> ## 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.

# Contact Phase Elbow Flexion

> Amount of elbow flexion at apex (ball contact).

<img src="https://mintcdn.com/upliftlabs/Ku7T6jLWrJyoK7uq/biomechanics/activities/tennis/images/elbow-angle.png?fit=max&auto=format&n=Ku7T6jLWrJyoK7uq&q=85&s=6a27c998ace10b9e281d914dccbe6c8b" alt="Elbow flexion at contact" width="500" height="500" data-path="biomechanics/activities/tennis/images/elbow-angle.png" />

## 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