> ## 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.

# Rise Time

> Time from seat off to stand for each sit-to-stand repetition, with its mean and change across the capture.

## Technical Details

* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** seconds (s); percent (%) for Change
* **Column Name:** `rise_time`, `mean_rise_time`, `rise_time_change`
* **Optimal Direction:** Lower is better
* **Measurement:** Time from [Seat Off](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/events/seat-off) to [Stand](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/events/stand) of the same repetition

## Variants

* **Rise Time** (`rise_time`) (per repetition): time from Seat Off to Stand.
* **Mean Rise Time** (`mean_rise_time`) (summary): average Rise Time across all analyzed repetitions.
* **Rise Time Change** (`rise_time_change`) (summary): percent change from the first to the last [valid](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/repetition-validity) repetition, `100 × (last − first) / first`. Positive values mean the rise got slower. Requires at least two valid repetitions.

## Description

Rise Time is the duration of the standing-up portion of each repetition.
A shorter Rise Time reflects a faster, more powerful rise.
Rise Time Change compares only valid repetitions, so a final partial stand does not distort the trend.

## Use Cases

* Speed of the rise, separate from the descent
* Fatigue across repetitions
* Comparison with [Descent Time](https://docs.uplift.ai/biomechanics/activities/stability/sit_to_stand/metrics/descent-time) to assess movement control


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.