Place a stability ball between your lower back and a wall. Stand with feet shoulder-width apart and slightly step forward so the ball is supporting your back. Engage your core and slowly lower your body by bending your knees and pushing your hips back, rolling the ball down the wall as you descend. Lower until your thighs are at about parallel to the floor, then drive through your heels to stand back up while keeping steady pressure into the ball throughout the movement.
Log your exercise ball wall squat sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.