Neutral position
Stay stable for three seconds so the current phone posture becomes this session's relative zero.
Motion logic
How should you read relative angle?
The app shows an estimate of the phone's posture relative to the calibrated position. It helps identify directions in a session; it is not a clinical goniometer reading.
One movement path
Find neutral, move away, come back.
Reach the target
When the relative angle reaches your target, extension or flexion counts once.
Return to neutral
The neutral zone unlocks the next count and reduces repeated counts near the threshold.
Why a count may not appear
No count does not always mean a bug.
The app rejects clearly invalid or off-axis samples. Slowing down and staying in one movement plane is usually more useful than forcing past the threshold.
- Calibration is incomplete. Fast movement, angular velocity, or an off-axis pose restarts the three-second window.
- You have not returned to neutral. Jitter during the same departure does not count repeatedly.
- The whole forearm moved together. Phone posture cannot distinguish every whole-arm movement.
- The target is not a prescription. Follow the target and repetition guidance given by a qualified professional.