Rep counting: Apple Watch vs phone camera

How each one counts

Watch apps estimate reps from the accelerometer and gyroscope in your wrist. Each time your arm goes through a recognisable pattern, that's a rep. It works best when the arm moves a lot and the same way each time, like a curl or a press.

A camera app tracks points on your body, such as hips, knees, shoulders and elbows, and counts a rep when a joint goes through a full range and comes back. Because it sees the whole body, it can count moves where your wrists barely move, like squats, and it can tell a full rep from a half rep.

Exercise by exercise

• Bicep curls and overhead presses: both approaches can do well.
• Squats and lunges: hard for a wrist, since your hands may stay still. A side-on camera sees depth directly.
• Push-ups: your hands are planted, so a wrist sensor sees little. A camera sees the elbow bend and body line.
• Sit-ups: wrist motion depends on where your hands are; a camera sees the torso.
• Jumping jacks and high knees: a watch picks up the rhythm; a camera also checks range.

Form feedback

This is the biggest gap. A watch can't see whether your hips sagged or your squat was shallow. A camera can score each rep and cue you, for example to go deeper or keep your body straight. Apex One scores form on all 10 moves it counts and speaks the count out loud.

Privacy

Watch data stays in its health app. With a camera, the question is where the video goes. Apex One processes the camera on your phone and the video stays on your device.

Convenience and cost

A watch is always on you, which is great for gym sessions moving between machines. A camera needs the phone propped side-on with your body in frame, which suits home workouts in one spot.

If you already own a watch, its apps cost little extra. Apex One+ is $19.99/mo or $99/yr in the US, and the squat demo is free in your browser. Some people use both: the watch for heart rate, the camera for reps and form.

Accuracy: where each one slips

Wrist-based counting tends to miss reps when your arm moves differently from rep to rep, when you pause mid-set, or when the move is mostly lower body. It can also add phantom reps when you adjust your grip or reach for a towel. For upper-body moves done smoothly, it can be close to right.

Camera counting slips when the phone can't see you properly: part of your body out of frame, poor light, or a cluttered background that confuses tracking. Set up well, it's very consistent, and because it measures the joint range, it won't count a half squat as a full one. Apex One only counts reps it fully tracked, so a missed rep shows up as one fewer, not a made-up extra.

Setting up a camera rep counter

• Prop the phone side-on at about hip height, 2 to 3 metres away.
• Keep your whole body in frame, head to feet, for the full movement.
• Face side-on for squats, push-ups, lunges and deadlifts; that's where depth and body line are clearest.
• Use even light and avoid strong light directly behind you.
• Start the set once the app confirms it can see you.

What the count is actually for

Counting isn't the goal on its own. The point is honest numbers: knowing your squat total really was 3 sets of 15 to full depth, so you can add a rep next week and know it's real progress. That's also why form matters. Ten clean reps beat fifteen rushed ones.

A camera that cues form and a watch that tracks heart rate answer different questions. If you care most about how hard your heart is working, a watch wins. If you care about rep quality and progress on strength moves, a camera wins.

A simple way to use both

Wear the watch for heart rate and the overall workout, and prop the phone for the strength sets. You'll get a full picture: how hard the session was, plus a rep-by-rep record with form scores for squats, push-ups, lunges, curls and the rest of the 10 moves Apex One counts.

Questions people ask before switching

• Do I need to wear anything? No. A camera counter only needs your phone propped up.
• Will it work in a small room? Yes, if you can stand about 2 to 3 metres from the phone and stay in frame.
• Does it work with dumbbells? Yes. Apex One counts curls, rows, presses and deadlifts with or without weights.
• Can it count every exercise? No. Apex One counts 10 moves; for anything else, count yourself or use a timer.

Bottom line

For home strength training, a camera usually counts more exercises correctly and adds form feedback a watch can't give. For cardio, heart rate and all-day tracking, a watch is the better tool. You can try camera counting free with the squat demo before deciding.

Which should you choose?

• Mostly gym machines and cables: a watch is simpler.
• Bodyweight training at home: a camera counts squats, push-ups and lunges far better.
• Want form feedback on every rep: camera.
• Want heart rate and calories: watch.

Count every rep with your phone

Questions

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