aft-position-at-contact
Fore/aft position (closer to/further from the pitcher) of the bat sweet spot relative to the pelvis (mid point of the hip joint centers) at ball contact. This measures the bat position at impact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `sweet_spot_fore_aft_position_at_contact`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Distance from pelvis to sweet spot
* **Direction:** Positive indicates closer to the pitcher, negative indicates further away from the pitcher relative to the pelvis
* **Timing:** At ball contact
* **Typical Range:** -0.2 to +0.4 meters
## Description
Sweet spot fore aft position at contact measures the forward-backward position of the bat's sweet spot relative to the pelvis at the moment of ball contact, indicating bat placement and timing.
## Use Cases
* Bat placement analysis
* Contact position assessment
* Timing evaluation
* Technique optimization
# Swing Path Angle
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/swing-path-angle
Plane angle of the bat swing path relative to horizontal in the 0.04 s leading up to ball contact. This measures the final approach angle of the bat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `swing_path_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Vertical angle of swing path
* **Timing:** the 0.04 s leading up to ball contact
* **Typical Range:** 5° to 40°
## Description
Swing path angle measures the vertical angle of the bat's path in the final 0.04 seconds before ball contact, indicating the final approach angle and swing plane.
## Use Cases
* Final approach analysis
* Swing path assessment
* Bat position assessment
# Time to Ball Contact
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/time-to-ball-contact
Duration between initiation and ball contact events. This measures the total swing time from start to contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s)
* **Column Name:** `time_to_ball_contact`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Ball contact time - Initiation time
* **Typical Range:** 0.75 – 1.02 s
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Time to ball contact measures the total duration of the swing from initiation to ball contact, providing insight into swing timing and rhythm.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 0.57 – 0.80 s | 0.00 | 0.57 | 0.68 | 0.80 | 0.92 |
| High School | 0.57 – 0.80 s | 0.00 | 0.57 | 0.68 | 0.80 | 0.92 |
| College | 0.65 – 0.89 s | 0.58 | 0.65 | 0.79 | 0.89 | 0.96 |
| Professional | 0.65 – 0.89 s | 0.58 | 0.65 | 0.79 | 0.89 | 0.96 |
| Broad (All Levels) | 0.61 – 0.87 s | 0.45 | 0.61 | 0.74 | 0.87 | 0.95 |
## Use Cases
* Swing timing analysis
* Rhythm assessment
# Time to Launch
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/time-to-launch
Duration between initiation and pelvis velocity initiation (launch) events. This measures the time from swing start to the beginning of power generation.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s)
* **Column Name:** `time_to_launch`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Pelvis initiation time - Initiation time
* **Typical Range:** 0.16 – 0.51 s
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Time to launch measures the duration from swing initiation to the start of pelvis velocity initiation (launch event), indicating the preparation phase before power generation begins.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 0.18 – 0.45 s | 0.00 | 0.18 | 0.34 | 0.45 | 0.55 |
| High School | 0.18 – 0.45 s | 0.00 | 0.18 | 0.34 | 0.45 | 0.55 |
| College | 0.33 – 0.57 s | 0.18 | 0.33 | 0.46 | 0.57 | 0.64 |
| Professional | 0.33 – 0.57 s | 0.18 | 0.33 | 0.46 | 0.57 | 0.64 |
| Broad (All Levels) | 0.26 – 0.52 s | 0.08 | 0.26 | 0.39 | 0.52 | 0.64 |
## Use Cases
* Preparation phase analysis
* Timing assessment
# Trunk Center of Mass Position X
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/trunk-center-of-mass-x
Trunk center of mass X position - for use with keypoint positions. This is a time series metric that tracks the trunk's forward/backward position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `trunk_center_of_mass_x`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Direction:** Forward/Backward
## Description
Trunk center of mass X position tracks the forward-backward position of the trunk's center of mass throughout the swing, providing insight into trunk movement patterns.
## Use Cases
* Trunk movement analysis
* Position tracking
# Trunk Center of Mass Position Y
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/trunk-center-of-mass-y
Trunk center of mass Y position (up/down) - for use with keypoint positions. This is a time series metric that tracks the trunk's vertical position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `trunk_center_of_mass_y`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Direction:** Vertical (up/down)
## Description
Trunk center of mass Y position tracks the vertical position of the trunk's center of mass throughout the swing, providing insight into trunk movement patterns and stability.
## Use Cases
* Trunk vertical movement analysis
* Position tracking
# Trunk Center of Mass Position Z
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/trunk-center-of-mass-z
Trunk center of mass Z position - for use with keypoint positions. This is a time series metric that tracks the trunk's lateral position throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `trunk_center_of_mass_z`
* **Aggregation:** mean
* **Precision:** 3
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Direction:** Lateral (side-to-side)
## Description
Trunk center of mass Z position tracks the lateral position of the trunk's center of mass throughout the swing, providing insight into trunk movement patterns and balance.
## Use Cases
* Trunk lateral movement analysis
* Position tracking
# Trunk Coil
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/trunk-coil
Max rotation angle that the trunk turns away from the pitcher. This measures the loading of the trunk during the swing.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_coil`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Maximum trunk rotation away from pitcher between [max foot raise](/biomechanics/activities/softball/hitting/events/max-foot-raise.mdx) and [foot contact](/biomechanics/activities/softball/hitting/events/foot-contact.mdx) events
* **Reference:** 0° = neutrally square to the pitcher, shoulders in line with the pitch
* **Typical Range:** 24 – 41 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Trunk coil measures the maximum rotation angle of the trunk away from the pitcher, indicating the loading and preparation of the core for power generation.
Neutrally square towards the pitcher (where the shoulders are in line with the pitch) would be 0 deg.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 26 – 38 ° | 20 | 26 | 33 | 38 | 47 |
| High School | 26 – 38 ° | 20 | 26 | 33 | 38 | 47 |
| College | 29 – 43 ° | 21 | 29 | 36 | 43 | 49 |
| Professional | 29 – 43 ° | 21 | 29 | 36 | 43 | 49 |
| Broad (All Levels) | 28 – 42 ° | 21 | 28 | 34 | 42 | 48 |
## Use Cases
* Core preparation assessment
* Rotation evaluation
## Interventions
* [Coil Drill](https://www.youtube.com/shorts/XcvnswS7stw)
* Focus Area: Back Hip Loading
* [Hook'Em Drill](https://youtu.be/IyCE0hey7-I)
* Focus Area: Back Hip Loading, Limited Separation
# Trunk Global Flexion
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/trunk-global-flexion
Amount of trunk sagittal plane flexion relative to the global coordinate system. This is a time series metric that tracks trunk flexion throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_global_flexion`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Plane:** Sagittal plane
* **Reference:** Global coordinate system
## Description
Trunk global flexion tracks the amount of forward-backward flexion of the trunk relative to the global coordinate system throughout the swing, providing insight into trunk posture and movement.
## Use Cases
* Trunk posture analysis
# Trunk Global Rotation
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/trunk-global-rotation
Amount of trunk transverse plane rotation relative to the global coordinate system. This is a time series metric that tracks trunk rotation throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_global_rotation`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Plane:** Transverse plane
* **Reference:** Global coordinate system
## Description
Trunk global rotation tracks the amount of rotation of the trunk relative to the global coordinate system throughout the swing, providing insight into trunk rotation patterns and power generation.
## Use Cases
* Trunk rotation analysis
# Trunk Global Tilt
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/trunk-global-tilt
Amount of trunk frontal plane side-to-side tilt relative to the global coordinate system. This is a time series metric that tracks trunk lateral tilt throughout the swing.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_global_tilt`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** N/A
* **Type:** Time series metric
* **Plane:** Frontal plane
* **Reference:** Global coordinate system
## Description
Trunk global tilt tracks the amount of side-to-side tilt of the trunk relative to the global coordinate system throughout the swing, providing insight into trunk posture and balance.
## Use Cases
* Trunk lateral posture analysis
* Tilt tracking
# Trunk Tilt at Launch
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/trunk-tilt-at-launch
Amount of side-to-side trunk tilt at launch event (pelvis velocity initiation). Positive values indicate tilting towards the pitcher and vice versa.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `trunk_tilt_at_launch`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Side-to-side trunk tilt
* **Timing:** At launch event
* **Typical Range:** 5 – 13 °
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Trunk tilt at launch measures the side-to-side tilt of the trunk at the moment of pelvis velocity initiation, indicating trunk posture and balance at the start of power generation.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.
| Population | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 3 – 10 ° | 0 | 3 | 6 | 10 | 14 |
| High School | 3 – 10 ° | 0 | 3 | 6 | 10 | 14 |
| College | 6 – 13 ° | 3 | 6 | 10 | 13 | 18 |
| Professional | 6 – 13 ° | 3 | 6 | 10 | 13 | 18 |
| Broad (All Levels) | 4 – 12 ° | 1 | 4 | 9 | 12 | 17 |
## Use Cases
* Trunk posture analysis
* Launch position evaluation
# Trunk to Arm Speed Up
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/trunk-to-arm-speed-up
Ratio (multiplication factor) of speed increase from trunk to arm. This measures the efficiency of power transfer from the core to the upper body.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio
* **Column Name:** `trunk_to_arm_velocity_speedup`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Peak arm angular velocity / Peak trunk angular velocity
* **Optimal Range:** 1.2-1.8
* **Optimal Direction:** Higher is better
## Description
Trunk to arm speed up measures the multiplication factor of velocity increase from the trunk to the arm, indicating the efficiency of power transfer through the kinetic chain.
## Normative Ranges
Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.
| Population | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth | 1.31 – 1.51 | 0.89 | 1.03 | 1.14 | 1.31 | 1.51 |
| High School | 1.31 – 1.51 | 0.89 | 1.03 | 1.14 | 1.31 | 1.51 |
| College | 1.37 – 1.54 | 0.92 | 1.06 | 1.21 | 1.37 | 1.54 |
| Professional | 1.37 – 1.54 | 0.92 | 1.06 | 1.21 | 1.37 | 1.54 |
| Broad (All Levels) | 1.36 – 1.55 | 0.90 | 1.04 | 1.19 | 1.36 | 1.55 |
## Use Cases
* Power transfer analysis
* Kinetic chain efficiency
# Vertical Pelvis Hike
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/metrics/vertical-pelvis-hike
Binary indicator of excessive vertical pelvis movement, determined if the pelvis keypoint finishes the swing (at ball contact) higher than where it started (at launch event).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `vertical_pelvis_hike`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Pelvis height at ball contact vs launch
* **Fault Condition:** Pelvis higher at ball contact than at launch
## Description
Vertical pelvis hike indicates excessive upward movement of the pelvis during the swing, which can compromise balance and power transfer efficiency.
## Use Cases
* Pelvis stability analysis
* Vertical movement assessment
* Technique correction
# Softball Hitting: Normative Ranges
Source: https://docs.uplift.ai/biomechanics/activities/softball/hitting/softball-hitting-norms
Full percentile reference tables (5th–95th) for softball hitting metrics, broken out by competition level.
This page collects the percentile summaries on individual [metric pages](/biomechanics/activities/softball/hitting), fully documented for each competition level.
See [Normative Ranges](/biomechanics/normative-ranges) for how to interpret these tables.
Distance metrics are shown in inches to match the display units used on individual metric pages.
Note: due to relatively low sample size in some subgroups, Softball Hitting Norms are identical for (youth, high school) and (college, pro).
## Youth Sample
Reference dataset built from 104 unique youth athletes performing a hit in 2025, pooled with the High School sample due to low individual subgroup sample size.
### Kinematic Sequence – Peak Segment Angular Velocities & Speedup Factors
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-pelvis-angular-velocity) | 361 | 384 | 406 | 455 | 494 | 537 | 554 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-trunk-angular-velocity) | 469 | 489 | 533 | 582 | 666 | 715 | 745 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-arm-angular-velocity) | 455 | 486 | 577 | 694 | 805 | 924 | 1020 | deg/s |
| [Trunk to Arm Speed Up](/biomechanics/activities/softball/hitting/metrics/trunk-to-arm-speed-up) | 0.80 | 0.89 | 1.03 | 1.14 | 1.31 | 1.51 | 1.67 | ratio |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/softball/hitting/metrics/pelvis-to-trunk-speed-up) | 1.08 | 1.13 | 1.23 | 1.33 | 1.42 | 1.48 | 1.53 | ratio |
### Times
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------ | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Time to Ball Contact](/biomechanics/activities/softball/hitting/metrics/time-to-ball-contact) | 0.00 | 0.00 | 0.57 | 0.68 | 0.80 | 0.92 | 1.02 | s |
| [Time to Launch](/biomechanics/activities/softball/hitting/metrics/time-to-launch) | 0.00 | 0.00 | 0.18 | 0.34 | 0.45 | 0.55 | 0.70 | s |
| [Pelvis Acceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-acceleration-time) | 0.14 | 0.14 | 0.16 | 0.19 | 0.33 | 0.38 | 0.39 | s |
| [Pelvis Deceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-deceleration-time) | 0.14 | 0.14 | 0.17 | 0.25 | 0.42 | 0.54 | 0.57 | s |
### Distance
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------------------------ | :---: | :---: | :---: | :---: | :---: | :---: | :---: | ----- |
| [Stride Length](/biomechanics/activities/softball/hitting/metrics/stride-length) | 18.2 | 20.7 | 23.6 | 25.3 | 27.7 | 29.5 | 31.0 | in |
| [Linear Stretch](/biomechanics/activities/softball/hitting/metrics/linear-stretch) | 13.7 | 16.5 | 19.3 | 22.0 | 25.4 | 27.2 | 28.5 | in |
| [Drifting Forward Magnitude](/biomechanics/activities/softball/hitting/metrics/drifting-forward-magnitude) | -0.9 | -0.6 | 0.1 | 0.7 | 1.5 | 2.9 | 3.7 | in |
| [Inter Elbow Distance at Elbow Slot](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-elbow-slot) | 0.205 | 0.218 | 0.254 | 0.302 | 0.358 | 0.395 | 0.408 | m |
| [Inter Elbow Distance at Ball Contact](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-ball-contact) | 0.187 | 0.203 | 0.231 | 0.282 | 0.344 | 0.391 | 0.410 | m |
| [Rear Arm Connection](/biomechanics/activities/softball/hitting/metrics/rear-arm-connection) | 8.9 | 9.5 | 10.3 | 11.1 | 12.2 | 13.5 | 13.9 | in |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-towards-pitcher) | -11.5 | -10.8 | -9.8 | -8.0 | -6.2 | -4.2 | -3.2 | in |
| [Relative Hand Position - Up](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-up) | -0.9 | -0.2 | 1.8 | 4.0 | 6.1 | 7.1 | 7.8 | in |
| [Relative Hand Position - Away from Body](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-away-from-body) | 0.0 | 0.8 | 2.3 | 4.5 | 5.9 | 7.3 | 8.0 | in |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/softball/hitting/metrics/max-x-factor) | 0 | 0 | 14 | 19 | 26 | 36 | 38 | deg |
| [Hip Hinge](/biomechanics/activities/softball/hitting/metrics/hip-hinge) | 43 | 44 | 54 | 60 | 67 | 73 | 79 | deg |
| [Trunk Coil](/biomechanics/activities/softball/hitting/metrics/trunk-coil) | 15 | 20 | 26 | 33 | 38 | 47 | 50 | deg |
| [Trunk Tilt at Launch](/biomechanics/activities/softball/hitting/metrics/trunk-tilt-at-launch) | -1 | 0 | 3 | 6 | 10 | 14 | 21 | deg |
| [Scap Load at Launch](/biomechanics/activities/softball/hitting/metrics/scap-load-at-launch) | -15 | -11 | -4 | 8 | 21 | 29 | 37 | deg |
| [Elbow Flexion at Launch](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-launch) | 110 | 117 | 124 | 128 | 132 | 135 | 135 | deg |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-ball-contact) | 47 | 50 | 60 | 74 | 88 | 97 | 103 | deg |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/softball/hitting/metrics/lead-knee-angle-at-ball-contact) | 9 | 10 | 11 | 15 | 20 | 28 | 34 | deg |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-flexion) | 22 | 24 | 27 | 33 | 37 | 40 | 42 | deg |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-tilt) | -7 | -1 | 3 | 12 | 19 | 26 | 28 | deg |
## High School Sample
Reference dataset built from 104 unique high school athletes performing a hit in 2025, pooled with the Youth sample due to low individual subgroup sample size.
### Kinematic Sequence – Peak Segment Angular Velocities & Speedup Factors
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-pelvis-angular-velocity) | 361 | 384 | 406 | 455 | 494 | 537 | 554 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-trunk-angular-velocity) | 469 | 489 | 533 | 582 | 666 | 715 | 745 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-arm-angular-velocity) | 455 | 486 | 577 | 694 | 805 | 924 | 1020 | deg/s |
| [Trunk to Arm Speed Up](/biomechanics/activities/softball/hitting/metrics/trunk-to-arm-speed-up) | 0.80 | 0.89 | 1.03 | 1.14 | 1.31 | 1.51 | 1.67 | ratio |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/softball/hitting/metrics/pelvis-to-trunk-speed-up) | 1.08 | 1.13 | 1.23 | 1.33 | 1.42 | 1.48 | 1.53 | ratio |
### Times
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------ | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Time to Ball Contact](/biomechanics/activities/softball/hitting/metrics/time-to-ball-contact) | 0.00 | 0.00 | 0.57 | 0.68 | 0.80 | 0.92 | 1.02 | s |
| [Time to Launch](/biomechanics/activities/softball/hitting/metrics/time-to-launch) | 0.00 | 0.00 | 0.18 | 0.34 | 0.45 | 0.55 | 0.70 | s |
| [Pelvis Acceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-acceleration-time) | 0.14 | 0.14 | 0.16 | 0.19 | 0.33 | 0.38 | 0.39 | s |
| [Pelvis Deceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-deceleration-time) | 0.14 | 0.14 | 0.17 | 0.25 | 0.42 | 0.54 | 0.57 | s |
### Distance
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------------------------ | :---: | :---: | :---: | :---: | :---: | :---: | :---: | ----- |
| [Stride Length](/biomechanics/activities/softball/hitting/metrics/stride-length) | 18.2 | 20.7 | 23.6 | 25.3 | 27.7 | 29.5 | 31.0 | in |
| [Linear Stretch](/biomechanics/activities/softball/hitting/metrics/linear-stretch) | 13.7 | 16.5 | 19.3 | 22.0 | 25.4 | 27.2 | 28.5 | in |
| [Drifting Forward Magnitude](/biomechanics/activities/softball/hitting/metrics/drifting-forward-magnitude) | -0.9 | -0.6 | 0.1 | 0.7 | 1.5 | 2.9 | 3.7 | in |
| [Inter Elbow Distance at Elbow Slot](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-elbow-slot) | 0.197 | 0.208 | 0.233 | 0.272 | 0.301 | 0.344 | 0.360 | m |
| [Inter Elbow Distance at Ball Contact](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-ball-contact) | 0.185 | 0.193 | 0.214 | 0.249 | 0.306 | 0.355 | 0.373 | m |
| [Rear Arm Connection](/biomechanics/activities/softball/hitting/metrics/rear-arm-connection) | 8.9 | 9.5 | 10.3 | 11.1 | 12.2 | 13.5 | 13.9 | in |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-towards-pitcher) | -11.5 | -10.8 | -9.8 | -8.0 | -6.2 | -4.2 | -3.2 | in |
| [Relative Hand Position - Up](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-up) | -0.9 | -0.2 | 1.8 | 4.0 | 6.1 | 7.1 | 7.8 | in |
| [Relative Hand Position - Away from Body](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-away-from-body) | 0.0 | 0.8 | 2.3 | 4.5 | 5.9 | 7.3 | 8.0 | in |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/softball/hitting/metrics/max-x-factor) | 0 | 0 | 14 | 19 | 26 | 36 | 38 | deg |
| [Hip Hinge](/biomechanics/activities/softball/hitting/metrics/hip-hinge) | 43 | 44 | 54 | 60 | 67 | 73 | 79 | deg |
| [Trunk Coil](/biomechanics/activities/softball/hitting/metrics/trunk-coil) | 15 | 20 | 26 | 33 | 38 | 47 | 50 | deg |
| [Trunk Tilt at Launch](/biomechanics/activities/softball/hitting/metrics/trunk-tilt-at-launch) | -1 | 0 | 3 | 6 | 10 | 14 | 21 | deg |
| [Scap Load at Launch](/biomechanics/activities/softball/hitting/metrics/scap-load-at-launch) | -15 | -11 | -4 | 8 | 21 | 29 | 37 | deg |
| [Elbow Flexion at Launch](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-launch) | 110 | 117 | 124 | 128 | 132 | 135 | 135 | deg |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-ball-contact) | 47 | 50 | 60 | 74 | 88 | 97 | 103 | deg |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/softball/hitting/metrics/lead-knee-angle-at-ball-contact) | 9 | 10 | 11 | 15 | 20 | 28 | 34 | deg |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-flexion) | 22 | 24 | 27 | 33 | 37 | 40 | 42 | deg |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-tilt) | -7 | -1 | 3 | 12 | 19 | 26 | 28 | deg |
## College Sample
Reference dataset built from 112 unique collegiate athletes performing a hit in 2025, pooled with the Professional sample due to low individual subgroup sample size.
### Kinematic Sequence – Peak Segment Angular Velocities & Speedup Factors
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-pelvis-angular-velocity) | 420 | 438 | 472 | 507 | 543 | 578 | 605 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-trunk-angular-velocity) | 510 | 553 | 595 | 645 | 692 | 746 | 770 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-arm-angular-velocity) | 501 | 588 | 684 | 792 | 919 | 1011 | 1054 | deg/s |
| [Trunk to Arm Speed Up](/biomechanics/activities/softball/hitting/metrics/trunk-to-arm-speed-up) | 0.87 | 0.92 | 1.06 | 1.21 | 1.37 | 1.54 | 1.66 | ratio |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/softball/hitting/metrics/pelvis-to-trunk-speed-up) | 1.08 | 1.12 | 1.18 | 1.28 | 1.34 | 1.42 | 1.44 | ratio |
### Times
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------ | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Time to Ball Contact](/biomechanics/activities/softball/hitting/metrics/time-to-ball-contact) | 0.42 | 0.58 | 0.65 | 0.79 | 0.89 | 0.96 | 1.04 | s |
| [Time to Launch](/biomechanics/activities/softball/hitting/metrics/time-to-launch) | 0.07 | 0.18 | 0.33 | 0.46 | 0.57 | 0.64 | 0.69 | s |
| [Pelvis Acceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-acceleration-time) | 0.14 | 0.15 | 0.17 | 0.18 | 0.30 | 0.34 | 0.36 | s |
| [Pelvis Deceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-deceleration-time) | 0.15 | 0.16 | 0.17 | 0.20 | 0.39 | 0.51 | 0.58 | s |
### Distance
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------------------------ | :---: | :---: | :---: | :---: | :---: | :---: | :---: | ----- |
| [Stride Length](/biomechanics/activities/softball/hitting/metrics/stride-length) | 21.3 | 23.0 | 26.1 | 28.8 | 31.6 | 34.3 | 36.7 | in |
| [Linear Stretch](/biomechanics/activities/softball/hitting/metrics/linear-stretch) | 14.1 | 15.4 | 19.9 | 23.2 | 27.3 | 30.6 | 32.1 | in |
| [Drifting Forward Magnitude](/biomechanics/activities/softball/hitting/metrics/drifting-forward-magnitude) | -1.0 | -0.6 | 0.0 | 0.7 | 1.5 | 2.2 | 3.3 | in |
| [Inter Elbow Distance at Elbow Slot](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-elbow-slot) | 0.216 | 0.235 | 0.295 | 0.341 | 0.388 | 0.403 | 0.422 | m |
| [Inter Elbow Distance at Ball Contact](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-ball-contact) | 0.209 | 0.231 | 0.259 | 0.313 | 0.372 | 0.403 | 0.420 | m |
| [Rear Arm Connection](/biomechanics/activities/softball/hitting/metrics/rear-arm-connection) | 10.5 | 11.2 | 12.6 | 14.0 | 15.4 | 16.8 | 18.4 | in |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-towards-pitcher) | -12.6 | -12.1 | -10.8 | -8.3 | -5.6 | -2.9 | 0.3 | in |
| [Relative Hand Position - Up](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-up) | -0.9 | 1.6 | 4.0 | 5.6 | 7.3 | 8.9 | 9.6 | in |
| [Relative Hand Position - Away from Body](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-away-from-body) | 1.8 | 3.3 | 4.7 | 6.7 | 8.5 | 10.1 | 11.0 | in |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/softball/hitting/metrics/max-x-factor) | 8 | 16 | 21 | 27 | 34 | 38 | 40 | deg |
| [Hip Hinge](/biomechanics/activities/softball/hitting/metrics/hip-hinge) | 42 | 44 | 49 | 55 | 62 | 69 | 72 | deg |
| [Trunk Coil](/biomechanics/activities/softball/hitting/metrics/trunk-coil) | 5 | 21 | 29 | 36 | 43 | 49 | 53 | deg |
| [Trunk Tilt at Launch](/biomechanics/activities/softball/hitting/metrics/trunk-tilt-at-launch) | 1 | 3 | 6 | 10 | 13 | 18 | 21 | deg |
| [Scap Load at Launch](/biomechanics/activities/softball/hitting/metrics/scap-load-at-launch) | -29 | -19 | -6 | 6 | 16 | 33 | 40 | deg |
| [Elbow Flexion at Launch](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-launch) | 110 | 118 | 125 | 130 | 135 | 137 | 138 | deg |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-ball-contact) | 41 | 45 | 56 | 72 | 86 | 98 | 103 | deg |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/softball/hitting/metrics/lead-knee-angle-at-ball-contact) | 6 | 7 | 9 | 12 | 17 | 21 | 27 | deg |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-flexion) | 20 | 25 | 29 | 33 | 37 | 40 | 43 | deg |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-tilt) | -4 | -1 | 3 | 9 | 17 | 23 | 25 | deg |
## Professional Sample
Reference dataset built from 112 unique professional athletes performing a hit in 2025, pooled with the College sample due to low individual subgroup sample size.
### Kinematic Sequence – Peak Segment Angular Velocities & Speedup Factors
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-pelvis-angular-velocity) | 420 | 438 | 472 | 507 | 543 | 578 | 605 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-trunk-angular-velocity) | 510 | 553 | 595 | 645 | 692 | 746 | 770 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-arm-angular-velocity) | 501 | 588 | 684 | 792 | 919 | 1011 | 1054 | deg/s |
| [Trunk to Arm Speed Up](/biomechanics/activities/softball/hitting/metrics/trunk-to-arm-speed-up) | 0.87 | 0.92 | 1.06 | 1.21 | 1.37 | 1.54 | 1.66 | ratio |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/softball/hitting/metrics/pelvis-to-trunk-speed-up) | 1.08 | 1.12 | 1.18 | 1.28 | 1.34 | 1.42 | 1.44 | ratio |
### Times
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------ | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Time to Ball Contact](/biomechanics/activities/softball/hitting/metrics/time-to-ball-contact) | 0.42 | 0.58 | 0.65 | 0.79 | 0.89 | 0.96 | 1.04 | s |
| [Time to Launch](/biomechanics/activities/softball/hitting/metrics/time-to-launch) | 0.07 | 0.18 | 0.33 | 0.46 | 0.57 | 0.64 | 0.69 | s |
| [Pelvis Acceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-acceleration-time) | 0.14 | 0.15 | 0.17 | 0.18 | 0.30 | 0.34 | 0.36 | s |
| [Pelvis Deceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-deceleration-time) | 0.15 | 0.16 | 0.17 | 0.20 | 0.39 | 0.51 | 0.58 | s |
### Distance
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------------------------ | :---: | :---: | :---: | :---: | :---: | :---: | :---: | ----- |
| [Stride Length](/biomechanics/activities/softball/hitting/metrics/stride-length) | 21.3 | 23.0 | 26.1 | 28.8 | 31.6 | 34.3 | 36.7 | in |
| [Linear Stretch](/biomechanics/activities/softball/hitting/metrics/linear-stretch) | 14.1 | 15.4 | 19.9 | 23.2 | 27.3 | 30.6 | 32.1 | in |
| [Drifting Forward Magnitude](/biomechanics/activities/softball/hitting/metrics/drifting-forward-magnitude) | -1.0 | -0.6 | 0.0 | 0.7 | 1.5 | 2.2 | 3.3 | in |
| [Inter Elbow Distance at Elbow Slot](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-elbow-slot) | 0.216 | 0.235 | 0.295 | 0.341 | 0.388 | 0.403 | 0.422 | m |
| [Inter Elbow Distance at Ball Contact](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-ball-contact) | 0.209 | 0.231 | 0.259 | 0.313 | 0.372 | 0.403 | 0.420 | m |
| [Rear Arm Connection](/biomechanics/activities/softball/hitting/metrics/rear-arm-connection) | 10.5 | 11.2 | 12.6 | 14.0 | 15.4 | 16.8 | 18.4 | in |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-towards-pitcher) | -12.6 | -12.1 | -10.8 | -8.3 | -5.6 | -2.9 | 0.3 | in |
| [Relative Hand Position - Up](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-up) | -0.9 | 1.6 | 4.0 | 5.6 | 7.3 | 8.9 | 9.6 | in |
| [Relative Hand Position - Away from Body](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-away-from-body) | 1.8 | 3.3 | 4.7 | 6.7 | 8.5 | 10.1 | 11.0 | in |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/softball/hitting/metrics/max-x-factor) | 8 | 16 | 21 | 27 | 34 | 38 | 40 | deg |
| [Hip Hinge](/biomechanics/activities/softball/hitting/metrics/hip-hinge) | 42 | 44 | 49 | 55 | 62 | 69 | 72 | deg |
| [Trunk Coil](/biomechanics/activities/softball/hitting/metrics/trunk-coil) | 5 | 21 | 29 | 36 | 43 | 49 | 53 | deg |
| [Trunk Tilt at Launch](/biomechanics/activities/softball/hitting/metrics/trunk-tilt-at-launch) | 1 | 3 | 6 | 10 | 13 | 18 | 21 | deg |
| [Scap Load at Launch](/biomechanics/activities/softball/hitting/metrics/scap-load-at-launch) | -29 | -19 | -6 | 6 | 16 | 33 | 40 | deg |
| [Elbow Flexion at Launch](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-launch) | 110 | 118 | 125 | 130 | 135 | 137 | 138 | deg |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-ball-contact) | 41 | 45 | 56 | 72 | 86 | 98 | 103 | deg |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/softball/hitting/metrics/lead-knee-angle-at-ball-contact) | 6 | 7 | 9 | 12 | 17 | 21 | 27 | deg |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-flexion) | 20 | 25 | 29 | 33 | 37 | 40 | 43 | deg |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-tilt) | -4 | -1 | 3 | 9 | 17 | 23 | 25 | deg |
## Broad Sample (All Levels)
Reference dataset built from 216 unique athletes performing a hit in 2025, pooled across all competition levels.
### Kinematic Sequence – Peak Segment Angular Velocities & Speedup Factors
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-pelvis-angular-velocity) | 384 | 402 | 437 | 485 | 526 | 564 | 584 | deg/s |
| [Peak Trunk Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-trunk-angular-velocity) | 487 | 511 | 563 | 630 | 683 | 739 | 770 | deg/s |
| [Peak Arm Angular Velocity](/biomechanics/activities/softball/hitting/metrics/peak-arm-angular-velocity) | 482 | 509 | 634 | 743 | 881 | 996 | 1047 | deg/s |
| [Trunk to Arm Speed Up](/biomechanics/activities/softball/hitting/metrics/trunk-to-arm-speed-up) | 0.81 | 0.90 | 1.04 | 1.19 | 1.36 | 1.55 | 1.67 | ratio |
| [Pelvis to Trunk Speed Up](/biomechanics/activities/softball/hitting/metrics/pelvis-to-trunk-speed-up) | 1.08 | 1.12 | 1.20 | 1.30 | 1.39 | 1.48 | 1.53 | ratio |
### Times
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------ | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Time to Ball Contact](/biomechanics/activities/softball/hitting/metrics/time-to-ball-contact) | 0.00 | 0.45 | 0.61 | 0.74 | 0.87 | 0.95 | 1.02 | s |
| [Time to Launch](/biomechanics/activities/softball/hitting/metrics/time-to-launch) | 0.00 | 0.08 | 0.26 | 0.39 | 0.52 | 0.64 | 0.70 | s |
| [Pelvis Acceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-acceleration-time) | 0.14 | 0.15 | 0.16 | 0.18 | 0.31 | 0.36 | 0.39 | s |
| [Pelvis Deceleration Time](/biomechanics/activities/softball/hitting/metrics/pelvis-deceleration-time) | 0.14 | 0.15 | 0.17 | 0.23 | 0.42 | 0.52 | 0.58 | s |
### Distance
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ------------------------------------------------------------------------------------------------------------------------------------ | :---: | :---: | :---: | :---: | :---: | :---: | :---: | ----- |
| [Stride Length](/biomechanics/activities/softball/hitting/metrics/stride-length) | 19.7 | 21.6 | 24.1 | 26.9 | 29.6 | 32.6 | 34.5 | in |
| [Linear Stretch](/biomechanics/activities/softball/hitting/metrics/linear-stretch) | 12.3 | 15.3 | 19.3 | 22.3 | 25.7 | 28.8 | 31.1 | in |
| [Drifting Forward Magnitude](/biomechanics/activities/softball/hitting/metrics/drifting-forward-magnitude) | -0.9 | -0.5 | 0.0 | 0.7 | 1.5 | 2.8 | 3.7 | in |
| [Inter Elbow Distance at Elbow Slot](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-elbow-slot) | 0.205 | 0.218 | 0.254 | 0.302 | 0.358 | 0.395 | 0.408 | m |
| [Inter Elbow Distance at Ball Contact](/biomechanics/activities/softball/hitting/metrics/inter-elbow-distance-at-ball-contact) | 0.187 | 0.203 | 0.231 | 0.282 | 0.344 | 0.391 | 0.410 | m |
| [Rear Arm Connection](/biomechanics/activities/softball/hitting/metrics/rear-arm-connection) | 9.4 | 9.9 | 11.0 | 12.6 | 14.4 | 15.8 | 17.6 | in |
| [Relative Hand Position - Towards Pitcher](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-towards-pitcher) | -12.2 | -11.6 | -10.1 | -8.1 | -6.1 | -3.7 | -1.6 | in |
| [Relative Hand Position - Up](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-up) | -1.0 | 0.3 | 2.6 | 4.7 | 6.6 | 8.0 | 8.9 | in |
| [Relative Hand Position - Away from Body](/biomechanics/activities/softball/hitting/metrics/relative-hand-position-away-from-body) | 0.4 | 1.4 | 3.6 | 5.6 | 7.6 | 9.2 | 10.1 | in |
### Angles
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :-: | :-: | :-: | :-: | :-: | ----- |
| [Max X Factor](/biomechanics/activities/softball/hitting/metrics/max-x-factor) | 0 | 10 | 17 | 24 | 31 | 37 | 39 | deg |
| [Hip Hinge](/biomechanics/activities/softball/hitting/metrics/hip-hinge) | 42 | 44 | 50 | 58 | 64 | 71 | 75 | deg |
| [Trunk Coil](/biomechanics/activities/softball/hitting/metrics/trunk-coil) | 14 | 21 | 28 | 34 | 42 | 48 | 51 | deg |
| [Trunk Tilt at Launch](/biomechanics/activities/softball/hitting/metrics/trunk-tilt-at-launch) | 0 | 1 | 4 | 9 | 12 | 17 | 21 | deg |
| [Scap Load at Launch](/biomechanics/activities/softball/hitting/metrics/scap-load-at-launch) | -24 | -15 | -4 | 7 | 19 | 33 | 40 | deg |
| [Elbow Flexion at Launch](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-launch) | 109 | 117 | 124 | 129 | 133 | 136 | 137 | deg |
| [Elbow Flexion at Ball Contact](/biomechanics/activities/softball/hitting/metrics/elbow-flexion-at-ball-contact) | 43 | 48 | 57 | 72 | 87 | 97 | 103 | deg |
| [Lead Knee Angle at Ball Contact](/biomechanics/activities/softball/hitting/metrics/lead-knee-angle-at-ball-contact) | 7 | 8 | 10 | 13 | 19 | 25 | 32 | deg |
| [Shoulder Rotation Plane Flexion](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-flexion) | 21 | 24 | 28 | 33 | 37 | 40 | 43 | deg |
| [Shoulder Rotation Plane Tilt](/biomechanics/activities/softball/hitting/metrics/shoulder-rotation-plane-tilt) | -6 | -1 | 3 | 11 | 18 | 25 | 27 | deg |
# Softball: Pitching
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching
Biomechanical analysis of softball windmill pitching
Evaluate windmill pitching mechanics to improve consistency, maximize energy transfer to the ball, and reduce risk for injury.
