Form Analysis Canvas
A general workbench for therapists, biomechanists and coaches: measure angles and distances on video, build your own calculations, chart them against the clip and export the numbers.
How far has this tool been checked?
Angles and distances are computed exactly from the points; the checks cover the arithmetic and the formula language. Where the points come from the body-tracking model, its error applies and has not been measured here.
Where the camera goes
Seen from above. Angles are measured round from the front of the athlete; 90° is square-on from the side. Reference line: plane of the movement being studied.
Perpendicular to the movement plane. Any angle or distance that lies in the plane of the movement.
How high, and how it should sit
Framing
Fixed camera, one person visible, the region you are measuring fully in frame.
The 70–90% band is our own guidance. No published source gives a camera distance in metres, so use it as a starting point and adjust until the whole movement fits.
Ready to record?
Tick each item as you set it up. This is a reminder, not a lock.
0 of 10 ready
All the camera settings
Every setting shows where it came from.
- Camera height
- No height is specified. Put the lens at about the height of the body region you are studying, level.
- Our guidance
- Distance
- No published distance exists. Stand back until the whole athlete fits with a small margin, so the athlete fills roughly 70-90% of the frame height. Use the 1x lens and move your feet, not the zoom.
- Our guidance
- Frame rate
- 30+ fps (recommended 60). Confirm the detected frame rate in the app; set the recorded rate for slow-motion clips.
- From published guidance
- Resolution
- 1080p recommended
- From published guidance
- Orientation
- Landscape or portrait both work.
- From published guidance
- Lens and zoom
- Use the 1x lens with no digital zoom. Avoid ultra-wide and fisheye lenses.
- From published guidance
- Lighting
- Improve light and contrast, keep the athlete large in frame and avoid glare. A background close in colour to a tracked marker confuses colour tracking.
- From published guidance
- Stability
- Tripod or fixed support, level with the horizon.
- From published guidance
- Calibration
- Draw a scale line across something of known length and enter that length, or track a standard sports ball. Without it, results stay in pixels and degrees.
- From published guidance
Before you start
- Create or open a project and give it a name.
- Upload an MP4, MOV or WebM clip and trim it to the part you need.
- Choose the pose model, units, which pose to measure and the frame rate.
- Set a scale line, colour regions or ball tracking if you need them.
Cues for the athlete
Plain coaching cues, one thing at a time.
General
- Check the detected frame rate before reading any speed or time.
- Measure in the plane the camera sees; out-of-plane movement distorts 2D angles.
Why camera position matters
Research behind these rules.
2D angles are only trustworthy when the limb moves in the plane the camera sees. Camera-side joints are measured more accurately than far-side joints, and timing is only as fine as one frame.