Bicycle Crunch Form Check
Wondering if your bicycle crunch is solid? Prop up your phone — GOODREPS watches your knee angle (hip → knee → ankle) live and scores every rep while you train your core and obliques. Free in your browser today; coming to Google Play and the App Store.
Coming to Google Play & the App Store▶ Try The Form Check
LIVEHOW TO DO A PROPER BICYCLE CRUNCH
Setup Lie on your back, side-on to the camera, hands by your head.
- Bring one elbow toward the opposite knee as you extend the other leg.
- Alternate sides in a pedaling motion.
- Keep it controlled — don't pull your neck.
Same sheet as the ⓘ panel in the app — animated demo included.
THREE STEPS TO A SCORED BICYCLE CRUNCH
Prop your phone and get in frame
Phone at roughly torso height, set up side-on to the camera. A quick camera test checks lighting, distance, and angle before you start.
The camera locks a 17-point skeleton on you
GOODREPS measures your knee angle (hip → knee → ankle) on-device — no wearables. A mat — no gear required.
Move — and watch the form bar
The bar fills from ~160° toward ~80° at the bottom. Cut range short and it tells you; full ROM is what counts.
WHAT THE CAMERA WATCHES
- Opposite elbow and knee meeting as you rotate.
- The non-working leg extending long.
- Shoulders leaving the floor — this is a crunch twist, not a tiny nod.
COMMON BICYCLE CRUNCH MISTAKES
Pulling on your neck
Hands support the head lightly. Elbows wide; chin untucked from the chest.
Flopping side to side without extending
Long legs matter. Extend fully on each switch.
Racing until form dies
Smooth pedals beat frantic ones the camera cannot score.
Holding your breath
Exhale on the twist. Inhale as you switch.
PRIVATE BY DESIGN
Pose detection runs in your browser via TensorFlow.js. Camera frames are analyzed in real time and immediately discarded — nothing is recorded, nothing leaves your phone, and we never see them. Sign-in is optional; skip it and everything stays local.
QUESTIONS, ANSWERED
Do I need any equipment to check my bicycle crunch form?
Just your phone for most variations. Add free weights when the pattern is clean — the app still scores the movement either way.
Does it work in a home gym or low light?
Run the built-in camera test first — it checks your lighting, distance, and angle with live green checks before you start. If a rep still slips through, manual counting is always one tap away.
Is my camera feed uploaded anywhere?
No. Pose detection runs entirely on your phone, in your browser. Frames are analyzed in real time and immediately discarded — nothing is recorded, nothing is uploaded.
RELATED GUIDES
Free forever — camera counting for all 60 exercises, no account needed. Pro (voice coaching, programs, depth-camera form checks) is $7/mo, $49/yr, or $99 once. No ads, ever.