Uplift offers dozens of events and metrics to track softball pitching across movement flags, arm circle kinematics, and more.
## Dimensions
Required Inputs for processing:
* **handedness:** the handedness of the pitcher \['left', 'right']
## Variables
Output variables from pitching analysis.
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
Automated events break down the pitch into phases or periods of interest. Many metrics occur at specific events.
| Event | Short Description | Column Name |
| -------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------- | ------------------------ |
| [Initiation](/biomechanics/activities/softball/pitching/events/initiation) | Start of the pitch, marked by max trunk forward flexion before the drive leg extends. | `initiation_frame` |
| [High Hand](/biomechanics/activities/softball/pitching/events/high-hand) | Highest point of the throwing hand during the windup. | `high_hand_frame` |
| [Max Knee Raise](/biomechanics/activities/softball/pitching/events/max-knee-raise) | Maximum lead knee height. | `max_knee_raise_frame` |
| [Low Hand](/biomechanics/activities/softball/pitching/events/low-hand) | Lowest point of the throwing hand after high hand. | `low_hand_frame` |
| [Power K Position](/biomechanics/activities/softball/pitching/events/power-k-position) | Throwing wrist drops below the shoulder after high hand. | `power_k_position_frame` |
| [Drive Start](/biomechanics/activities/softball/pitching/events/drive-start) | Stepping (lead) ankle passes the pushing (drive) ankle. | `drive_start_frame` |
| [Foot Contact](/biomechanics/activities/softball/pitching/events/foot-contact) | Front foot contacts the ground. | `foot_contact_frame` |
| [Release](/biomechanics/activities/softball/pitching/events/release) | Estimated timing of ball release. | `ball_release_frame` |
| [Finish](/biomechanics/activities/softball/pitching/events/finish) | Peak wrist height after release, marking the follow-through. | `finish_frame` |
### Movement Flag Metrics
Movement flags identify poor or suboptimal mechanics for timing and body positioning during the pitch.
| Metric | Short Description | Column Name |
| ------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------ | ------------------------- |
| [Pre-Tracking](/biomechanics/activities/softball/pitching/metrics/pre-tracking) | Shoulders or hips rotate more than 40° away from the target before the drive phase begins. | `pre_tracking_flag` |
| [Lack of Knee Drive](/biomechanics/activities/softball/pitching/metrics/lack-of-knee-drive) | Loading (dominant-side) knee fails to drive past the toe before the drive phase begins. | `lack_of_knee_drive_flag` |
| [Trunk Not Stacked](/biomechanics/activities/softball/pitching/metrics/trunk-not-stacked) | Trunk flexion, tilt, or twist exceeds 30° between high hand and release. | `trunk_not_stacked_flag` |
| [Knee Collapse](/biomechanics/activities/softball/pitching/metrics/knee-collapse) | Front knee flexes more than 20° between foot contact and release. | `knee_collapse_flag` |
### Linear Metrics & Time
Show distances, positions, and speeds relevant to pitching.
| Metric | Units | Short Description | Column Name |
| ------------------------------------------------------------------------------------------------------------------- | ----------- | ----------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------- |
| [Stride Length](/biomechanics/activities/softball/pitching/metrics/stride-length) | % of height | Distance between the dominant ankle at initiation and the lead ankle at foot contact, normalized by height. | `stride_length` |
| [Wrist Height at Release](/biomechanics/activities/softball/pitching/metrics/wrist-height-at-release) | % of height | Wrist height above ground level at release. | `wrist_height_at_release` |
| [Wrist Position vs. Pelvis at Release](/biomechanics/activities/softball/pitching/metrics/wrist-position-vs-pelvis) | % of height | Wrist forward, up, and side position relative to the pelvis at release. | `wrist_forward_position_vs_pelvis`, `wrist_up_position_vs_pelvis`, `wrist_side_position_vs_pelvis` |
| [Handedness](/biomechanics/activities/softball/pitching/metrics/handedness) | N/A | Pitcher handedness \['right' or 'left']. | `handedness` |
| [Time to Release](/biomechanics/activities/softball/pitching/metrics/time-to-release) | s | Duration from initiation to ball release. | `time_to_release` |
### Angular Metrics
These metrics describe joint angles and segment angles relative to global orientation.
| Metric | Units | Short Description | Column Name |
| ----------------------------------------------------------------------------------------------------------------------------- | ----- | ---------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| [Shin Angle at Loading](/biomechanics/activities/softball/pitching/metrics/shin-angle-at-loading) | deg | Max forward shin angle during the loading phase (initiation to high hand). | `shin_angle_at_loading` |
| [Max Trunk Flexion](/biomechanics/activities/softball/pitching/metrics/max-trunk-flexion) | deg | Max forward trunk flexion angle near initiation. | `max_trunk_flexion` |
| [Max X Factor](/biomechanics/activities/softball/pitching/metrics/max-x-factor) | deg | Max hip-shoulder separation between drive start and release. | `max_x_factor` |
| [Average Arm Circle Radius](/biomechanics/activities/softball/pitching/metrics/average-arm-circle-radius) | ratio | Average shoulder-to-wrist distance during the arm circle, normalized by arm length. | `average_arm_circle_radius` |
| [Average Elbow Angle During Rotation](/biomechanics/activities/softball/pitching/metrics/average-elbow-angle-during-rotation) | deg | Average elbow flexion angle during the arm circle (drive start to release). | `average_elbow_angle_during_rotation` |
| [Foot Plant Angle](/biomechanics/activities/softball/pitching/metrics/foot-plant-angle) | deg | Lead foot angle relative to the pitch direction at foot contact. | `foot_plant_angle` |
| [Trunk Global Flexion, Tilt & Twist](/biomechanics/activities/softball/pitching/metrics/trunk-global-orientation) | deg | Trunk flexion, lateral tilt, and rotation relative to global at foot contact and ball release. | `trunk_global_flexion_at_foot_contact`, `trunk_global_flexion_at_ball_release`, `trunk_global_tilt_at_foot_contact`, `trunk_global_tilt_at_ball_release`, `trunk_global_twist_at_foot_contact`, `trunk_global_twist_at_ball_release` |
## Notes
* All movement flags (true/false = 1/0) return -1 if metric unable to be calculated.
# Drive Start
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/events/drive-start
Start of the drive phase of the softball pitch.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `drive_start_frame`
* **Required for QA:** False
* **Measurement:** First frame after high hand where the stepping (lead) ankle passes in front of the pushing (drive) ankle, in the pitch direction
## Description
Drive Start marks the beginning of the drive phase, when the lead leg begins stepping toward the plate and passes the pushing leg. This timing anchors several angular metrics that describe the rotational phase of the delivery.
## Use Cases
* Drive phase identification
* Rotational sequencing analysis
# Finish
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/events/finish
Follow-through peak in wrist height after ball release.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `finish_frame`
* **Required for QA:** False
* **Measurement:** First peak in throwing wrist height within 1 second after low hand
## Description
Finish marks the end of the pitching motion, identified as the first peak in throwing wrist height after the low hand event as the arm decelerates through follow-through.
## Use Cases
* Pitch timing analysis
* Follow-through assessment
# Foot Contact
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/events/foot-contact
Front foot contacts the ground during the softball pitch.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `foot_contact_frame`
* **Required for QA:** True
* **Measurement:** Front foot ground contact, combining lead ankle/toe height and velocity methods between max knee raise and low hand
## Description
Foot Contact identifies when the front (lead) foot plants on the ground during the pitch delivery. It is detected using a combination of lead ankle and toe height, as well as ankle and toe velocity, to find the moment the foot becomes stationary on the ground.
## Use Cases
* Delivery phase identification
* Stride length calculation
* Angular metrics at foot contact
# High Hand
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/events/high-hand
Highest point of the throwing hand during the windup.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `high_hand_frame`
* **Required for QA:** False
* **Measurement:** Highest local peak of the throwing wrist during the windmill windup
## Description
High Hand marks the top of the arm circle during the windmill windup, identified as the highest local peak in throwing wrist height.
## Use Cases
* Pitch timing analysis
* Windup phase identification
# Initiation
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/events/initiation
Initial movement beginning the softball pitch.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `initiation_frame`
* **Required for QA:** False
* **Measurement:** Frame of max forward trunk flexion in the 2 seconds before max knee raise
## Description
Initiation represents the very beginning of the pitching sequence, identified as the point of maximum forward trunk flexion before the drive leg begins to extend.
## Use Cases
* Pitch timing analysis
* Event timing comparisons - time to release
# Low Hand
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/events/low-hand
Lowest point of the throwing hand after high hand.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `low_hand_frame`
* **Required for QA:** False
* **Measurement:** First local peak (low point) of the throwing wrist after high hand
## Description
Low Hand marks the bottom of the arm circle following the high hand event, as the throwing arm swings down and back before accelerating toward release.
## Use Cases
* Pitch timing analysis
* Ball release detection
* Foot contact detection
# Max Knee Raise
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/events/max-knee-raise
Maximum lead knee height during the softball pitch.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `max_knee_raise_frame`
* **Required for QA:** True
* **Measurement:** Frame of maximum lead knee height, searched within 0.25 s after high hand
## Description
Max Knee Raise identifies the frame of peak lead knee height, which represents the balance point of the leg lift before the drive and delivery phases.
## Use Cases
* Balance point identification
* Stride length calculation
* Foot contact detection
# Power K Position
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/events/power-k-position
Throwing wrist drops below the shoulder after high hand.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `power_k_position_frame`
* **Required for QA:** False
* **Measurement:** First frame between high hand and low hand where the throwing wrist passes below the throwing shoulder
## Description
Power K Position marks the classic "power K" body position of the windmill delivery, identified as the first instant the throwing wrist drops below the throwing shoulder after the high hand event.
## Use Cases
* Delivery phase identification
* Arm circle timing analysis
# Release
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/events/release
Estimated timing of ball release during the softball pitch.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `ball_release_frame`
* **Required for QA:** True
* **Measurement:** Low hand event plus a fixed 3-frame offset, calibrated against ground-truth release timing
## Description
Release marks the estimated instant of ball release during the windmill delivery, computed as a small offset from the low hand event.
## Use Cases
* Ball release timing analysis
* Downstream release-based metrics (wrist height, trunk angles, arm slot)
# Average Arm Circle Radius
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/average-arm-circle-radius
Average shoulder-to-wrist distance during the arm circle, normalized by arm length.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio
* **Column Name:** `average_arm_circle_radius`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Average shoulder-to-wrist distance divided by (upper arm length + forearm length)
* **Timing:** Between drive start and release events
* **Optimal Direction:** Higher is better
## Description
Average arm circle radius measures how extended the throwing arm stays during the windmill arm circle, calculated as the average shoulder-to-wrist distance (normalized by arm segment length) between drive start and release. Values closer to 1 indicate a fully extended arm circle.
## Use Cases
* Arm circle consistency assessment
* Mechanics evaluation
# Average Elbow Angle During Rotation
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/average-elbow-angle-during-rotation
Average elbow flexion angle during the arm circle rotation phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `average_elbow_angle_during_rotation`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Average throwing-arm elbow flexion angle
* **Timing:** Between drive start and release events
* **Optimal Direction:** Higher is better
## Description
Average elbow angle during rotation measures the average flexion angle of the throwing elbow throughout the arm circle's rotation phase, from drive start to release. Higher (more extended) values indicate a straighter arm through the circle.
## Use Cases
* Arm circle consistency assessment
* Mechanics evaluation
# Foot Plant Angle
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/foot-plant-angle
Lead foot angle relative to the pitch direction at foot contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `foot_plant_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Angle of the lead foot's heel-to-toe vector relative to the pitch direction
* **Timing:** At foot contact event, using keypoints rotated to the pitch direction
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Foot plant angle measures the orientation of the lead foot relative to the direction of the pitch at the instant of foot contact, indicating whether the front foot lands open, closed, or aligned toward the target.
## Use Cases
* Front-side alignment assessment
* Mechanics evaluation
# Handedness
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/handedness
Handedness of the athlete ('right' or 'left') as input parameter.
## Technical Details
* **Variable Type:** Dimension
* **Data Type:** String
* **Units:** N/A
* **Column Name:** `handedness`
* **Aggregation:** mode
* **Precision:** 0
* **Optimal Direction:** N/A
* **Values:** 'right' or 'left'
## Description
Handedness specifies which side the athlete throws from (right-handed or left-handed).
This is a required input parameter that affects the interpretation of all other pitching metrics.
## Use Cases
* Throwing side identification
* Data analysis
# Knee Collapse
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/knee-collapse
Binary indicator if the front knee flexes more than 20° between foot contact and release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `knee_collapse_flag`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Change in front knee flexion angle from foot contact to release
* **Threshold:** Front knee flexes more than 20° from its angle at foot contact
## Description
Knee collapse is a binary indicator that flags when the front (lead) knee bends more than 20° from its foot-contact angle by the time of ball release, which can reduce the stability of the front leg block and limit energy transfer into the pitch.
## Use Cases
* Front-side stability assessment
* Mechanics evaluation
* Injury risk identification
## Corrective Drills
### 1. Firm Front Leg Drill
Practice the delivery focusing on maintaining a firm, extended front leg from foot contact through release, blocking rather than continuing to bend the front knee. Use video from the side to check knee angle at foot contact versus release. Perform 3 sets of 10 repetitions.
[Search YouTube: softball pitching firm front leg drill block](https://www.youtube.com/results?search_query=softball+pitching+firm+front+leg+drill+block)
### 2. Wall Sit Stability Drill
Build front-leg stability with wall sits and single-leg balance holds targeting the quadriceps and glutes, then apply the improved stability to the delivery. Consistent lower-body strength supports a stable front-leg block at release. Perform 2-3 sets of 20-30 second holds.
[Search YouTube: softball pitching front leg stability strength drill](https://www.youtube.com/results?search_query=softball+pitching+front+leg+stability+strength+drill)
# Lack of Knee Drive
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/lack-of-knee-drive
Binary indicator if the loading knee fails to drive past the toe before the drive phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `lack_of_knee_drive_flag`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Loading knee position relative to the ankle at drive start
* **Threshold:** Loading knee does not pass in front of the ankle
## Description
Lack of knee drive is a binary indicator that flags when the loading (dominant-side) knee does not drive forward past its own toe by the start of the drive phase, indicating reduced lower-body power generation into the delivery.
## Use Cases
* Leg drive assessment
* Power generation evaluation
## Corrective Drills
### 1. Knee-Over-Toe Drive Drill
From the balance point at max knee raise, practice driving the loading knee forward past the toe before initiating the step, pausing briefly to check position. Use a side-view mirror or video to confirm the knee clears the toe. Perform 3 sets of 10 repetitions.
[Search YouTube: softball pitching knee drive drill balance point](https://www.youtube.com/results?search_query=softball+pitching+knee+drive+drill+balance+point)
### 2. Resistance Band Knee Drive
Attach a light resistance band around the loading knee, anchored behind the pitcher. Practice driving the knee forward against the band's resistance to reinforce an aggressive, forward knee drive pattern. Perform 2 sets of 8-10 repetitions per side.
[Search YouTube: softball pitching resistance band knee drive drill](https://www.youtube.com/results?search_query=softball+pitching+resistance+band+knee+drive+drill)
# Max Trunk Flexion
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/max-trunk-flexion
Max forward trunk flexion angle near pitch initiation.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `max_trunk_flexion`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Max forward trunk flexion relative to global vertical
* **Timing:** Within a 0.25 s window centered on the initiation event
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Max trunk flexion measures the maximum forward-flexed angle of the trunk relative to global vertical near the initiation event, which reflects how far the athlete bends forward at the start of the pitching motion.
## Use Cases
* Initiation posture assessment
* Mechanics evaluation
# Max X Factor
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/max-x-factor
Max hip-shoulder separation between drive start and release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `max_x_factor`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Max trunk rotation angle relative to the pelvis (hip-shoulder separation)
* **Timing:** Between drive start and release events
* **Optimal Direction:** Higher is better
## Description
Max X factor measures the maximum hip-shoulder separation (trunk rotation relative to the pelvis) achieved between the drive start and release events, reflecting how much rotational energy the athlete stores for delivery.
## Use Cases
* Power generation assessment
* Mechanics evaluation
# Pre-Tracking
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/pre-tracking
Binary indicator if shoulders or hips rotate away from the target before the drive phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `pre_tracking_flag`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Trunk and pelvis rotation away from the target between initiation and drive start
* **Threshold:** Trunk or pelvis rotates more than 40° away from the target
## Description
Pre-tracking is a binary indicator that flags when the shoulders and/or hips rotate away from the target by more than 40° before the drive phase begins, which can indicate the pitcher is opening up too early in the delivery.
## Use Cases
* Trunk and pelvis sequencing assessment
* Mechanics evaluation
## Corrective Drills
### 1. Target-Facing Windup Drill
Stand facing the target (catcher) with feet together. Perform slow-motion windups while keeping the shoulders and hips square to the target through the initiation phase, only allowing rotation to begin at the drive step. Use a mirror or video to confirm the trunk and pelvis stay facing forward. Perform 3 sets of 10 slow repetitions.
[Search YouTube: softball pitching windup drill stay closed](https://www.youtube.com/results?search_query=softball+pitching+windup+drill+stay+closed+to+target)
### 2. Wall Drill for Hip/Shoulder Alignment
Stand with the back foot against a wall, facing the target. Work through the windup and leg lift while keeping the hips and shoulders aligned with the target line. The wall provides a tactile reference to prevent premature rotation. Perform 20 repetitions before bullpen sessions.
[Search YouTube: softball pitching wall drill hip shoulder alignment](https://www.youtube.com/results?search_query=softball+pitching+wall+drill+hip+shoulder+alignment)
# Shin Angle at Loading
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/shin-angle-at-loading
Max forward shin angle during the loading phase of the pitch.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Column Name:** `shin_angle_at_loading`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Max forward lean of the loading-leg shin segment relative to vertical
* **Timing:** Between initiation and high hand events
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Shin angle at loading measures the maximum forward lean of the loading (dominant-side) shin relative to vertical during the loading phase of the pitch, between initiation and high hand.
## Use Cases
* Loading phase assessment
* Mechanics evaluation
# Stride Length
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/stride-length
Length of stride as percentage of athlete height.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** % of height
* **Column Name:** `stride_length`
* **Aggregation:** mean
* **Precision:** 0
* **Calculation:** Distance between the dominant ankle at initiation and the lead ankle at foot contact, normalized by height
* **Optimal Direction:** Higher is better
## Description
Stride length measures the length of the stride as a percentage of the athlete's height.
It is calculated as the distance between the dominant (drive-side) ankle position at initiation and the lead ankle position at foot contact, normalized by the athlete's estimated height.
## Use Cases
* Stride analysis
* Mechanics evaluation
# Time to Release
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/time-to-release
Time from initiation to ball release. This measures the total duration of the pitching motion.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s)
* **Column Name:** `time_to_release`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Ball release time - Initiation time
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Time to release measures the total duration of the pitching motion from initiation to ball release, indicating the overall timing of the windmill delivery from first movement to release.
## Use Cases
* Pitch timing analysis
# Trunk Global Flexion, Tilt & Twist
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/trunk-global-orientation
Trunk flexion, lateral tilt, and rotation relative to global orientation at foot contact and ball release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** deg
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Calculation:** Kinematics recomputed from keypoints rotated to the pitch direction
| Direction | Timing | Column Name |
| --------- | ------------ | -------------------------------------- |
| Flexion | Foot Contact | `trunk_global_flexion_at_foot_contact` |
| Flexion | Ball Release | `trunk_global_flexion_at_ball_release` |
| Tilt | Foot Contact | `trunk_global_tilt_at_foot_contact` |
| Tilt | Ball Release | `trunk_global_tilt_at_ball_release` |
| Twist | Foot Contact | `trunk_global_twist_at_foot_contact` |
| Twist | Ball Release | `trunk_global_twist_at_ball_release` |
## Description
These six metrics describe the trunk's orientation relative to global reference axes at two key delivery instants — foot contact and ball release:
* **Flexion** — forward-bend of the trunk relative to global vertical.
* **Tilt** — lateral (side-to-side) lean of the trunk relative to global vertical, with positive values toward the throwing side.
* **Twist** — rotation of the trunk relative to global orientation, where 0° represents the trunk facing the target.
Comparing the foot-contact and release values for each direction shows how much the trunk continues to flex, tilt, or rotate during the final phase of the delivery.
## Use Cases
* Posture and stacking assessment
* Rotational sequencing assessment
* Mechanics evaluation
# Trunk Not Stacked
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/trunk-not-stacked
Binary indicator if trunk flexion, tilt, or twist exceeds threshold between high hand and release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean
* **Units:** True/False
* **Column Name:** `trunk_not_stacked_flag`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Trunk flexion, lateral tilt, and twist (relative to pelvis) between high hand and release
* **Threshold:** Any of trunk flexion, tilt, or twist exceeds 30°
## Description
Trunk not stacked is a binary indicator that flags when the trunk is excessively flexed, tilted, or twisted (more than 30° in any direction relative to the pelvis) during the delivery phase from high hand to release, which reduces the efficiency of the athlete's posture over their base of support.
## Use Cases
* Posture and stacking assessment
* Mechanics evaluation
## Corrective Drills
### 1. Posture Wall Drill
Stand tall with the back against a wall, then walk through the arm circle and delivery while keeping the trunk upright and stacked over the hips, minimizing lateral lean and excessive twist. Use the wall for tactile feedback on trunk position. Perform 3 sets of 10 slow repetitions.
[Search YouTube: softball pitching posture drill stacked trunk](https://www.youtube.com/results?search_query=softball+pitching+posture+drill+stacked+trunk)
### 2. Video Pause at Release Drill
Throw at half-speed into a net while recording from the side and front. Pause the video at release to check that the trunk is upright and centered rather than excessively flexed, tilted, or twisted. Repeat and self-correct across repetitions.
[Search YouTube: softball pitching video analysis trunk posture release](https://www.youtube.com/results?search_query=softball+pitching+video+analysis+trunk+posture+release)
# Wrist Height at Release
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/wrist-height-at-release
Wrist height above ground level at release, normalized by athlete height.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** % of height
* **Column Name:** `wrist_height_at_release`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Throwing wrist height at release relative to ground level, normalized by athlete height
* **Reference:** Ground level estimated from the average of the rear toe at initiation and lead toe at foot contact
* **Timing:** At ball release event
* **Optimal Direction:** Middle — moderate values are optimal
## Description
Wrist height at release measures how high the throwing wrist is above the ground at the instant of ball release, normalized by the athlete's estimated height. Ground level is estimated from the rear toe position at initiation and the lead toe position at foot contact.
## Use Cases
* Release point consistency
* Mechanics evaluation
# Wrist Position vs. Pelvis at Release
Source: https://docs.uplift.ai/biomechanics/activities/softball/pitching/metrics/wrist-position-vs-pelvis
Wrist position relative to the pelvis at release, in the forward, up, and side directions.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** % of height
* **Aggregation:** mean
* **Precision:** 0
* **Timing:** At ball release event, using keypoints rotated to the pitch direction
* **Calculation:** Wrist position relative to the pelvis midpoint, normalized by athlete height
| Direction | Reference | Column Name |
| ------------------ | -------------------------------------- | ---------------------------------- |
| Forward (fore/aft) | Positive = in front of the pelvis | `wrist_forward_position_vs_pelvis` |
| Up (vertical) | Positive = above the pelvis | `wrist_up_position_vs_pelvis` |
| Side (lateral) | Positive = throwing side of the pelvis | `wrist_side_position_vs_pelvis` |
## Description
These three metrics describe where the throwing wrist is positioned relative to the pelvis midpoint at the instant of ball release:
* **Forward** — how far in front of (or behind) the pelvis the wrist is, along the pitch direction. Optimal direction: higher is better.
* **Up** — how far above (or below) the pelvis the wrist is. Because softball pitches are released underhand, this value is typically negative. Optimal direction: middle — moderate values are optimal.
* **Side** — how far toward the throwing side (or glove side) of the pelvis the wrist is. Optimal direction: middle — moderate values are optimal.
Together, these three values describe the full 3D release point of the pitch relative to the athlete's base.
## Use Cases
* Release point assessment
* Mechanics analysis
# Bodyweight Squat
Source: https://docs.uplift.ai/biomechanics/activities/squat/body_weight
Biomechanical analysis of bodyweight squat movements, including events, phases, and discrete metrics.
## Overview
The bodyweight squat is a fundamental movement assessment that evaluates an athlete's ability to perform a basic squatting motion with proper form and range of motion. This movement is commonly used in athletic assessment and training as it provides valuable information about lower extremity mobility, strength, and movement patterns.
![Example image of a man doing a bodyweight squat, bottom position]()
## Instructions
Stand with feet shoulder-width apart, toes forward or slightly out.
Descend as far as possible by bending at the hips and knees, keeping the chest up and knees in line with the toes.
Stand back up to the start position.
Perform at a natural, controlled pace without pausing at the bottom.
## Dimensions
Required inputs for processing:
* **None**
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Description | Column Name |
| ------------------------------------------------------------------ | ----------------------------------------- | ------------------------ |
| [Initiation](/biomechanics/activities/squat/events/initiation) | the start of the squat | `squat_initiation_frame` |
| [Bottom1](/biomechanics/activities/squat/events/bottom1) | the first instance of maximum squat depth | \`\` |
| [Bottom](/biomechanics/activities/squat/events/bottom) | the instant of maximum squat depth | `squat_bottom_frame` |
| [Ascent Start](/biomechanics/activities/squat/events/ascent-start) | the start of upward movement | \`\` |
| [End](/biomechanics/activities/squat/events/end) | the end of the movement | `squat_end_frame` |
### Movement Flags and General Metrics
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------------------------- | ------- | ---------------------------------------------------------------------------- | ------------------------------- |
| [Bottom Time](/biomechanics/activities/squat/metrics/bottom-time) | seconds | Time spent at bottom position | `time_while_at_bottom` |
| [Continuous](/biomechanics/activities/squat/metrics/continuous) | N/A | Whether squat is continuous (1) or has pause (0) | `continuous_motion` |
| [Hips Feet Stationary](/biomechanics/activities/squat/metrics/hips-feet-stationary) | N/A | Whether hips and feet remain stationary (1) or not (0) | `hips_feet_stationary` |
| [Knees Track](/biomechanics/activities/squat/metrics/knees-track) | N/A | Whether knees track properly (1) or not (0) | `knees_track` |
| [Eccentric Hip-Knee Dominance](/biomechanics/activities/squat/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during eccentric phase (0=hip dominant, 1=knee dominant) | `eccentric_hip_knee_dominance` |
| [Concentric Hip-Knee Dominance](/biomechanics/activities/squat/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during concentric phase (0=hip dominant, 1=knee dominant) | `concentric_hip_knee_dominance` |
| [Vertical Hip Lower Than Vertical Knee](/biomechanics/activities/squat/metrics/hip-below-knee) | N/A | Whether hips go below knees (1) or not (0) | `hip_below_knee` |
| [Vertical Hip Lower Than Vertical Knee Distance](/biomechanics/activities/squat/metrics/hip-below-knee) | meters | Distance between hip and knee at bottom | `hip_below_knee_distance` |
| [Trunk Tibia Parallel](/biomechanics/activities/squat/metrics/trunk-tibia-parallel) | N/A | Whether trunk and tibia are parallel (1) or not (0) | `trunk_tibia_parallel` |
| [Trunk Tibia Angle](/biomechanics/activities/squat/metrics/trunk-tibia-angle) | degrees | Angle between trunk and tibia | `trunk_tibia_angle` |
### Distance and Velocity Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------- | ------ | ---------------------------------------------------- | ---------------------------------- |
| [Right Valgus Bottom](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Right knee valgus at bottom position | `right_knee_valgus_at_bottom` |
| [Left Valgus Bottom](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Left knee valgus at bottom position | `left_knee_valgus_at_bottom` |
| [Right Valgus Eccentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum right knee valgus during eccentric phase | `right_valgus_distance_eccentric` |
| [Left Valgus Eccentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum left knee valgus during eccentric phase | `left_valgus_distance_eccentric` |
| [Right Valgus Concentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum right knee valgus during concentric phase | `right_valgus_distance_concentric` |
| [Left Valgus Concentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum left knee valgus during concentric phase | `left_valgus_distance_concentric` |
| [Depth](/biomechanics/activities/squat/metrics/depth) | meters | Vertical displacement of pelvis from start to bottom | `squat_depth` |
| [Eccentric Velocity](/biomechanics/activities/squat/metrics/eccentric-velocity) | m/s | Average velocity during eccentric phase | `max_eccentric_velocity` |
| [Concentric Velocity](/biomechanics/activities/squat/metrics/concentric-velocity) | m/s | Average velocity during concentric phase | `max_concentric_velocity` |
### Joint Angle Metrics
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------- | ------- | ---------------------------------------- | -------------------------------- |
| [Max Trunk Angle](/biomechanics/activities/squat/metrics/max-trunk-angle) | degrees | Maximum trunk angle relative to vertical | \`\` |
| [Left Peak Hip Flexion](/biomechanics/activities/squat/metrics/peak-hip-flexion) | degrees | Maximum left hip flexion angle | `peak_left_hip_flexion_angle` |
| [Right Peak Hip Flexion](/biomechanics/activities/squat/metrics/peak-hip-flexion) | degrees | Maximum right hip flexion angle | `peak_right_hip_flexion_angle` |
| [Left Peak Knee Flexion](/biomechanics/activities/squat/metrics/peak-knee-flexion) | degrees | Maximum left knee flexion angle | `peak_left_knee_flexion_angle` |
| [Right Peak Knee Flexion](/biomechanics/activities/squat/metrics/peak-knee-flexion) | degrees | Maximum right knee flexion angle | `peak_right_knee_flexion_angle` |
| [Left Peak Ankle Flexion](/biomechanics/activities/squat/metrics/peak-ankle-flexion) | degrees | Maximum left ankle flexion angle | `peak_left_ankle_flexion_angle` |
| [Right Peak Ankle Flexion](/biomechanics/activities/squat/metrics/peak-ankle-flexion) | degrees | Maximum right ankle flexion angle | `peak_right_ankle_flexion_angle` |
## Notes
* Kinematic data typically captured at 120Hz for Squatting
# Ascent Start
Source: https://docs.uplift.ai/biomechanics/activities/squat/events/ascent-start
The start of upward movement from the bottom of the squat.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** \`\`
* **Required for QA:** False
* **Measurement:** Start of the concentric (upward) phase
## Description
Ascent Start marks when the athlete begins moving upward from the bottom of the squat.
It defines the beginning of the concentric phase and can be used to compute concentric velocity and phase duration.
## Use Cases
* Concentric phase duration (ascent start to end)
* Concentric velocity and power
* Bottom hold time (bottom1/bottom to ascent start)
# Bottom
Source: https://docs.uplift.ai/biomechanics/activities/squat/events/bottom
The instant of maximum squat depth.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `squat_bottom_frame`
* **Required for QA:** True
* **Measurement:** Frame at which maximum squat depth is achieved
## Description
Bottom marks the instant when the pelvis reaches its lowest point (maximum squat depth) during the downward phase.
This event separates the eccentric (descent) phase from the concentric (ascent) phase.
## Use Cases
* Eccentric vs. concentric phase definition
* Joint angle metrics at bottom (e.g., hip, knee, ankle flexion)
* Knee valgus at bottom
# Bottom1
Source: https://docs.uplift.ai/biomechanics/activities/squat/events/bottom1
The first instance of maximum squat depth.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** \`\`
* **Required for QA:** False
* **Measurement:** First frame at which maximum squat depth is reached
## Description
Bottom1 marks the first instant when the pelvis (or relevant segment) reaches maximum squat depth during the descent.
It can be used to distinguish continuous squats from paused squats and to define the start of the bottom hold.
In continuous squats (without holding at the bottom), Bottom1 may be the same as [Bottom](/biomechanics/activities/squat/events/bottom).
## Use Cases
* Distinguishing continuous vs. paused squat
* Bottom phase definition
* Timing of depth-related metrics
# End
Source: https://docs.uplift.ai/biomechanics/activities/squat/events/end
The end of the squat movement, when the person returns to standing.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `squat_end_frame`
* **Required for QA:** True
* **Measurement:** End of the squat trial (return to standing)
## Description
End marks the completion of the squat when the athlete has returned to a standing position. This event closes the concentric phase and the full rep.
