> ## 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.

# Handedness

> Handedness of the athlete (left or right) for the tennis serve.

## Technical Details

* **Variable Type:** Discrete Metric / Dimension
* **Data Type:** Categorical
* **Units:** N/A
* **Column Name:** (implementation-specific)
* **Measurement:** Player handedness (e.g., 'left', 'right') used to define dominant arm and side

## Description

Handedness indicates which hand the player uses to serve. It is typically a required input for processing (with [Dimensions](/biomechanics/activities/tennis/overhand_serve#dimensions)) and is used to interpret dominant-side events and metrics (e.g., low arm, apex, shoulder external rotation).

## Use Cases

* Defining dominant vs. non-dominant side for metrics
* Filtering and grouping by handedness
* Consistent interpretation of limb-specific metrics