Flapp
Video biomechanics · Run & Bike

Your technique, measured

Every joint angle against reference ranges, a 0–100 score and a fix-first plan.

Analyze Video

A few choices, one clip from the side. 20–90 seconds to a report.

What are you analysing?

A clip for the full report, or one photo for a static bike fit.

Sport

Your clip

Drop a file, pick one from your phone, or film right here with a framing guide.

clip.mp4

Position

Where your hands are. Pick the family, then the exact position.

Road
Aero
Upright

Details

All optional. Auto-detect is right for nearly every clip.

Setup & body details optional

Want us to look at something specific? optional

Your coaching notes answer it first. If this clip can’t — a view the camera didn’t see, a force we can’t measure — you’ll be told that instead of given a guess.

Upload a video to continue

Free account · monthly analyses included

Compare plans
  • Your clip never reaches an AI service — only anonymous joint angles do
  • Clips auto-delete (7 days free, 30 on a plan); photos are never written to disk
  • No ad trackers, nothing sold — privacy policy
How to film it

Three things decide whether the numbers are worth reading. Don’t overthink the rest — a phone propped against a water bottle works.

  1. Fill the frame. Head to feet should span about two thirds of it. Sky above and ground below are what wreck the measurement — this rule is worth more than every other one here combined.

  2. Hold the phone upright. Portrait puts nearly twice as many pixels on your legs as landscape.

  3. Film from the side, camera at hip height. A few degrees off exactly 90° actually helps separate the legs. Turning to follow you is fine — it’s up-and-down shake that hurts, not panning.

A few more things that help
  • Stand back 6–8 m and zoom in 2–3× rather than filming close — a close-up wide lens bends the angles at the edges
  • On the bike, film from the non-drive side (chainring away from the camera) — the chainring sits right behind your ankle at the bottom of the stroke and can pull the tracking off your foot
  • 5–10 seconds with you actually in shot, one person in frame — start recording once you’re already running, not before
  • A treadmill is the easiest way to get all of this at once: you stay put, so the camera can sit close, still, and pointed at one spot
  • Normal speed or slow-mo — both work. Slow-mo sharpens joint detail; its cadence & timing are estimates and aren’t graded
  • Light behind the camera, not behind you — a silhouette loses limbs