## Use Cases
* Concentric phase duration (ascent start or bottom to end)
* Full rep duration (initiation to end)
* Trial length and data trimming
# Initiation
Source: https://docs.uplift.ai/biomechanics/activities/squat/events/initiation
The start of the squat, when the person begins to move downward.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `squat_initiation_frame`
* **Required for QA:** False
* **Measurement:** Start of the squat movement
## Description
Initiation represents the very beginning of the squat when the athlete begins the downward (eccentric) movement. This event is used to define the start of the squat and for calculating phase durations.
## Use Cases
* Squat phase timing analysis
* Eccentric phase duration (initiation to bottom)
* Time to bottom and full rep duration
# Bottom Time
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/bottom-time
Time spent at the bottom position of the squat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s)
* **Column Name:** `time_while_at_bottom`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Duration spent at or near [Bottom](/biomechanics/activities/squat/events/bottom) (between bottom1 and ascent start)
## Description
Bottom time is the duration the athlete holds the bottom position of the squat. It is used in bodyweight, overhead, and single-leg squats. Together with the [Continuous](/biomechanics/activities/squat/metrics/continuous) metric, it helps distinguish paused vs. continuous squats.
## Use Cases
* Paused vs. continuous squat classification
* Tempo and control assessment
* Protocol compliance (e.g., required pause duration)
# Concentric Velocity
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/concentric-velocity
Average vertical velocity during the squat concentric (upward) phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** m/s
* **Column Name:** `max_concentric_velocity`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Higher is better
* **Calculation:** The average center of mass vertical velocity from [Ascent Start](/biomechanics/activities/squat/events/ascent-start) to [End](/biomechanics/activities/squat/events/end)
## Description
Concentric velocity is the average velocity of the pelvis center during the upward (concentric) phase of the squat.
It reflects speed of ascent and can indicate effort or intent.
## Use Cases
* Ascent speed and power proxy
* Consistency across reps
* Comparison across squat types
# Continuous
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/continuous
Binary indicator of whether the squat is continuous (1) or has a pause at the bottom (0).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = continuous, 0 = has pause
* **Column Name:** `continuous_motion`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** N/A
* **Measurement:** continuous if [Bottom Time](/biomechanics/activities/squat/metrics/bottom-time) is \< 0.3 seconds, otherwise paused
## Description
Continuous indicates whether the squat was performed without a deliberate pause at the bottom (1) or with a pause (0).
It is used in bodyweight, overhead, and single-leg squats and is often derived from [Bottom Time](/biomechanics/activities/squat/metrics/bottom-time).
## Use Cases
* Movement type classification
* Filtering or stratifying analyses (e.g., continuous only)
* Protocol and instruction adherence
# Depth
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/depth
Vertical displacement of the pelvis from start to bottom of the squat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** `squat_depth`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Higher is better
* **Measurement:** Vertical displacement of the pelvis from [Initiation](/biomechanics/activities/squat/events/initiation) to [Bottom](/biomechanics/activities/squat/events/bottom)
## Description
Depth is the vertical distance the pelvis travels from the start of the squat to the bottom position.
It can reflect squat range of motion and functional ability.
## Use Cases
* Range of motion assessment
* Consistency of squat depth across reps
* Comparison across squat variations
# Eccentric Velocity
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/eccentric-velocity
Average vertical velocity during the squat eccentric (downward) phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** m/s
* **Column Name:** `max_eccentric_velocity`
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Middle — moderate values are optimal
* **Calculation:** average pelvis vertical velocity from [Initiation](/biomechanics/activities/squat/events/initiation) to [Bottom](/biomechanics/activities/squat/events/bottom)
## Description
Eccentric velocity is the average or maximum velocity of the center of mass during the downward (eccentric) phase of the squat.
It reflects how quickly the athlete descends and can be used for tempo and loading assessment.
## Use Cases
* Tempo and control of descent
* Consistency across reps
* Comparison across squat types
# Hip Below Knee / Hips Pass Knees and Distance
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/hip-below-knee
Whether the hips go below the level of the knees at squat bottom, and the distance.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary) for pass/below, float for distance
* **Units:** 1 = yes, 0 = no (binary); meters (m) for distance
* **Column Name:** Varies by squat type (see below)
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:**
* Whether the hip joint centers reach below the knee joint centers at maximum depth
* Distance between hip and knee at bottom,
* positive (+) values indicate hip distance BELOW knees
* negative (-) values indicate hip distance ABOVE knees
## Events / Phases
* **Bodyweight / Overhead:**
* Vertical Hip Lower Than Vertical Knee — binary: `hip_below_knee`
* distance: `hip_below_knee_distance`
* **SFMA:**
* Hips Pass Knees — binary: `sfma_squat_hips_pass_knees`
* distance column may be implementation-specific (e.g., distance between hips and knees at maximum hip depth)
## Description
This metric indicates whether the athlete achieves sufficient depth such that the hips go below the level of the knees.
The distance variant quantifies how far the hip is relative to the knee at bottom.
Used in bodyweight, overhead, and SFMA squats.
## Use Cases
* Depth and range of motion (e.g., "hips below knees" standard)
* SFMA movement quality and functional classification
* Screening and normative comparison
# Hip Knee Dominance
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/hip-knee-dominance
Ratio of hip vs. knee contribution (0 = hip dominant, 1 = knee dominant) during eccentric or concentric phase.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio (0–1)
* **Column Name:** Varies by phase and squat type
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Relative contribution of hip vs. knee motion during the specified phase
## Events / Phases
This metric can be reported for different phases depending on squat type:
* **Eccentric:** From [Initiation](/biomechanics/activities/squat/events/initiation) to [Bottom](/biomechanics/activities/squat/events/bottom).
* Column examples: `eccentric_hip_knee_dominance` (bodyweight, overhead); `left_eccentric_hip_knee_dominance`, `right_eccentric_hip_knee_dominance` (single leg).
* **Concentric:** From [Ascent Start](/biomechanics/activities/squat/events/ascent-start) to [End](/biomechanics/activities/squat/events/end).
* Column examples: `concentric_hip_knee_dominance` (bodyweight, overhead); `left_concentric_hip_knee_dominance`, `right_concentric_hip_knee_dominance` (single leg).
## Description
Hip knee dominance describes how much the athlete uses the hip versus the knee during the eccentric or concentric phase of the squat. A value of 0 indicates hip-dominant strategy; 1 indicates knee-dominant. Single-leg squats report left/right-specific columns for each phase.
## Use Cases
* Movement strategy and injury risk (e.g., knee-dominant loading)
* Coaching and technique feedback
* Bilateral or single-leg comparison across phases
# Hips Feet Stationary
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/hips-feet-stationary
Binary indicator of whether the hips and feet refrain from rotating inwards or outwards during the squat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = yes, 0 = no
* **Column Name:** `hips_feet_stationary`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Assessment of whether hips and feet rotation stays relatively neutral during the squat
* Outward threshold: 10 degrees
* Inward threshold: 5 degrees
## Description
Hips feet stationary is a binary indicator that the athlete's hips and feet don't rotate during the squat.
It reflects stability and proper mechanics, avoiding excessive strain on the knee joint.
## Use Cases
* Balance and stability assessment
* Test validity (e.g., discounting trials with steps or excessive movement)
* Screening for control
# Knee Valgus
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/knee-valgus
Medial knee displacement (valgus motion) at bottom or over eccentric/concentric phases during the squat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** Varies by event/phase and squat type
* **Aggregation:** mean
* **Precision:** 2
* **Optimal Direction:** Lower is better
* **Measurement:** Medial displacement of the knee
* **Direction:** outward positive (+), inward negative (-)
## Events / Phases
This metric can be reported at different events or phases depending on squat type:
* **At Bottom:** At the [Bottom](/biomechanics/activities/squat/events/bottom) event.
* Column examples: `right_knee_valgus_at_bottom`, `left_knee_valgus_at_bottom` (bodyweight, overhead, single leg).
* **Eccentric Full:** Maximum knee valgus during the eccentric phase ([Initiation](/biomechanics/activities/squat/events/initiation) to [Bottom](/biomechanics/activities/squat/events/bottom)).
* Column examples: `right_valgus_distance_eccentric`, `left_valgus_distance_eccentric` (bodyweight, overhead); `left_valgus_distance_eccentric`, `right_valgus_distance_eccentric` (single leg, per stance leg).
* **Concentric Full:** Maximum knee valgus during the concentric phase ([Ascent Start](/biomechanics/activities/squat/events/ascent-start) to [End](/biomechanics/activities/squat/events/end)).
* Column examples: `right_valgus_distance_Concentric` / `right_valgus_distance_concentric`, `left_valgus_distance_concentric` (bodyweight, overhead); single leg uses left/right per stance leg.
## Description
Knee valgus measures the amount of medial (inward) knee motion during the squat.
Excessive knee valgus motion is associated with increased injury risk and suboptimal loading.
Reported separately for left and right in bilateral squats; single-leg squats report the stance-leg side.
## Use Cases
* Injury risk screening
* Movement quality and knee control
* Bilateral comparison
# Knees Track
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/knees-track
Binary indicator of whether the knees track properly over the toes during the squat (1 = yes, 0 = no).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = yes, 0 = no
* **Column Name:** `knees_track`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Lower is better
* **Measurement:** knee-to-ankle separation ratio: the relative distance between knees and ankles
* Distance threshold: 85% - the the knee-knee distance drops below 85% of the ankle-ankle distance, then the knees do not track
## Description
Knees track is a binary flag indicating whether the knees track properly over the toes (or within an acceptable range) during the squat.
Knees track is determined using the knee to ankle separation ratio, measuring the relative distances between both knees and both ankles.
If the knee-to-knee distance crosses below 85% of the ankle-to-ankle distance, then the knees do not track, flagging suboptimal mechanics.
Poor tracking (e.g., excessive knee valgus or inward motion) is associated with injury risk.
Used in bodyweight, overhead, and single-leg squats.
## Use Cases
* Movement quality and injury risk screening
* Coaching feedback
* Knee control assessment
# Max Trunk Angle
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/max-trunk-angle
Maximum sagittal plane trunk angle relative to vertical during the squat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** \`\`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Maximum trunk angle relative to vertical during the squat
## Events / Phases
* **Bodyweight squat:** `max trunk angle`
* **SFMA squat:** `sfma_squat_trunk_peak_angle`
## Description
Max trunk angle captures how far forward (or from vertical) the trunk leans at its maximum during the squat. It is used in bodyweight and SFMA squat assessments to describe posture and compensation.
## Use Cases
* Posture and forward lean assessment
* SFMA movement quality
* Comparison with normative or task-specific targets
# Peak Ankle Flexion
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/peak-ankle-flexion
Maximum ankle flexion (dorsiflexion) angle during the squat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** Varies by squat type (see Events/Phases)
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum ankle flexion angle during the squat
## Events / Phases
* **Bodyweight / Overhead (bilateral):** `peak_left_ankle_flexion_angle`, `peak_right_ankle_flexion_angle`.
* **Single leg:** `peak_ankle_flexion_angle` (stance leg only).
* **SFMA:** `sfma_squat_left_ankle_peak_angle`, `sfma_squat_right_ankle_peak_angle` (documented as "Maximum Left/Right Ankle Angle").
## Description
Peak ankle flexion is the maximum ankle (dorsiflexion) angle achieved during the squat, typically at or around [Bottom](/biomechanics/activities/squat/events/bottom). It reflects ankle mobility and is used in bodyweight, overhead, single-leg, and SFMA squats.
## Use Cases
* Ankle mobility and range of motion
* Bilateral comparison
* Movement quality and consistency
# Peak Hip Flexion
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/peak-hip-flexion
Maximum hip flexion angle during the squat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** Varies by squat type (see Events/Phases)
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum hip flexion angle during the squat
## Events / Phases
* **Bodyweight / Overhead (bilateral):** `peak_left_hip_flexion_angle`, `peak_right_hip_flexion_angle`.
* **Single leg:** `peak_hip_flexion_angle` (stance leg only)
* **SFMA:** `sfma_squat_left_hip_peak_angle`, `sfma_squat_right_hip_peak_angle`
## Description
Peak hip flexion is the maximum hip flexion angle achieved during the squat, typically at or around [Bottom](/biomechanics/activities/squat/events/bottom).
It reflects hip range of motion and loading depth.
Bilateral squats report left and right; single-leg and SFMA report per side as applicable.
## Use Cases
* Hip mobility and range of motion
* Bilateral comparison
* Movement quality and consistency
# Peak Knee Flexion
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/peak-knee-flexion
Maximum knee flexion angle during the squat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** Varies by squat type (see Events/Phases)
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Maximum knee flexion angle during the squat
## Events / Phases
* **Bodyweight / Overhead (bilateral):** `peak_left_knee_flexion_angle`, `peak_right_knee_flexion_angle`.
* **Single leg:** `peak_knee_flexion_angle` (stance leg only)
* **SFMA:** `sfma_squat_left_knee_peak_angle`, `sfma_squat_right_knee_peak_angle`
## Description
Peak knee flexion is the maximum knee flexion angle achieved during the squat, typically at or around [Bottom](/biomechanics/activities/squat/events/bottom).
It reflects knee range of motion and loading depth.
Bilateral squats report left and right; single-leg and SFMA report per side as applicable.
## Use Cases
* Knee mobility and range of motion
* Bilateral comparison
* Movement quality and consistency
# Functional (SFMA)
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/sfma-functional
Binary indicator of whether the SFMA squat is classified as functional (1) or not (0) based on hips pass knees and wrists pass ankles.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = functional, 0 = not functional
* **Column Name:** `sfma_squat_functional`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Composite classification: movement is functional if both [Hips Pass Knees](/biomechanics/activities/squat/metrics/hip-below-knee) and [Wrists Pass Ankles](/biomechanics/activities/squat/metrics/wrists-pass-ankles) are achieved
## Description
Functional is an SFMA squat–specific metric that summarizes whether the movement meets the criteria for a "functional" squat: hips pass knees and wrists pass ankles. It is derived from the binary metrics for those two criteria and is used in clinical and screening contexts.
## Use Cases
* SFMA movement classification
* Screening and outcome tracking
* Clinical decision support
# Sufficient Knee Flexion
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/sufficient-knee-flexion
Binary indicator of whether knee flexion is sufficient (1) or not (0) during the single-leg squat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = sufficient, 0 = insufficient
* **Column Name:** (implementation-specific; may be unset in documentation)
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Assessment of whether the stance-leg knee achieves sufficient flexion (threshold = 60 degrees) during the single-leg squat
## Description
Sufficient knee flexion is a binary metric used in the single-leg squat to indicate whether the athlete achieved adequate knee flexion (at least 60 degrees) on the stance leg.
It complements continuous [Peak Knee Flexion](/biomechanics/activities/squat/metrics/peak-knee-flexion) for pass/fail or screening use.
## Use Cases
* Single-leg squat quality and depth
* Screening and normative comparison
* Protocol compliance (e.g., "squat to 60°")
# Trunk Tibia Angle
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/trunk-tibia-angle
Angle between the trunk and tibia segments at the bottom of the squat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `trunk_tibia_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Angle between trunk and tibia at [Bottom](/biomechanics/activities/squat/events/bottom)
## Description
Trunk tibia angle is the continuous measure of the angle between the trunk and tibia at the bottom of the squat.
It is used in bodyweight, overhead, and single-leg squats.
The binary version is [Trunk Tibia Parallel](/biomechanics/activities/squat/metrics/trunk-tibia-parallel).
## Use Cases
* Quantifying forward lean or upright posture at bottom
* Movement quality and consistency
* Comparison across squat types and athletes
# Trunk Tibia Parallel
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/trunk-tibia-parallel
Binary indicator of whether the trunk and tibia are parallel (1) or not (0) at bottom.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = parallel, 0 = not parallel
* **Column Name:** `trunk_tibia_parallel`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Assessment of whether trunk and tibia segment sagittal plane angles are parallel (within 20 deg of each other) at the bottom of the squat
## Description
Trunk tibia parallel is a binary flag indicating whether the trunk and tibia are near parallel (20 degree threshold) at the bottom position.
It is used in bodyweight, overhead, and single-leg squats as a simple posture and technique indicator.
Its counterpart is [Trunk Tibia Angle](/biomechanics/activities/squat/metrics/trunk-tibia-angle).
## Use Cases
* Posture and technique at bottom
* Movement quality screening
* Coaching feedback
# Wrist Past Feet
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/wrist-past-feet
Binary indicator of whether the wrists move in front of the toes or not during an overhead squat.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = yes, 0 = no
* **Column Name:** `wrist_past_feet`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Whether the wrists move in front of the toes during the overhead squat
## Description
Wrist past feet is a binary metric specific to the overhead squat.
It indicates whether the athlete can keep the wrists (arms overhead) behind the line of the feet when at the bottom of the squat.
Proper performance reflects thoracic and shoulder mobility and trunk control to maintain the overhead position.
## Use Cases
* Overhead squat mobility assessment
* Thoracic and shoulder mobility screening
* Movement quality for overhead squat
# Wrists Pass Ankles
Source: https://docs.uplift.ai/biomechanics/activities/squat/metrics/wrists-pass-ankles
Whether the wrists move beyond the ankles at maximum wrist height during the SFMA squat, and their distance.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary) for pass; Float for distance
* **Units:** 1 = yes, 0 = no (binary); meters (m) for distance
* **Column Name:** `sfma_squat_wrists_pass_ankles` (binary); distance column may be implementation-specific
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Whether the wrists move beyond the ankles at maximum wrist height during the SFMA squat; optionally the distance between wrists and ankles
## Description
Wrists pass ankles is specific to the SFMA squat. At the bottom, the athlete swings the arms down and back; this metric indicates whether the wrists reach or pass the ankles. It is used together with [Hips Pass Knees](/biomechanics/activities/squat/metrics/hip-below-knee) to determine [Functional](/biomechanics/activities/squat/metrics/sfma-functional) classification.
## Use Cases
* SFMA squat mobility and movement quality
* Functional classification (with hips pass knees)
* Upper-quarter and trunk mobility screening
# Overhead Squat
Source: https://docs.uplift.ai/biomechanics/activities/squat/overhead
Biomechanical analysis of overhead squat movements, including events, phases, and discrete metrics.
## Overview
An overhead squat is an advanced compound exercise that involves performing a squat while holding one's arms (or a weight) directly overhead. It builds upon the fundamental bodyweight squat by significantly increasing the demand on stability, mobility, and core strength.
The exercise requires excellent flexibility in the ankles, hips, thoracic spine, and shoulders, as the lifter must maintain an upright torso and the weight directly over the midfoot throughout the entire movement. Muscles worked include the quadriceps, hamstrings, and glutes in the lower body, along with substantial engagement of the core (abdominals, obliques, spinal erectors), deltoids, and triceps to stabilize the overhead load.
Due to the elevated center of gravity, the overhead squat is a highly challenging exercise that not only strengthens the muscles but also significantly improves balance, coordination, and functional mobility. It is often used as a diagnostic tool to assess movement limitations and as an accessory exercise for Olympic lifts like the snatch.
![Example image of a man doing an overhead squat, bottom position]()
## Instructions
Hold a bar, dowel, or arms directly overhead. Squat down as deep as possible while keeping the weight over the midfoot and the torso upright. Stand back up to the start position. Perform in a controlled manner; the bar and body should move as one unit.
## Dimensions
Required inputs for processing:
* **None**
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Description | Column Name |
| ------------------------------------------------------------------ | ----------------------------------------- | ------------------------ |
| [Initiation](/biomechanics/activities/squat/events/initiation) | the start of the squat | `squat_initiation_frame` |
| [Bottom1](/biomechanics/activities/squat/events/bottom1) | the first instance of maximum squat depth | \`\` |
| [Bottom](/biomechanics/activities/squat/events/bottom) | the instant of maximum squat depth | `squat_bottom_frame` |
| [Ascent Start](/biomechanics/activities/squat/events/ascent-start) | the start of upward movement | \`\` |
| [End](/biomechanics/activities/squat/events/end) | the end of the movement | `squat_end_frame` |
### Movement Flags and General Metrics
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------------------------- | ------- | ---------------------------------------------------------------------------- | ------------------------------- |
| [Wrist Past Feet](/biomechanics/activities/squat/metrics/wrist-past-feet) | N/A | Whether wrists move beyond feet (1) or not (0) | `wrist_past_feet` |
| [Bottom Time](/biomechanics/activities/squat/metrics/bottom-time) | seconds | Time spent at bottom position | `time_while_at_bottom` |
| [Continuous](/biomechanics/activities/squat/metrics/continuous) | N/A | Whether squat is continuous (1) or has pause (0) | `continuous_motion` |
| [Eccentric Hip-Knee Dominance](/biomechanics/activities/squat/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during eccentric phase (0=hip dominant, 1=knee dominant) | `eccentric_hip_knee_dominance` |
| [Concentric Hip-Knee Dominance](/biomechanics/activities/squat/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during concentric phase (0=hip dominant, 1=knee dominant) | `concentric_hip_knee_dominance` |
| [Vertical Hip Lower Than Vertical Knee](/biomechanics/activities/squat/metrics/hip-below-knee) | N/A | Whether hips go below knees (1) or not (0) | `hip_below_knee` |
| [Vertical Hip Lower Than Vertical Knee Distance](/biomechanics/activities/squat/metrics/hip-below-knee) | meters | Distance between hip and knee at bottom | `hip_below_knee_distance` |
| [Trunk Tibia Parallel](/biomechanics/activities/squat/metrics/trunk-tibia-parallel) | N/A | Whether trunk and tibia are parallel (1) or not (0) | `trunk_tibia_parallel` |
| [Trunk Tibia Angle](/biomechanics/activities/squat/metrics/trunk-tibia-angle) | degrees | Angle between trunk and tibia | `trunk_tibia_angle` |
| [Hips Feet Stationary](/biomechanics/activities/squat/metrics/hips-feet-stationary) | N/A | Whether hips and feet remain stationary (1) or not (0) | `hips_feet_stationary` |
| [Knees Track](/biomechanics/activities/squat/metrics/knees-track) | N/A | Whether knees track properly (1) or not (0) | `knees_track` |
### Distance and Velocity Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------- | ------ | ---------------------------------------------------- | ---------------------------------- |
| [Right Valgus Bottom](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Right knee valgus at bottom position | `right_knee_valgus_at_bottom` |
| [Left Valgus Bottom](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Left knee valgus at bottom position | `left_knee_valgus_at_bottom` |
| [Right Valgus Eccentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum right knee valgus during eccentric phase | `right_valgus_distance_eccentric` |
| [Left Valgus Eccentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum left knee valgus during eccentric phase | `left_valgus_distance_eccentric` |
| [Right Valgus Concentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum right knee valgus during concentric phase | `right_valgus_distance_concentric` |
| [Left Valgus Concentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum left knee valgus during concentric phase | `left_valgus_distance_concentric` |
| [Depth](/biomechanics/activities/squat/metrics/depth) | meters | Vertical displacement of pelvis from start to bottom | `squat_depth` |
| [Eccentric Velocity](/biomechanics/activities/squat/metrics/eccentric-velocity) | m/s | Max velocity during eccentric phase | `max_eccentric_velocity` |
| [Concentric Velocity](/biomechanics/activities/squat/metrics/concentric-velocity) | m/s | Max velocity during concentric phase | `max_concentric_velocity` |
### Joint Angle Metrics
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------- | ------- | --------------------------------- | -------------------------------- |
| [Left Peak Hip Flexion](/biomechanics/activities/squat/metrics/peak-hip-flexion) | degrees | Maximum left hip flexion angle | `peak_left_hip_flexion_angle` |
| [Right Peak Hip Flexion](/biomechanics/activities/squat/metrics/peak-hip-flexion) | degrees | Maximum right hip flexion angle | `peak_right_hip_flexion_angle` |
| [Left Peak Knee Flexion](/biomechanics/activities/squat/metrics/peak-knee-flexion) | degrees | Maximum left knee flexion angle | `peak_left_knee_flexion_angle` |
| [Right Peak Knee Flexion](/biomechanics/activities/squat/metrics/peak-knee-flexion) | degrees | Maximum right knee flexion angle | `peak_right_knee_flexion_angle` |
| [Left Peak Ankle Flexion](/biomechanics/activities/squat/metrics/peak-ankle-flexion) | degrees | Maximum left ankle flexion angle | `peak_left_ankle_flexion_angle` |
| [Right Peak Ankle Flexion](/biomechanics/activities/squat/metrics/peak-ankle-flexion) | degrees | Maximum right ankle flexion angle | `peak_right_ankle_flexion_angle` |
## Notes
* Kinematic data typically captured at 120Hz for Squatting
# SFMA Squat
Source: https://docs.uplift.ai/biomechanics/activities/squat/sfma_squat
Biomechanical analysis of SFMA squat movements, including events, phases, and discrete metrics.
## Overview
The SFMA (Selective Functional Movement Assessment) squat is one of seven fundamental movement patterns assessed in individuals experiencing musculoskeletal pain. Unlike a generic squat, the SFMA squat is not just about performing the movement, but about observing its quality and identifying underlying dysfunction.
The SFMA squat involves standing with feet shoulder-width apart, toes facing forward, and arms extended forward with palms facing down. The individual then slowly descends as deep as possible into a squat position, aiming to keep heels on the floor, and head and chest facing forward. At the bottom, swing the arms down and back while keeping elbows extended, bringing your hands as close to the floor as possible. Then swing the arms back forward and stand back up to complete the movement.
The assessment is highly qualitative, with trained clinicians often observing for specific deviations and compensations. The goal is to determine if any limitations are due to:
* **Mobility issues:** Problems with joint range of motion (e.g., tight ankles, hips, or thoracic spine) or tissue extensibility (e.g., tight muscles).
* **Stability/motor control issues:** Difficulties with neuromuscular coordination, muscle activation, or maintaining control throughout the movement.
## Instructions
Stand with feet shoulder-width apart, toes facing forward, arms extended forward with palms down. Slowly descend as deep as possible into a squat, heels on the floor, head and chest facing forward. At the bottom, swing the arms down and back (elbows extended), bringing the hands as close to the floor as possible, then swing the arms forward and stand back up to complete one repetition.
## Example Videos
## Dimensions
Required inputs for processing:
* **None**
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Description | Column Name |
| ------------------------------------------------------------------ | ----------------------------------------- | ----------- |
| [Initiation](/biomechanics/activities/squat/events/initiation) | the start of the squat | \`\` |
| [Bottom1](/biomechanics/activities/squat/events/bottom1) | the first instance of maximum squat depth | \`\` |
| [Bottom](/biomechanics/activities/squat/events/bottom) | the instant of maximum squat depth | \`\` |
| [Ascent Start](/biomechanics/activities/squat/events/ascent-start) | the start of upward movement | \`\` |
| [End](/biomechanics/activities/squat/events/end) | the end of the movement | \`\` |
### Movement Flags and Distance Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------------- | ------ | ---------------------------------------------------------------------------------------------------------- | ------------------------------- |
| [Wrists Pass Ankles](/biomechanics/activities/squat/metrics/wrists-pass-ankles) | N/A | Whether wrists move beyond ankles (1) or not (0) | `sfma_squat_wrists_pass_ankles` |
| [Wrists Pass Ankles Distance](/biomechanics/activities/squat/metrics/wrists-pass-ankles) | meters | Distance between wrists and ankles at maximum wrist height | \`\` |
| [Hips Pass Knees](/biomechanics/activities/squat/metrics/hip-below-knee) | N/A | Whether hips go below knees (1) or not (0) | `sfma_squat_hips_pass_knees` |
| [Hips Pass Knees Distance](/biomechanics/activities/squat/metrics/hip-below-knee) | meters | Distance between hips and knees at maximum hip depth | \`\` |
| [Functional](/biomechanics/activities/squat/metrics/sfma-functional) | N/A | Whether movement is functional (1) or not (0) based on whether both hips pass knees and wrists pass ankles | `sfma_squat_functional` |
| [Depth](/biomechanics/activities/squat/metrics/depth) | meters | Vertical displacement of pelvis from start to bottom | `squat_depth` |
### Joint Angle Metrics
| Metric | Units | Description | Column Name |
| -------------------------------------------------------------------------------------- | ------- | ---------------------------------------- | ----------------------------------- |
| [Maximum Trunk Angle](/biomechanics/activities/squat/metrics/max-trunk-angle) | degrees | Maximum trunk angle relative to vertical | `sfma_squat_trunk_peak_angle` |
| [Maximum Left Hip Angle](/biomechanics/activities/squat/metrics/peak-hip-flexion) | degrees | Maximum left hip flexion angle | `sfma_squat_left_hip_peak_angle` |
| [Maximum Right Hip Angle](/biomechanics/activities/squat/metrics/peak-hip-flexion) | degrees | Maximum right hip flexion angle | `sfma_squat_right_hip_peak_angle` |
| [Maximum Left Knee Angle](/biomechanics/activities/squat/metrics/peak-knee-flexion) | degrees | Maximum left knee flexion angle | `sfma_squat_left_knee_peak_angle` |
| [Maximum Right Knee Angle](/biomechanics/activities/squat/metrics/peak-knee-flexion) | degrees | Maximum right knee flexion angle | `sfma_squat_right_knee_peak_angle` |
| [Maximum Left Ankle Angle](/biomechanics/activities/squat/metrics/peak-ankle-flexion) | degrees | Maximum left ankle flexion angle | `sfma_squat_left_ankle_peak_angle` |
| [Maximum Right Ankle Angle](/biomechanics/activities/squat/metrics/peak-ankle-flexion) | degrees | Maximum right ankle flexion angle | `sfma_squat_right_ankle_peak_angle` |
## Notes
* Kinematic data typically captured at 120Hz for Squatting
# Single Leg Squat
Source: https://docs.uplift.ai/biomechanics/activities/squat/single_leg
Biomechanical analysis of single leg squat movements, including events, phases, and discrete metrics.
## Overview
The single leg squat is a unilateral movement assessment that evaluates an athlete's ability to perform a squatting motion on one leg while maintaining balance and proper form. This movement is commonly used in athletic assessment and training as it provides valuable information about unilateral strength, balance, and lower extremity function.
![Example image of a man doing a single leg squat, bottom position]()
## Instructions
Stand on one leg (the leg specified by footedness); the other leg can be extended in front or held slightly behind. Descend by bending the stance knee and hip while keeping the knee aligned over the toes and the torso as upright as possible. Go to a comfortable depth, then stand back up. Perform in a controlled manner.
## Dimensions
Required inputs for processing:
* **Footedness:** The foot \['left', 'right'] that supports the body and maintains contact with the ground.
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Description | Column Name |
| ------------------------------------------------------------------ | ----------------------------------------- | ------------------------ |
| [Initiation](/biomechanics/activities/squat/events/initiation) | the start of the squat | `squat_initiation_frame` |
| [Bottom1](/biomechanics/activities/squat/events/bottom1) | the first instance of maximum squat depth | \`\` |
| [Bottom](/biomechanics/activities/squat/events/bottom) | the instant of maximum squat depth | `squat_bottom_frame` |
| [Ascent Start](/biomechanics/activities/squat/events/ascent-start) | the start of upward movement | \`\` |
| [End](/biomechanics/activities/squat/events/end) | the end of the movement | `squat_end_frame` |
### Movement Flags and General Metrics
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------------------------ | ------- | ------------------------------------------------------------------------------------------ | ------------------------------------- |
| [Bottom Time](/biomechanics/activities/squat/metrics/bottom-time) | seconds | Time spent at bottom position | `time_while_at_bottom` |
| [Continuous](/biomechanics/activities/squat/metrics/continuous) | N/A | Whether squat is continuous (1) or has pause (0) | `continuous_motion` |
| [Left Eccentric Hip-Knee Dominance](/biomechanics/activities/squat/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during eccentric phase for left leg (0=hip dominant, 1=knee dominant) | `left_eccentric_hip_knee_dominance` |
| [Right Eccentric Hip-Knee Dominance](/biomechanics/activities/squat/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during eccentric phase for right leg (0=hip dominant, 1=knee dominant) | `right_eccentric_hip_knee_dominance` |
| [Left Concentric Hip-Knee Dominance](/biomechanics/activities/squat/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during concentric phase for left leg (0=hip dominant, 1=knee dominant) | `left_concentric_hip_knee_dominance` |
| [Right Concentric Hip-Knee Dominance](/biomechanics/activities/squat/metrics/hip-knee-dominance) | ratio | Hip-knee dominance during concentric phase for right leg (0=hip dominant, 1=knee dominant) | `right_concentric_hip_knee_dominance` |
| [Trunk Tibia Parallel](/biomechanics/activities/squat/metrics/trunk-tibia-parallel) | N/A | Whether trunk and tibia are parallel (1) or not (0) | `trunk_tibia_parallel` |
| [Trunk Tibia Angle](/biomechanics/activities/squat/metrics/trunk-tibia-angle) | degrees | Angle between trunk and tibia | `trunk_tibia_angle` |
| [Hips Feet Stationary](/biomechanics/activities/squat/metrics/hips-feet-stationary) | N/A | Whether hips and feet remain stationary (1) or not (0) | `hips_feet_stationary` |
| [Knees Track](/biomechanics/activities/squat/metrics/knees-track) | N/A | Whether knees track in line with feet (1) or not (0) | `knees_track` |
| [Sufficient Knee Flexion](/biomechanics/activities/squat/metrics/sufficient-knee-flexion) | N/A | Whether knee flexion reaches at least 60 degrees (1) or not (0) | \`\` |
### Distance and Velocity Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------- | ------ | ------------------------------------------------------------------- | ---------------------------------- |
| [Left Valgus Bottom](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Left knee valgus at bottom position (left leg squat) | `left_knee_valgus_at_bottom` |
| [Right Valgus Bottom](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Right knee valgus at bottom position (right leg squat) | `right_knee_valgus_at_bottom` |
| [Left Valgus Eccentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum left knee valgus during eccentric phase (left leg squat) | `left_valgus_distance_eccentric` |
| [Right Valgus Eccentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum right knee valgus during eccentric phase (right leg squat) | `right_valgus_distance_eccentric` |
| [Left Valgus Concentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum left knee valgus during concentric phase (left leg squat) | `left_valgus_distance_concentric` |
| [Right Valgus Concentric Full](/biomechanics/activities/squat/metrics/knee-valgus) | meters | Maximum right knee valgus during concentric phase (right leg squat) | `right_valgus_distance_concentric` |
| [Depth](/biomechanics/activities/squat/metrics/depth) | meters | Vertical displacement of pelvis from start to bottom | `squat_depth` |
| [Eccentric Velocity](/biomechanics/activities/squat/metrics/eccentric-velocity) | m/s | Max velocity during eccentric phase | `max_eccentric_velocity` |
| [Concentric Velocity](/biomechanics/activities/squat/metrics/concentric-velocity) | m/s | Max velocity during concentric phase | `max_concentric_velocity` |
### Joint Angle Metrics
| Metric | Units | Description | Column Name |
| ------------------------------------------------------------------------------- | ------- | ----------------------------------------- | -------------------------- |
| [Peak Hip Flexion](/biomechanics/activities/squat/metrics/peak-hip-flexion) | degrees | Maximum hip flexion angle of stance leg | `peak_hip_flexion_angle` |
| [Peak Knee Flexion](/biomechanics/activities/squat/metrics/peak-knee-flexion) | degrees | Maximum knee flexion angle of stance leg | `peak_knee_flexion_angle` |
| [Peak Ankle Flexion](/biomechanics/activities/squat/metrics/peak-ankle-flexion) | degrees | Maximum ankle flexion angle of stance leg | `peak_ankle_flexion_angle` |
## Notes
* Kinematic data typically captured at 120Hz for Squatting
# Plank
Source: https://docs.uplift.ai/biomechanics/activities/stability/plank
Biomechanical analysis of plank holds, including side, front, and static stability measurements.
