About PE Rep Counter

PE Rep Counter counts your jumping jacks, squats and star jumps from your camera, and times your stretches, against clear, measurable rules. A rep counts only on a full cycle: arms overhead AND feet out for jacks, thighs flat at the bottom AND a full stand at the top for squats, feet off the floor in a full star for star jumps. Half reps do not count, and every miss gets one named hint. Stretch mode banks good-form seconds only: the clock pauses whenever the position breaks. One person at a time. Nothing ever leaves your device.

How it works

• Your camera faces you (front view) for jumping jacks, star jumps and stretches, and sits to your SIDE for squats. The app tracks your body joints (shoulders, wrists, hips, knees, ankles, nose) with the MediaPipe Pose Landmarker, running entirely in your browser. No video is sent anywhere.
• Set your standing position first. Stand tall facing the camera, arms relaxed at your sides, for 2 seconds. The app measures your height, shoulder width, torso length and leg length from that stand, and scales every threshold to your body and your distance from the camera. Re-measure any time in a lesson or in Settings.
• Each video frame is turned into a few numbers: how high your wrists are, how wide your feet are, how far your hips have dropped, your knee angle, whether your feet have left the floor. Those numbers are checked against the rules below.
• Feedback is one named hint at a time, within about a second: arms up, feet out, go lower, stand all the way up, jump higher, reach higher, lean further. A rep that never completes the full cycle is rejected with the named reason, never just a score.
• The camera is only on while you are in a lesson. It turns off when you go back to the exercise list, press Turn off, or switch to another tab.
• One person at a time. The app tracks joint positions, not faces or names, and no names or photos are stored anywhere.

The rules

• Jumping jacks: rest (arms down, feet together), then arms overhead (both wrists at least 15% of torso length above the shoulders) AND feet out (ankle spread at least 1.8x shoulder width), then back to rest. Arms up without feet out is rejected ("Feet out wide"); feet out without arms up is rejected ("Arms up overhead"); a partial attempt is rejected ("Bigger jump").
• Squats: hips drop at least 35% of leg length with knees bent to 110 degrees or less, then hips return within 10% of the start height with knees opened to 160 degrees or more. A dip that never reaches the down line is rejected ("Go lower"). Coming back up without straightening the legs is rejected ("Stand all the way up").
• Star jumps: both feet leave the floor (at least 4% of body length up) with arms wide (wrist spread at least 2.0x shoulder width, wrists up) and legs wide (ankle spread at least 1.8x shoulder width), then land and reset. Spreading the limbs without leaving the floor is rejected ("Jump: your feet never left the floor").
• Stretches: good-form seconds accumulate only while the position holds. Overhead reach: both wrists at least 5% of torso length above the shoulders while standing tall (hips within 10% of the standing height). Side bends: shoulders at least 15% of torso length to the side of the hips, with one arm overhead. Total elapsed time keeps running separately, so you can see how much of your hold was clean.
• Not seen, not counted: if the app cannot see your head, hips and feet clearly, it says so instead of guessing.

Levels, workouts and quizzes

• Jumping jack levels: Steady jacks (open), Jack practice set (50 points), Jack challenge (150 points). Same full-cycle rule at every level.
• Squat levels: Learn the squat (open), Squat practice set (50 points), Squat challenge (150 points). Same down-and-stand rule at every level.
• Star jump levels: Learn the star jump (open), Star practice set (50 points), Star challenge (150 points). Same full-star rule at every level.
• Stretches: Overhead reach, Side bend left, Side bend right (open, 15 good-form seconds each), Long hold (150 points, 30 seconds).
• Workouts: PE circuit (10 jacks, 10 squats, 5 star jumps, 15-second stretch), Leg builder (3 x 10 squats), Warm-up (10 jacks + stretch). Only clean reps count toward a stage.
• Quizzes: 10 clean jumping jacks, 10 clean squats, 5 clean star jumps, or a 20-second clean stretch. Passing a quiz is +20 bonus points and the Quiz Passed badge.
• Points and levels: +10 per clean rep, +1 per good-form stretch second. Levels: First Rep, Warming Up, PE Star, Rep Machine. Badges: First Clean Rep, First Stretch Hold, Perfect Set, Thirty Seconds, 7-Day Streak, Quiz Passed, PE Circuit Done. Confetti and chimes celebrate wins and can be turned off in Settings.

What it cannot see

• The app needs the right view for each exercise: front view for jacks, star jumps and stretches, side view for squats. From the wrong angle it cannot judge the rep, so it will not count it.
• Loose clothing, poor light, a cluttered background, or another person in frame can confuse the pose tracker. If it cannot see you clearly, it says so.
• The app does not check breathing, speed, landing softness, or how the exercise feels. It does not know if you are injured, tired, or in pain. Stop if anything hurts.
• Pose tracking is approximate. A rep the app counts may not be perfect, and a rep it rejects may have been fine. The rules are the authority inside the app; a real PE teacher is the authority outside it.
• PE-teacher review sought: we are seeking review of this app by PE teachers and fitness instructors, in parallel with its release. Review is not a gate: the app is live while review is sought, and corrections will be folded in as they arrive.

Learn more

These links open other websites in a new tab. PE Rep Counter is not affiliated with any of them and sends them nothing.

Privacy

• Your video never leaves your device. It is analysed in your browser frame by frame and immediately discarded. Nothing is recorded, uploaded or shared.
• One person at a time, no names or photos stored. The app tracks joint positions, not faces or names. It never asks for a name and never saves a photo or video frame.
• No accounts, ads, cookies, analytics or trackers. The app loads nothing from other websites: the code is served from this site, and a security policy blocks connections anywhere else.
• Stored on your device only: which items you have tried, your points, badges, practice days and settings, your standing-position calibration, and whether you have seen the welcome message, in your browser's local storage. Clear it any time in Settings → Clear progress, or with the Offline proof → Delete all my data button, or by clearing this site's data in your browser.
• Offline copy: after your first visit, your browser keeps a copy of the app so it works offline. Clearing site data removes it.
• The camera is only on while you are in a lesson. It turns off when you go back to the exercise list, press “Turn off”, or switch to another tab.
• Hosting: like any website, the server that delivers the app's files may keep standard technical logs (such as IP addresses) of those downloads. The app itself sends nothing.
• Reference links go to other websites, which have their own privacy policies.

Disclaimer

• This is a home practice tool, not a teacher, therapist or safety device. Everything runs on your device: no video, audio or images are sent anywhere. Feedback is automatic and can be wrong. For real instruction, learn from a PE teacher or qualified fitness instructor, linked on the Resources page.
• Not a fitness assessment. Stop if anything hurts. Follow school safety rules: clear the space around you, warm up first, rest between sets, and use with teacher supervision at school. If you have a health condition, an injury, or pain, check with a doctor or qualified professional before exercising.
• The app is provided “as is”, without warranty of any kind.

Accessibility

• Everything works with a keyboard. Feedback is announced to screen readers, and animations follow your device's “reduce motion” setting. Sound and confetti can be turned off in Settings.
• The live check depends on a camera and on moving in front of it. If that does not work for you, the rules, level and workout descriptions and reference links still work on their own.

Credits

• Pose tracking: MediaPipe Pose Landmarker (lite), Apache 2.0, bundled with the app. See THIRD_PARTY_NOTICES.md.
• The form rules (jack cycle, squat depth, star jump, stretch holds) are original to this app and documented above.
• Reference links: SHAPE America, Wikipedia, ACE Fitness, linked, not embedded.
• Built with the on-device coach pattern from the Push-up and Plank Coach app.

PE Rep Counter version 1.0.0