> ## 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.

# Trunk Tibia Angle

> Angle between the trunk and tibia segments at the bottom of the squat.

## Technical Details

* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** degrees (°)
* **Column Name:** `trunk_tibia_angle`
* **Aggregation:** mean
* **Precision:** 0
* **Optimal Direction:** Middle — moderate values are optimal
* **Measurement:** Angle between trunk and tibia at [Bottom](/biomechanics/activities/squat/events/bottom)

## Description

Trunk tibia angle is the continuous measure of the angle between the trunk and tibia at the bottom of the squat.
It is used in bodyweight, overhead, and single-leg squats.
The binary version is [Trunk Tibia Parallel](/biomechanics/activities/squat/metrics/trunk-tibia-parallel).

## Use Cases

* Quantifying forward lean or upright posture at bottom
* Movement quality and consistency
* Comparison across squat types and athletes