> ## 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:** 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