Hip thrust on stability ball - with alternate heel raise

Lie with your middle back resting on the ball and your feet flat on the floor hips width apart.
Cross your arms over your chest.

Engage your core muscles and tighten your buttock muscles to lift your hips up into the bridge position.
Raise one of your heels up from the ground.
Do not allow your pelvic to drop.
Slowly return to the starting position and repeat the movement with the opposite leg.