How an AI Rep Counter Works (So You Never Have to Count Again)

Step 1: Your body becomes a skeleton of 33 points

When you start a live session, Hughie runs an on-device pose-detection model against every camera frame. The model finds landmarks — shoulders, elbows, wrists, hips, knees, ankles, and more — roughly 33 points that together form a live skeleton of your body. This runs many times per second, entirely on your phone's processor.

Step 2: Joint angles tell the story of a rep

Each exercise has a geometric signature. A push-up is your elbow angle closing as you descend and opening to lockout while your body stays in line. A squat is your hip and knee angles closing to depth and opening to full standing. A jumping jack is arms and legs cycling between closed and extended. A plank is a held shoulder–hip–ankle line.

The counter is a state machine riding those angles: top position → descending → bottom position → ascending → rep counted. The app confirms it can see you before the countdown, and if you drift out of frame mid-set it prompts you to reposition.

Step 3: The video stays on your device

This is the part worth being picky about when choosing a rep counter app: where does the video go? In Hughie, nowhere. The camera frames are processed live on-device and discarded — never recorded, never stored, never uploaded. What Hughie does save is your workout: your reps and sets, how deep each rep went, and where your phone was placed, so he can track your progress. If you agree to AI data sharing, some workout data is sent to OpenAI to write your coach notes, programs, and chat replies. For coach notes, that includes the joint angles from each rep. It isn't used to train AI models, and you can turn AI data sharing off anytime in Settings.

Why automatic counting changes behavior, not just logging

Manual logging fails at the exact moment training gets hard: end of a set, out of breath, arms shaking. Automatic counting removes that failure point and adds something a notebook can't — a live number climbing while you move. Hughie adds motivation on top: voice encouragement during the set, a weekly streak that grows each week you hit your goal, reminders on the days you pick, and a Saturday check-in on how your week is going. Daily challenges and accessories for Hughie are a bonus.

See your skeleton count its first rep

Hughie's live tracking is free to try — 21 exercises from squats and crunches to high knees and squat jumps, counted in real time.

AI rep counter FAQ

How accurate is camera rep counting?

Good conditions — full body in frame, decent lighting — make it reliable, but lighting, framing, and camera quality genuinely vary by phone. That's why every set is editable: tap it on the summary and correct the count before saving, and the fix flows into all your stats. If an exercise keeps miscounting on your device, report it in-app (Settings → Contact Us). I build Hughie on my own, so reports come straight to me, and detector fixes ship fast.

Does it need an internet connection?

Pose detection runs on-device. Your connection is used to sync your account and for Hughie's chat, programs, and coach notes, not for counting reps.

Which exercises does Hughie count?

21 exercises across Beginner, Intermediate, and Advanced tiers — from jumping jacks, squats, crunches, glute bridges, and wall sits up through planks, high knees, split squats, squat jumps, and knee tuck jumps.