> ## 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.

# Initiation

> Initial movement beginning the softball pitch.

## Technical Details

* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `initiation_frame`
* **Required for QA:** False
* **Measurement:** Frame of max forward trunk flexion in the 2 seconds before max knee raise

## Description

Initiation represents the very beginning of the pitching sequence, identified as the point of maximum forward trunk flexion before the drive leg begins to extend.

## Use Cases

* Pitch timing analysis
* Event timing comparisons - time to release