1. Lie faceup on the floor with your arms at your sides and your heels on a stability ball.
2. Keeping your legs straight and your toes pulled toward your shins, raise your hips so your body forms a straight line from ankles to shoulders.
3. Lower yourself back down to the starting position.
4. Continue for the full set.
Be sure to: Maintain a straight line from your head to your heels, keeping your torso engaged throughout the movement.
You should feel it: Working your glutes and to a lesser degree your hamstrings and lower back.