The single leg wall ball squat is a small knee bend on one leg, with a gym ball pinned between the outside of that hip and a wall. The ball gives your side some support while the standing leg does the work, so you can concentrate on keeping the knee in line and the pelvis level. It trains the front of the thigh (quadriceps), the buttock and side hip muscles, and your balance on one leg.

How to do the single leg wall ball squat

Stand side-on to a wall with a gym ball between the wall and the outside of your hip. Lean in just enough to hold the ball in place, with your feet under your hips.
Reach both arms straight out in front of you at chest height and bring your hands together.
Shift your weight onto the leg next to the ball and lift the other foot a little off the floor, bending that knee, as in the video.
Slowly bend the standing knee as though you were starting to sit on a chair, and let the ball roll a short way down the wall. Your kneecap should stay lined up with your second toe.
Keep your back straight and your chest up, then press down through your heel and the ball of your foot to rise slowly back up. Finish your reps, then turn to face the other way and work the other leg.

What you should feel

Work in the front of the thigh and the buttock of the standing leg, with the outside of that hip helping to stop the knee rolling in. The ball should feel like light support at your side, not something you rest your weight on.

Common mistakes

The knee rolling inward toward the other leg as you bend.
Slumping into the ball so it holds you up.
Going too deep too soon. A small bend with good control is the aim at first.
Your pelvis dipping toward the lifted foot.

How often

Programs often begin with 6 to 10 slow bends on each leg, done for 2 or 3 sets, a few times a week. Your physio will adjust this.

Stop and check with your physio if

Sharp pain in the knee, pain around the kneecap that builds with each bend, or the knee gives way.
You feel dizzy, lightheaded, faint or sick, or the room seems to spin. Hold your support, sit down and get medical advice the same day before you practice again. If you faint, it does not settle within a few minutes of sitting still, your vision suddenly blurs or goes double, or you cannot stand or walk steadily, call emergency services.
The ball slips away or you start to lose your balance. Lower the lifted foot and step away from the wall.

From the clinic

The voice guide asks you to raise the free knee in front of you to a right angle. In the video she keeps that foot just off the floor with the knee bent, and the steps follow the video, as it is the easier position to balance in. The bend she shows is fairly shallow, which is a sensible depth to start with. Use a well-inflated ball and a clear, smooth patch of wall.

Wear flat shoes that fit well and grip the floor, not socks, tights or bare feet. Set a sturdy chair or counter in front of you, within reach, before you lift the foot. If you have fallen in the last year, feel unsteady on your feet or use medicines that sometimes cause dizziness, hold on with one hand and get your balance checked by your physio first. If you have high blood pressure, breathe steadily through every repetition and never hold your breath.

A sudden loss of balance is different. Call emergency services straight away for any sign of a stroke, even if it goes away: sudden dizziness with unsteadiness or falling over, a face that droops on one side, an arm you cannot lift or keep up, slurred or muddled speech, weakness or numbness on one side of your body or face, sudden blurred vision, double vision or loss of sight, or a sudden severe headache.

With a chair instead of the ball, the supported single leg squat trains the same bend. If one leg is too much for now, the two-legged ball wall squat is a good step back.

After a knee fracture or knee surgery, including a knee replacement, follow your surgeon's or physio's plan, and start this exercise only when they have cleared you. If you have had a hip replacement, get the go-ahead from your surgeon or physio before you try the single leg wall ball squat. Some operations limit this kind of work for the first months, so the timing depends on your surgery.

Written and checked by the PocketPhysio editorial team. Last updated 2026-09-28.

This page is general education, not a diagnosis or a personal treatment plan. If you have pain, an injury or a health condition, see a physiotherapist or doctor before starting new exercises.

Single leg wall ball squat