Plank counter
A plank timer that only counts the seconds your body is straight. Your camera watches the shoulder–hip–ankle line and pauses the timer when your hips sag or pike. Runs in your browser.
Set up the camera (side-on, camera at floor level)
- Put the phone on the floor 1.5–2 m to your side, landscape, lens pointing at your body.
- Make sure your shoulder, hip and ankle on the near side are visible.
- Forearm or straight-arm plank both work.
How the counter decides what counts
The timer runs only while the angle shoulder–hip–ankle is 160° or straighter and your body is roughly horizontal (height difference shoulder-to-ankle less than 0.6× the length). Otherwise it pauses and shows what to fix.
These are our counting rules for the app, not an official standard. Angles come from Google MediaPipe pose landmarks and can be off by several degrees with loose clothing or poor light.
Form points
- Elbows under shoulders (forearm plank) or hands under shoulders (straight-arm).
- Push the floor away, brace your stomach and squeeze your glutes so the hips stay level.
- Breathe steadily; stop when you can no longer hold a straight line.
Common problems
- Hips dropping toward the floor — the timer pauses.
- Hips piked high — also outside the line, the timer pauses.
- Camera behind your head: the hip angle cannot be measured head-on; turn side-on.
Exercise at your own risk and stop if you feel pain or dizziness. This app counts movements; it is not medical or physiotherapy advice.