Primary Muscle Group: Quadriceps femoris, Gluteus

Muscle Groups Worked in This Exercise: Thigh flexors.

Preparation: Sit on the ball with your feet on the floor. Slide down the ball, walking your feet forward, until your lower back rests against the ball. Your thighs should be parallel to the floor, so make sure your feet are far enough from the ball. Place the band under your feet and grasp an end of the band in each hand and bring your hands up by your hips.

Breathing: Exhale while straightening legs, inhale as you return to start.

Execution: One at a time, straighten your legs out in front of you and then back down to start position. Alternate your legs after completing all reps.

Comments: This is similar to a squat that you would do at the gym, only it is protective of your knees. The band simply adds extra resistance.