> For the complete documentation index, see [llms.txt](https://docs.velogicfit.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.velogicfit.com/section-04-aero/sustainability-test.md).

# Sustainability Test

Learn how to use the auto-capture sustainability test function to evaluate how long riders can maintain positions

> **Info:** The Sustainability Test function was introduced with the Aero module of Velogic Studio, but doesn't require a frontal camera to run; you can use it just with lateral cameras too.

The Sustainability Test function is simply "auto-capture on a timer". Its intended use is to see how long a rider can hold a new position before something changes, usually due to fatigue.

To start a Sustainability Test, click the small arrow on the right-hand side of the Capture button on step 2, and then click "Sustainability Test":

![Capture button dropdown menu showing Sustainability Test option for automatic timed capture functionality](https://11145950-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FjxwtZYYk0lvusnMTywNR%2Fuploads%2Fgit-blob-dc9a3fc16ac082499ef5f1c3a5a69a99a1256f99%2Fsustainability-test-1.png?alt=media)

This will open a small configuration window, where you can set how often you want a capture to be taken, and for over what period:

![Sustainability Test configuration window with settings for capture frequency and total test duration](https://11145950-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FjxwtZYYk0lvusnMTywNR%2Fuploads%2Fgit-blob-61a9689b158bd2bb1f0777f426597a452323dc23%2Fsustainability-test-2.png?alt=media)

When you click START, the Capture Area will change to show you information on the progress of the sustainability test:\
![Active Sustainability Test interface showing progress indicators and real-time capture countdown with cancel option](https://11145950-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FjxwtZYYk0lvusnMTywNR%2Fuploads%2Fgit-blob-2b70c835fe843dcce9eadbbf7619d614021a86b1%2Fsustainability-test-3.png?alt=media)

You can cancel at any time. When each capture is taken, it will be automatically named with the time of the capture.

When the test is complete, you can consider using [Spark Lines in the fit log](/section-02-using-velogic-studio/spark-lines.md) to get a quick idea of if/when the important parameters changed during the fit.


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