## Overview
The plank is a core stability assessment that evaluates an athlete's ability to maintain a static position with proper form.
This movement is commonly used in athletic assessment and training as it provides valuable information about core strength, stability, and endurance.
## Instructions
**Front Plank**:
Start in a prone position with your forearms on the ground, elbows directly under your shoulders. Your body should form a straight line from your head to your heels.
Engage your core muscles and hold this position while maintaining proper alignment. Keep your neck neutral and avoid letting your hips sag or rise.
**Side Plank**:
Start lying on your side with your legs stacked and your bottom forearm on the ground, elbow directly under your shoulder.
Lift your hips off the ground so your body forms a straight line from your head to your feet. Keep your top arm extended upward or place it on your hip.
Maintain this position while engaging your core and oblique muscles. Avoid letting your hips drop or rotating your torso.
## Dimensions
Required inputs for processing:
* **None**
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Events
| Event | Description | Column Name |
| ----- | --------------------------- | ----------- |
| Start | the start of the plank hold | start |
| End | the end of the plank hold | end |
## Discrete Metrics
| Metric | Units | Description | Column Name |
| ---------------------------- | ------- | -------------------------------------------- | ----------- |
| Side | N/A | Side of plank ('left', 'right', or 'front') | \`\` |
| Duration | seconds | Duration of the plank hold | \`\` |
| Average Pelvis Velocity | m/s | Average velocity of pelvis during plank hold | \`\` |
| Trunk Initial Angle Sagittal | degrees | Initial trunk angle in sagittal plane | \`\` |
| Trunk Initial Angle Frontal | degrees | Initial trunk angle in frontal plane | \`\` |
## Notes
* Kinematic data typically captured at 30-60 Hz for stability activities
* Side is determined by shoulder abduction angles (threshold of 45 degrees)
* Duration is capped at 10 seconds
# SFMA Back Bend
Source: https://docs.uplift.ai/biomechanics/activities/stability/sfma_back_bend
Biomechanical analysis of SFMA back bend movement assessment, including shoulder flexion and hip extension range of motion.
## Overview
The SFMA back bend is a standardized movement assessment used in the Selective Functional Movement Assessment (SFMA) protocol to evaluate spinal extension and identify potential sources of pain or limitation. This assessment provides valuable information about thoracic and lumbar spine mobility.
## Instructions
From a standing position, raise both arms forward and above you and reach upwards and behind you as far as possible.
Allow your hips to come forward and your shoulders and head to move back. Hold max extended position for \~1 second
then return to standing.
## Example Videos
## Dimensions
Required inputs for processing:
* **None**
## Movement Grading as Functional
Classification as "Functional" requires:
* Shoulder flexion ROM ≥ 165°
* Hips pass in front of toes
* Shoulders pass behind heels
* No shoulder compensation (a 10° reduction in shoulder flexion when nearing peak extension)
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Discrete Metrics
| Metric | Units | Description | Column Name |
| --------------------------- | ------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------- |
| Max Shoulder Flexion | degrees | Maximum shoulder flexion angle (average of left & right) | `max_shoulder_flexion` |
| Shoulder Flexion ROM | degrees | Range of shoulder flexion motion (average of left & right) | \`\` |
| Max Hip Extension | degrees | Maximum hip extension angle (average of left & right) | \`\` |
| Hips Pass Toes | bool | Whether hips move forward past toes | `sfma_back_bend_hips_pass_toes` |
| Shoulders Pass Heels | bool | Whether shoulders move backward past heels | `sfma_back_bend_shoulders_pass_heels` |
| Hips To Toes Distance | meters | Horizontal distance from hips to toes at maximum reach. Positive value indicates reaching past mark, negative value indicates insufficient reach. | \`\` |
| Shoulders To Heels Distance | meters | Horizontal distance from shoulders to heels at maximum reach. Positive value indicates reaching past mark, negative value indicates insufficient reach. | \`\` |
| Shoulder Compensation | bool | Whether shoulder compensation occurred (> 10° reduction in shoulder flexion) | `sfma_back_bend_shoulder_compensation` |
| Functional | bool | Whether movement is functional (see above) | `sfma_back_bend_functional` |
## Notes
* Kinematic data typically captured at 60Hz for stability activities
# SFMA Toe Touch
Source: https://docs.uplift.ai/biomechanics/activities/stability/sfma_toe_touch
Biomechanical analysis of SFMA toe touch movement assessment, including forward bending and hip flexion range of motion.
## Overview
The SFMA (Selective Functional Movement Assessment) toe touch assessment evaluates the range of motion and quality of movement in the spine during forward bending. This assessment measures the ability to achieve sufficient hip flexion while maintaining proper alignment and identifying any compensations.
## Instructions
From a standing position, bend forward and reach as low to the ground as possible while keeping your knees straight.
## Example Videos
## Dimensions
Required inputs for processing:
* **None**
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Discrete Metrics
| Metric | Units | Description | Column Name |
| ------------------------- | ------- | --------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------- |
| Knee Flexion ROM | degrees | Range of knee flexion motion (average of left & right ROMs) | `sfma_toe_touch_knee_flexion_ROM` |
| Pass Knee Flexion | - | Whether knee flexion is within acceptable range (≤ 15°) | `sfma_toe_touch_pass_knee_flexion` |
| Wrists Pass Ankles | - | Whether wrists reach below ankles | `sfma_toe_touch_wrists_pass_ankles` |
| Wrists To Ankles Distance | meters | Vertical distance from wrists to ankles at maximum reach. Positive value indicates reaching past mark, negative value indicates insufficient reach. | `wrists_pass_ankles_distance` |
| Hips Pass Heels | - | Whether hips move backward past heels | `sfma_toe_touch_hips_pass_heels` |
| Hips To Heels Distance | meters | Horizontal distance from hips to heels at maximum reach. Positive value indicates reaching past mark, negative value indicates insufficient reach | `hips_pass_heels_distance` |
| Functional | - | Whether movement is functional (meets all criteria) | `sfma_toe_touch_functional` |
## Notes
* Kinematic data typically captured at 30-60 Hz for stability activities
* Functional movement requires:
* Knee flexion ROM ≤ 15°
* Hips pass behind heels
* Wrists pass below ankles
# Single Leg Stance
Source: https://docs.uplift.ai/biomechanics/activities/stability/single_leg_stance
Biomechanical analysis of single leg stance balance assessment, including sway measurements and trunk lean evaluation.
## Overview
Single leg stance is a fundamental balance exercise and a common component of everyday movement, from walking and running to climbing stairs.
## Instructions
Stand upright on one leg while the other leg is lifted off the ground. For greater challenge, repeat with eyes closed.
## Example Videos
### Eyes Open
### Left
### Right
### Eyes Closed
### Left
### Right
## Dimensions
Required inputs for processing:
* **Footedness:** The foot maintaining balance *\['left', 'right']*
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Events
| Metric | Description | Column Name |
| ---------- | ---------------------------------- | ----------- |
| Initiation | the start of the single leg stance | \`\` |
| End | the end of the single leg stance | \`\` |
## Discrete Metrics
| Metric | Units | Description | Column Name |
| ---------------------------- | ------- | ---------------------------------------------------------------------------------- | ------------------------------------------------ |
| Stance Time | seconds | Duration of the single leg stance | `single_leg_stance_stance_time` |
| Stance Time Clearance | - | Whether stance time passed threshold (1) or not (0) | `single_leg_stance_time_clearance` |
| Mean Sway Velocity | m/s | Average velocity of body center of mass during stance | `single_leg_stance_mean_sway_velocity` |
| Percentile 75 Sway Velocity | m/s | 75th percentile of sway velocity during stance | `single_leg_stance_percentile75_sway_velocity` |
| Mediolateral Displacement | meters | Maximum range of mediolateral (left/right) displacement of center of mass | `single_leg_stance_mediolateral_displacement` |
| Anteroposterior Displacement | meters | Maximum range of anteroposterior (forward/backward) displacement of center of mass | `single_leg_stance_anteroposterior_displacement` |
| Sway Area | m² | Square area of sway calculated from the product of ML and AP displacement | `single_leg_stance_sway_area` |
| Left Trunk Lean | degrees | Maximum left trunk lean in frontal plane | \`\` |
| Right Trunk Lean | degrees | Maximum right trunk lean in frontal plane | \`\` |
| Excessive Trunk Lean | - | Whether trunk lean exceeds threshold (1) or not (0) | `single_leg_stance_excessive_trunk_lean` |
## Notes
* Kinematic data typically captured at 30-60 Hz for stability activities
* Stance time clearance threshold is set to 10 seconds
* Excessive trunk lean threshold is set to 10 degrees
# Y-Balance Lower Quarter
Source: https://docs.uplift.ai/biomechanics/activities/stability/y_balance_lower_quarter
Biomechanical analysis of Y-Balance lower quarter test, including reach distance and stability measurements.
## Overview
The Y Balance Lower Quarter Test is a standardized, reliable, and widely used clinical assessment tool designed to
evaluate an individual's dynamic single-leg balance and neuromuscular control at their "limits of stability."
It is often employed to identify injury risk, track rehabilitation progress, and determine readiness for return to sport.
## Instructions
Stand barefoot on one leg (the stance leg) in the center of a specialized platform or marked "Y" shape on the floor.
While maintaining balance on the stance leg, use the mobile leg to reach as far as possible in three specific directions:
* Anterior (forward): Reaching directly forward from the stance foot.
* Posteromedial (backward and inward): Reaching diagonally backward and across the body.
* Posterolateral (backward and outward): Reaching diagonally backward and away from the body.
## Example Videos
### Left
### Right
## Dimensions
Required inputs for processing:
* **Footedness:** The foot maintaining balance *\['left', 'right']*
* **Direction:** The direction of the reach *\['Anterior', 'Posteromedial', 'Posterolateral']*
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Events
| Metric | Description | Column Name |
| ------ | ----------------------------------------------------- | ----------- |
| Bottom | the instant of lowest center of mass during the reach | \`\` |
## Discrete Metrics
| Metric | Units | Description | Column Name |
| ----------------------------------- | ------- | --------------------------------------------------- | ------------------------------------- |
| Reach Distance | meters | Maximum reach distance in anterior direction | `reach_distance` |
| Reach Distance Relative | ratio | Maximum reach distance normalized by leg length | `reach_distance_relative` |
| Trunk Range of Motion Frontal Plane | degrees | Range of trunk motion in frontal plane during reach | `trunk_frontal_plane_range_of_motion` |
| Stance Knee Medial Translation | meters | Medial translation of stance knee during reach | `stance_knee_medial_translation` |
| Stance Hip Range of Motion Flexion | degrees | Range of hip flexion during reach | `stance_hip_flexion_range_of_motion` |
| Stance Hip Max Flexion | degrees | Maximum hip flexion during reach | `stance_hip_max_flexion` |
| Stance Knee Range of Motion Flexion | degrees | Range of knee flexion during reach | `stance_knee_flexion_range_of_motion` |
| Stance Knee Max Flexion | degrees | Maximum knee flexion during reach | `stance_knee_max_flexion` |
## Notes
* Kinematic data typically captured at 30-60 Hz for stability activities
* Test requires footedness specification ('left' or 'right')
* Leg length is used to normalize reach distance. Relative reach distance of 1.1 = reaching 110% of average leg length.
* Knee medial translation is a valgus displacement measure: how far did the knee move laterally?
# Y-Balance Upper Quarter
Source: https://docs.uplift.ai/biomechanics/activities/stability/y_balance_upper_quarter
Biomechanical analysis of Y-Balance upper quarter test, including reach distance and stability measurements.
## Overview
The Y Balance Upper Quarter Test is a standardized and reliable clinical assessment used to evaluate an individual's dynamic upper extremity stability, mobility, and neuromuscular control. Similar to its lower quarter counterpart, it helps clinicians identify asymmetries and potential risk factors for injury in the shoulder, elbow, wrist, and core.
## Instructions
The test is performed in a closed kinetic chain position, typically a push-up stance. The individual places one hand (the stance hand) firmly on a central platform or designated starting point. While maintaining this stable base, they then use the other hand (the reach hand) to push a reaching indicator or simply reach as far as possible in three specific directions relative to the stance hand:
* Medial: Reaching directly sideways, parallel to the body.
* Superolateral (Superior-Lateral): Reaching diagonally upward and away from the body.
* Inferolateral (Inferior-Lateral): Reaching diagonally downward and away from the body.
## Dimensions
Required inputs for processing:
* **Footedness:** The foot maintaining balance *\['left', 'right']*
* **Direction:** The direction of the reach *\['Medial', 'Superolateral', 'Inferolateral']*
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Discrete Metrics
| Metric | Units | Description | Column Name |
| ------ | ----- | ----------- | ----------- |
## Notes
* Kinematic data typically captured at 30-60 Hz for stability activities
# Tennis: Backhand
Source: https://docs.uplift.ai/biomechanics/activities/tennis/backhand
Biomechanical analysis of tennis backhand strokes.
## Overview
The backhand is a groundstroke in which the ball is struck on the side of the body opposite the dominant hand (or with the non-dominant hand in front in a two-handed backhand).
It can be played with one or two hands and with different grips and swing paths (e.g., slice vs topspin).
Backhand mechanics involve trunk rotation, shoulder and arm coordination, and lower-body drive; technique varies considerably between one-handed and two-handed styles and between players.
## Dimensions
Required inputs for processing are not yet defined. When supported, typical dimensions may include:
* **handedness:** the handedness of the player \['left', 'right']
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Notes
* This movement is documented for completeness; event and metric definitions may be added in a future update.
# Apex
Source: https://docs.uplift.ai/biomechanics/activities/tennis/events/apex
Maximum height of the dominant-side wrist joint center during the serve. A proxy for ball contact.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** 'apex\_event'
* **Required for QA:** True
* **Measurement:** Frame at which the dominant-side wrist reaches maximum height
## Description
Apex marks the instant when the dominant-side wrist joint center reaches its maximum height during the serve, which typically coincides with ball contact.
Contact-phase metrics (elbow flexion, shoulder abduction, X factor, trunk tilt, wrist velocity, wrist height) are reported at this event.
## Use Cases
* Ball contact timing
* Contact-phase metrics (joint angles, wrist velocity, wrist height)
* Acceleration phase end and follow-through start
# Ball Release
Source: https://docs.uplift.ai/biomechanics/activities/tennis/events/ball-release
The estimated timing of the ball toss during the serve.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `ball_release_event`
* **Required for QA:** False
* **Measurement:** Estimated frame of ball toss release, marked by:
* when the hand passes above the face, or
* when the hand reaches its max upwards velocity before apex
## Description
Ball Release marks when the ball is released from the hand during the toss, estimated from hand motion.
It separates the start of the preparation phase from the [Release](/biomechanics/activities/tennis/overhand_serve#phases) and [Loading](/biomechanics/activities/tennis/overhand_serve#phases) phases and is used for timing and [Loading Phase Ball Release Angle](/biomechanics/activities/tennis/metrics/loading-phase-ball-release-angle) metrics.
## Use Cases
* Toss consistency and timing
* Loading phase definition (ball release to low arm)
* Ball release angle assessment
# Initiation
Source: https://docs.uplift.ai/biomechanics/activities/tennis/events/initiation
The start of the tennis serve.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `initiation_event`
* **Required for QA:** False
* **Measurement:** the low point of the non-dominant hand before [Ball Release](/biomechanics/activities/tennis/events/ball-release)
## Description
Initiation marks the very beginning of the serve when the player starts the motion by identifying the low point of the non-dominant hand before ball release.
This event defines the start of the [Preparation](/biomechanics/activities/tennis/overhand_serve#phases) phase and is used for phase duration calculations.
## Use Cases
* Serve phase timing analysis
* Preparation phase duration (initiation to ball release)
* Full serve duration (initiation to termination)
# Low Arm
Source: https://docs.uplift.ai/biomechanics/activities/tennis/events/low-arm
The low point of the dominant arm just prior to ball contact.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** \`low\_arm\_event'
* **Required for QA:** False
* **Measurement:** Frame at which the dominant arm reaches its lowest point before the upward swing between [Ball Release](/biomechanics/activities/tennis/events/ball-release) and [Apex](/biomechanics/activities/tennis/events/apex) events
## Description
Low Arm marks the instant when the dominant (serving) arm reaches its lowest point during the preparation phase, after [Ball Release](/biomechanics/activities/tennis/events/ball-release) and before the [Cocking](/biomechanics/activities/tennis/overhand_serve#phases) phase.
It defines the end of the loading phase and the start of the cocking phase.
## Use Cases
* Loading phase duration (ball release to low arm)
* Cocking phase start (low arm to max shoulder ER)
* Serve rhythm and timing
# Max Shoulder ER
Source: https://docs.uplift.ai/biomechanics/activities/tennis/events/max-shoulder-er
The instant of maximum shoulder external rotation between ball release and apex.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `max_shoulder_external_rotation_event`
* **Required for QA:** False
* **Measurement:** Frame at which shoulder external rotation is maximum (between ball release and apex)
## Description
Max Shoulder ER marks the instant of maximum shoulder external rotation during the serve, typically occurring in the [Cocking](/biomechanics/activities/tennis/overhand_serve#phases) phase (between [Low Arm](/biomechanics/activities/tennis/events/low-arm) and ball contact).
It defines the end of the cocking phase and the start of the [Acceleration](/biomechanics/activities/tennis/overhand_serve#phases) phase.
## Use Cases
* Cocking phase duration and shoulder load
* [Cocking Phase Max Shoulder External Rotation](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-external-rotation) timing
* Acceleration phase start (max shoulder ER to ball contact)
# Peak Forearm Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/events/peak-forearm-velocity
The instant of peak forearm forward angular velocity, used to determine forward kinematic sequence.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** \`\`
* **Required for QA:** False
* **Measurement:** Frame at which the forearm segment reaches its peak forward angular velocity
## Description
Peak Forearm Velocity marks the instant when the forearm reaches its maximum forward angular velocity (somersaulting forward in the direction of the serve).
It is used together with [Peak Upper Arm Velocity](/biomechanics/activities/tennis/events/peak-upper-arm-velocity) and [Peak Torso Velocity](/biomechanics/activities/tennis/events/peak-torso-velocity) to determine the [Forward Kinematic Sequence](/biomechanics/activities/tennis/metrics/forward-kinematic-sequence)—the order in which segments reach their peak (optimal: torso → upper arm → forearm).
## Use Cases
* Forward kinematic sequence determination
* Timing of segment peak velocities
* Technique and sequencing analysis
# Peak Torso Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/events/peak-torso-velocity
The instant of peak torso forward angular velocity, used to determine forward kinematic sequence.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** \`\`
* **Required for QA:** False
* **Measurement:** Frame at which the torso segment reaches its peak forward angular velocity
## Description
Peak Torso Velocity marks the instant when the torso reaches its maximum forward angular velocity (somersaulting in the serve direction).
It is used together with [Peak Upper Arm Velocity](/biomechanics/activities/tennis/events/peak-upper-arm-velocity) and [Peak Forearm Velocity](/biomechanics/activities/tennis/events/peak-forearm-velocity) to determine the [Forward Kinematic Sequence](/biomechanics/activities/tennis/metrics/forward-kinematic-sequence)—the order in which segments reach their peak (optimal: torso → upper arm → forearm).
## Use Cases
* Forward kinematic sequence determination
* Timing of segment peak velocities
* Technique and sequencing analysis
# Peak Upper Arm Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/events/peak-upper-arm-velocity
The instant of peak upper arm forward angular velocity, used to determine forward kinematic sequence.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** \`\`
* **Required for QA:** False
* **Measurement:** Frame at which the upper arm segment reaches its peak forward angular velocity
## Description
Peak Upper Arm Velocity marks the instant when the upper arm reaches its maximum forward angular velocity (somersaulting in the serve direction).
It is used together with [Peak Torso Velocity](/biomechanics/activities/tennis/events/peak-torso-velocity) and [Peak Forearm Velocity](/biomechanics/activities/tennis/events/peak-forearm-velocity) to determine the [Forward Kinematic Sequence](/biomechanics/activities/tennis/metrics/forward-kinematic-sequence)—the order in which segments reach their peak (optimal: torso → upper arm → forearm).
## Use Cases
* Forward kinematic sequence determination
* Timing of segment peak velocities
* Technique and sequencing analysis
# Termination
Source: https://docs.uplift.ai/biomechanics/activities/tennis/events/termination
End of the tennis serve—when the movement is complete.
## Technical Details
* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `termination_event`
* **Required for QA:** False
* **Measurement:** Finds the local minimum height of the non-dominant wrist after [Apex](biomechanics/activities/tennis/events/apex).
## Description
Termination marks the end of the serve when the player has completed the follow-through.
It closes the [Follow Thru](/biomechanics/activities/tennis/overhand_serve#phases) (deceleration) phase and the full serve trial.
## Use Cases
* Follow-through duration (ball contact to termination)
* Full serve duration (initiation to termination)
* Trial length and data trimming
# Cocking Phase Lack of External Rotation
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/cocking-phase-lack-external-rotation
Binary indicator if shoulder external rotation (layback) during the cocking phase is below the acceptable threshold.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `cocking_phase_lack_external_rotation`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** [Cocking Phase Max Shoulder External Rotation](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-external-rotation)
* **Threshold:** Max shoulder external rotation less than 180°
## Description
Cocking phase lack of external rotation is a binary indicator that flags when the dominant shoulder does not reach at least 180° of external rotation (layback) during the cocking phase, which limits the elastic energy available for the acceleration phase.
## Use Cases
* Layback and shoulder loading assessment
* Injury risk identification
* Mechanics evaluation
# Contact Phase Arm Out of Slot Position
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/contact-phase-arm-out-of-slot-position
Binary indicator if the dominant arm is not lifted directly above the body at ball contact.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `contact_phase_arm_out_of_slot_position`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** [Contact Phase Shoulder Abduction](/biomechanics/activities/tennis/metrics/contact-phase-shoulder-abduction) at [Apex](/biomechanics/activities/tennis/events/apex)
* **Threshold:** Shoulder abduction less than 110° or greater than 140°
## Description
Contact phase arm out of slot position is a binary indicator that flags when the dominant shoulder is abducted outside the 110°–140° range at ball contact, indicating the arm is not in an optimal overhead "slot" position to strike the ball.
## Use Cases
* Contact position assessment
* Mechanics evaluation
# Contact Phase Open Pelvis Rotation
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/contact-phase-open-pelvis-rotation
If pelvis rotation at ball contact is above the acceptable threshold.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `contact_phase_open_pelvis_rotation`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Pelvis rotation at [Apex](/biomechanics/activities/tennis/events/apex)
* **Threshold:** Pelvis rotation greater than -30°
## Description
Contact phase open pelvis rotation is a binary indicator that flags when the pelvis has rotated too far towards the serve direction (past -30°) at the time of ball contact
This indicates the hips are "opening up" too early relative to the arm and ball.
## Use Cases
* Rotational sequencing assessment
* Mechanics evaluation
# Contact Phase Open Trunk Rotation
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/contact-phase-open-trunk-rotation
If trunk rotation at ball contact is above the acceptable threshold.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `contact_phase_open_trunk_rotation`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Trunk rotation (transverse plane) relative to the serve direction at [Apex](/biomechanics/activities/tennis/events/apex)
* **Threshold:** Trunk rotation greater than -20°
## Description
Contact phase open trunk rotation is a binary indicator that flags when the trunk has rotated too far in the serve direction (past -20°) at the time of ball contact.
This indicates the torso is "opening up" too early relative to the arm and ball.
## Use Cases
* Rotational sequencing assessment
* Mechanics evaluation
# Landing Phase Excessive Forward Drift
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/landing-phase-excessive-forward-drift
If the body drifts too far forward after the serve.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `landing_phase_excessive_forward_drift`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Forward (fore/aft) body displacement between [Apex](/biomechanics/activities/tennis/events/apex) and [Termination](/biomechanics/activities/tennis/events/termination), normalized by athlete height
* **Threshold:** Forward displacement greater than 50% of height
## Description
Landing phase excessive forward drift is a binary indicator that flags if the body moves forward (into the court, in the serve direction) by more than 50% of the athlete's height directly after the serve.
This can indicate a lack of balance and control on landing.
## Use Cases
* Landing balance and control assessment
* Injury risk identification
# Landing Phase Excessive Forward Lean
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/landing-phase-excessive-forward-lean
Leaning too far forward after the serve.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `landing_phase_excessive_forward_lean`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Trunk forward flexion at [Termination](/biomechanics/activities/tennis/events/termination)
* **Threshold:** Trunk flexion greater than 60° past vertical
## Description
Landing phase excessive forward lean is a binary indicator that flags if the trunk leans forward more than 60° at the finish of the serve.
This can indicate lack of deceleration control, increased strain through the low back, and poor positioning to prepare for a return volley.
## Use Cases
* Follow-through and deceleration assessment
* Injury risk identification
# Landing Phase Excessive Side Drift
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/landing-phase-excessive-side-drift
If the body drifts too far sideways after the serve.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `landing_phase_excessive_side_drift`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Displacement Open Side Per Height between [Apex](/biomechanics/activities/tennis/events/apex) and [Termination](/biomechanics/activities/tennis/events/termination), normalized by athlete height
* **Threshold:** Open-side displacement greater than 0.30x height, or less than -0.10x height
## Description
Landing phase excessive side drift is a binary indicator that flags if the body moves too far toward the open side (or too far toward the opposite side) after the serve.
This can indicate a lack of balance and control on landing.
## Use Cases
* Landing balance and control assessment
* Injury risk identification
# Landing Phase Excessive Side Lean
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/landing-phase-excessive-side-lean
Leaning too far sideways after the serve.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `landing_phase_excessive_side_lean`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Trunk lateral (side-to-side) tilt at [Termination](/biomechanics/activities/tennis/events/termination)
* **Threshold:** Absolute trunk tilt greater than 30° (to either side)
## Description
Landing phase excessive side lean is a binary indicator that flags if the trunk is tilted sideways more than 30° (in either direction) at the finish of the serve.
This can indicate poor deceleration control, increased lateral low back strain, and poor positioning to prepare for a return volley.
## Use Cases
* Follow-through and deceleration assessment
* Injury risk identification
# Loading Phase Excessive Knee Valgus
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/loading-phase-excessive-knee-valgus
If knee valgus exceeds the acceptable threshold on either leg during the loading phase.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `loading_phase_excessive_knee_valgus`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Front and back knee valgus classification level during the loading phase
* **Threshold:** Front or back knee valgus classified as "high"
## Description
Loading phase excessive knee valgus is a binary indicator that flags when either the front or back knee is classified as having a "high" level of inward (valgus) collapse during the loading phase, which is a common indicator of increased lower-body injury risk.
High knee valgus occurs when the knee moves medially (inwards towards the centerline of the body) more than 6% of height.
Moderate knee valgus occurs when the knee moves medially more than 2% of body height.
Normalized distances (% of height) aid in metric consistency across athletes of various sizes.
## Use Cases
* Injury risk identification
* Lower-body mechanics evaluation
# Loading Phase Knee Asymmetry
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/loading-phase-knee-asymmetry
Binary indicator if there is significant asymmetry in knee flexion between the front and back legs during loading.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `loading_phase_knee_asymmetry`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Difference between [Loading Phase Max Knee Flexion Front Leg](/biomechanics/activities/tennis/metrics/loading-phase-knee-flexion) and [Loading Phase Max Knee Flexion Back Leg](/biomechanics/activities/tennis/metrics/loading-phase-knee-flexion)
* **Threshold:** Front-to-back knee flexion difference greater than 15°
## Description
Loading phase knee asymmetry is a binary indicator that flags when there is more than a 15° difference in maximum knee flexion between the front and back legs during the loading phase, which can indicate an uneven weight distribution or loading pattern between the legs.
## Use Cases
* Lower-body load distribution assessment
* Mechanics evaluation
# Loading Phase Lack of Pelvis Coil
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/loading-phase-lack-pelvis-coil
Binary indicator if pelvis coil is below the acceptable threshold during the loading phase.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `loading_phase_lack_pelvis_coil`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** [Pelvis Coil](/biomechanics/activities/tennis/metrics/pelvis-coil)
* **Threshold:** Pelvis coil less than 110°
## Description
Loading phase lack of pelvis coil is a binary indicator that flags when the pelvis does not rotate away from the serve direction by at least 110° during the loading phase, which limits the amount of rotational energy stored before the serve.
## Use Cases
* Rotational loading assessment
* Power generation evaluation
# Loading Phase Lack of Pelvis Drop
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/loading-phase-lack-pelvis-drop
Binary indicator if the pelvis does not sufficiently tilt/drop during the loading phase.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `loading_phase_lack_pelvis_drop`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** [Loading Phase Pelvis Tilt](/biomechanics/activities/tennis/metrics/loading-phase-pelvis-tilt)
* **Threshold:** Pelvis tilt greater than 0°
## Description
Loading phase lack of pelvis drop is a binary indicator that flags when the pelvis does not tilt sideways toward the rear during the loading phase, which reduces the hip-over-hip tilt used to load the serve.
## Use Cases
* Loading posture assessment
* Mechanics evaluation
# Loading Phase Lack of Shoulder Drop
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/loading-phase-lack-shoulder-drop
Binary indicator if the trunk does not sufficiently tilt/drop during the loading phase.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `loading_phase_lack_shoulder_drop`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** [Loading Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/loading-phase-trunk-tilt)
* **Threshold:** Trunk tilt greater than -5°
## Description
Loading phase lack of shoulder drop is a binary indicator that flags when the trunk does not tilt sideways toward the rear (dropping the dominant shoulder) by at least 5° during the loading phase, which reduces the shoulder-over-shoulder tilt used to load the serve.
## Use Cases
* Loading posture assessment
* Mechanics evaluation
# Loading Phase Lack of Trunk Coil
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/loading-phase-lack-trunk-coil
Binary indicator if trunk coil is below the acceptable threshold during the loading phase.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `loading_phase_lack_trunk_coil`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** [Trunk Coil](/biomechanics/activities/tennis/metrics/trunk-coil)
* **Threshold:** Trunk coil less than 110°
## Description
Loading phase lack of trunk coil is a binary indicator that flags when the trunk does not rotate away from the serve direction by at least 110° during the loading phase, which limits the amount of rotational energy stored before the serve.
## Use Cases
* Rotational loading assessment
* Power generation evaluation
# Loading Phase Pinpoint Break
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/loading-phase-pinpoint-break
If the athlete breaks from a pinpoint stance during loading.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `loading_phase_pinpoint_break`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Front ankle position relative to back ankle (in the serve direction) at [Low Arm](/biomechanics/activities/tennis/events/low-arm)
* **Threshold:** Front ankle is further forward than the back ankle at low arm
## Description
Loading phase pinpoint break is a binary indicator that flags when a player breaks their pinpoint stance.
This occurs if the back ankle (dominant side) moves forward closer to the baseline than the front ankle (non-dominant side) at the low arm event.
Breaking the pinpoint position can reduce base stability during the loading phase.
## Use Cases
* Stance consistency assessment
* Mechanics evaluation
# Release Phase Elbow Not Straight
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/release-phase-elbow-not-straight
Binary indicator if the non-dominant elbow is not straight enough at ball toss.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `release_phase_elbow_not_straight`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** Non-dominant elbow flexion angle at [Ball Release](/biomechanics/activities/tennis/events/ball-release)
* **Threshold:** Non-dominant elbow flexion angle greater than 30°
## Description
Release phase elbow not straight is a binary indicator that flags when the non-dominant (tossing) elbow is bent more than 30° at the instant of ball release.
Releasing the ball with a bent elbow can reduce the consistency and height of the ball toss.
## Use Cases
* Toss arm mechanics assessment
* Mechanics evaluation
# Release Phase Off-Arm to Body Position
Source: https://docs.uplift.ai/biomechanics/activities/tennis/flags/release-phase-off-arm-to-body-position
Binary indicator if the ball toss angle is outside the acceptable range at ball release.
## Technical Details
* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `release_phase_off_arm_to_body_position`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** [Loading Phase Ball Release Angle](/biomechanics/activities/tennis/metrics/loading-phase-ball-release-angle) at [Ball Release](/biomechanics/activities/tennis/events/ball-release)
* **Threshold:** Ball toss angle greater than 180° or less than 90°
## Description
Release phase off-arm to body position is a binary indicator that flags when the non-dominant (tossing) arm angle relative to the torso falls outside the acceptable 90°–180° range at ball release, which can indicate an inconsistent or poorly placed ball toss.
## Use Cases
* Toss placement and consistency
* Mechanics evaluation
# Tennis: Forehand
Source: https://docs.uplift.ai/biomechanics/activities/tennis/forehand
Biomechanical analysis of tennis forehand strokes.
## Overview
The forehand is a groundstroke in which the ball is struck on the same side of the body as the dominant hand, with the palm facing the net at contact (or leading the swing).
It is often the primary offensive shot in a player’s game and can be hit with topspin, slice, or flat trajectory.
Forehand mechanics typically involve trunk rotation, shoulder and arm coordination, and lower-body contribution; grip and swing path vary by player and intent.
## Dimensions
Required inputs for processing are not yet defined. When supported, typical dimensions may include:
* **handedness:** the handedness of the player \['left', 'right']
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Notes
* This movement is documented for completeness; event and metric definitions may be added in a future update.
