> ## 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.

# Ascent Start

> The start of upward movement from the bottom of the squat.

## Technical Details

* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** \`\`
* **Required for QA:** False
* **Measurement:** Start of the concentric (upward) phase

## Description

Ascent Start marks when the athlete begins moving upward from the bottom of the squat.
It defines the beginning of the concentric phase and can be used to compute concentric velocity and phase duration.

## Use Cases

* Concentric phase duration (ascent start to end)
* Concentric velocity and power
* Bottom hold time (bottom1/bottom to ascent start)