Film a 10-second side-view clip of your run or ride — or just upload a single photo. Flapp finds 33 body landmarks, measures every joint angle against reference ranges and hands back a technique score, an annotated overlay and a coaching plan — in minutes, not sessions.
A phone clip or one photo is enoughFree account · 10 analyses / month
Trunk lean is 7° — right where it should be. Next lever: land with the foot under your hips, not out in front.
A real report
Not a mockup — the screens below are a real Flapp analysis of a real triathlete's trainer ride. Every number is measured from the video.
Click to enlarge
Score · grade · confidence — then every joint, measured against reference ranges
Bike fit · before / after · same rider, same road
Flapp flagged a closed hip — 35° against a 45–62° reference — and a collapsed pelvic rotation. Two position corrections later, the same rider re-filmed the same stretch of road. Drag the handle.
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Trackside · no lab, no booking
Form analysis meant a marker suit, a treadmill and a technician with a clipboard — booked weeks out, delivered days later. The measuring has moved. The phone in your armband does it at the track, between two reps, and tells you what to change while the session is still warm.
Side-on, roughly hip height, ten seconds of your normal stride. Between reps and short on time? A single photo is enough for a full angle read-out.
Flapp runs in the browser on the phone already in your hand. No app to install, no cable, no laptop waiting at home.
A photo is measured in about five seconds, a ten-second clip in 30–60. Every joint printed where it happened — green in range, amber drifting, red out of range.
One thing to change and the drill that changes it — applied on the very next repetition, not read off a report next Tuesday.
Side view · captured
Reading 33 landmarks
Run 100 / 100
Every angle inside its band — nothing to fix on this one. When something is out, it comes back red, with the drill that closes the gap.
Force plates, a marker suit, a technician. More precise than a phone will ever be — and Flapp doesn't pretend otherwise. It's also an appointment, a drive across town and a few hundred dollars. Most runners get one. Once. If ever.
The pose tracking that used to need a room full of cameras now runs on the phone in your armband. Not force plates — but a measurement you can actually take today, after a shoe change, mid-block, at the end of a hard session. Frequency beats precision when you're chasing a habit.
How it works
No sensors, no lab, no motion-capture suit. The camera you already own is the instrument — Flapp does the measuring.
Prop your phone at hip height, side-on, and capture 10–20 seconds of running or riding. Short on time? One side-view photo is enough for a full angle read-out.
Pose estimation locks onto 33 landmarks — ankles, knees, hips, spine, shoulders. A photo is measured on the spot; a clip is measured on every frame, through the full movement cycle.
A 0–100 score with a grade, every angle against reference ranges, an annotated overlay and an AI action plan telling you what to change first.
Instrument readings
Coaches eyeball form. Flapp measures it — and shows you exactly where you sit inside, or outside, the reference range.
Cycle-by-cycle repeatability, joint coordination and your averaged movement against reference-athlete norm bands — the analysis a sports lab charges hundreds for.
Knee, hip, elbow, shoulder, trunk — each with your value, the reference range, and a verdict: optimal, acceptable, or out of range.
Your trunk angle translated into drag: how close you are to a time-trial tuck, and whether chasing more is worth the watts.
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From numbers to orders
Data without direction is noise. Every report ends with a coach's note that reads like a coach wrote it — because the AI is briefed like one.
One prioritized issue per session — what's wrong, why it matters, and the drill that fixes it. "Press your forearms into the pads", not "improve your position".
The angles you should protect, named and explained — so you don't break a strength while chasing a weakness.
Every note closes with a single thing to hold in your head on the next ride or run. Not a checklist — one cue.
Want a human in the loop too? Expert Review adds a personal breakdown from a competing triathlete on top of the AI — $39, any plan.
Built by an Ironman 70.3 triathlete who got tired of filming his own rides and squinting at the replay.
Two disciplines, one lens
Running · side view
Most running injuries trace back to mechanics you can't feel and can't see at full speed. Flapp slows it down and puts numbers on it.
Treadmill or outdoor · any pace
Cycling · side view
A pro fit is worth it — once. Flapp keeps you honest between fits, after a saddle swap, or when that knee starts talking on long rides.
Trainer clip is perfect · 10 seconds is enough
Pricing
10 analyses a month cost nothing, forever. Pay only when you want the exact numbers, the video and the coaching.
Starter
See the tech work and try the process.
No card required
Enthusiast
The full analysis for one discipline.
or $9 / month · yearly saves ~36%
Full
Every setup you ride, and a human in the loop.
billed annually
Expert Review
A real triathlete reads your analysis and tells you which single thing to change.
Prices in USD · cancel anytime · secure checkout by Stripe · billed by Clariva
FAQ
Your next easy run or trainer session is all the data you need. Film 10 seconds, upload it, and get your score today.
Analyze your form — freeFree account · 10 analyses / month · no card required
See four real reports first — complete analyses of real footage
Your clip never reaches an AI service · clips auto-delete · no ad trackers — privacy policy