# Acceleration Phase Max Elbow Extension Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/acceleration-phase-elbow-extension-velocity
Maximum extension velocity of the dominant elbow during the acceleration phase of the serve.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/second (°/s)
* **Column Name:** `max_elbow_extension_velocity`
* **Measurement:** Maximum elbow extension angular velocity of the dominant arm during the acceleration phase ([Max Shoulder ER](/biomechanics/activities/tennis/events/max-shoulder-er) to [Apex](/biomechanics/activities/tennis/events/apex))
## Description
Acceleration phase max elbow extension velocity is the maximum rate of elbow extension of the dominant (serving) arm during the acceleration phase. It reflects how quickly the elbow extends as the arm moves toward ball contact and contributes to racket speed and the kinetic chain.
## Use Cases
* Upper-arm kinetic chain and timing
* Elbow contribution to serve speed
* Technique and consistency comparison
# Acceleration Phase Max Knee Extension Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/acceleration-phase-knee-extension-velocity
Maximum knee extension velocity of the front and back leg during the acceleration phase.
![Knee extension velocity during acceleration]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/second (°/s)
* **Column Name:** `acceleration_phase_max_front_knee_extension_velocity` or `acceleration_phase_max_back_knee_extension_velocity`
* **Measurement:** Maximum knee extension angular velocity during the acceleration phase ([Max Shoulder ER](/biomechanics/activities/tennis/events/max-shoulder-er) to [Apex](/biomechanics/activities/tennis/events/apex))
## Description
This metric describes the maximum knee extension velocity for each leg during the acceleration phase of the serve.
The maximum value should align with the jumping portion of the serve, correlating with jump height.
It reflects lower-body drive and contribution to the kinetic chain as the player extends toward ball contact.
## Use Cases
* Lower-body drive and timing
* Kinetic chain assessment
* Technique comparison
# Cocking Phase Max X Factor
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/cocking-phase-max-x-factor
Maximum hip-shoulder separation (X-Factor) reached during the cocking phase of the serve.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `cocking_phase_max_x_factor`
* **Measurement:** Maximum transverse-plane angle between the shoulders and hips during the cocking phase
## Description
Cocking phase max X-Factor measures the largest hip-shoulder separation reached while the arm is cocking back before acceleration, reflecting how much torso coil the server builds before driving into the ball. Higher values generally indicate greater potential for power transfer.
## Use Cases
* Power generation assessment
* Cocking phase mechanics
* Comparison with Contact Phase X Factor
# Cocking Phase Max Shoulder External Rotation
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-external-rotation
Maximum amount of shoulder external rotation during the cocking phase of the serve.
![Shoulder external rotation during cocking]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `cocking_phase_max_shoulder_external_rotation`
* **Measurement:** Maximum shoulder external rotation angle marks the end of cocking phase at [Max Shoulder ER](/biomechanics/activities/tennis/events/max-shoulder-er))
## Description
This metric is the maximum external rotation of the dominant shoulder during the cocking phase.
Greater external rotation permits more range of motion to accelerate into the serve.
The instant of maximum is the [Max Shoulder ER](/biomechanics/activities/tennis/events/max-shoulder-er) event.
## Use Cases
* Shoulder loading, range of motion, and injury risk context
* Technique and power potential
# Cocking Phase Shoulder Horizontal Abduction
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-horizontal-abduction
Maximum horizontal abduction of the dominant shoulder during the cocking phase of the serve.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `cocking_phase_shoulder_horizontal_abduction`
* **Measurement:** Maximum horizontal abduction angle of the dominant shoulder during the cocking phase
## Description
Cocking phase shoulder horizontal abduction measures how far the dominant upper arm moves behind the plane of the shoulders while cocking back before acceleration. It reflects the depth of the cocking position ahead of the throwing motion.
## Use Cases
* Cocking phase mechanics
* Shoulder loading assessment
* Injury risk screening
# Cocking Phase Shoulder Hyperangulation
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-hyperangulation
Maximum shoulder horizontal abduction during the cocking phase of the serve.
![Shoulder hyperangulation during cocking]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `cocking_phase_shoulder_hyperangulation`
* **Measurement:** Maximum horizontal abduction (hyperangulation) of the shoulder during the cocking phase ([Low Arm](/biomechanics/activities/tennis/events/low-arm) to [Max Shoulder ER](/biomechanics/activities/tennis/events/max-shoulder-er))
## Description
Shoulder hyperangulation is the maximum horizontal abduction of the dominant shoulder during the cocking phase—the "elbow back" position.
It can be used alongside external rotation for technique and load assessment.
## Use Cases
* Shoulder position and technique
* Injury risk and load assessment
# Contact Phase Elbow Flexion
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/contact-phase-elbow-flexion
Amount of elbow flexion at apex (ball contact).
![Elbow flexion at contact]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `contact_phase_elbow_flexion`
* **Measurement:** Elbow flexion angle at [Apex](/biomechanics/activities/tennis/events/apex)
## Description
Contact phase elbow flexion is the elbow angle of the dominant arm at the moment of ball contact (apex).
It reflects arm position at contact and is used for technique and consistency assessment.
## Use Cases
* Arm position at contact
* Technique and consistency
* Efficiency analysis
# Contact Phase Pelvis Rotation
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/contact-phase-pelvis-rotation
Pelvis rotation angle relative to its starting orientation at apex (ball contact).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `contact_phase_pelvis_rotation`
* **Measurement:** Transverse-plane pelvis rotation at [Apex](/biomechanics/activities/tennis/events/apex) (ball contact)
## Description
Contact phase pelvis rotation measures how far the pelvis has rotated (twisted) by the moment of ball contact, relative to its starting orientation. It reflects how much of the pelvis's rotational range has been used by contact, which relates to the [Contact Phase Open Pelvis Rotation](/biomechanics/activities/tennis/flags/contact-phase-open-pelvis-rotation) movement flag.
## Use Cases
* Pelvis rotation timing
* Kinetic chain sequencing
* Related to Contact Phase Open Pelvis Rotation flag
# Contact Phase Shoulder Abduction
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/contact-phase-shoulder-abduction
Amount of shoulder abduction at apex (ball contact).
![Shoulder abduction at contact]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `contact_phase_shoulder_abduction`
* **Measurement:** Shoulder abduction angle (dominant arm) at [Apex](/biomechanics/activities/tennis/events/apex)
## Description
Contact phase shoulder abduction is the sideways lift angle of the dominant arm at ball contact.
It reflects the height and position of the arm at the moment of impact.
## Use Cases
* Shoulder position at contact
* Technique and consistency
# Contact Phase Trunk Flexion
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/contact-phase-trunk-flexion
Forward or backward trunk flexion at apex (ball contact).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `contact_phase_trunk_flexion`
* **Measurement:** Sagittal-plane trunk flexion at [Apex](/biomechanics/activities/tennis/events/apex) (ball contact)
## Description
Contact phase trunk flexion is the forward/backward bend of the trunk at ball contact. Positive values indicate forward flexion, negative values indicate backward extension. It reflects posture at the moment of impact and can be compared with [Finish Phase Trunk Flexion](/biomechanics/activities/tennis/metrics/finish-phase-trunk-flexion) to track trunk motion through the rest of the serve.
## Use Cases
* Posture at contact
* Trunk control and consistency
* Comparison with finish-phase trunk flexion
# Contact Phase Trunk Rotation
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/contact-phase-trunk-rotation
Trunk rotation angle relative to its starting orientation at apex (ball contact).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `contact_phase_trunk_rotation`
* **Measurement:** Transverse-plane trunk rotation at [Apex](/biomechanics/activities/tennis/events/apex) (ball contact)
## Description
Contact phase trunk rotation measures how far the trunk has rotated (twisted) by the moment of ball contact, relative to its starting orientation. It reflects how much of the trunk's rotational range has been used by contact, which relates to the [Contact Phase Open Trunk Rotation](/biomechanics/activities/tennis/flags/contact-phase-open-trunk-rotation) movement flag.
## Use Cases
* Trunk rotation timing
* Kinetic chain sequencing
* Related to Contact Phase Open Trunk Rotation flag
# Contact Phase Trunk Tilt
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/contact-phase-trunk-tilt
Degrees of side-side trunk tilt at apex (ball contact).
![Trunk tilt at contact]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `contact_phase_trunk_tilt`
* **Measurement:** Lateral (side-side) trunk tilt at [Apex](/biomechanics/activities/tennis/events/apex) (ball contact)
## Description
Contact phase trunk tilt is the lateral trunk tilt at ball contact.
It reflects posture at the moment of impact and can be compared with [Loading Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/loading-phase-trunk-tilt) to assess trunk motion through the serve.
Negative values indicate leaning to the dominant side, positive values indicate leaning to the non-dominant side.
## Use Cases
* Posture at contact
* Trunk control and consistency
* Comparison with loading-phase trunk tilt
# Contact Phase Wrist Height
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/contact-phase-wrist-height
Height of the wrist at apex (ball contact) measured from the ground.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters (m)
* **Column Name:** (implementation-specific)
* **Measurement:** Vertical height of the dominant-side wrist joint center above the ground at [Apex](/biomechanics/activities/tennis/events/apex) (ball contact)
## Description
Contact phase wrist height is the height of the wrist at ball contact. It reflects contact point and can indicate consistency of toss and strike height.
## Use Cases
* Contact point consistency
* Toss and strike height
* Comparison across players or trials
# Contact Phase Wrist Height (Normalized)
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/contact-phase-wrist-height-normalized
Height of the dominant-side wrist at apex (ball contact), expressed as a multiple of athlete height.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** × height (ratio to athlete height)
* **Column Name:** `contact_phase_wrist_height_per_ht`
* **Measurement:** Vertical height of the dominant-side wrist joint center above the ground at [Apex](/biomechanics/activities/tennis/events/apex), divided by athlete height
## Description
Contact phase wrist height (normalized) expresses the wrist height at ball contact as a multiple of the athlete's own height, rather than an absolute distance. Normalizing by height makes the metric comparable across athletes of different sizes. Values above 1.0 indicate contact is made above the athlete's own standing height, typical of an overhand serve reaching upward. This is distinct from [Contact Phase Wrist Height](/biomechanics/activities/tennis/metrics/contact-phase-wrist-height), which reports the same measurement as an absolute distance in meters.
## Use Cases
* Contact point consistency across athlete sizes
* Toss and strike height
* Comparison across players or trials
# Contact Phase Wrist Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/contact-phase-wrist-velocity
Linear speed of the wrist joint center at apex (ball contact).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** meters/second (m/s)
* **Column Name:** (implementation-specific)
* **Measurement:** Linear velocity magnitude (or component) of the dominant-side wrist joint center at [Apex](/biomechanics/activities/tennis/events/apex) (ball contact)
## Description
Contact phase wrist velocity is the linear speed of the wrist at ball contact. It is a proxy for racket-head speed and reflects the outcome of the kinematic chain at the moment of impact.
## Use Cases
* Racket speed proxy and serve power
* Technique and consistency
* Comparison across players or trials
# Contact Phase Wrist Velocity (Normalized)
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/contact-phase-wrist-velocity-normalized
Speed of the dominant-side wrist at apex (ball contact), reported alongside the height-normalized dataset.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** unconfirmed
* **Column Name:** `contact_phase_wrist_velocity_per_ht`
* **Measurement:** Velocity of the dominant-side wrist joint center at [Apex](/biomechanics/activities/tennis/events/apex)
## Description
Contact phase wrist velocity (normalized) is a proxy for racket-head speed at the moment of impact. Despite the `_per_ht` naming, observed values (roughly 700–900 in the Broad Sample at the median) are far too large to be a simple ratio to athlete height, and are more consistent with an angular velocity in degrees/second — this page flags the unit as unconfirmed rather than asserting one until it can be verified against the processing code. This is distinct from [Contact Phase Wrist Velocity](/biomechanics/activities/tennis/metrics/contact-phase-wrist-velocity), which reports a linear speed in meters/second.
## Use Cases
* Racket speed proxy and serve power
* Technique and consistency
* Comparison across players or trials
# Contact Phase X Factor
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/contact-phase-x-factor
Angle between the shoulders and hips in the transverse plane (twisting) at apex (ball contact).
![X factor as viewed from above]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `contact_phase_x_factor`
* **Measurement:** Shoulder-hip separation angle (transverse plane) at [Apex](/biomechanics/activities/tennis/events/apex)
## Description
Contact phase X factor is the twist angular difference between torso and pelvis rotation (transverse plane) at ball contact.
It indicates how much upper-body rotation has been "uncoiled" at contact and can be compared with [Loading Phase Shoulder Hip Separation](/biomechanics/activities/tennis/metrics/loading-phase-shoulder-hip-separation).
X factor is also known as hip shoulder separation.
## Use Cases
* Uncoiling and rotation at contact
* Kinetic chain and technique
* Comparison with loading-phase separation
# Forward Displacement (Normalized)
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/displacement-forward
Forward body displacement between ball contact and finish, expressed as a multiple of athlete height.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** × height (ratio to athlete height)
* **Column Name:** `displacement_forward`
* **Measurement:** Forward body displacement between [Apex](/biomechanics/activities/tennis/events/apex) (ball contact) and [Termination](/biomechanics/activities/tennis/events/termination), divided by athlete height
## Description
Forward displacement (normalized) measures how far the body moves forward, toward the net, between ball contact and the finish of the serve, expressed as a multiple of the athlete's height so it is comparable across athletes of different sizes. It provides the underlying continuous measurement behind the [Landing Phase Excessive Forward Drift](/biomechanics/activities/tennis/flags/landing-phase-excessive-forward-drift) movement flag, which flags forward displacement greater than 0.50x height.
## Use Cases
* Momentum and follow-through analysis
* Related to Landing Phase Excessive Forward Drift flag
* Court positioning after the serve
# Open-Side Displacement (Normalized)
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/displacement-open-side
Open-side body displacement between ball contact and finish, expressed as a multiple of athlete height.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** × height (ratio to athlete height)
* **Column Name:** `displacement_open_side`
* **Measurement:** Open-side (lateral, non-dominant side) body displacement between [Apex](/biomechanics/activities/tennis/events/apex) (ball contact) and [Termination](/biomechanics/activities/tennis/events/termination), divided by athlete height
## Description
Open-side displacement (normalized) measures how far the body drifts laterally toward the non-dominant (open) side between ball contact and the finish of the serve, expressed as a multiple of the athlete's height. It provides the underlying continuous measurement behind the [Landing Phase Excessive Side Drift](/biomechanics/activities/tennis/flags/landing-phase-excessive-side-drift) movement flag, which flags displacement greater than 0.30x height (or less than -0.10x height).
## Use Cases
* Lateral stability analysis
* Related to Landing Phase Excessive Side Drift flag
* Balance and follow-through assessment
# Vertical Displacement (Normalized)
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/displacement-vertical
Vertical body displacement between ball contact and finish, expressed as a multiple of athlete height.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** × height (ratio to athlete height)
* **Column Name:** `displacement_vertical`
* **Measurement:** Vertical body displacement between [Apex](/biomechanics/activities/tennis/events/apex) (ball contact) and [Termination](/biomechanics/activities/tennis/events/termination), divided by athlete height
## Description
Vertical displacement (normalized) measures how much the body drops (or rises) between ball contact and the finish of the serve, expressed as a multiple of the athlete's height so it is comparable across athletes of different sizes.
## Use Cases
* Landing mechanics analysis
* Momentum dissipation after contact
* Comparison across players or trials
# Finish Phase Trunk Flexion
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/finish-phase-trunk-flexion
Forward or backward trunk flexion at the finish of the serve.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `finish_phase_trunk_flexion`
* **Measurement:** Sagittal-plane trunk flexion at [Termination](/biomechanics/activities/tennis/events/termination)
## Description
Finish phase trunk flexion is the forward/backward bend of the trunk at the end of the serve. Positive values indicate forward flexion, negative values indicate backward extension. It provides the underlying continuous measurement behind the [Landing Phase Excessive Forward Lean](/biomechanics/activities/tennis/flags/landing-phase-excessive-forward-lean) movement flag, which flags forward flexion greater than 60°.
## Use Cases
* Follow-through posture
* Related to Landing Phase Excessive Forward Lean flag
* Injury risk screening
# Finish Phase Trunk Tilt
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/finish-phase-trunk-tilt
Lateral (side-to-side) trunk tilt at the finish of the serve.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `finish_phase_trunk_tilt`
* **Measurement:** Lateral (side-side) trunk tilt at [Termination](/biomechanics/activities/tennis/events/termination)
## Description
Finish phase trunk tilt is the lateral trunk tilt at the end of the serve. It provides the underlying continuous measurement behind the [Landing Phase Excessive Side Lean](/biomechanics/activities/tennis/flags/landing-phase-excessive-side-lean) movement flag, which flags absolute side tilt greater than 30°.
## Use Cases
* Follow-through posture
* Related to Landing Phase Excessive Side Lean flag
* Injury risk screening
# Forward Angular Velocity Time Series
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/forward-angular-velocity-time-series
Time series of instantaneous forward angular velocity for torso, upper arm, and forearm. Used to evaluate kinematic sequence.
## Technical Details
* **Variable Type:** Time Series Metric
* **Data Type:** Float array
* **Units:** deg/s
* **Column Name:** `torso_forward_angular_velocity`, `upper_arm_forward_angular_velocity`, `forearm_forward_angular_velocity`
* **Measurement:** Instantaneous forward (somersault) angular velocity of each segment over time, measured in the serve direction
## Description
These time series metrics give the forward angular velocity of the torso, upper arm, and forearm throughout the serve.
They are used to determine the [Kinematic Sequence](/biomechanics/activities/tennis/metrics/forward-kinematic-sequence) (order of peak velocities).
## Use Cases
* Kinematic sequencing
* Detailed technique and timing analysis
# Forward Kinematic Sequence
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/forward-kinematic-sequence
Sequence of peak forward angular velocities (torso, upper arm, forearm). Optimal sequence is 'torso-upper_arm-forearm'.
![Forward kinematic sequence]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Categorical / Array
* **Units:** N/A
* **Column Name:** `forward_kinematic_sequence`
* **Measurement:** Order in which segments reach peak forward angular velocity
## Description
Kinematic sequence describes the order in which the torso, upper arm, and forearm reach their peak forward angular velocities during the serve.
The optimal sequence is proximal-to-distal: torso → upper arm → forearm, supporting efficient energy transfer to the racket.
Derived from [Peak Torso](/biomechanics/activities/tennis/metrics/peak-torso-forward-angular-velocity), [Peak Upper Arm](/biomechanics/activities/tennis/metrics/peak-upper-arm-forward-angular-velocity), and [Peak Forearm](/biomechanics/activities/tennis/metrics/peak-forearm-forward-angular-velocity) forward angular velocities; time-series versions are in [Forward Angular Velocity Time Series](/biomechanics/activities/tennis/metrics/forward-angular-velocity-time-series).
## Use Cases
* Technique quality and sequencing
* Comparison with optimal sequence (torso-upper\_arm-forearm)
* Coaching and training feedback
# Forward Trunk Arm Speedup
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/forward-trunk-arm-speedup
Speedup factor of peak forward angular velocities from the torso to the upper arm.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** N/A (ratio/factor)
* **Column Name:** `forward_trunk_arm_speedup`
* **Measurement:** Ratio (or factor) of [Peak Upper Arm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-upper-arm-forward-angular-velocity) to [Peak Torso Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-torso-forward-angular-velocity)—how much the upper arm speeds up relative to the torso in the serve direction
## Description
Forward trunk arm speedup quantifies the increase in peak angular velocity from the torso to the upper arm during the serve. A value greater than 1 indicates the upper arm reaches a higher peak forward angular velocity than the torso, supporting efficient [Forward Kinematic Sequence](/biomechanics/activities/tennis/metrics/forward-kinematic-sequence) (torso → upper arm → forearm).
## Use Cases
* Kinetic chain and energy transfer assessment
* Technique quality (proximal-to-distal speedup)
* Coaching and training feedback
# Forward Upper Arm Forearm Speedup
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/forward-upper-arm-forearm-speedup
Speedup factor of peak forward angular velocities from the upper arm to the forearm.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** N/A (ratio/factor)
* **Column Name:** `forward_upper_arm_forearm_speedup`
* **Measurement:** Ratio (or factor) of [Peak Forearm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-forearm-forward-angular-velocity) to [Peak Upper Arm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-upper-arm-forward-angular-velocity)—how much the forearm speeds up relative to the upper arm in the serve direction
## Description
Forward upper arm forearm speedup quantifies the increase in peak angular velocity from the upper arm to the forearm during the serve. A value greater than 1 indicates the forearm reaches a higher peak forward angular velocity than the upper arm, completing the optimal [Forward Kinematic Sequence](/biomechanics/activities/tennis/metrics/forward-kinematic-sequence) (torso → upper arm → forearm).
## Use Cases
* Kinetic chain and energy transfer assessment
* Technique quality (proximal-to-distal speedup)
* Coaching and training feedback
# Handedness
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/handedness
Handedness of the athlete (left or right) for the tennis serve.
## Technical Details
* **Variable Type:** Discrete Metric / Dimension
* **Data Type:** Categorical
* **Units:** N/A
* **Column Name:** (implementation-specific)
* **Measurement:** Player handedness (e.g., 'left', 'right') used to define dominant arm and side
## Description
Handedness indicates which hand the player uses to serve. It is typically a required input for processing (with [Dimensions](/biomechanics/activities/tennis/overhand_serve#dimensions)) and is used to interpret dominant-side events and metrics (e.g., low arm, apex, shoulder external rotation).
## Use Cases
* Defining dominant vs. non-dominant side for metrics
* Filtering and grouping by handedness
* Consistent interpretation of limb-specific metrics
# Loading Phase Ball Release Angle
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/loading-phase-ball-release-angle
Arm angle relative to torso at the instance of ball release
![Ball toss angle at release]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `loading_phase_ball_toss_angle`
* **Measurement:** Angle between wrist and shoulders at [Ball Release](/biomechanics/activities/tennis/events/ball-release)
* 90° = arm directly in front of non-dominant shoulder
* 180° = arm positioned sideways from torso
## Description
Ball release angle describes where the arm is positioned relative to the shoulders at ball release event.
It affects toss consistency and timing.
Values are typically between 90° (directly in front of non-dominant shoulder) and 180° (arm fully sideways from torso).
## Use Cases
* Toss placement and consistency
* Timing and rhythm
* Coaching feedback
# Loading Phase Max Knee Flexion
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/loading-phase-knee-flexion
Maximum knee flexion of the front leg and back leg during the loading phase of the serve.
![Knee flexion during loading phase]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `loading_phase_max_front_knee_flexion`, `loading_phase_max_back_knee_flexion`
* **Measurement:** Maximum knee flexion angle during the loading phase ([Ball Release](/biomechanics/activities/tennis/events/ball-release) to [Low Arm](/biomechanics/activities/tennis/events/low-arm))
## Description
This metric captures the maximum knee flexion achieved by each leg during the loading phase of the serve.
Greater flexion can indicate more lower-body drive and a higher jump.
Metrics are reported separately for front and back leg.
## Use Cases
* Lower-body loading and drive
* Stance and technique comparison
* Consistency across trials
# Loading Phase Pelvis Tilt
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/loading-phase-pelvis-tilt
Maximum pelvis side-side tilt towards the rear during the loading phase of the serve.
![Pelvis tilt during loading]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `loading_phase_pelvis_tilt`
* **Measurement:** Maximum pelvis lateral (side-side) tilt towards the rear during the loading phase ([Ball Release](/biomechanics/activities/tennis/events/ball-release) to [Low Arm](/biomechanics/activities/tennis/events/low-arm))
* Negative values indicate leaning to the dominant side
* Positive values indicate leaning to the non-dominant side
## Description
Loading phase pelvis tilt is the maximum lateral tilt of the pelvis toward the rear during the loading phase. It reflects lower-body coiling and base position before the arm accelerates.
## Use Cases
* Lower-body coiling and loading
* Pelvis-trunk coordination
* Technique and consistency
# Loading Phase Shoulder Hip Separation
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/loading-phase-shoulder-hip-separation
Maximum difference in rotation of the shoulders and hips (separation angle) during the loading phase.
![Hip shoulder separation during loading]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `loading_phase_shoulder_hip_separation`
* **Measurement:** Maximum separation angle between shoulder and hip rotation in the transverse plane during the loading phase ([Ball Release](/biomechanics/activities/tennis/events/ball-release) to [Low Arm](/biomechanics/activities/tennis/events/low-arm))
## Description
Shoulder hip separation during loading is the maximum angular (twist) difference between the torso and pelvis (transverse plane) during the loading phase.
It indicates how much the upper body is "coiled" relative to the lower body before the serve.
Also known as X Factor.
## Use Cases
* Coiling and kinetic chain assessment
* Comparison with [Contact Phase X Factor](/biomechanics/activities/tennis/metrics/contact-phase-x-factor) at apex
* Technique and power potential
# Loading Phase Trunk Tilt
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/loading-phase-trunk-tilt
Maximum trunk side-side tilt towards the rear during the loading phase of the serve.
![Trunk tilt during loading]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `loading_phase_trunk_tilt`
* **Measurement:** Maximum trunk lateral (side-side) tilt towards the rear during the loading phase ([Ball Release](/biomechanics/activities/tennis/events/ball-release) to [Low Arm](/biomechanics/activities/tennis/events/low-arm))
* Negative values indicate leaning to the dominant side
* Positive values indicate leaning to the non-dominant side
## Description
Loading phase trunk tilt is the maximum lateral tilt of the trunk toward the rear (back) side during the loading phase.
It reflects preparatory posture before the upward swing.
## Use Cases
* Loading assessment
* Trunk control during preparation
* Comparison with contact-phase trunk tilt
# Max Back Knee Valgus (Normalized)
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/max-back-knee-valgus
Maximum inward (valgus) collapse of the back knee during the serve, expressed as a multiple of athlete height.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** × height (ratio to athlete height)
* **Column Name:** `max_back_knee_valgus_upward_per_ht`
* **Measurement:** Maximum medial (inward) displacement of the back knee during the serve, divided by athlete height
## Description
Max back knee valgus (normalized) measures how far the back knee collapses inward, toward the centerline of the body, at its most extreme point during the serve, expressed as a multiple of the athlete's height. More negative values indicate greater inward collapse. It is closely related to the [Loading Phase Excessive Knee Valgus](/biomechanics/activities/tennis/flags/loading-phase-excessive-knee-valgus) movement flag.
## Use Cases
* Injury risk identification
* Lower-body mechanics evaluation
* Related to Loading Phase Excessive Knee Valgus flag
# Max Front Knee Valgus (Normalized)
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/max-front-knee-valgus
Maximum inward (valgus) collapse of the front knee during the serve, expressed as a multiple of athlete height.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** × height (ratio to athlete height)
* **Column Name:** `max_front_knee_valgus_upward_per_ht`
* **Measurement:** Maximum medial (inward) displacement of the front knee during the serve, divided by athlete height
## Description
Max front knee valgus (normalized) measures how far the front knee collapses inward, toward the centerline of the body, at its most extreme point during the serve, expressed as a multiple of the athlete's height. More negative values indicate greater inward collapse. It is closely related to the [Loading Phase Excessive Knee Valgus](/biomechanics/activities/tennis/flags/loading-phase-excessive-knee-valgus) movement flag.
## Use Cases
* Injury risk identification
* Lower-body mechanics evaluation
* Related to Loading Phase Excessive Knee Valgus flag
# Peak Forearm Forward Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/peak-forearm-forward-angular-velocity
Peak forward angular velocity of the forearm segment in the serve direction.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/second (°/s)
* **Column Name:** `peak_forearm_forward_angular_velocity`
* **Measurement:** Peak forward (serve-direction) angular velocity of the forearm segment, typically near [Apex](/biomechanics/activities/tennis/events/apex)
## Description
Peak forearm forward angular velocity is the maximum angular velocity of the forearm in the serve direction.
It is the third segment in the optimal [Kinematic Sequence](/biomechanics/activities/tennis/metrics/forward-kinematic-sequence) (torso → upper arm → forearm), reflecting distal segment speed at contact.
## Use Cases
* Kinematic sequence and energy transfer
* Technique quality (optimal sequence)
* Racket speed proxy and comparison with torso/upper arm
# Peak Pelvis Twist Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/peak-pelvis-twist-angular-velocity
Peak twist angular velocity of the pelvis segment in the serve direction.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/second (°/s)
* **Column Name:** `pelvis_peak_twist_angular_velocity`
* **Measurement:** Peak twist (transverse plane, like a tornado) angular velocity of the pelvis
## Description
Peak pelvis twist angular velocity is the maximum twisting angular velocity of the pelvis in the transverse plane (like a tornado).
It is the most proximal segment in the [Twist Kinematic Sequence](/biomechanics/activities/tennis/metrics/twist-kinematic-sequence) (pelvis-torso-upper\_arm), reflecting lower-body contribution to the kinetic chain.
## Use Cases
* Twist kinematic sequence and energy transfer
* Lower-body contribution to serve
* Comparison with peak torso and upper arm twist velocities
# Peak Torso Forward Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/peak-torso-forward-angular-velocity
Peak forward angular velocity of the torso segment in the serve direction.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/second (°/s)
* **Column Name:** `peak_torso_forward_angular_velocity`
* **Measurement:** Peak forward (somersault) angular velocity of the torso segment in teh serve direction
## Description
Peak torso forward angular velocity is the maximum angular velocity of the torso in the serve direction.
It is the first segment in the optimal [Kinematic Sequence](/biomechanics/activities/tennis/metrics/forward-kinematic-sequence) (torso → upper arm → forearm), reflecting proximal-to-distal energy transfer.
## Use Cases
* Kinematic sequence and energy transfer
* Technique quality (optimal sequence)
* Comparison with peak upper arm and forearm velocities
# Peak Torso Twist Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/peak-torso-twist-angular-velocity
Peak twist angular velocity of the torso segment.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/second (°/s)
* **Column Name:** `trunk_peak_twist_angular_velocity`
* **Measurement:** Peak twist (like a tornado) angular velocity of the torso
## Description
Peak torso twist angular velocity is the maximum twist angular velocity of the torso in the transverse plane (like a tornado).
It is part of the [Twist Kinematic Sequence](/biomechanics/activities/tennis/metrics/twist-kinematic-sequence) (torso-upper\_arm-forearm), reflecting trunk contribution to the kinetic chain.
## Use Cases
* Twist kinematic sequence and energy transfer
* Trunk contribution to serve
* Comparison with peak pelvis and upper arm twist velocities
# Peak Upper Arm Forward Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/peak-upper-arm-forward-angular-velocity
Peak forward angular velocity of the upper arm segment in the serve direction.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/second (°/s)
* **Column Name:** `peak_upper_arm_forward_angular_velocity`
* **Measurement:** Peak forward (somersault) angular velocity of the upper arm segment
## Description
Peak upper arm forward angular velocity is the rotation speed of the upper arm in the serve direction (somersaulting forward).
It is the second segment in the optimal [Kinematic Sequence](/biomechanics/activities/tennis/metrics/forward-kinematic-sequence) (torso → upper arm → forearm).
## Use Cases
* Kinematic sequence and energy transfer
* Technique quality (optimal sequence)
* Comparison with peak torso and forearm velocities
# Peak Upper Arm Twist Angular Velocity
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/peak-upper-arm-twist-angular-velocity
Peak twist angular velocity of the upper arm segment.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees/second (°/s)
* **Column Name:** `arm_peak_twist_angular_velocity`
* **Measurement:** Peak twist (like a tornado) angular velocity of the upper arm
## Description
Peak upper arm twist angular velocity is the maximum rotation speed of the upper arm in the transverse plane (twisting like a tornado).
It is part of the [Twist Kinematic Sequence](/biomechanics/activities/tennis/metrics/twist-kinematic-sequence) (torso-upper\_arm-forearm), reflecting upper arm contribution to the kinetic chain.
## Use Cases
* Twist kinematic sequence and energy transfer
* Arm contribution to serve
* Comparison with peak torso and forearm twist velocities
# Pelvis Coil
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/pelvis-coil
Maximum amount of pelvis twist rotation away from the serve direction (preloading the twist before the serve).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `pelvis_coil`
* **Measurement:** Maximum pelvis twist rotation away from the serve direction during the preparation/loading phase
* reflects how much the pelvis is "coiled up" before uncoiling toward contact
## Description
Pelvis coil is the maximum twist rotation of the pelvis away from the serve direction during the early phases of the serve.
It reflects lower-body preloading before the acceleration phase and contributes to [Pelvis Stretch](/biomechanics/activities/tennis/metrics/pelvis-stretch) (twist range of motion).
## Use Cases
* Lower-body coiling and loading assessment
* Pelvis contribution to kinetic chain
* Comparison with trunk coil and stretch metrics
# Pelvis Stretch
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/pelvis-stretch
Twist range of motion of the pelvis during the serve.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `pelvis_stretch`
* **Measurement:** Total twist (like a tornado) range of motion of the pelvis during the serve
* typically from maximum coil (away from serve direction) to maximum uncoiling during follow through
## Description
Pelvis stretch is the twist range of motion of the pelvis through the serve.
It captures how much the pelvis rotates in the twist direction from the coiled position ([Pelvis Coil](/biomechanics/activities/tennis/metrics/pelvis-coil)) through the acceleration phase to contact.
Greater stretch can indicate more lower-body contribution to the kinetic chain.
## Use Cases
* Pelvis mobility and range of motion
* Lower-body kinetic chain contribution
* Comparison with trunk stretch
# Release Phase Elbow Angle
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/release-phase-elbow-angle
Non-dominant (tossing) elbow flexion angle at ball release.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `release_phase_elbow_angle`
* **Measurement:** Non-dominant elbow flexion angle at [Ball Release](/biomechanics/activities/tennis/events/ball-release)
## Description
Release phase elbow angle measures how straight the non-dominant (tossing) arm's elbow is at the moment the ball is released from the hand. It provides the underlying continuous measurement behind the [Release Phase Elbow Not Straight](/biomechanics/activities/tennis/flags/release-phase-elbow-not-straight) movement flag, which flags flexion greater than 30°.
## Use Cases
* Toss consistency
* Related to Release Phase Elbow Not Straight flag
* Coaching feedback
# Stance Position
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/stance-position
Classification of serve stance position: platform or pinpoint.
![Serve start position]()
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Categorical
* **Units:** N/A
* **Column Name:** (implementation-specific)
* **Measurement:** Serve stance type — 'platform' (feet remain relatively fixed) or 'pinpoint' (back foot steps forward to meet front foot)
## Description
Stance position describes how the player positions the feet during the serve. In a platform stance, the feet stay in a fixed relationship; in a pinpoint stance, the back foot moves toward the front foot during the motion. This can affect timing, balance, and lower-body metrics.
