> ## 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.

# Bottom

> The instant of maximum squat depth.

## Technical Details

* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `squat_bottom_frame`
* **Required for QA:** True
* **Measurement:** Frame at which maximum squat depth is achieved

## Description

Bottom marks the instant when the pelvis reaches its lowest point (maximum squat depth) during the downward phase.
This event separates the eccentric (descent) phase from the concentric (ascent) phase.

## Use Cases

* Eccentric vs. concentric phase definition
* Joint angle metrics at bottom (e.g., hip, knee, ankle flexion)
* Knee valgus at bottom