Primary Muscle Group: Quadriceps femoris, Gluteus
Muscle Groups Worked in This Exercise: Buttock, Hamstrings
Preparation: Lie on your back, bend your knees and place both feet against the ball. Your arms should be resting at your sides with palms facing down. Lift your hips and low back off the floor. You will be balancing on your heels (on the ball) and your upper back.
Breathing: Inhale as you bend your knees in, exhale as you straighten your legs out again.
Execution: Now, bend your knees and pull the ball towards your hips. Don't forget to inhale! To make this one a little harder, lift your torso higher until only your shoulders are touching the floor. Extend your legs out again and exhale.
Comments: This slight variation really packs a punch and you'll notice the difference in your glutes right away.