Fit-ball Wall Squat
Step 1 Stand tall with your chest up and weight in your heels, feet hip-width apart and toes pointing slightly outwards. Place a gym ball between your lower back and the wall.
Step 2 Keeping your chest up and weight in your heels, descend into a full squat. Lean into the ball as it rolls down the wall.
Step 3 Drive through your heels to stand.