> ## 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.

# Repetition Validity

> Whether each sit-to-stand repetition reached a full stand, and the number of repetitions that did not.

## Technical Details

* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A (Valid Repetition); count (Invalid Repetition Count)
* **Column Name:** `valid_repetition` (Valid Repetition), `invalid_repetition_count` (Invalid Repetition Count)
* **Optimal Direction:** Valid Repetition: higher is better (1); Invalid Repetition Count: lower is better
* **Threshold:** A repetition is valid (1) when its [Rise Height](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/rise-height) is at least 80% of the largest Rise Height in the capture. Repetitions whose Rise Height cannot be measured are invalid (0).

## Variants

* **Valid Repetition** (`valid_repetition`) (per repetition): 1 if the repetition reached a full stand, 0 otherwise.
* **Invalid Repetition Count** (`invalid_repetition_count`) (summary): number of analyzed repetitions with Valid Repetition = 0.

## Description

A repetition is flagged as invalid when the person did not stand up as fully as in their best repetition, for example a partial stand at the end of a timed test.
Because the threshold is relative to the person's own largest rise, it adapts to different body sizes and chair heights.

Invalid repetitions are still counted in [Repetition Count](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/repetition-count) and included in the averages, but are skipped by [Rise Time Change](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/rise-time) and [Relative Power Change](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/relative-power).

## Use Cases

* Identifying incomplete repetitions
* Deciding whether a capture meets the protocol
* Filtering repetitions before custom analysis


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