Pushup form, and what the camera checks before it counts a rep

The four cues

The app shows these before every pushup session, and they are the whole technique:

• Body straight, head to heels. Squeeze the glutes and brace the stomach so the hips neither sag nor rise.
• Hands wider than shoulders, fingers forward, directly under or slightly outside the shoulder line.
• Lower until the chest is near the ground, elbows at roughly 45 degrees to the body rather than flared out.
• Push through the palms to a full lockout at the top. That top position is where the rep is counted.

Where to put the phone

Pose detection needs to see the joints it measures, so the camera has to see your shoulders, elbows and wrists through the whole movement, and ideally your hips and ankles for the body line. Prop the phone at floor level or on a low shelf a couple of metres away, facing you, with the whole body in frame and the room lit from the front or the side rather than behind you. A bright window behind you turns you into a silhouette and the landmarks drift. If the app cannot see enough of you it pauses itself and asks you to get back in frame, and a paused rep is never counted.

What the counter measures

The counter tracks the elbow angle, the angle between the upper arm and the forearm, from the shoulder, elbow and wrist landmarks, and requires the landmarks it uses to be detected with reasonable confidence before it trusts a frame. A rep is a full cycle: the angle closes as you lower, passes the threshold for the bottom, then opens to the threshold for the top. A shallow dip that never reaches the bottom threshold does not start a rep; a lockout that never arrives does not finish one. The app also runs form checks during the movement and shows feedback on screen, “Go lower”, “Extend arms fully”, “Keep arms even”, “Raise your hips”, “Slow down”, with a haptic tap for each counted rep, so you can keep your eyes on the floor.

The three pushups that do not count

The half rep, where the elbows bend to ninety degrees and no further, fails the bottom threshold. The hips-up rep, where the body bends at the waist so the chest reaches the floor without the arms doing the work, fails the body-line check and is usually a sign the set is too long. The bounce, where the chest hits the floor and rebounds, often counts, because it does pass through the thresholds, and it is the one to police yourself, since it is hard on the shoulders and teaches nothing. Go down under control, pause, push.

Building from zero

If a full pushup is not there yet, the earned-minutes system still works; it just needs the rate turned up with Premium or the squat used instead. Build the pushup off a kitchen counter, then a low step, then the floor from the knees, and move to full pushups when you can do ten clean ones from the knees. The camera counts full pushups by the elbow and body-line rules, so knee pushups may or may not register depending on how much of you it sees; treat them as training rather than currency, and let squats pay for the feed meanwhile.