> ## 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.

# Stand

> The instant of maximum pelvis height while standing in each sit-to-stand repetition.

## Technical Details

* **Variable Type:** Event
* **Data Type:** Integer
* **Units:** Frame number
* **Column Name:** `stand_frame`
* **Required for QA:** True
* **Recurring:** One frame per repetition
* **Measurement:** Frame of maximum pelvis height during the standing phase of the repetition

## Description

Stand marks the top of each repetition, when the hip center (pelvis keypoint) reaches its highest point.
A repetition is counted when the pelvis rises above 70% of the range between the seated and standing heights, after having been below 30% of that range.
The seated and standing heights are the 5th and 95th percentiles of the smoothed pelvis height over the capture.
This hysteresis prevents small bounces from being counted as extra repetitions.
If the total sit-to-stand range is less than 0.1 m, no repetitions are detected.

Stand ends the [Rise](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand#phases) phase and starts the [Descent](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand#phases) phase.

## Use Cases

* [Repetition Count](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/repetition-count)
* [Rise Time](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/rise-time) and [Descent Time](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/descent-time)
* [Time to Final Stand](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/total-time)
* End of the window for [Rise Height](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/rise-height) and [Relative Power](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/relative-power)


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