> ## Documentation Index
> Fetch the complete documentation index at: https://docs.uplift.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Trunk Global Flexion, Tilt & Twist

> 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