Side Squat with the Exercise Ball

Starting Position	Put your stability ball on the wall at shoulder height. Stabilize the ball between your shoulder and the wall. Cross arms over your chest. Take a step out from the wall. Place your feet one in front of the other and maintain a neutral spine.
Action	While keeping your trunk stable and your chest up, slowly lower yourself down and back up. Slowly lower yourself back down.
Prime Movers	Quadriceps, glutes, hips, and trunk.
Physio Tips	Don't allow your hips to sag or your back to bend forward To avoid knee injury be sure that your outside knee does not move in front of your foot.
Progression	Try moving further away from the wall. Try standing on the inside leg only. Hold a weight across your chest. Try Single Leg Side Squat. Try Squat Leg Raise.