Set-up: Position a stability ball by your feet and your upper back on a mat.
Lift: Place your heels on the stability ball. Lift your hips off the floor so that a straight line forms between your shoulders, hips and heels. Keeping the hips elevated and the core tight, bring the heels toward your body, rolling the ball towards your rear end.
Instructions and effects for the Stability Ball Hamstring Curl exercise 
