Bicep Curl Form Check
Wondering if your bicep curl is solid? Prop up your phone — GOODREPS watches your elbow angle (shoulder → elbow → wrist) live and scores every rep while you train your biceps, with forearms assisting. 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 BICEP CURL
Setup Stand facing the camera, a weight in each hand, arms hanging straight, palms forward.
- Curl the weights up toward your shoulders, elbows pinned to your sides.
- Squeeze at the top, then lower under control until your arms are fully straight.
- Don't swing — only your forearms move.
Same sheet as the ⓘ panel in the app — animated demo included.
THREE STEPS TO A SCORED BICEP CURL
Prop your phone and get in frame
Phone at roughly torso height, stand facing 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 elbow angle (shoulder → elbow → wrist) on-device — no wearables. A pair of dumbbells — or anything with a bit of weight; log it and track PRs.
Move — and watch the form bar
The bar fills from ~155° toward ~45° at the bottom. Cut range short and it tells you; full ROM is what counts.
WHAT THE CAMERA WATCHES
- Your elbow angle, live — from roughly 155° hanging straight up toward 45° at the squeeze. Half-curls that never straighten back out don't bank.
- Your personal range of motion — after 3 clean reps the counter calibrates to how you move, so it stays honest without being unfair.
- Whether you actually finish the rep — cut it short at the bottom and the form cue is right there: "Extend fully."
COMMON BICEP CURL MISTAKES
Swinging the weight up
If your torso rocks, your hips are curling — not your biceps. Pin your elbows to your sides and let the forearm do all the travel.
Never straightening the arm
Stopping halfway down keeps constant tension off the muscle's full range. Let the arm reach full extension before the next rep — the counter checks for it.
Rushing the lowering half
Dropping the weight wastes the best part of the rep. Take two beats on the way down; your biceps grow on the negative too.
Wrists curling inward
Bent wrists shift the load to your forearms. Keep them neutral, like you're holding a tray handle.
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 dumbbells to count bicep curls?
Any weight works — dumbbells, resistance bands, even a loaded backpack. Log whatever you're lifting and the app tracks your PRs across sessions.
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.