HOW: Get set-up laying flat on your stomach with your knees bent and feet supported on a swiss ball, that is being stabilized by a partner. Begin the exercise by rapidly alternating bending and straightening your knees - kicking your heels into the ball while not moving the rest of your body.
FEEL: You will feel your hamstrings and glutes working with this exercise.
COMPENSATION: Do not excessively arch your back or lift your hips off the ground.
