What this tool does
Estimates vertical jump height from one tri-axial accelerometer — typically a phone in your pocket or a small sensor on your lower back. It finds the vertical axis automatically and reports jump height by two validated methods.
Recording a good trial
- Attach the sensor firmly. Lower back (over L5/sacrum, the centre-of-mass position) is the validated placement; a phone in a tight pocket also works but is a little less accurate.
- Start the accelerometer app, stand still for ~1 second, then perform a single maximal jump and land.
- Land in roughly the take-off posture — legs near-extended, landing on the balls of the feet. Landing with bent hips/knees makes the flight-time method over-read.
- Export the CSV (time + x/y/z acceleration) and upload it here.
Reading the results
- Flight-time height uses the free-fall duration (h = g·t²/8); impulse–momentum integrates acceleration to take-off velocity (h = v²/2g). When they agree, you can trust the number.
- If auto-detection misses, drag the Move start / Take-off / Landing lines on the chart — everything recomputes live.
Method & references
Flight-time at an L5 sensor is valid against force plates (bias ≈ 0.01 m; Rantalainen et al., Sensors 2022). Flight-time over-reads with flexed landing (Watkins et al., IJSPP 2024). Lower back / pelvis is the standard COM proxy for jump IMUs.