## Use Cases
* Technique classification
* Comparing mechanics across stance types
* Coaching and consistency assessment
# Time to Contact
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/time-to-contact
Duration from the start of the serve to ball contact.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s)
* **Column Name:** `time_to_contact`
* **Measurement:** Duration from [Initiation](/biomechanics/activities/tennis/events/initiation) to [Apex](/biomechanics/activities/tennis/events/apex) (ball contact)
## Description
Time to contact measures how long the serve takes from its initial movement to ball contact. Shorter times generally reflect a quicker, more compact motion, while longer times can reflect a more deliberate rhythm or timing inefficiencies.
## Use Cases
* Serve tempo and rhythm analysis
* Timing consistency across trials
* Comparison across players
# Trunk Coil
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/trunk-coil
Maximum amount of trunk twist rotation away from the serve direction (preloading the twist before the serve).
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `trunk_coil`
* **Measurement:** Maximum trunk twist rotation away from the serve direction during the preparation/loading phase
* how much the trunk is "coiled up" before uncoiling toward contact
## Description
Trunk coil is the maximum twist rotation of the trunk away from the serve direction during the early phases of the serve.
It reflects preloading of the trunk before the acceleration phase and contributes to [Trunk Stretch](/biomechanics/activities/tennis/metrics/trunk-stretch) (twist range of motion).
## Use Cases
* Coiling and loading assessment
* Trunk contribution to kinetic chain
* Comparison with pelvis coil and stretch metrics
# Trunk Stretch
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/trunk-stretch
Twist range of motion of the trunk during the serve.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `trunk_stretch`
* **Measurement:** Total twist (like a tornado) range of motion of the trunk during the serve
* typically from maximum coil (away from serve direction) to maximum rotation during follow through
## Description
Trunk stretch is the twist range of motion of the trunk through the serve.
It captures how much the trunk rotates in the twist direction from the coiled position ([Trunk Coil](/biomechanics/activities/tennis/metrics/trunk-coil)) through the acceleration phase to contact.
Greater stretch can indicate more potential for energy transfer.
## Use Cases
* Trunk mobility and range of motion
* Kinetic chain and energy transfer
* Comparison with pelvis stretch
# Twist Kinematic Sequence
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/twist-kinematic-sequence
Sequence of peak twist angular velocities (pelvis, torso, upper arm). Optimal sequence is 'pelvis-torso-upper_arm'.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Categorical / Array
* **Units:** N/A
* **Column Name:** `twist_kinematic_sequence`
* **Measurement:** Order in which segments reach peak twist (like a tornado) angular velocity
## Description
Twist kinematic sequence describes the order in which the pelvis, torso, and upper arm reach their peak twist angular velocities during the serve.
The optimal sequence is proximal-to-distal: pelvis → torso → upper arm, supporting efficient energy transfer.
Related segment peaks:
* [Peak Pelvis Twist](/biomechanics/activities/tennis/metrics/peak-pelvis-twist-angular-velocity)
* [Peak Torso Twist](/biomechanics/activities/tennis/metrics/peak-torso-twist-angular-velocity)
* [Peak Upper Arm Twist](/biomechanics/activities/tennis/metrics/peak-upper-arm-twist-angular-velocity)
Speedup factors:
* [Twist Trunk Arm Speedup](/biomechanics/activities/tennis/metrics/twist-trunk-arm-speedup)
* [Twist Pelvis Trunk Speedup](/biomechanics/activities/tennis/metrics/twist-pelvis-torso-speedup)
## Use Cases
* Technique quality and twist sequencing
* Comparison with optimal sequence
* Coaching and training feedback
# Twist Pelvis Torso Speedup
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/twist-pelvis-torso-speedup
Speedup factor of peak twist angular velocities from the pelvis to the torso.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** N/A (ratio/factor)
* **Column Name:** `twist_pelvis_trunk_speedup`
* **Measurement:** Ratio (or factor) of [Peak Pelvis Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-pelvis-twist-angular-velocity) to [Peak Torso Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-torso-twist-angular-velocity)
## Description
Twist upper arm forearm speedup quantifies the increase in peak twist angular velocity from the upper arm to the forearm during the serve.
A value greater than 1 indicates the forearm reaches a higher peak twist angular velocity than the upper arm, completing the optimal [Twist Kinematic Sequence](/biomechanics/activities/tennis/metrics/twist-kinematic-sequence) (pelvis → torso → upper arm).
## Use Cases
* Twist kinetic chain and energy transfer
* Technique quality (proximal-to-distal speedup)
* Coaching and training feedback
# Twist Trunk Arm Speedup
Source: https://docs.uplift.ai/biomechanics/activities/tennis/metrics/twist-trunk-arm-speedup
Speedup factor of peak twist angular velocities from the torso to the upper arm.
## Technical Details
* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** N/A (ratio/factor)
* **Column Name:** `twist_trunk_arm_speedup`
* **Measurement:** Ratio (or factor) of peak upper arm twist angular velocity to [Peak Torso Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-torso-twist-angular-velocity)—how much the upper arm twist speeds up relative to the torso
## Description
Twist trunk arm speedup quantifies the increase in peak twist angular velocity from the torso to the upper arm during the serve.
A value greater than 1 indicates the upper arm reaches a higher peak twist angular velocity than the torso, supporting efficient [Twist Kinematic Sequence](/biomechanics/activities/tennis/metrics/twist-kinematic-sequence).
## Use Cases
* Twist kinetic chain and energy transfer
* Technique quality (proximal-to-distal speedup)
* Coaching and training feedback
# Tennis: Overhand Serve
Source: https://docs.uplift.ai/biomechanics/activities/tennis/overhand_serve
Documentation of tennis overhand events, phases, and metrics.
Evaluate serve mechanics to improve consistency and maximize energy transfer to the ball.
## Dimensions
Required Inputs for processing:
* **handedness:** the handedness of the player \['left', 'right']
* **serve stance position:** the stance type used for the serve \['pinpoint', 'platform']
## Phases of the serve
Stages adopted from [Kovacs & Ellenbecker, 2011](https://pmc.ncbi.nlm.nih.gov/articles/PMC3445225/).
( [Video](https://www.youtube.com/watch?v=EBLIZS_iNq8) )
| Phase | Stage | Start | End | Event or Phase |
| ------------ | ------------ | ------------ | -------------------- | -------------- |
| Preparation | Start | Initiation | Initiation | Event |
| Preparation | Release | Initiation | Ball Release | Phase |
| Preparation | Loading | Ball Release | Low Arm | Phase |
| Preparation | Cocking | Low Arm | Max Shoulder Ext Rot | Phase |
| Acceleration | Acceleration | Max Sho ER | Ball Contact | Phase |
| Acceleration | Ball Contact | Ball Contact | Ball Contact | Event |
| Follow Thru | Deceleration | Ball Contact | Termination | Phase |
| Follow Thru | Finish | Termination | Termination | Event |
## Variables
Output variables from tennis overhand serve analysis.
### Normative Ranges
See [Tennis Overhand Serve Norms](/biomechanics/activities/tennis/tennis-overhand-serve-norms) for the full 5th–95th percentile reference tables by competition level (Youth, Professional, Broad).
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Description | Column Name |
| ----------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------- | -------------------------------------- |
| [Initiation](/biomechanics/activities/tennis/events/initiation) | the start of the tennis serve | `initiation_event` |
| [Ball Release](/biomechanics/activities/tennis/events/ball-release) | the estimated timing of ball toss release | `ball_release_event` |
| [Low Arm](/biomechanics/activities/tennis/events/low-arm) | the low point of the dominant arm prior to ball contact | `low_arm_event` |
| [Max Shoulder ER](/biomechanics/activities/tennis/events/max-shoulder-er) | the instant of maximum shoulder external rotation between ball release and apex | `max_shoulder_external_rotation_event` |
| [Apex](/biomechanics/activities/tennis/events/apex) | maximum height of the dominant-side wrist joint center during the serve | `apex_event` |
| [Termination](/biomechanics/activities/tennis/events/termination) | end of the tennis serve | `termination_event` |
| [Peak Forearm Velocity](/biomechanics/activities/tennis/events/peak-forearm-velocity) | the instant of peak forearm forward angular velocity, used to determine forward kinematic sequence | \`\` |
| [Peak Upper Arm Velocity](/biomechanics/activities/tennis/events/peak-upper-arm-velocity) | the instant of peak upper arm forward angular velocity, used to determine forward kinematic sequence | \`\` |
| [Peak Torso Velocity](/biomechanics/activities/tennis/events/peak-torso-velocity) | the instant of peak torso forward angular velocity, used to determine forward kinematic sequence | \`\` |
### Forward Kinematic Sequence Metrics
| Metric | Units | Description | Column Name |
| -------------------------------------------------------------------------------------------------------------------------- | -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------- |
| [Peak Torso Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-torso-forward-angular-velocity) | degrees/second | Peak forward angular velocity of the torso segment in the serve direction | `peak_torso_forward_angular_velocity` |
| [Peak Upper Arm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-upper-arm-forward-angular-velocity) | degrees/second | Peak forward angular velocity of the upper arm segment in the serve direction | `peak_upper_arm_forward_angular_velocity` |
| [Peak Forearm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-forearm-forward-angular-velocity) | degrees/second | Peak forward angular velocity of the forearm segment in the serve direction | `peak_forearm_forward_angular_velocity` |
| [Forward Kinematic Sequence](/biomechanics/activities/tennis/metrics/forward-kinematic-sequence) | N/A | Sequence of peak forward angular velocities. Optimal sequence is 'torso-upper\_arm-forearm' | `forward_kinematic_sequence` |
| [Forward Trunk Arm Speedup](/biomechanics/activities/tennis/metrics/forward-trunk-arm-speedup) | N/A | Speedup factor of peak forward angular velocities from the torso to the upper arm. | `forward_trunk_arm_speedup` |
| [Forward Upper Arm Forearm Speedup](/biomechanics/activities/tennis/metrics/forward-upper-arm-forearm-speedup) | N/A | Speedup factor of peak forward angular velocities from the upper arm to the forearm. | `forward_upper_arm_forearm_speedup` |
| [Upper Arm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/forward-angular-velocity-time-series) | deg/s | Time series values of the instantaneous forward angular velocity (serve direction) of the upper arm segment. Evaluate near apex (ball contact event) to visualize kinematic sequencing | `upper_arm_forward_angular_velocity` |
| [Torso Forward Angular Velocity](/biomechanics/activities/tennis/metrics/forward-angular-velocity-time-series) | deg/s | Time series values of the instantaneous forward angular velocity (serve direction) of the torso segment. Evaluate near apex (ball contact event) to visualize kinematic sequencing | `torso_forward_angular_velocity` |
| [Forearm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/forward-angular-velocity-time-series) | deg/s | Time series values of the instantaneous forward angular velocity (serve direction) of the forearm segment. Evaluate near apex (ball contact event) to visualize kinematic sequencing | `forearm_forward_angular_velocity` |
### Twist Kinematic Sequence Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------------------------------------------- | -------------- | ----------------------------------------------------------------------------------------- | ------------------------------------ |
| [Peak Pelvis Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-pelvis-twist-angular-velocity) | degrees/second | Peak twist angular velocity of the pelvis segment in the serve direction | `pelvis_peak_twist_angular_velocity` |
| [Peak Torso Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-torso-twist-angular-velocity) | degrees/second | Peak twist angular velocity of the torso segment in the serve direction | `trunk_peak_twist_angular_velocity` |
| [Peak Upper Arm Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-upper-arm-twist-angular-velocity) | degrees/second | Peak twist angular velocity of the upper arm segment in the serve direction | `arm_peak_twist_angular_velocity` |
| [Twist Kinematic Sequence](/biomechanics/activities/tennis/metrics/twist-kinematic-sequence) | N/A | Sequence of peak twist angular velocities. Optimal sequence is 'torso-upper\_arm-forearm' | `twist_kinematic_sequence` |
| [Twist Trunk Arm Speedup](/biomechanics/activities/tennis/metrics/twist-trunk-arm-speedup) | N/A | Speedup factor of peak twist angular velocities from the torso to the upper arm. | `twist_trunk_arm_speedup` |
| [Twist Pelvis Torso Speedup](/biomechanics/activities/tennis/metrics/twist-pelvis-torso-speedup) | N/A | Speedup factor of peak twist angular velocities from the pelvis to the trunk. | `twist_pelvis_trunk_speedup` |
### Movement Flag Metrics
Movement flags identify poor or suboptimal mechanics for timing and body positioning during the serve.
| Metric | Description | Column Name |
| ---------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------- | ---------------------------------------- |
| [Release Phase Off-Arm to Body Position](/biomechanics/activities/tennis/flags/release-phase-off-arm-to-body-position) | Ball toss angle is outside the acceptable 90°–180° range at ball release. | `release_phase_off_arm_to_body_position` |
| [Release Phase Elbow Not Straight](/biomechanics/activities/tennis/flags/release-phase-elbow-not-straight) | Non-dominant elbow flexion exceeds 30° at ball release. | `release_phase_elbow_not_straight` |
| [Loading Phase Knee Asymmetry](/biomechanics/activities/tennis/flags/loading-phase-knee-asymmetry) | Front-to-back knee flexion difference exceeds 15° during loading. | `loading_phase_knee_asymmetry` |
| [Loading Phase Pinpoint Break](/biomechanics/activities/tennis/flags/loading-phase-pinpoint-break) | Athlete breaks from a pinpoint stance during loading. | `loading_phase_pinpoint_break` |
| [Loading Phase Lack of Trunk Coil](/biomechanics/activities/tennis/flags/loading-phase-lack-trunk-coil) | Trunk coil is below 110° during loading. | `loading_phase_lack_trunk_coil` |
| [Loading Phase Lack of Pelvis Coil](/biomechanics/activities/tennis/flags/loading-phase-lack-pelvis-coil) | Pelvis coil is below 110° during loading. | `loading_phase_lack_pelvis_coil` |
| [Loading Phase Lack of Shoulder Drop](/biomechanics/activities/tennis/flags/loading-phase-lack-shoulder-drop) | Trunk does not tilt toward the rear by at least 5° during loading. | `loading_phase_lack_shoulder_drop` |
| [Loading Phase Lack of Pelvis Drop](/biomechanics/activities/tennis/flags/loading-phase-lack-pelvis-drop) | Pelvis does not tilt toward the rear during loading. | `loading_phase_lack_pelvis_drop` |
| [Loading Phase Excessive Knee Valgus](/biomechanics/activities/tennis/flags/loading-phase-excessive-knee-valgus) | Front or back knee valgus classified as "high" during loading. | `loading_phase_excessive_knee_valgus` |
| [Cocking Phase Lack of External Rotation](/biomechanics/activities/tennis/flags/cocking-phase-lack-external-rotation) | Max shoulder external rotation is below 180° during cocking. | `cocking_phase_lack_external_rotation` |
| [Contact Phase Arm Out of Slot Position](/biomechanics/activities/tennis/flags/contact-phase-arm-out-of-slot-position) | Shoulder abduction is outside the 110°–140° range at ball contact. | `contact_phase_arm_out_of_slot_position` |
| [Contact Phase Open Trunk Rotation](/biomechanics/activities/tennis/flags/contact-phase-open-trunk-rotation) | Trunk rotation has not passed -20° by ball contact. | `contact_phase_open_trunk_rotation` |
| [Contact Phase Open Pelvis Rotation](/biomechanics/activities/tennis/flags/contact-phase-open-pelvis-rotation) | Pelvis rotation has not passed -30° by ball contact. | `contact_phase_open_pelvis_rotation` |
| [Landing Phase Excessive Forward Lean](/biomechanics/activities/tennis/flags/landing-phase-excessive-forward-lean) | Trunk forward flexion exceeds 60° at finish. | `landing_phase_excessive_forward_lean` |
| [Landing Phase Excessive Side Lean](/biomechanics/activities/tennis/flags/landing-phase-excessive-side-lean) | Absolute trunk side tilt exceeds 30° at finish. | `landing_phase_excessive_side_lean` |
| [Landing Phase Excessive Forward Drift](/biomechanics/activities/tennis/flags/landing-phase-excessive-forward-drift) | Forward body displacement exceeds 0.50x height between contact and finish. | `landing_phase_excessive_forward_drift` |
| [Landing Phase Excessive Side Drift](/biomechanics/activities/tennis/flags/landing-phase-excessive-side-drift) | Open-side body displacement exceeds 0.30x height (or -0.10x height) between contact and finish. | `landing_phase_excessive_side_drift` |
### Loading Phase Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------------------------------------------- | -------- | ------------------------------------------------------------------------------------------------------------------ | --------------------------------------- |
| [Loading Phase Max Knee Flexion Front Leg](/biomechanics/activities/tennis/metrics/loading-phase-knee-flexion) | degrees | Maximum amount of front leg knee flexion during the loading phase of the serve | `loading_phase_max_front_knee_flexion` |
| [Loading Phase Max Knee Flexion Back Leg](/biomechanics/activities/tennis/metrics/loading-phase-knee-flexion) | degrees | Maximum amount of back leg knee flexion during the loading phase of the serve | `loading_phase_max_back_knee_flexion` |
| [Loading Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/loading-phase-trunk-tilt) | degrees | Maximum amount of trunk side-side tilt towards the rear during the loading phase of the serve | `loading_phase_trunk_tilt` |
| [Loading Phase Pelvis Tilt](/biomechanics/activities/tennis/metrics/loading-phase-pelvis-tilt) | degrees | Maximum amount of pelvis side-side tilt towards the rear during the loading phase of the serve | `loading_phase_pelvis_tilt` |
| [Loading Phase Shoulder Hip Separation](/biomechanics/activities/tennis/metrics/loading-phase-shoulder-hip-separation) | degrees | Maximum difference in rotation of the shoulders and hips during the loading phase of the serve | `loading_phase_shoulder_hip_separation` |
| [Loading Phase Ball Release Angle](/biomechanics/activities/tennis/metrics/loading-phase-ball-release-angle) | degrees | Transverse plane arm angle at the instance of ball release | `loading_phase_ball_toss_angle` |
| [Trunk Coil](/biomechanics/activities/tennis/metrics/trunk-coil) | deg | Maximum amount of trunk twist rotation away from the serve direction, like preloading the twist before the serve. | `trunk_coil` |
| [Pelvis Coil](/biomechanics/activities/tennis/metrics/pelvis-coil) | deg | Maximum amount of pelvis twist rotation away from the serve direction, like preloading the twist before the serve. | `pelvis_coil` |
| [Release Phase Elbow Angle](/biomechanics/activities/tennis/metrics/release-phase-elbow-angle) | degrees | Non-dominant (tossing) elbow flexion angle at ball release | `release_phase_elbow_angle` |
| [Max Front Knee Valgus (Normalized)](/biomechanics/activities/tennis/metrics/max-front-knee-valgus) | × height | Maximum inward collapse of the front knee during the serve, normalized to athlete height | `max_front_knee_valgus_upward_per_ht` |
| [Max Back Knee Valgus (Normalized)](/biomechanics/activities/tennis/metrics/max-back-knee-valgus) | × height | Maximum inward collapse of the back knee during the serve, normalized to athlete height | `max_back_knee_valgus_upward_per_ht` |
### Cocking and Acceleration Phase Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | ------------------------------------------------------------------------------------------- | ------------------------------------------------------ |
| [Cocking Phase Max Shoulder External Rotation](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-external-rotation) | degrees | Maximum amount of shoulder external rotation during the cocking phase of the serve | `cocking_phase_max_shoulder_external_rotation` |
| [Cocking Phase Shoulder Hyperangulation](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-hyperangulation) | degrees | Maximum amount of shoulder horizontal abduction during the cocking phase of the serve | `cocking_phase_shoulder_hyperangulation` |
| [Cocking Phase Max X Factor](/biomechanics/activities/tennis/metrics/cocking-phase-max-x-factor) | degrees | Maximum hip-shoulder separation during the cocking phase of the serve | `cocking_phase_max_x_factor` |
| [Cocking Phase Shoulder Horizontal Abduction](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-horizontal-abduction) | degrees | Maximum horizontal abduction of the dominant shoulder during the cocking phase of the serve | `cocking_phase_shoulder_horizontal_abduction` |
| [Acceleration Phase Max Knee Extension Velocity Front Leg](/biomechanics/activities/tennis/metrics/acceleration-phase-knee-extension-velocity) | degrees/second | Maximum knee extension velocity of the front leg during the acceleration phase of the serve | `acceleration_phase_max_front_knee_extension_velocity` |
| [Acceleration Phase Max Knee Extension Velocity Back Leg](/biomechanics/activities/tennis/metrics/acceleration-phase-knee-extension-velocity) | degrees/second | Maximum knee extension velocity of the back leg during the acceleration phase of the serve | `acceleration_phase_max_back_knee_extension_velocity` |
| [Acceleration Phase Max Elbow Extension Velocity](/biomechanics/activities/tennis/metrics/acceleration-phase-elbow-extension-velocity) | degrees/second | Maximum extension velocity of the dominant elbow during the acceleration phase of the serve | `max_elbow_extension_velocity` |
### Contact Phase Metrics
| Metric | Units | Description | Column Name |
| ---------------------------------------------------------------------------------------------------------------------------- | ----------- | ------------------------------------------------------------------------------ | ------------------------------------- |
| [Contact Phase Elbow Flexion](/biomechanics/activities/tennis/metrics/contact-phase-elbow-flexion) | degrees | Amount of elbow flexion at apex | `contact_phase_elbow_flexion` |
| [Contact Phase Shoulder Abduction](/biomechanics/activities/tennis/metrics/contact-phase-shoulder-abduction) | degrees | Amount of shoulder abduction at apex | `contact_phase_shoulder_abduction` |
| [Contact Phase X Factor](/biomechanics/activities/tennis/metrics/contact-phase-x-factor) | degrees | Angle between the shoulders to hips in the transverse plane (twisting) at apex | `contact_phase_x_factor` |
| [Time to Contact](/biomechanics/activities/tennis/metrics/time-to-contact) | seconds | Duration from initiation to ball contact | `time_to_contact` |
| [Contact Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/contact-phase-trunk-tilt) | degrees | Degrees of side-side trunk tilt at apex | `contact_phase_trunk_tilt` |
| [Contact Phase Trunk Flexion](/biomechanics/activities/tennis/metrics/contact-phase-trunk-flexion) | degrees | Forward/backward trunk flexion at apex | `contact_phase_trunk_flexion` |
| [Contact Phase Trunk Rotation](/biomechanics/activities/tennis/metrics/contact-phase-trunk-rotation) | degrees | Trunk rotation relative to its starting orientation at apex | `contact_phase_trunk_rotation` |
| [Contact Phase Pelvis Rotation](/biomechanics/activities/tennis/metrics/contact-phase-pelvis-rotation) | degrees | Pelvis rotation relative to its starting orientation at apex | `contact_phase_pelvis_rotation` |
| [Contact Phase Wrist Height (Normalized)](/biomechanics/activities/tennis/metrics/contact-phase-wrist-height-normalized) | × height | Wrist height at apex, normalized to athlete height | `contact_phase_wrist_height_per_ht` |
| [Contact Phase Wrist Velocity (Normalized)](/biomechanics/activities/tennis/metrics/contact-phase-wrist-velocity-normalized) | unconfirmed | Wrist speed at apex, reported alongside the height-normalized dataset | `contact_phase_wrist_velocity_per_ht` |
| [Trunk Stretch](/biomechanics/activities/tennis/metrics/trunk-stretch) | deg | Twist range of motion of the trunk. | `trunk_stretch` |
| [Pelvis Stretch](/biomechanics/activities/tennis/metrics/pelvis-stretch) | deg | Twist range of motion of the pelvis. | `pelvis_stretch` |
### Landing Phase Metrics
| Metric | Units | Description | Column Name |
| ----------------------------------------------------------------------------------------------------- | -------- | ------------------------------------------------------------------------------------ | ---------------------------- |
| [Finish Phase Trunk Flexion](/biomechanics/activities/tennis/metrics/finish-phase-trunk-flexion) | degrees | Forward/backward trunk flexion at the finish of the serve | `finish_phase_trunk_flexion` |
| [Finish Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/finish-phase-trunk-tilt) | degrees | Lateral trunk tilt at the finish of the serve | `finish_phase_trunk_tilt` |
| [Forward Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-forward) | × height | Forward body displacement between contact and finish, normalized to athlete height | `displacement_forward` |
| [Open-Side Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-open-side) | × height | Open-side body displacement between contact and finish, normalized to athlete height | `displacement_open_side` |
| [Vertical Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-vertical) | × height | Vertical body displacement between contact and finish, normalized to athlete height | `displacement_vertical` |
## Notes
* Kinematic data typically captured at 240Hz for Tennis Overhand Serve
# Tennis Overhand Serve: Normative Ranges
Source: https://docs.uplift.ai/biomechanics/activities/tennis/tennis-overhand-serve-norms
Full percentile reference tables (5th–95th) for tennis overhand serve metrics, broken out by competition level.
This page collects the complete normative reference tables for the tennis overhand serve — the full 5th–95th percentile range for each competition level, drawn from the same normative dataset that backs the [Normative Ranges](/biomechanics/normative-ranges) guide. See that page for how to interpret these tables.
Each competition-level dataset was built by pooling all valid serve sessions per athlete, selecting the single session closest to that athlete's overall average across all metrics, then re-analyzing with the latest biomechanical analysis software and removing sessions that failed Uplift's quality assurance tests. Unlike baseball, the tennis dataset currently only supports **Youth**, **Professional**, and **Broad (All Levels)** populations — College and High School brackets are not yet available.
## Youth Sample
Reference dataset built from 50 unique youth athletes (227 valid serve sessions before selecting one representative session per athlete) performing a serve in 2025.
### Kinematic Sequence – Forward (Serve Direction) Angular Velocities & Speedups
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Torso Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-torso-forward-angular-velocity) | 147 | 160 | 184 | 206 | 234 | 256 | 264 | deg/s |
| [Peak Upper Arm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-upper-arm-forward-angular-velocity) | 653 | 680 | 805 | 887 | 997 | 1073 | 1120 | deg/s |
| [Peak Forearm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-forearm-forward-angular-velocity) | 746 | 776 | 858 | 976 | 1101 | 1212 | 1256 | deg/s |
| [Forward Trunk Arm Speedup](/biomechanics/activities/tennis/metrics/forward-trunk-arm-speedup) | 3.22 | 3.38 | 3.80 | 4.32 | 4.91 | 5.45 | 5.88 | ratio |
| [Forward Upper Arm Forearm Speedup](/biomechanics/activities/tennis/metrics/forward-upper-arm-forearm-speedup) | 0.80 | 0.85 | 0.97 | 1.09 | 1.25 | 1.41 | 1.54 | ratio |
### Kinematic Sequence – Twist Angular Velocities & Speedups
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-pelvis-twist-angular-velocity) | 190 | 215 | 284 | 366 | 446 | 495 | 512 | deg/s |
| [Peak Torso Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-torso-twist-angular-velocity) | 253 | 282 | 335 | 379 | 417 | 450 | 473 | deg/s |
| [Peak Upper Arm Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-upper-arm-twist-angular-velocity) | 214 | 270 | 333 | 411 | 495 | 566 | 628 | deg/s |
| [Twist Trunk Arm Speedup](/biomechanics/activities/tennis/metrics/twist-trunk-arm-speedup) | 0.60 | 0.71 | 0.89 | 1.10 | 1.35 | 1.60 | 1.75 | ratio |
| [Twist Pelvis Torso Speedup](/biomechanics/activities/tennis/metrics/twist-pelvis-torso-speedup) | 0.70 | 0.78 | 0.87 | 1.05 | 1.26 | 1.58 | 1.71 | ratio |
### Loading Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------- | :----: | :----: | :----: | :----: | :----: | :----: | :----: | -------- |
| [Loading Phase Max Knee Flexion Front Leg](/biomechanics/activities/tennis/metrics/loading-phase-knee-flexion) | 50 | 53 | 59 | 68 | 78 | 85 | 89 | deg |
| [Loading Phase Max Knee Flexion Back Leg](/biomechanics/activities/tennis/metrics/loading-phase-knee-flexion) | 42 | 53 | 65 | 70 | 81 | 87 | 93 | deg |
| [Loading Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/loading-phase-trunk-tilt) | -29 | -25 | -21 | -15 | -11 | -6 | -1 | deg |
| [Loading Phase Pelvis Tilt](/biomechanics/activities/tennis/metrics/loading-phase-pelvis-tilt) | -9 | -8 | -6 | -3 | 0 | 1 | 2 | deg |
| [Loading Phase Shoulder Hip Separation](/biomechanics/activities/tennis/metrics/loading-phase-shoulder-hip-separation) | 0 | 3 | 11 | 19 | 29 | 35 | 40 | deg |
| [Loading Phase Ball Release Angle](/biomechanics/activities/tennis/metrics/loading-phase-ball-release-angle) | 76 | 95 | 105 | 122 | 137 | 152 | 156 | deg |
| [Trunk Coil](/biomechanics/activities/tennis/metrics/trunk-coil) | -142 | -138 | -130 | -119 | -111 | -104 | -99 | deg |
| [Pelvis Coil](/biomechanics/activities/tennis/metrics/pelvis-coil) | -132 | -129 | -122 | -113 | -108 | -99 | -87 | deg |
| [Trunk Stretch](/biomechanics/activities/tennis/metrics/trunk-stretch) | 124 | 137 | 151 | 160 | 171 | 181 | 186 | deg |
| [Pelvis Stretch](/biomechanics/activities/tennis/metrics/pelvis-stretch) | 86 | 102 | 118 | 130 | 144 | 158 | 164 | deg |
| [Release Phase Elbow Angle](/biomechanics/activities/tennis/metrics/release-phase-elbow-angle) | 1 | 2 | 7 | 19 | 27 | 40 | 44 | deg |
| [Max Front Knee Valgus (Normalized)](/biomechanics/activities/tennis/metrics/max-front-knee-valgus) | -0.041 | -0.036 | -0.029 | -0.021 | -0.016 | -0.009 | -0.006 | × height |
| [Max Back Knee Valgus (Normalized)](/biomechanics/activities/tennis/metrics/max-back-knee-valgus) | -0.023 | -0.021 | -0.017 | -0.011 | -0.006 | -0.004 | -0.003 | × height |
### Cocking and Acceleration Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Cocking Phase Max Shoulder External Rotation](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-external-rotation) | 154 | 163 | 170 | 179 | 188 | 194 | 199 | deg |
| [Cocking Phase Shoulder Hyperangulation](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-hyperangulation) | 136 | 141 | 146 | 155 | 163 | 172 | 178 | deg |
| [Cocking Phase Max X Factor](/biomechanics/activities/tennis/metrics/cocking-phase-max-x-factor) | -6 | 0 | 9 | 17 | 26 | 35 | 38 | deg |
| [Cocking Phase Shoulder Horizontal Abduction](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-horizontal-abduction) | 61 | 68 | 75 | 87 | 98 | 102 | 104 | deg |
| [Acceleration Phase Max Knee Extension Velocity Front Leg](/biomechanics/activities/tennis/metrics/acceleration-phase-knee-extension-velocity) | 238 | 269 | 298 | 345 | 381 | 414 | 431 | deg/s |
| [Acceleration Phase Max Knee Extension Velocity Back Leg](/biomechanics/activities/tennis/metrics/acceleration-phase-knee-extension-velocity) | 182 | 223 | 304 | 351 | 394 | 420 | 433 | deg/s |
| [Acceleration Phase Max Elbow Extension Velocity](/biomechanics/activities/tennis/metrics/acceleration-phase-elbow-extension-velocity) | 852 | 920 | 1037 | 1155 | 1251 | 1329 | 1422 | deg/s |
### Contact Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----------- |
| [Contact Phase Elbow Flexion](/biomechanics/activities/tennis/metrics/contact-phase-elbow-flexion) | 29 | 31 | 39 | 46 | 53 | 60 | 63 | deg |
| [Contact Phase Shoulder Abduction](/biomechanics/activities/tennis/metrics/contact-phase-shoulder-abduction) | 103 | 106 | 113 | 123 | 129 | 135 | 139 | deg |
| [Contact Phase X Factor](/biomechanics/activities/tennis/metrics/contact-phase-x-factor) | -8 | -5 | -1 | 3 | 8 | 14 | 16 | deg |
| [Contact Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/contact-phase-trunk-tilt) | 29 | 31 | 34 | 38 | 42 | 46 | 47 | deg |
| [Time to Contact](/biomechanics/activities/tennis/metrics/time-to-contact) | 0.60 | 0.72 | 0.80 | 0.91 | 1.00 | 1.11 | 1.17 | s |
| [Contact Phase Trunk Flexion](/biomechanics/activities/tennis/metrics/contact-phase-trunk-flexion) | 1 | 4 | 10 | 14 | 20 | 30 | 32 | deg |
| [Contact Phase Trunk Rotation](/biomechanics/activities/tennis/metrics/contact-phase-trunk-rotation) | -40 | -38 | -33 | -24 | -12 | -5 | -2 | deg |
| [Contact Phase Pelvis Rotation](/biomechanics/activities/tennis/metrics/contact-phase-pelvis-rotation) | -43 | -42 | -38 | -33 | -25 | -19 | -14 | deg |
| [Contact Phase Wrist Height (Normalized)](/biomechanics/activities/tennis/metrics/contact-phase-wrist-height-normalized) | 1.14 | 1.16 | 1.19 | 1.22 | 1.24 | 1.27 | 1.28 | × height |
| [Contact Phase Wrist Velocity (Normalized)](/biomechanics/activities/tennis/metrics/contact-phase-wrist-velocity-normalized) | 761 | 800 | 829 | 858 | 889 | 921 | 932 | unconfirmed |
### Landing Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ----------------------------------------------------------------------------------------------------- | :----: | :---: | :---: | :---: | :---: | :---: | :---: | -------- |
| [Finish Phase Trunk Flexion](/biomechanics/activities/tennis/metrics/finish-phase-trunk-flexion) | 35 | 40 | 45 | 50 | 55 | 63 | 67 | deg |
| [Finish Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/finish-phase-trunk-tilt) | -15 | -12 | -7 | -1 | 4 | 8 | 13 | deg |
| [Forward Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-forward) | 0.072 | 0.151 | 0.270 | 0.361 | 0.440 | 0.509 | 0.538 | × height |
| [Open-Side Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-open-side) | -0.033 | 0.000 | 0.089 | 0.176 | 0.263 | 0.346 | 0.384 | × height |
| [Vertical Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-vertical) | 0.095 | 0.112 | 0.129 | 0.148 | 0.168 | 0.192 | 0.202 | × height |
## Professional Sample
Reference dataset built from 32 unique professional athletes (300 valid serve sessions before selecting one representative session per athlete) performing a serve in 2025.
