Low plank hold: how Upfit checks your form

The low plank hold is a forearm plank. It is a timed hold, so there are no reps to count. Upfit watches the line of your body and speaks when it breaks.

How do I do a low plank hold?

Lie face down, then rest on your forearms with your elbows under your shoulders and your toes tucked. Lift your body into one long line from shoulders to heels. Brace your abs and squeeze your glutes. Breathe normally. End the hold when you can no longer keep the line.

How do I set up my phone for a plank?

Planks are tracked side-on, unlike most Upfit moves. Put the phone on the floor and lie with your side to it, so the camera sees your whole profile from head to feet. The app tells you which way to face. From the side the camera can see whether your hips are level, high or low.

What does Upfit check on a low plank hold?

Upfit compares your hips with your shoulders and your knees with your hips. It looks for three faults:

• Hips sagging below the line of your shoulders.
• Hips piking up into an upside-down V.
• Knees down, when you drop to your knees on the mat.

A fault only counts if it lasts. Upfit looks at a window of about two and a half seconds and needs the bad posture for most of it. A brief dip or a breath does not trigger a cue. If knees down and a tilt fault happen together, knees down is called out first.

How is a plank hold counted?

There are no reps. On iPhone 11 and newer, the on-screen count is the number of whole seconds you have held the plank with good form. It pauses when your form breaks and resumes when you recover, and the coach calls out the time every few seconds. On older iPhones the app does not run this hold clock, so do not read that number as a hold time.

What does the coach say?

These are real lines from the app's voice set:

• "Lift the hips out of the forearm plank — no sagging into the mat!"
• "Drop the hips back into the forearm plank — you're piking like a downward dog!"
• "Knees off the floor — get back on the toes over those forearms!"

Watch: how Upfit checks a low plank

A short walkthrough of how to do it, the phone set-up, what the camera checks and what the coach says.

What can't Upfit check on a low plank hold?

Upfit does not check where your elbows are, even though the coach tells you to put them under your shoulders. It does not check your neck or head, whether your legs are straight, or your breathing. It only reads body tilt and whether your knees are down.

Where can I read more?

• What Upfit can't check, including how the form score works
• How Upfit works
• All exercise pages

Upfit is an iPhone app, out now on the App Store. It is a fitness app, not medical advice. Stop if you feel pain or dizziness.