> ## 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.

# Acceleration Phase Max 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