### Kinematic Sequence – Forward (Serve Direction) Angular Velocities & Speedups
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Torso Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-torso-forward-angular-velocity) | 168 | 180 | 198 | 216 | 237 | 263 | 277 | deg/s |
| [Peak Upper Arm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-upper-arm-forward-angular-velocity) | 696 | 764 | 837 | 924 | 1031 | 1088 | 1116 | deg/s |
| [Peak Forearm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-forearm-forward-angular-velocity) | 637 | 772 | 921 | 1041 | 1142 | 1281 | 1325 | deg/s |
| [Forward Trunk Arm Speedup](/biomechanics/activities/tennis/metrics/forward-trunk-arm-speedup) | 3.29 | 3.38 | 3.74 | 4.22 | 4.81 | 5.27 | 5.42 | ratio |
| [Forward Upper Arm Forearm Speedup](/biomechanics/activities/tennis/metrics/forward-upper-arm-forearm-speedup) | 0.57 | 0.76 | 0.98 | 1.16 | 1.31 | 1.45 | 1.54 | ratio |
### Kinematic Sequence – Twist Angular Velocities & Speedups
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-pelvis-twist-angular-velocity) | 190 | 253 | 334 | 382 | 414 | 446 | 461 | deg/s |
| [Peak Torso Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-torso-twist-angular-velocity) | 259 | 275 | 316 | 353 | 391 | 425 | 441 | deg/s |
| [Peak Upper Arm Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-upper-arm-twist-angular-velocity) | 182 | 225 | 304 | 381 | 462 | 572 | 620 | deg/s |
| [Twist Trunk Arm Speedup](/biomechanics/activities/tennis/metrics/twist-trunk-arm-speedup) | 0.56 | 0.69 | 0.90 | 1.07 | 1.28 | 1.55 | 1.77 | ratio |
| [Twist Pelvis Torso Speedup](/biomechanics/activities/tennis/metrics/twist-pelvis-torso-speedup) | 0.70 | 0.74 | 0.84 | 0.94 | 1.07 | 1.48 | 1.75 | ratio |
### Loading Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------- | :----: | :----: | :----: | :----: | :----: | :----: | :----: | -------- |
| [Loading Phase Max Knee Flexion Front Leg](/biomechanics/activities/tennis/metrics/loading-phase-knee-flexion) | 53 | 56 | 61 | 67 | 77 | 86 | 88 | deg |
| [Loading Phase Max Knee Flexion Back Leg](/biomechanics/activities/tennis/metrics/loading-phase-knee-flexion) | 56 | 62 | 71 | 78 | 85 | 89 | 93 | deg |
| [Loading Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/loading-phase-trunk-tilt) | -30 | -28 | -26 | -23 | -19 | -14 | -12 | deg |
| [Loading Phase Pelvis Tilt](/biomechanics/activities/tennis/metrics/loading-phase-pelvis-tilt) | -11 | -9 | -7 | -5 | -4 | -1 | 1 | deg |
| [Loading Phase Shoulder Hip Separation](/biomechanics/activities/tennis/metrics/loading-phase-shoulder-hip-separation) | 5 | 7 | 10 | 16 | 23 | 31 | 34 | deg |
| [Loading Phase Ball Release Angle](/biomechanics/activities/tennis/metrics/loading-phase-ball-release-angle) | 71 | 89 | 100 | 116 | 132 | 144 | 157 | deg |
| [Trunk Coil](/biomechanics/activities/tennis/metrics/trunk-coil) | -139 | -136 | -129 | -122 | -116 | -109 | -104 | deg |
| [Pelvis Coil](/biomechanics/activities/tennis/metrics/pelvis-coil) | -130 | -129 | -125 | -117 | -111 | -101 | -88 | deg |
| [Trunk Stretch](/biomechanics/activities/tennis/metrics/trunk-stretch) | 128 | 135 | 146 | 155 | 162 | 170 | 173 | deg |
| [Pelvis Stretch](/biomechanics/activities/tennis/metrics/pelvis-stretch) | 94 | 103 | 113 | 125 | 135 | 142 | 146 | deg |
| [Release Phase Elbow Angle](/biomechanics/activities/tennis/metrics/release-phase-elbow-angle) | 2 | 5 | 14 | 27 | 36 | 41 | 45 | deg |
| [Max Front Knee Valgus (Normalized)](/biomechanics/activities/tennis/metrics/max-front-knee-valgus) | -0.039 | -0.035 | -0.028 | -0.022 | -0.014 | -0.008 | -0.006 | × height |
| [Max Back Knee Valgus (Normalized)](/biomechanics/activities/tennis/metrics/max-back-knee-valgus) | -0.021 | -0.019 | -0.015 | -0.011 | -0.007 | -0.005 | -0.004 | × height |
### Cocking and Acceleration Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Cocking Phase Max Shoulder External Rotation](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-external-rotation) | 169 | 172 | 180 | 187 | 192 | 196 | 199 | deg |
| [Cocking Phase Shoulder Hyperangulation](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-hyperangulation) | 138 | 145 | 154 | 160 | 168 | 176 | 184 | deg |
| [Cocking Phase Max X Factor](/biomechanics/activities/tennis/metrics/cocking-phase-max-x-factor) | 4 | 6 | 9 | 16 | 23 | 31 | 33 | deg |
| [Cocking Phase Shoulder Horizontal Abduction](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-horizontal-abduction) | 84 | 88 | 93 | 98 | 104 | 109 | 111 | deg |
| [Acceleration Phase Max Knee Extension Velocity Front Leg](/biomechanics/activities/tennis/metrics/acceleration-phase-knee-extension-velocity) | 265 | 281 | 314 | 343 | 393 | 435 | 444 | deg/s |
| [Acceleration Phase Max Knee Extension Velocity Back Leg](/biomechanics/activities/tennis/metrics/acceleration-phase-knee-extension-velocity) | 238 | 262 | 326 | 367 | 404 | 439 | 465 | deg/s |
| [Acceleration Phase Max Elbow Extension Velocity](/biomechanics/activities/tennis/metrics/acceleration-phase-elbow-extension-velocity) | 787 | 913 | 1058 | 1126 | 1192 | 1283 | 1338 | deg/s |
### Contact Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----------- |
| [Contact Phase Elbow Flexion](/biomechanics/activities/tennis/metrics/contact-phase-elbow-flexion) | 24 | 27 | 31 | 37 | 44 | 49 | 54 | deg |
| [Contact Phase Shoulder Abduction](/biomechanics/activities/tennis/metrics/contact-phase-shoulder-abduction) | 118 | 123 | 128 | 135 | 142 | 146 | 148 | deg |
| [Contact Phase X Factor](/biomechanics/activities/tennis/metrics/contact-phase-x-factor) | -4 | -2 | 2 | 5 | 10 | 15 | 19 | deg |
| [Contact Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/contact-phase-trunk-tilt) | 24 | 26 | 30 | 33 | 36 | 40 | 42 | deg |
| [Time to Contact](/biomechanics/activities/tennis/metrics/time-to-contact) | 0.30 | 0.65 | 0.86 | 0.97 | 1.04 | 1.10 | 1.15 | s |
| [Contact Phase Trunk Flexion](/biomechanics/activities/tennis/metrics/contact-phase-trunk-flexion) | -2 | -1 | 4 | 9 | 12 | 16 | 19 | deg |
| [Contact Phase Trunk Rotation](/biomechanics/activities/tennis/metrics/contact-phase-trunk-rotation) | -55 | -51 | -39 | -32 | -25 | -20 | -12 | deg |
| [Contact Phase Pelvis Rotation](/biomechanics/activities/tennis/metrics/contact-phase-pelvis-rotation) | -71 | -59 | -45 | -40 | -35 | -30 | -25 | deg |
| [Contact Phase Wrist Height (Normalized)](/biomechanics/activities/tennis/metrics/contact-phase-wrist-height-normalized) | 1.19 | 1.21 | 1.23 | 1.25 | 1.27 | 1.29 | 1.30 | × height |
| [Contact Phase Wrist Velocity (Normalized)](/biomechanics/activities/tennis/metrics/contact-phase-wrist-velocity-normalized) | 718 | 744 | 807 | 835 | 860 | 877 | 890 | unconfirmed |
### Landing Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ----------------------------------------------------------------------------------------------------- | :----: | :---: | :---: | :---: | :---: | :---: | :---: | -------- |
| [Finish Phase Trunk Flexion](/biomechanics/activities/tennis/metrics/finish-phase-trunk-flexion) | 27 | 32 | 39 | 46 | 52 | 58 | 61 | deg |
| [Finish Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/finish-phase-trunk-tilt) | -15 | -12 | -7 | -1 | 6 | 11 | 15 | deg |
| [Forward Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-forward) | 0.163 | 0.205 | 0.269 | 0.370 | 0.455 | 0.531 | 0.616 | × height |
| [Open-Side Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-open-side) | -0.032 | 0.001 | 0.060 | 0.167 | 0.291 | 0.371 | 0.433 | × height |
| [Vertical Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-vertical) | 0.114 | 0.118 | 0.130 | 0.158 | 0.180 | 0.203 | 0.255 | × height |
## Broad Sample (All Levels)
Reference dataset built from 82 unique athletes (527 valid serve sessions before selecting one representative session per athlete) performing a serve in 2025, pooled across all competition levels.
### Kinematic Sequence – Forward (Serve Direction) Angular Velocities & Speedups
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| -------------------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Torso Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-torso-forward-angular-velocity) | 147 | 165 | 190 | 211 | 235 | 259 | 270 | deg/s |
| [Peak Upper Arm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-upper-arm-forward-angular-velocity) | 651 | 723 | 825 | 905 | 1018 | 1085 | 1117 | deg/s |
| [Peak Forearm Forward Angular Velocity](/biomechanics/activities/tennis/metrics/peak-forearm-forward-angular-velocity) | 676 | 764 | 875 | 1013 | 1130 | 1251 | 1307 | deg/s |
| [Forward Trunk Arm Speedup](/biomechanics/activities/tennis/metrics/forward-trunk-arm-speedup) | 3.27 | 3.38 | 3.76 | 4.29 | 4.89 | 5.42 | 5.84 | ratio |
| [Forward Upper Arm Forearm Speedup](/biomechanics/activities/tennis/metrics/forward-upper-arm-forearm-speedup) | 0.71 | 0.80 | 0.97 | 1.13 | 1.30 | 1.45 | 1.55 | ratio |
### Kinematic Sequence – Twist Angular Velocities & Speedups
Prefer higher velocities and speedup factors for better performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Peak Pelvis Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-pelvis-twist-angular-velocity) | 190 | 224 | 305 | 376 | 422 | 462 | 494 | deg/s |
| [Peak Torso Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-torso-twist-angular-velocity) | 256 | 279 | 324 | 364 | 401 | 435 | 461 | deg/s |
| [Peak Upper Arm Twist Angular Velocity](/biomechanics/activities/tennis/metrics/peak-upper-arm-twist-angular-velocity) | 191 | 238 | 320 | 397 | 492 | 594 | 660 | deg/s |
| [Twist Trunk Arm Speedup](/biomechanics/activities/tennis/metrics/twist-trunk-arm-speedup) | 0.59 | 0.70 | 0.90 | 1.09 | 1.32 | 1.66 | 1.92 | ratio |
| [Twist Pelvis Torso Speedup](/biomechanics/activities/tennis/metrics/twist-pelvis-torso-speedup) | 0.70 | 0.76 | 0.85 | 0.98 | 1.18 | 1.56 | 1.73 | ratio |
### Loading Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------- | :----: | :----: | :----: | :----: | :----: | :----: | :----: | -------- |
| [Loading Phase Max Knee Flexion Front Leg](/biomechanics/activities/tennis/metrics/loading-phase-knee-flexion) | 51 | 54 | 60 | 68 | 78 | 85 | 89 | deg |
| [Loading Phase Max Knee Flexion Back Leg](/biomechanics/activities/tennis/metrics/loading-phase-knee-flexion) | 52 | 56 | 67 | 75 | 84 | 89 | 93 | deg |
| [Loading Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/loading-phase-trunk-tilt) | -29 | -28 | -25 | -20 | -14 | -9 | -5 | deg |
| [Loading Phase Pelvis Tilt](/biomechanics/activities/tennis/metrics/loading-phase-pelvis-tilt) | -11 | -9 | -7 | -5 | -2 | 0 | 2 | deg |
| [Loading Phase Shoulder Hip Separation](/biomechanics/activities/tennis/metrics/loading-phase-shoulder-hip-separation) | 2 | 5 | 10 | 17 | 25 | 34 | 37 | deg |
| [Loading Phase Ball Release Angle](/biomechanics/activities/tennis/metrics/loading-phase-ball-release-angle) | 71 | 91 | 104 | 118 | 135 | 149 | 157 | deg |
| [Trunk Coil](/biomechanics/activities/tennis/metrics/trunk-coil) | -141 | -138 | -129 | -122 | -113 | -106 | -100 | deg |
| [Pelvis Coil](/biomechanics/activities/tennis/metrics/pelvis-coil) | -132 | -129 | -124 | -116 | -109 | -99 | -86 | deg |
| [Trunk Stretch](/biomechanics/activities/tennis/metrics/trunk-stretch) | 127 | 136 | 147 | 156 | 166 | 174 | 180 | deg |
| [Pelvis Stretch](/biomechanics/activities/tennis/metrics/pelvis-stretch) | 86 | 102 | 115 | 127 | 138 | 148 | 155 | deg |
| [Release Phase Elbow Angle](/biomechanics/activities/tennis/metrics/release-phase-elbow-angle) | 1 | 3 | 11 | 22 | 34 | 41 | 47 | deg |
| [Max Front Knee Valgus (Normalized)](/biomechanics/activities/tennis/metrics/max-front-knee-valgus) | -0.040 | -0.035 | -0.028 | -0.021 | -0.014 | -0.008 | -0.006 | × height |
| [Max Back Knee Valgus (Normalized)](/biomechanics/activities/tennis/metrics/max-back-knee-valgus) | -0.022 | -0.020 | -0.015 | -0.011 | -0.007 | -0.005 | -0.004 | × height |
### Cocking and Acceleration Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------------------------------- | :-: | :-: | :--: | :--: | :--: | :--: | :--: | ----- |
| [Cocking Phase Max Shoulder External Rotation](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-external-rotation) | 155 | 167 | 174 | 183 | 191 | 196 | 199 | deg |
| [Cocking Phase Shoulder Hyperangulation](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-hyperangulation) | 132 | 141 | 149 | 158 | 165 | 174 | 181 | deg |
| [Cocking Phase Max X Factor](/biomechanics/activities/tennis/metrics/cocking-phase-max-x-factor) | 0 | 3 | 9 | 17 | 24 | 33 | 36 | deg |
| [Cocking Phase Shoulder Horizontal Abduction](/biomechanics/activities/tennis/metrics/cocking-phase-shoulder-horizontal-abduction) | 60 | 72 | 86 | 95 | 101 | 107 | 110 | deg |
| [Acceleration Phase Max Knee Extension Velocity Front Leg](/biomechanics/activities/tennis/metrics/acceleration-phase-knee-extension-velocity) | 251 | 272 | 307 | 345 | 389 | 428 | 440 | deg/s |
| [Acceleration Phase Max Knee Extension Velocity Back Leg](/biomechanics/activities/tennis/metrics/acceleration-phase-knee-extension-velocity) | 211 | 250 | 312 | 359 | 396 | 430 | 448 | deg/s |
| [Acceleration Phase Max Elbow Extension Velocity](/biomechanics/activities/tennis/metrics/acceleration-phase-elbow-extension-velocity) | 787 | 902 | 1049 | 1136 | 1220 | 1312 | 1352 | deg/s |
### Contact Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ---------------------------------------------------------------------------------------------------------------------------- | :--: | :--: | :--: | :--: | :--: | :--: | :--: | ----------- |
| [Contact Phase Elbow Flexion](/biomechanics/activities/tennis/metrics/contact-phase-elbow-flexion) | 25 | 28 | 34 | 41 | 49 | 57 | 63 | deg |
| [Contact Phase Shoulder Abduction](/biomechanics/activities/tennis/metrics/contact-phase-shoulder-abduction) | 106 | 112 | 122 | 129 | 138 | 144 | 147 | deg |
| [Contact Phase X Factor](/biomechanics/activities/tennis/metrics/contact-phase-x-factor) | -5 | -3 | 1 | 5 | 10 | 15 | 18 | deg |
| [Contact Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/contact-phase-trunk-tilt) | 23 | 27 | 31 | 35 | 39 | 43 | 46 | deg |
| [Time to Contact](/biomechanics/activities/tennis/metrics/time-to-contact) | 0.31 | 0.67 | 0.82 | 0.94 | 1.03 | 1.12 | 1.18 | s |
| [Contact Phase Trunk Flexion](/biomechanics/activities/tennis/metrics/contact-phase-trunk-flexion) | -2 | 1 | 6 | 10 | 15 | 21 | 28 | deg |
| [Contact Phase Trunk Rotation](/biomechanics/activities/tennis/metrics/contact-phase-trunk-rotation) | -53 | -45 | -37 | -30 | -21 | -10 | -5 | deg |
| [Contact Phase Pelvis Rotation](/biomechanics/activities/tennis/metrics/contact-phase-pelvis-rotation) | -66 | -51 | -42 | -37 | -31 | -23 | -19 | deg |
| [Contact Phase Wrist Height (Normalized)](/biomechanics/activities/tennis/metrics/contact-phase-wrist-height-normalized) | 1.15 | 1.18 | 1.21 | 1.24 | 1.26 | 1.28 | 1.29 | × height |
| [Contact Phase Wrist Velocity (Normalized)](/biomechanics/activities/tennis/metrics/contact-phase-wrist-velocity-normalized) | 704 | 745 | 813 | 843 | 869 | 899 | 917 | unconfirmed |
### Landing Phase
Deviations from center indicate atypical positioning, not necessarily poor performance.
| Variable | 5% | 10% | 25% | 50% | 75% | 90% | 95% | Units |
| ----------------------------------------------------------------------------------------------------- | :----: | :---: | :---: | :---: | :---: | :---: | :---: | -------- |
| [Finish Phase Trunk Flexion](/biomechanics/activities/tennis/metrics/finish-phase-trunk-flexion) | 29 | 35 | 42 | 48 | 55 | 61 | 65 | deg |
| [Finish Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/finish-phase-trunk-tilt) | -16 | -12 | -7 | -1 | 5 | 11 | 14 | deg |
| [Forward Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-forward) | 0.065 | 0.160 | 0.261 | 0.362 | 0.446 | 0.519 | 0.574 | × height |
| [Open-Side Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-open-side) | -0.037 | 0.000 | 0.073 | 0.169 | 0.277 | 0.354 | 0.411 | × height |
| [Vertical Displacement (Normalized)](/biomechanics/activities/tennis/metrics/displacement-vertical) | 0.108 | 0.117 | 0.130 | 0.154 | 0.179 | 0.200 | 0.237 | × height |
# Tennis: Underhand Serve
Source: https://docs.uplift.ai/biomechanics/activities/tennis/underhand_serve
Biomechanical analysis of tennis underhand (underarm) serve.
## Overview
The underhand serve is a serve in which the ball is struck with an underarm or underhand motion rather than an overhand motion.
It is used less commonly in competitive play but appears in recreational tennis, as a tactical variation, or when a player has limitations that make the overhand serve difficult.
The motion typically involves a shorter wind-up, lower toss, and a swing path that contacts the ball below shoulder height, with less reliance on the full kinetic chain used in the overhand serve.
## Dimensions
Required inputs for processing are not yet defined. When supported, typical dimensions may include:
* **handedness:** the handedness of the player \['left', 'right']
## Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
## Notes
* This movement is documented for completeness; event and metric definitions may be added in a future update.
# Track and Field: Discus
Source: https://docs.uplift.ai/biomechanics/activities/track_and_field/discus
Biomechanical analysis of discus throw movements, including events, phases, and discrete metrics.
## Overview
The discus throw is a track and field throwing event in which the athlete rotates one and a half turns within a circle to accelerate a discus before releasing it at speed and at an optimal angle.
The thrower begins with a preparatory wind-up, pivots off the non-dominant foot into an airborne turn, plants the dominant foot in the center of the circle, and drives through the legs and trunk before releasing the discus off the fingers with the arm extended.
Distance depends on release speed, release angle, and the sequencing of the legs, hips, and trunk ahead of the arm.
Biomechanical analysis of the discus throw can address foot-off and foot-down timing through the turn, hip-shoulder separation built during the turn, arm and shoulder positioning at release, and release speed, height, and angle.
## Dimensions
Required inputs for processing are not yet defined. When supported, typical dimensions may include:
* **handedness:** the handedness of the athlete \['left', 'right'], which determines throw direction and rotation
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Acronym | Description |
| --------------------- | ------- | --------------------------------------------------------- |
| Peak Backswing | PB | the peak backswing position prior to the throw |
| Dominant Foot Off | DFO | the instance when the dominant foot leaves the ground |
| NonDominant Foot Off | NDFO | the instance when the nondominant foot leaves the ground |
| Dominant Foot Down | DFO | the instance when the dominant foot touches the ground |
| NonDominant Foot Down | NDFO | the instance when the nondominant foot touches the ground |
| Release | R | release of the discus |
### Phases and Stages of the Discus Throw
| Phase | Start | End |
| ----------- | ----- | ---- |
| Preparation | PB | DFO |
| Entry | DFO | NDFO |
| Airborne | NDFO | DFD |
| Transition | DFD | NDFD |
| Delivery | NDFD | R |
### Discrete Metrics
| Metric | Units | Description |
| ---------------------------------- | ------- | --------------------------------------------------------------------------------- |
| Handedness | N/A | Calculated handedness of the athlete ('right' or 'left') |
| Preparation Phase | seconds | Time between peak backswing and dominant foot off |
| Entry Phase | seconds | Time between dominant foot off and non-dominant foot off |
| Airborne Phase | seconds | Time between non-dominant foot off and dominant foot down |
| Transition Phase | seconds | Time between dominant foot down and non-dominant foot down |
| Delivery Phase | seconds | Time between non-dominant foot down and release |
| Speed at DFO | m/s | Speed of the discus at dominant foot off |
| Speed at NDFO | m/s | Speed of the discus at non-dominant foot off |
| Speed at DFD | m/s | Speed of the discus at dominant foot down |
| Speed at NDFD | m/s | Speed of the discus at non-dominant foot down |
| Speed at Release | m/s | Speed of the discus at release |
| Horizontal Release Speed | m/s | Horizontal component of discus speed at release |
| Vertical Release Speed | m/s | Vertical component of discus speed at release |
| Hip-Shoulder Separation at DFO | degrees | Transverse angle between hips and shoulders at dominant foot off |
| Hip-Shoulder Separation at NDFO | degrees | Transverse angle between hips and shoulders at non-dominant foot off |
| Hip-Shoulder Separation at DFD | degrees | Transverse angle between hips and shoulders at dominant foot down |
| Hip-Shoulder Separation at NDFD | degrees | Transverse angle between hips and shoulders at non-dominant foot down |
| Hip-Shoulder Separation at Release | degrees | Transverse angle between hips and shoulders at release |
| Arm Elevation Angle at DFO | degrees | Angle of throwing arm relative to horizontal at dominant foot off |
| Arm Elevation Angle at NDFO | degrees | Angle of throwing arm relative to horizontal at non-dominant foot off |
| Arm Elevation Angle at DFD | degrees | Angle of throwing arm relative to horizontal at dominant foot down |
| Arm Elevation Angle at NDFD | degrees | Angle of throwing arm relative to horizontal at non-dominant foot down |
| Arm Elevation Angle at Release | degrees | Angle of throwing arm relative to horizontal at release |
| Shoulder-Arm Separation at DFO | degrees | Angle between shoulder line and arm at dominant foot off |
| Shoulder-Arm Separation at NDFO | degrees | Angle between shoulder line and arm at non-dominant foot off |
| Shoulder-Arm Separation at DFD | degrees | Angle between shoulder line and arm at dominant foot down |
| Shoulder-Arm Separation at NDFD | degrees | Angle between shoulder line and arm at non-dominant foot down |
| Shoulder-Arm Separation at Release | degrees | Angle between shoulder line and arm at release |
| Base of Support Width | meters | Distance between ankles at non-dominant foot down |
| Relative Release Height | meters | Vertical distance between discus and shoulder at release |
| Height at Release | meters | Absolute height of discus at release |
| Release Angle | degrees | Angle of discus trajectory at release |
| Distance | meters | Estimated distance thrown |
| Trunk Flexion at Release | degrees | Trunk sagittal flexion angle at release (forward = positive, backward = negative) |
| Release Style | N/A | Classification of release style ('Reverse' or 'Fixed Foot') |
## Notes
* Kinematic data typically captured at 240Hz
# Track & Field: Hammer Throw
Source: https://docs.uplift.ai/biomechanics/activities/track_and_field/hammer_throw
Biomechanical analysis of hammer throw movements, including events, phases, and discrete metrics.
## Overview
The hammer throw is a track and field throwing event in which the athlete spins with a metal ball (the hammer) attached by wire to a handle, building angular velocity through several turns in a circle before releasing the hammer forward and upward.
The thrower typically begins with one or two preliminary swings, then enters the circle and executes three or four full rotations (turns) while maintaining a low center of mass and driving the hammer in an accelerating path.
Release occurs with both feet in contact with the circle; the angle and height of release, together with release speed, determine the distance. Key biomechanical factors include rotational speed and timing of the turns, trunk and shoulder sequencing relative to the lower body, double-support vs single-support phases, and release angle and velocity.
Biomechanical analysis of the hammer throw can address turn rhythm and speed progression, body position and lean during rotation, timing of release, and release parameters (angle, height, velocity).
## Dimensions
Required inputs for processing are not yet defined. When supported, typical dimensions may include:
* **handedness or rotation direction:** the direction of rotation in the circle \['left', 'right'], if applicable
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Data Type | Acronym | Description |
| ------ | --------- | ------- | ----------- |
| | | | |
### Discrete Metrics
| Metric | Data Type | Units | Description |
| ------ | --------- | ----- | ----------- |
| | | | |
## Notes
* Events and metrics are placeholders; definitions will be added in a future update.
# Track & Field: High Jump
Source: https://docs.uplift.ai/biomechanics/activities/track_and_field/high_jump
Biomechanical analysis of high jump movements, including events, phases, and discrete metrics.
## Overview
The high jump is a track and field event in which the athlete runs a curved approach, takes off from one foot, and clears a horizontal bar by rotating the body so the back or shoulder crosses the bar face-up (Fosbury flop) or with other techniques.
The approach is typically a J- or curve-shaped run that angles the athlete toward the bar and creates rotation at takeoff.
The takeoff foot is planted, the free leg and arms drive upward, and the athlete rotates to clear the bar and lands on the back or shoulders in the pit.
Success depends on approach speed and curve, takeoff position and angle, vertical and horizontal velocity at takeoff, and efficient bar clearance (center of mass passing under the bar while the body arches over it).
Biomechanical analysis of the high jump can address approach speed and curvature, takeoff foot placement and angle, takeoff leg and arm drive, flight trajectory and rotation, and bar-clearance technique.
## Dimensions
Required inputs for processing are not yet defined. When supported, typical dimensions may include:
* **takeoff leg or footedness:** the leg used for takeoff \['left', 'right'], which determines approach side and rotation direction
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Data Type | Acronym | Description |
| ------ | --------- | ------- | ----------- |
| | | | |
### Discrete Metrics
| Metric | Data Type | Units | Description |
| ------ | --------- | ----- | ----------- |
| | | | |
## Notes
* Events and metrics are placeholders; definitions will be added in a future update.
# Track and Field: Shot Put
Source: https://docs.uplift.ai/biomechanics/activities/track_and_field/shot_put
Biomechanical analysis of shot put throw movements, including events, phases, and discrete metrics.
## Overview
The shot put is a track and field throwing event in which the athlete accelerates a metal ball (the shot) across the throwing circle — using either a glide or spin technique — before releasing it from the shoulder with full extension of the throwing arm.
The thrower drives across the circle with the legs and hips, transferring momentum through the trunk into the arm, and releases the shot at an angle that balances height and distance.
Distance depends on release speed, release angle and height, and how efficiently the lower body's momentum transfers into the throw.
Biomechanical analysis of the shot put can address foot-off and foot-down timing across the circle, trunk and hip-shoulder separation, arm position and trunk lean at release, and release speed, height, and angle.
## Dimensions
Required inputs for processing are not yet defined. When supported, typical dimensions may include:
* **handedness:** the handedness of the athlete \['left', 'right'], which determines throw direction and rotation
## Output Variables
### Generic Outputs
Every capture includes session metadata, standard joint angle/velocity time series, and 3D keypoint positions common to all movements. See [Generic Outputs](/biomechanics/generic-outputs) for the full list.
### Events
| Metric | Acronym | Description |
| --------------------- | ------- | --------------------------------------------------------- |
| Dominant Foot Off | DFO | the instance when the dominant foot leaves the ground |
| NonDominant Foot Off | NDFO | the instance when the nondominant foot leaves the ground |
| Dominant Foot Down | DFD | the instance when the dominant foot touches the ground |
| NonDominant Foot Down | NDFD | the instance when the nondominant foot touches the ground |
| Release | R | release of the shot |
### Phases and Stages of the Shot Put
| Phase | Start | End |
| ---------- | ----- | ---- |
| Entry | DFO | NDFO |
| Airborne | NDFO | DFD |
| Transition | DFD | NDFD |
| Delivery | NDFD | R |
### Discrete Metrics
| Metric | Units | Description |
| ---------------------------------- | ------- | ------------------------------------------------------------------------ |
| Handedness | N/A | Calculated handedness of the athlete ('right' or 'left') |
| Entry Phase | seconds | Time between dominant foot off and non-dominant foot off |
| Airborne Phase | seconds | Time between non-dominant foot off and dominant foot down |
| Transition Phase | seconds | Time between dominant foot down and non-dominant foot down |
| Delivery Phase | seconds | Time between non-dominant foot down and release |
| Height at DFO | meters | Height of the shot at dominant foot off |
| Height at NDFO | meters | Height of the shot at non-dominant foot off |
| Height at DFD | meters | Height of the shot at dominant foot down |
| Height at NDFD | meters | Height of the shot at non-dominant foot down |
| Height at Release | meters | Height of the shot at release |
| Speed at DFO | m/s | Speed of the shot at dominant foot off |
| Speed at NDFO | m/s | Speed of the shot at non-dominant foot off |
| Speed at DFD | m/s | Speed of the shot at dominant foot down |
| Speed at NDFD | m/s | Speed of the shot at non-dominant foot down |
| Speed at Release | m/s | Speed of the shot at release |
| Path Length | meters | Total path length of the shot from DFO to release |
| Release Angle | degrees | Angle of shot trajectory at release |
| Airborne Phase Distance | meters | Distance travelled by pelvis during airborne phase |
| Base of Support Width | meters | Width between ankles at non-dominant foot down |
| Trunk Flexion at Release | degrees | Trunk flexion angle at release (forward = positive, backward = negative) |
| Trunk Tilt at Release | degrees | Trunk tilt angle at release |
| Hip-Shoulder Separation at Release | degrees | Angle between hips and shoulders at release |
| Distance | meters | Estimated distance thrown |
## Notes
* Kinematic data typically captured at 240Hz
# Biomechanics Glossary
Source: https://docs.uplift.ai/biomechanics/biomech-glossary
Standard terms and definitions across the Uplift Platform
This glossary aims to provide a base of understanding for biomechanics vocabulary. Across the Uplift movement analysis platform, you'll likely encounter these general terms.
This glossary does not cover metric and event definitions for specific movements. Please refer to the [Movement Library](/biomechanics/movement-library) for specific details on movement analyses.
# A
* **Abduction**: Movement of a limb or body part away from the midline of the body. Think of lifting your arm out to the side.
* **Acceleration**: The time derivative (rate of change) of velocity, m/s^2.
* **Adduction**: Movement of a limb or body part toward the midline of the body. Bringing your arm back down to your side.
* **Angular Velocity**: The rate of change of angular position of a rotating body, usually expressed in degrees per second (°/s) or radians per second (rad/s). This is a key metric for understanding the speed of rotation during a pitch or swing.
* **Anterior**: Situated at or directed toward the front of the body.
* **Axis of Rotation**: an imaginary line about which an object rotates. It's a fixed point or line that remains stationary while the rest of the object moves in a circular path around it. The center line of the knee joint generally acts as the axis of rotation for knee flexion and extension.
# B
* **Base of Support**: The area or distance covered on the ground enclosed by points of contact with the body (such as feet). A wider base generally provides more stability.
* **Biomechanics**: The study of how biological systems respond to mechanical forces, applying principles of physics to understand how organisms move and interact with their environment.
* **Biomechanical Efficiency**: The ability to produce a desired movement outcome with minimal energy expenditure and/or stress on the body. This is a key goal for maximizing performance and preventing injury.
# C
* **Center of Mass (CoM)**: The point in an object or system that responds to external forces as if the total mass of the system were concentrated at this point. Understanding how the CoM shifts based on body segment positioning is vital for balance and force generation. Also known as the center of gravity.
* **Circumduction**: A conical or circular movement of a limb, combining flexion, extension, abduction, and adduction. Think of drawing a circle with your arm.
* **Co-contraction**: The simultaneous activation of opposing muscles around a joint. While some co-contraction is necessary for stability, excessive co-contraction can reduce efficiency. For example, co-contracting the biceps and triceps stabilizes the elbow joint. Also known as co-activation.
* **Concentric**: When a muscle generates force and shortens, opposite of eccentric. For example, during the upward phase of a bicep curl, the biceps muscle is acting concentrically.
* **Contralateral**: Relating to the opposite side of the body from which a particular structure or condition occurs. Think "opposite side".
# D
* **Distal**: Situated away from the center of the body or the point of attachment. Your hand is distal to your elbow.
# E
* **Eccentric**: General term for the phase when a muscle is lengthening under tension. This is crucial for deceleration and controlling movements. For example, walking down stairs and lowering a dumbbell from a bicep curl are eccentric motions.
* **Extension**: Straightening a joint, increasing the angle between the bones.
* **External Rotation**: Rotation away from the midline of the body. For the throwing shoulder, this is a critical phase for building potential energy.
# F
* **Flexion**: Bending a joint, decreasing the angle between the bones.
* **Frames per second (fps)**: How many frames a camera records per second, also known as hertz (Hz). Uplift can record movements at 30, 60, 120, and 240 frames per second. Uplift records faster motions at higher fps in order to measure the motion more accurately.
* **Force**: An interaction that, when unopposed, will change the motion of an object. Measured in Newtons (N). Understanding the forces generated during a swing or pitch is essential.
* **Force Plate (or Platform)**: A device that measures the ground reaction forces exerted by an individual during movement.
* **Frontal Plane**: Movement in the frontal plane is side to side and up and down. This plane splits the front and back portions of the body. Also known as the cartwheel plane. Jumping jacks and the "YMCA" dance primarily occur in this plane.
