Place your left heel on the ball and stand up straight. Pick a position to focus on, because this move has a lot to do with balance. Slowly squat down until your standing leg is at a 90-degree angle. Slowly come back up. When doing a squat, your knee should not come over your toes. It also helps if you are sitting back on your heel. This move is great for your thighs and butt. After you do 10 reps with your right leg, switch. Place your right heel on the ball, with your left leg standing, and repeat.