Form check
Plank form check: one line, held.
A plank has no reps, so there is nothing to count and only one thing to watch: the line from your shoulders through your hips to your ankles, and whether it stays a line for the whole hold. Here is what a coach looks for and what the coach in Loopform AI says.
What a good hold looks like
- One line. Shoulders, hips and ankles on a straight line from the side. Not a bridge, not a tent.
- Hips level with the shoulders. The camera reads how far the hip sits from the shoulder-to-ankle line. Below it is sagging; above it is piking.
- Shoulders over the elbows on a forearm plank, over the wrists on a straight-arm plank.
- Breathing. Holding your breath is not bracing. Squeeze the glutes, pull the belly in, keep breathing.
The two faults and what the coach says
Hips sagging
The hips drop below the line as the hold goes on and the lower back takes the strain. Squeeze the glutes hard, tuck the pelvis slightly, and if the line still breaks, the hold is over: a sagging plank is not building anything good.
The coach says: "Hips are sagging. Squeeze your glutes." · "Tighten the core, hips up in line." · "Brace. You're dipping through the middle."
Hips piked
The hips rise above the line into a tent. It feels easier because it is: the lever is shorter. Lower the hips until you can feel the stomach working again.
The coach says: "Hips too high. Flatten out." · "Drop the hips, body in one line." · "You're piking. Bring the hips down."
How to check yourself
- Phone on the floor, propped up a little, 6 to 8 feet to your side; get into the plank side-on to it, head to feet in frame. The filming guide has the rest.
- Scrub the video from the first second to the last. A plank that starts straight and ends sagging tells you your real hold time: the point where the line broke.
- Stop the hold when the line goes, not when the clock says. Three honest twenty-second holds beat one minute of sag.
How Loopform AI coaches it
Side-on to the phone on the floor, the coach times the hold and turns every second into a "rep", carrying whatever it saw in that second. The clock only runs while your body is a line near the floor; drop to your knees or sit up and it pauses, then resumes where it left off, so the number you hear is seconds actually held. It counts out loud along the way: "20 seconds." "30. Keep breathing." "That's 40. Stay long." And it tells you, once, if the hips sag or pike.
Rep counting and form cues are free, with or without a subscription. Video never leaves your phone unless you share a clip. Android arrives in January.