COMING TO iOS · JOIN THE WAITLIST
Your technique, measured.
Film a set. 4Form AI tracks your joints frame by frame and shows you the angles, with the range each one should sit in. Same clip, same numbers, every time.
Free to start. No card required. We measure; we don’t diagnose.
142°
KNEE · FRAME 088
148 frames.
One reading.
Nothing is inferred from a description of your set. A pose tracker runs over the clip on your phone, joint by joint, frame by frame, and the analysis is only created once real angles exist.
Outside the band at depth. The flag carries the angle that produced it.
Three steps, no wearables.
Film side-on
Whole body in frame, ten seconds or longer. Any phone camera. No markers, no sensors, no gym rig.
We measure it
Pose tracking runs over every frame and accumulates real joint angles. Progress shows the actual frame count, because that is what is happening.
You read it
Plain-language instructions, not recited joint angles. The exact degrees are one tap away in the skeleton view.
A score without its range is a scoreboard.
Every number arrives against the band it came from: your own working range across your measured history, not an abstract hundred. That is the difference between a reading and a rating.
Measured sessions only. An unscored clip has no measurement behind its number, so it never enters the band.
One reading, one thing to do next.
Home is an instrument panel, not a feed. The Form Index sits against your band; below it, the single highest-signal correction from your last clip.
Break at the hip first, then the knee. Two counts down, one up.
Hip folded past the band at the bottom of every rep.
Observed 73° to 169°, against a band of 80° to 175°. Flags carry evidence: the angle that produced this one is on the ruler below.
The write-up gives you instructions. The skeleton overlay keeps the exact degrees, frame by frame, for when you want to check the work yourself.
We measure joint angles. We don’t diagnose injuries, and we don’t claim to prevent them. Measurement happens on your device, and your clips are never uploaded. We only ever receive the numbers.
Ordered by how well side-on tracking holds up.
Sports supported: Weightlifting, Running, CrossFit, Boxing, Martial Arts, Gymnastics, Basketball, Soccer, Tennis, Golf, Swimming, Cycling, Rowing, Volleyball, Baseball, Track & Field, Skiing, Climbing, Dance, Fencing, and Other.
Three clips a month is a warm‑up.
Paid plans aren’t on sale yet. You can see what’s coming, but nothing can be purchased or charged right now.
Measurement, flags and history stay yours. Everything you’ve already measured keeps working.
Elite is still in development. We’re not selling it until the features behind it are real.
When plans go on sale, purchases will be handled entirely by the App Store or Google Play. 4Form AI will never see or store your card details.
Questions we get asked.
Do I need a special camera?
No. Any phone camera, filmed side-on, whole body in frame, ten seconds or longer. No markers and no wearables.
Is this an injury screen?
No. We measure joint angles against published bands and tell you where you sat outside them. We don’t diagnose, and we don’t claim to prevent injury.
Will the same clip give the same score twice?
Yes. Scores are computed from measured angles, not written by a model from your session title. Same clip, same numbers.
What happens to my video?
Measurement runs on your device. Deleting a session removes the local video with it. Your profile photo is device-local and never uploaded.
Who can sign up?
Thirteen and over. Sign-up asks for a date of birth for that reason.
When does it ship?
iOS first. Join the waitlist and you’ll get one email when TestFlight opens, not a newsletter.
Stop guessing at your form.
One email when the TestFlight build opens. Nothing else, and nothing sold in between.