Flapp
Video biomechanics · Run & Bike

Your technique, measured

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

Video biomechanics · Run & Bike

Analyze a clip

One side-view clip, 20–90 seconds to a report.

What are we analysing?

Position

Road
Aero
Upright

How was it filmed?

Your side facing the camera

Auto works on most clips; set it yourself if the skeleton ever lands on the wrong leg.

Your clip

clip.mp4
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Details · optional
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 in the app, nothing sold — privacy policy
How to film it
  1. Fill the frame Head to feet spans about two thirds of the screen — worth more than every other rule here.

  2. Hold the phone upright Portrait gives nearly twice the pixels on your legs.

  3. Side view, at hip height Turning to follow you is fine; up-and-down shake is not.

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
  • Ride as you race: eyes on the road about 10 m ahead, not on the floor or a screen — a dropped head measures lower than you can hold in a race
  • 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