> ## 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 Parallel

> Binary indicator of whether the trunk and tibia are parallel (1) or not (0) at bottom.

## Technical Details

* **Variable Type:** Discrete Metric
* **Data Type:** Boolean (binary)
* **Units:** 1 = parallel, 0 = not parallel
* **Column Name:** `trunk_tibia_parallel`
* **Aggregation:** rate
* **Precision:** 0
* **Optimal Direction:** Higher is better
* **Measurement:** Assessment of whether trunk and tibia segment sagittal plane angles are parallel (within 20 deg of each other) at the bottom of the squat

## Description

Trunk tibia parallel is a binary flag indicating whether the trunk and tibia are near parallel (20 degree threshold) at the bottom position.
It is used in bodyweight, overhead, and single-leg squats as a simple posture and technique indicator.
Its counterpart is [Trunk Tibia Angle](/biomechanics/activities/squat/metrics/trunk-tibia-angle).

## Use Cases

* Posture and technique at bottom
* Movement quality screening
* Coaching feedback