Squat Leg Raise with a High Ball

Starting Position	Put your exercise ball against the wall at the level of the top of your shoulders so that your head is resting on it as well. Stabilize the ball between your upper back and head and the wall. Place your hand on your thighs, at your sides or cross your arms over your chest. Take a step out from the wall. Keep your chin tucked in, don't tilt your head back Place your feet hip width apart and maintain a neutral spine. While keeping your trunk stable and your chest up, slowly lower yourself down until your thighs are horizontal.
Action	Straighten one knee. Hold this position.
Prime Movers	Quadriceps, glutes, hips, and trunk.
Physio Tips	Don't allow your hips to sag or your back to arch To avoid knee injury be sure that your knees do not move beyond the tip of your toes.
Progression	Hold a weight across your chest. Try Side Squat. Try Single Leg Side Squat.