> ## 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.

# 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
* **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