Why One Heel Lifts Off the Ground When You Squat (And How to Fix It)

A heel that pops up mid-squat is almost always a sign of restricted ankle mobility, not a balance flaw. Squat University describes a patient whose left heel lifted off the ground every time he squatted, making it impossible for him to stay balanced.

A good squat keeps the entire foot firmly planted across three points of contact: the heel and the base of the big toe and pinky toe. When testing this patient's ankle mobility, his left ankle was significantly more restricted than his right. He reported feeling a firm block across the front of the joint whenever he tried to drive his knee forward over his toe — the motion every squat demands as you sink deeper.

The test is simple: try to drive your knee forward over your toe while keeping your heel flat on the floor. If you hit a firm block at the front of the ankle joint before your heel has any reason to lift, that's a restriction in the ankle itself, not tight calves.

In the case Squat University walks through, this exact test uncovered a clear side-to-side difference — the left ankle was noticeably more limited than the right, which lined up perfectly with the heel that kept popping off the ground on that side during squats.

Rather than stretching the calf, Squat University used a joint mobilization to restore normal ankle glide. Here's the exact process used with the patient:

1. Place a light resistance band just below the ankle bones.
2. Keep the heel firmly on the floor.
3. Drive the knee forward and then back, staying within a comfortable range.
4. Repeat for 10 reps.
5. Retest the squat to check heel position and depth.

The point isn't to crank out more range of motion by force — it's to help the ankle joint glide the way it's supposed to. After this single set, the patient squatted noticeably deeper while keeping his heel planted, which Squat University points to as proof he was finally moving in the right direction.