> ## 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.

# Finish Phase Trunk Flexion

> Forward or backward trunk flexion at the finish of the serve.

## Technical Details

* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `finish_phase_trunk_flexion`
* **Measurement:** Sagittal-plane trunk flexion at [Termination](/biomechanics/activities/tennis/events/termination)

## Description

Finish phase trunk flexion is the forward/backward bend of the trunk at the end of the serve. Positive values indicate forward flexion, negative values indicate backward extension. It provides the underlying continuous measurement behind the [Landing Phase Excessive Forward Lean](/biomechanics/activities/tennis/flags/landing-phase-excessive-forward-lean) movement flag, which flags forward flexion greater than 60°.

## Use Cases

* Follow-through posture
* Related to Landing Phase Excessive Forward Lean flag
* Injury risk screening