> ## 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 lowest point of the pelvis before the jump.

## Technical Details

* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `bottom_of_jump_frame`
* **Required for QA:** False
* **Measurement:** Lowest pelvis height during the jumping eccentric phase

## Description

Bottom marks the instant when the pelvis reaches its lowest point during the downward (eccentric) phase of the jump, immediately before the concentric push.
This event separates the jumping eccentric phase from the jumping concentric phase.

## Use Cases

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