# G
* **Global Coordinate System (GCS)**: This provides an absolute reference frame in space for defining the position and orientation of body segments or instruments. It's typically a fixed, 3D cartesian coordinate system (x, y, z) with a defined origin (0,0,0). The GCS is used to describe the overall movement of a body or system, while local coordinate systems define the movement of individual segments relative to each other.
* **Gravity**: a fundamental force of attraction between any two objects with mass or energy. In biomechanics, this is simplified as a constant acceleration value of g = 9.81 m/s acting straight down through the global coordinate system. Gravitational force is calculated by multiplying g by an object's mass in kg.
* **Ground Reaction Force (GRF)**: The force exerted by the ground on a body in contact with it. Newton's Third Law states that for every action, there is an equal and opposite reaction. Analyzing GRF helps understand how an athlete interacts with the ground to generate power.
* **Goniometer**: A hand-held device used to measure a joint angle, it looks like a protractor with a long arm to help with aligning along a body segment.
# I
* **Inertia**: The tendency of an object to resist changes in its state of motion. A heavier object has more inertia than a light object if both objects have the same motion state.
* **Internal Rotation**: Rotation toward the midline of the body. In throwing, this is a powerful movement that accelerates the arm.
* **Ipsilateral**: Relating to the same side of the body from which a particular structure or condition occurs. Think "same side".
# J
* **Jerk**: the time derivative (rate of change) of acceleration (m/s^3). This is not commonly used outside of signal processing of acceleration data.
# K
* **Kinematics**: The study of motion without considering the forces causing the motion. This includes displacement, velocity, acceleration, and angles. Uplift focuses on kinematic analysis because it does not measure forces.
* **Kinetics**: The study of motion with consideration of the forces causing the motion. This involves analyzing forces, torques, and momentum.
# L
* **Lag**: A delay or offset in the timing of different body segments during a movement. Optimal lag in movements like throwing can contribute to increased velocity.
* **Lateral**: Situated away from the midline of the body.
* **Linear Velocity**: The rate of change of linear position, usually expressed in meters per second (m/s). Important for understanding the speed of the ball or the athlete's movement.
* **Local Coordinate System (LCS)**: a coordinate system defined entirely within an object, with its own origin, axes, and scale. Uplift uses LCSs to calculate joint angles, for example, we create a torso LCS and an upper arm LCS to calculate the shoulder joint angles.
# M
* **Medial**: Situated toward the midline of the body.
* **Momentum**: The product of an object's mass and its velocity (p=mv). Conservation of momentum plays a role in multi-segment movements.
* **Motion Capture**: The process of recording the movement of objects or people, often using specialized cameras and markers.
# N
* **Newtons**: SI unit of measurement for force. 1 Newton = 0.225 pounds.
# P
* **Posterior**: Situated at or directed toward the back.
* **Pronation**: Rotation of the forearm so that the palm faces posteriorly (thumb facing downward or backward). Also refers to the inward rolling motion of the foot during gait.
* **Proximal**: Situated close to the center of the body or the point of attachment. Your shoulder is proximal to your elbow.
# R
* **Range of Motion (ROM)**: The full movement potential of a joint, typically measured in degrees. Maintaining adequate ROM is crucial for performance and injury prevention.
* **Rotation**: Movement around an axis. Essential for generating power in throwing and hitting.
# S
* **Sagittal Plane**: The sagittal plane is a vertical plane which passes through the body from front to back. It divides the body into a left section and a right section. Also known as the somersault plane. Walking, running, and somersaulting primarily occur in this plane.
* **Scapular Loading**: The process of retracting and protracting the scapula (shoulder blade) to store elastic energy during the wind-up phase of throwing. Efficient scapular loading is linked to higher throwing velocities.
* **Segmental Coordination**: The timing and sequencing of movements of different body segments. Optimal coordination allows for efficient transfer of energy throughout the kinetic chain.
* **Stability**: The ability to resist disturbance to one's equilibrium. Important for maintaining balance during dynamic movements.
* **Supination**: Rotation of the forearm so that the palm faces anteriorly (thumb pointing upward or forward). Also refers to the outward rolling motion of the foot during gait.
# T
* **Torque**: A rotational force, calculated as the product of force and the perpendicular distance from the axis of rotation (moment arm) (τ = r × F). Torque is what causes rotation at the joints.
* **Transverse Plane**: The transverse plane, also known as the axial plane or horizontal plane, divides the body into superior (top) and inferior (bottom) halves. Twisting and turning motion occurs in this plane.
* **Trunk Rotation**: The twisting movement of the torso around the spine. A critical component for generating power in baseball movements.
# V
* **Valgus**: Angulation of a joint such that the distal segment is deviated laterally (away from the midline). Often discussed in the context of elbow stress during a throw or knee motion under high force. Can also be thought of as knock-kneed.
* **Varus**: Angulation of a joint such that the distal segment is deviated medially (toward the midline). Can also be thought of as bow-legged.
* **Velocity (linear)**: The rate of change of position with respect to time, including both speed and direction. Crucial for analyzing the speed of body segments and the ball.
# X
* **X Factor**: Typically for baseball or movements that require a large amount of body twisting motion. X Factor refers to the transverse plane difference between the pelvis (hip to hip) and torso (shoulder to shoulder) angles because it creates an "X" when nonzero as viewed from above. Also known as hip-shoulder separation.
# Generic Outputs
Source: https://docs.uplift.ai/biomechanics/generic-outputs
Standard Joint Angles, Joint Velocities, and Keypoints.
Uplift includes generic outputs of joint angles, joint velocities, and 3D keypoints for all recorded movements.
Movements without specific events and metrics (such as *"other-other"*) will include these outputs.
## Metadata
* Specific information about the recorded session. Columns may include:
* `athlete_name` - as entered during capture
* `athleteid` - automatically generated id for the athlete
* `sessionid` - automatically generated id for the session
* `orgid` - automatically generated id for the organization
* `capture_time` - timestamp of session capture in [Unix Epoch](https://www.epochconverter.com/)
* `fps` - frames per second
* `activity` - general activity being performed (baseball, jumping, gait, etc.)
* `movement` - specific movement being performed (pitching, countermovement, running, etc.)
* `handedness` - dominant hand of the athlete (as performed during the movement) \[if applicable]
* `footedness` - dominant foot of the athlete (as performed during the movement) \[if applicable]
* `approved_by_biomech_qa` - boolean variable indicating whether the session passed Uplift's internal biomechanics quality assurance \[0 = failed, 1 = passed]
* `time` - row variable indicating the elapsed time in seconds since beginning of the capture \[0, 0.01, 0.02, ...]
* `frame` - row variable indicating the frame number since beginning of the capture \[0, 1, 2, ...]
* `video_count` - the number of cameras/videos used for the capture (2 or 1)
## Generic Kinematics
* Lists the joint angles (degrees) and velocities (degrees/second) for all joints included in the biomechanical model.
* These columns are generally paired with the angle preceding the velocity (i.e., 'left\_shoulder\_flexion', 'left\_shoulder\_flexion\_velocity').
* Available outputs may depend on keypoint model and biomechanical processing versions.
| Joint Angle (deg) | Joint Velocity (deg/s) |
| --------------------------------------------------------- | ------------------------------------------------------------------- |
| head\_extension | head\_extension\_velocity |
| head\_lateral\_flexion\_clockwise | head\_lateral\_flexion\_clockwise\_velocity |
| head\_twist\_clockwise | head\_twist\_clockwise\_velocity |
| right\_shoulder\_flexion | right\_shoulder\_flexion\_velocity |
| right\_shoulder\_adduction | right\_shoulder\_adduction\_velocity |
| right\_shoulder\_external\_rotation | right\_shoulder\_external\_rotation\_velocity |
| right\_shoulder\_horizontal\_adduction | |
| left\_shoulder\_flexion | left\_shoulder\_flexion\_velocity |
| left\_shoulder\_adduction | left\_shoulder\_adduction\_velocity |
| left\_shoulder\_external\_rotation | left\_shoulder\_external\_rotation\_velocity |
| left\_shoulder\_horizontal\_adduction | |
| right\_elbow\_flexion | right\_elbow\_flexion\_velocity |
| left\_elbow\_flexion | left\_elbow\_flexion\_velocity |
| right\_hip\_flexion\_with\_respect\_to\_trunk | right\_hip\_flexion\_velocity\_with\_respect\_to\_trunk |
| right\_hip\_adduction\_with\_respect\_to\_trunk | right\_hip\_adduction\_velocity\_with\_respect\_to\_trunk |
| left\_hip\_flexion\_with\_respect\_to\_trunk | left\_hip\_flexion\_velocity\_with\_respect\_to\_trunk |
| left\_hip\_adduction\_with\_respect\_to\_trunk | left\_hip\_adduction\_velocity\_with\_respect\_to\_trunk |
| right\_knee\_extension | right\_knee\_extension\_velocity |
| left\_knee\_extension | left\_knee\_extension\_velocity |
| | pelvis\_rotational\_velocity\_with\_respect\_to\_ground |
| | trunk\_rotational\_velocity\_with\_respect\_to\_ground |
| | right\_arm\_rotational\_velocity\_with\_respect\_to\_ground |
| | left\_arm\_rotational\_velocity\_with\_respect\_to\_ground |
| trunk\_twist\_clockwise | trunk\_twist\_clockwise\_velocity |
| trunk\_lateral\_flexion\_right | |
| trunk\_angle\_global\_sagittal | |
| trunk\_angle\_global\_frontal | |
| trunk\_angle\_global\_twist | |
| right\_ankle\_dorsiflexion | right\_ankle\_dorsiflexion\_velocity |
| left\_ankle\_dorsiflexion | left\_ankle\_dorsiflexion\_velocity |
| right\_hip\_internal\_rotation\_with\_respect\_to\_trunk | right\_hip\_internal\_rotation\_velocity\_with\_respect\_to\_trunk |
| right\_hip\_adduction\_with\_respect\_to\_pelvis | right\_hip\_adduction\_velocity\_with\_respect\_to\_pelvis |
| right\_hip\_internal\_rotation\_with\_respect\_to\_pelvis | right\_hip\_internal\_rotation\_velocity\_with\_respect\_to\_pelvis |
| left\_hip\_internal\_rotation\_with\_respect\_to\_trunk | left\_hip\_internal\_rotation\_velocity\_with\_respect\_to\_trunk |
| left\_hip\_adduction\_with\_respect\_to\_pelvis | left\_hip\_adduction\_velocity\_with\_respect\_to\_pelvis |
| left\_hip\_internal\_rotation\_with\_respect\_to\_pelvis | left\_hip\_internal\_rotation\_velocity\_with\_respect\_to\_pelvis |
| right\_knee\_varus | right\_knee\_varus\_velocity |
| right\_knee\_internal\_rotation | right\_knee\_internal\_rotation\_velocity |
| left\_knee\_varus | left\_knee\_varus\_velocity |
| left\_knee\_internal\_rotation | left\_knee\_internal\_rotation\_velocity |
## Generic Keypoints
* Lists the X/Y/Z keypoint positions (units: meters) in the global coordinate system.
* Keypoint columns end in "\_3d\_x", "\_3d\_y", and "\_3d\_z".
* Number and location of keypoints may differ by keypoint model and biomechanical processing versions.
| # | X | Y | Z |
| -- | -------------------------- | -------------------------- | -------------------------- |
| 1 | nose\_3d\_x | nose\_3d\_y | nose\_3d\_z |
| 2 | left\_eye\_3d\_x | left\_eye\_3d\_y | left\_eye\_3d\_z |
| 3 | right\_eye\_3d\_x | right\_eye\_3d\_y | right\_eye\_3d\_z |
| 4 | left\_ear\_3d\_x | left\_ear\_3d\_y | left\_ear\_3d\_z |
| 5 | right\_ear\_3d\_x | right\_ear\_3d\_y | right\_ear\_3d\_z |
| 6 | mid\_head\_3d\_x | mid\_head\_3d\_y | mid\_head\_3d\_z |
| 7 | proximal\_neck\_3d\_x | proximal\_neck\_3d\_y | proximal\_neck\_3d\_z |
| 8 | left\_shoulder\_jc\_3d\_x | left\_shoulder\_jc\_3d\_y | left\_shoulder\_jc\_3d\_z |
| 9 | right\_shoulder\_jc\_3d\_x | right\_shoulder\_jc\_3d\_y | right\_shoulder\_jc\_3d\_z |
| 10 | left\_elbow\_jc\_3d\_x | left\_elbow\_jc\_3d\_y | left\_elbow\_jc\_3d\_z |
| 11 | right\_elbow\_jc\_3d\_x | right\_elbow\_jc\_3d\_y | right\_elbow\_jc\_3d\_z |
| 12 | left\_wrist\_jc\_3d\_x | left\_wrist\_jc\_3d\_y | left\_wrist\_jc\_3d\_z |
| 13 | right\_wrist\_jc\_3d\_x | right\_wrist\_jc\_3d\_y | right\_wrist\_jc\_3d\_z |
| 14 | pelvis\_3d\_x | pelvis\_3d\_y | pelvis\_3d\_z |
| 15 | left\_hip\_jc\_3d\_x | left\_hip\_jc\_3d\_y | left\_hip\_jc\_3d\_z |
| 16 | right\_hip\_jc\_3d\_x | right\_hip\_jc\_3d\_y | right\_hip\_jc\_3d\_z |
| 17 | left\_knee\_jc\_3d\_x | left\_knee\_jc\_3d\_y | left\_knee\_jc\_3d\_z |
| 18 | right\_knee\_jc\_3d\_x | right\_knee\_jc\_3d\_y | right\_knee\_jc\_3d\_z |
| 19 | left\_ankle\_jc\_3d\_x | left\_ankle\_jc\_3d\_y | left\_ankle\_jc\_3d\_z |
| 20 | right\_ankle\_jc\_3d\_x | right\_ankle\_jc\_3d\_y | right\_ankle\_jc\_3d\_z |
| 21 | left\_heel\_3d\_x | left\_heel\_3d\_y | left\_heel\_3d\_z |
| 22 | right\_heel\_3d\_x | right\_heel\_3d\_y | right\_heel\_3d\_z |
| 23 | left\_mid\_toe\_3d\_x | left\_mid\_toe\_3d\_y | left\_mid\_toe\_3d\_z |
| 24 | right\_mid\_toe\_3d\_x | right\_mid\_toe\_3d\_y | right\_mid\_toe\_3d\_z |
| 25 | left\_first\_toe\_3d\_x | left\_first\_toe\_3d\_y | left\_first\_toe\_3d\_z |
| 26 | right\_first\_toe\_3d\_x | right\_first\_toe\_3d\_y | right\_first\_toe\_3d\_z |
| 27 | left\_fifth\_toe\_3d\_x | left\_fifth\_toe\_3d\_y | left\_fifth\_toe\_3d\_z |
| 28 | right\_fifth\_toe\_3d\_x | right\_fifth\_toe\_3d\_y | right\_fifth\_toe\_3d\_z |
# Instructions
Source: https://docs.uplift.ai/biomechanics/instructions
How to use the Uplift Movement Library Documentation
The Uplift Movement Library is the complete list of all activities, movements, events, and metrics in the Uplift ecosystem.
Use it to determine:
* which activities and movements Uplift supports
* what events and metrics are included
* how the events and metrics are calculated
* what the biomechanical metrics mean
Uplift refers to movements via both the general activity and specific movement (such as *baseball-hitting, jump-countermovement, or track\_and\_field-discus*).
Within each *activity-movement* page, view the required input dimensions as well as all variables (events & metrics) to describe movement performance.
## Common Terms
* **Session:** A single captured movement or attempt, representing the core unit of data collection. These are tagged with a unique alphanumeric session\_id. Sessions captured in a sequence (multiple reps or protocol) will have consecutive session\_ids (ABC123\_1, ABC123\_2, ...).
* **Dimension:** A labeling or categorization system for Sessions, Metrics, or Events, aiding in organization and filtering. Some dimensions are required for proper processing (such as *Handedness: left*)
* **Activity:** the general activity performed *(baseball, jump, stability)*
* **Movement:** the specific movement performed *(pitching, countermovement, y\_balance\_lower\_quarter)*
* **Event:** A specific point in time within the single movement that marks a critical instant or boundary *(ball release, jump landing, bottom)*
* **Phase:** A distinct segment of the movement within a single session, generally bounded by specific events.
* **Metric:** A measured or calculated value that reflects some aspect of the athlete’s movement over the duration of the session
* **Discrete Metric:** A single, distilled value extracted from the time-series or raw data within a session, used for quick comparisons or reporting.
*Note:* For brevity, metrics and discrete metrics are often referred to as "Metrics"
## Technical Details
Each metric and event page includes a **Technical Details** section that describes how the variable is defined, stored, and interpreted. The parameters are:
* **Variable Type:** The role of this variable in the data model.
* `Discrete Metric` — a single numeric value extracted from a session (e.g. peak velocity, angle at an event).
* `Continuous Metric` — a time-series signal rather than a single scalar.
* `Flag` — a boolean per-trial indicator derived from a threshold rule.
* `Dimension` — a categorical label used to organize or filter data (e.g. handedness, arm slot type).
* **Data Type:** The storage type of the value.
* `Float` — a decimal number (e.g. 523.4 deg/s).
* `Boolean` — true or false.
* `String` — a text category (e.g. `"pelvis-trunk-arm"`).
* **Units:** The measurement unit(s) for the metric. Some metrics list two units:
* `raw` — the unit returned by the CSV export and Data API (e.g. meters).
* `display` — the unit shown in Uplift reports and AI summaries (e.g. inches).
When only one unit is listed, it applies to both raw and display values.
* **Column Name:** The exact column name in the StarRocks database view. Use this when querying or referencing data programmatically — a mismatch will cause a "column cannot be resolved" error.
* **Aggregation:** How multiple trials within a session are collapsed into a single representative value.
* `mean` — arithmetic average across trials (used for most continuous metrics).
* `rate` — percentage of trials where the flag fired (used for boolean flags).
* `mode` — most frequently occurring value (used for categorical/string metrics).
* **Precision:** Number of decimal places shown in the UI (e.g. `0` = integer display, `2` = two decimal places).
* **Unknown Value:** The sentinel value stored when a metric could not be measured for a trial (currently `-1` for all boolean flags). Filter these out before computing statistics.
* **Measurement / Calculation:** What the value physically represents or how it is derived from the raw pose data.
* **Timing:** The event at which a discrete metric is sampled (e.g. *at ball release*, *at foot contact*).
* **Reference:** The coordinate frame or zero point used to interpret the value (e.g. `0° = facing home plate`).
* **Threshold:** For flag metrics, the condition that must be met to set the flag to `true`.
* **Typical Range:** The range of values seen across the broad athlete population. Values outside this range may indicate a data quality issue or an unusual movement pattern.
* **Optimal Direction:** How to interpret whether a higher or lower value is desirable.
* `Higher is better` — larger values indicate better performance (e.g. peak velocity).
* `Lower is better` — smaller values indicate better performance (e.g. time under load).
* `Middle — moderate values are optimal` — a range centred around an ideal value; extremes in either direction are suboptimal. See **Optimal Range** for the target window.
* `N/A` — no universal good/bad direction; interpretation depends on context (e.g. arm slot angle, which varies by pitching style).
* **Optimal Range:** For `Middle` metrics, the target window (min–max) that represents ideal performance. Defined as the 25th–75th percentile range from the normative dataset unless otherwise noted.
# Movement Library
Source: https://docs.uplift.ai/biomechanics/movement-library
Uplift Biomechanics Analysis Documentation
Welcome to our comprehensive Uplift Biomechanics documentation. Here you'll find details about the movement analyses we support and descriptions of each event and metric.
Assess sport-specific movements
Measure general movement ability, performance, or injury risk
Test for movement dysfunction and pain with SFMA
Capture any movement with Uplift
## Instructions
See [this article](/biomechanics/instructions) for details on how to use the Uplift Movement Library.
## Sport-Specific Activities
Sport-specific biomechanical analysis includes event detection and custom metrics. Be sure to label movement class and handedness correctly!
Capture 5-10 reps to get an accurate description of sport-specific biomechanics.
### Baseball
* [Pitching](/biomechanics/activities/baseball/pitching)
* [Hitting](/biomechanics/activities/baseball/hitting)
### Softball
* [Hitting](/biomechanics/activities/softball/hitting)
* [Pitching](/biomechanics/activities/softball/pitching)
### Tennis
* [Overhand Serve](/biomechanics/activities/tennis/overhand_serve)
* [Underhand Serve](/biomechanics/activities/tennis/underhand_serve)
* [Forehand](/biomechanics/activities/tennis/forehand)
* [Backhand](/biomechanics/activities/tennis/backhand)
### Track & Field
* [Discus](/biomechanics/activities/track_and_field/discus)
* [Shot Put](/biomechanics/activities/track_and_field/shot_put)
* [Hammer Throw](/biomechanics/activities/track_and_field/hammer_throw)
* [High Jump](/biomechanics/activities/track_and_field/high_jump)
### Golf
* [Swing](/biomechanics/activities/golf/swing)
### Basketball
* [Jump Shot](/biomechanics/activities/basketball/jump_shot)
* [Free Throw](/biomechanics/activities/basketball/free_throw)
* [Layup](/biomechanics/activities/basketball/layup)
## General Movement Activities
Movement assessments include general motions that can be indicators of ability, performance, or injury risk.
It's standard to capture in 2-3 reps and/or in a protocol with other movements.
### Agility
* [5-0-5](/biomechanics/activities/agility/5_0_5)
### Gait
* [Running](/biomechanics/activities/gait/running)
* [Walking](/biomechanics/activities/gait/walking)
### Jump
* [Countermovement Jump](/biomechanics/activities/jump/countermovement)
* [Single Leg Jump](/biomechanics/activities/jump/single_leg)
* [Squat Jump](/biomechanics/activities/jump/squat)
* [Drop Vertical Jump](/biomechanics/activities/jump/drop_vertical)
* [Broad Jump](/biomechanics/activities/jump/broad)
* [Single Leg Broad Jump](/biomechanics/activities/jump/single_leg_broad)
### Squat
* [Bodyweight Squat](/biomechanics/activities/squat/body_weight)
* [Single Leg Squat](/biomechanics/activities/squat/single_leg)
* [Overhead Squat](/biomechanics/activities/squat/overhead)
* [SFMA Squat](/biomechanics/activities/squat/sfma_squat)
### Lunge
* [Forward Lunge](/biomechanics/activities/lunge/forward)
### Stability
* [Single Leg Stance](/biomechanics/activities/stability/single_leg_stance)
* [SFMA Back Bend](/biomechanics/activities/stability/sfma_back_bend)
* [SFMA Toe Touch](/biomechanics/activities/stability/sfma_toe_touch)
* [Y Balance - Lower Quarter](/biomechanics/activities/stability/y_balance_lower_quarter)
* [Y Balance - Upper Quarter](/biomechanics/activities/stability/y_balance_upper_quarter)
* [Plank](/biomechanics/activities/stability/plank)
### Range Of Motion
* [Ankle Flexion](/biomechanics/activities/range_of_motion/ankle_flexion)
* [Cervical Flexion/Extension](/biomechanics/activities/range_of_motion/cervical_flexion_extension)
* [Cervical Rotation](/biomechanics/activities/range_of_motion/cervical_rotation)
* [SFMA Shoulder Extension](/biomechanics/activities/range_of_motion/sfma_shoulder_extension)
* [SFMA Shoulder Flexion](/biomechanics/activities/range_of_motion/sfma_shoulder_flexion)
* [Shoulder 9090 (Internal/External Rotation)](/biomechanics/activities/range_of_motion/shoulder_9090)
* [Shoulder Flexion (and Extension)](/biomechanics/activities/range_of_motion/shoulder_flexion)
* [T-Spine Rotation](/biomechanics/activities/range_of_motion/t_spine)
## Selective Functional Movement Assessment
The Selective Functional Movement Assessment (SFMA protocol) includes a wide variety of movements to identify any discomfort or pain from body motion.
* [SFMA Back Bend](/biomechanics/activities/stability/sfma_back_bend)
* [SFMA Toe Touch](/biomechanics/activities/stability/sfma_toe_touch)
* [SFMA Shoulder Extension](/biomechanics/activities/range_of_motion/sfma_shoulder_extension)
* [SFMA Shoulder Flexion](/biomechanics/activities/range_of_motion/sfma_shoulder_flexion)
* [SFMA Squat](/biomechanics/activities/squat/sfma_squat)
## Free-Form Movement
Capture any motion! For best results, stay fully within all camera views and with only one person in view at a time. Select movement-activity: "other-other".
Uplift offers [Generic Outputs](/biomechanics/generic-outputs) for all movements, including: joint angles, joint velocities, 3D keypoints, and metadata.
# Normative Ranges
Source: https://docs.uplift.ai/biomechanics/normative-ranges
How to Interpret Uplift Normative Data
Uplift Normative Ranges allow for comparison of an athlete's performance data against a peer population.
All results were manually-reviewed and filtered to remove outliers and poor-quality sessions before computing percentiles.
Use these tables to understand what a good value looks like for a given population, and to give context to the exact percentile shown in a report.
## Published Normative Ranges
### Sport-Specific
The current documented ranges for each sport and group size per level.
| Movement | Youth | High School | College | Professional | Broad (All Levels) |
| ---------------------------------------------------------------------------------------- | :---: | :---------: | :-----: | :----------: | :----------------: |
| [Baseball: Hitting](/biomechanics/activities/baseball/hitting/baseball-hitting-norms) | 239 | 202 | 156 | 293 | 890 |
| [Baseball: Pitching](/biomechanics/activities/baseball/pitching/baseball-pitching-norms) | 206 | 226 | 167 | 155 | 754 |
| [Softball: Hitting](/biomechanics/activities/softball/hitting/softball-hitting-norms) | 104 | 104 | 112 | 112 | 216 |
| [Tennis: Overhand Serve](/biomechanics/activities/tennis/tennis-overhand-serve-norms) | 227 | — | — | 300 | 527 |
Softball Hitting session counts are pooled across Youth/High School and College/Professional.
Tennis Overhand Serve does not yet have High School or College samples.
## Competition Levels
Metric pages show a summary table with five percentile cuts (10th, 25th, 50th, 75th, 90th) and up to five competition levels.
| Population | Description |
| ---------------------- | --------------------------------------------- |
| **Youth** | Middle school or younger (typically under 14) |
| **High School** | Ages 14–18 |
| **College** | Collegiate athletes |
| **Professional** | Professional or elite athletes |
| **Broad (All Levels)** | All athletes combined for a general reference |
## How competition levels were determined:
3 different methods:
* **User-specified**: account owner or user actively labelled the athlete's level.
* **Organizational association**: Collected by a collegiate or professional team. Even if that athlete does not officially play for that team, we assume that they have the capacity to compete on the organization's level.
* **Manually-Labelled**: determined via Uplift Biomechanist video review, subjectively gauging athlete age/size and coordination.
For each sport-specific movement:
* **Baseball Hitting**: user-specified and organizational association
* **Baseball Pitching**: user-specified and organizational association
* **Softball Hitting**: organizational association and manually-labelled
* **Tennis Overhand Serve**: user-specified
## Interpreting Percentiles
Uplift reports may show an exact percentile (e.g. 77th, 33rd) for each continuous metric, telling you where the athlete ranks within their population group.
* **77th percentile** → the athlete's value is higher than 77% of similar athletes.
* **33rd percentile** → the athlete's value is higher than only 33% — roughly the lower third.
Use these bands as a quick guide for *Higher is better* metrics:
| Percentile | What it means |
| -------------- | -------------------------------- |
| 90th + | Elite — top 10% |
| 75th – 89th | Above average |
| 25th – 74th | Average |
| 11th – 24th | Below average |
| 10th and below | Low — likely a training priority |
However, direction matters. A high percentile isn't always the target.
The **Optimal Range** column highlights the target window based on the metric's direction:
* **Higher is better** (>75th): The higher the better. This generally includes rotational or linear velocities, and sometimes range of motion.
* **Middle is optimal** (25th-75th): Extremes in either direction are suboptimal. Typical for positional metrics, like joint angles during a motion.
* **Lower is better** (\<25th): Where a lower percentile is desired. These are not as common, but do occur, such as lead knee angle at ball contact during hitting.
Percentiles are most useful when tracked over time. A shift from the 40th to the 60th percentile across a training block signals real progress, even if both sit in the "average" band.
# Pose QA & Biomech QA
Source: https://docs.uplift.ai/biomechanics/pose-biomech-qa
Ensuring quality outputs from automated processing.
Uplift runs two different quality assurance (QA) tests on all captures.
These tests ensure viable data was received, the correct motion was recorded, and results are within an expected range.
You can easily omit QA-failed sessions by filtering 'ApprovedByBiomechQA' = 1.
![Pose QA and Biomech QA act like a swiss cheese model to omit poor quality data from entering an organization's or athlete's reports.]()
Pose QA and Biomech QA act like a swiss cheese model to omit poor quality data from entering an organization's or athlete's reports.
## Pose QA
PoseQA applies a series of heuristics to determine whether a person is detected with confidence and is fully in frame for most of the movement.
This process ensures that keypoint quality is sufficient to continue with movement analysis.
Broadly, these checks involve:
* having sufficient overlap of frames where a person is detected in both camera views
* a person is detected in-frame for a certain percentage of the movement duration
* keypoint confidence values meet minimum thresholds
* ensuring projection of 3D keypoints and 2D detection/keypoints align with expected distributions for each body segment
## Biomech QA
Biomech QA tests the calculated values of events and metrics for a specific movement-activity.
Note: `other-other` (general movement) does not have any Biomech QA tests.
For example, `baseball-pitching` biomech QA looks for:
* Events
* certain events present: \[twist, max knee raise, foot contact, release]
* events occur within a 2 s window: \[max knee raise, foot contact, release]
* Metrics
* pelvis and trunk angular velocities are not excessively noisy (via rolling standard deviation tolerance)
* x\_factor near foot contact event not greater than 120 deg
* forearm length (dominant arm distance between elbow and wrist joint centers) not greater than 0.5 m
* peak\_pelvis\_angular\_velocity between 200 and 1000 deg/s
* peak\_trunk\_angular\_velocity between 300 and 1500 deg/s
* peak\_arm\_angular\_velocity between 500 and 2500 deg/s
In another example, `jump-countermovement` Biomech QA looks for:
* Events
* all events are present: \[initiation, bottom, takeoff, peak jump, landing, landing bottom, termination]
* ensure events occur in the correct order: \[initiation -> bottom -> takeoff -> peak jump -> landing -> landing bottom -> termination]
* Metrics
* check that metrics have reasonable values:
* jump height between 0.075 m (\~3 inches) and 1.3 m (\~51 inches)
* contraction time (from initiation to takeoff) less than 2.5 seconds (otherwise its not a countermovement jump)
* hip knee dominance (for eccentric, concentric, and landing phases) between 0 and 1
* bilateral thigh length standard deviations under 0.065 m (\~2.5 in)
# Overview
Source: https://docs.uplift.ai/home
Uplift Capture is a powerful biomechanical analysis platform that helps athletes, trainers, and organizations access and understand their movement data. Our API enables you to programmatically access your biomechanical data, integrate 3D motion capture analysis into your applications, and build powerful solutions around human movement analysis.
![Hero Dark]()
## Getting Started
Before diving into the API reference, here's what you need to know:
Explore our comprehensive API documentation and endpoints
Learn how to authenticate your API requests
Explore practical examples to get started with API requests and authentication
## Additional Resources
Our comprehensive documentation includes these important references:
Understanding 3D data transformation and handling
Understand our error codes and troubleshooting
Visit our Help Center for additional support
# 3D Data Transformation
Source: https://docs.uplift.ai/samples/3d-data-transformation
A demo script that applies rotations and translations to 3D data.
## Overview
The **3D Data Transformation Script** demonstrates how to convert 3D coordinate data from one reference frame to another, following the standard used within our system. This script is designed to transform data into the same reference frame found in the downloaded CSV files, ensuring consistency and compatibility across different datasets.
## Key Features
* **Rotation and Translation**: Transform data from the camera reference frame to the Uplift reference frame using customizable rotations and translations.
* **CSV File Input and Output**: Work with 3D data stored in CSV files, where the script reads the input, applies transformations, and outputs the transformed data to a new CSV file.
## Data differences to the CSV Download from the Web app
This API provides raw, untransformed 3D data in the primary camera coordinate frame to ensure maximum flexibility and accuracy across different usecases. The CSV export applies transformations such as OpenGL rotation and left hip centering specifically for visualization, but not all clients require these changes.
Different clients may have different needs when working with the data. By providing raw data in the primary camera coordinate frame, each client can apply transformations suited to their own rendering pipeline or analytical framework rather than having to undo predefined adjustments. This also preserves data integrity and prevents potential data loss that could occur from applying transformations before distribution.
Some clients may also prefer different reference frames, such as foot-centered instead of left-hip-centered. If the API imposed a specific transformation, it could create unnecessary complexity for users who need a different structure. Additionally, reference points like the left hip can be noisy due to tracking inconsistencies, making it unreliable as a fixed transformation for all use cases. Providing raw data in the primary camera coordinate frame ensures that clients can choose the most stable and meaningful reference frame for their application.
For those who need the CSV-style transformations, we provide scripts that apply the same adjustments.
## Learn More
For detailed instructions on setting up and running the script, including how to customize the transformations, explore the full documentation available in the [script’s repository](https://github.com/upliftlabs/uplift-sample-api-app/tree/main/utilities).
# Sample Apps
Source: https://docs.uplift.ai/samples/apps
Learn about the Uplift API Sample Repo and its tools for working with APIs and transforming 3D data.
The Uplift API Sample Repo is a developer-friendly demo for interacting with the Uplift API. It provides sample implementations in both Node.js and Python, along with a specialized script for 3D data transformations. These resources are designed to streamline common workflows such as making API requests, handling pagination, exporting data, and transforming 3D datasets.
### Key Components
* **Node.js and Python Sample Applications**\
Two sample apps—one built with Node.js and the other with Python—demonstrate how to interact with the Uplift API. Both provide examples of making API calls, handling pagination, and exporting data to organized files.
* **3D Data Transformation Demo Script**\
A demo script that showcases how to process 3D data by applying rotations and translations to coordinate points, providing a practical example for developers working with spatial datasets.\
→ [Learn More About 3D Data Transformation](/samples/3d-data-transformation)
## Learn More
* Review [Retrieving Data in Batches](../api-reference/retrieving-data-batches) to paginate and control API responses.
* For the complete code and additional details, visit the [Uplift Sample API App Repo](https://github.com/upliftlabs/uplift-sample-api-app).