Starting Position: Sit on the stability ball with your feet flat on the floor. Engage your abdominals to support your spine. Slowly tuck your tailbone under, curling the spine. Begin to walk your feet away from the ball until your head, shoulders and upper back are resting on the ball. Knees should be bent to 90 degrees and your thighs and torso should be at or near parallel to the floor. Knees should be hip-width apart and your feet should be facing forward. Distribute your weight evenly through both feet.
Pull your shoulders down and back to make firm contact with the ball. Maintain this position throughout the exercise. Bring your arms over your chest, reaching your arms toward the ceiling. Straighten your elbows and keep your hands together. Press your hands toward one another to help maintain stability and control during the movement.
Rotational Movement: Exhale. Brace your torso by contracting your abdominal/core muscles to stabilize your spine. Slowly rotate your torso to one side while keeping your shoulders on the ball and feet firmly planted on the floor. Keep your hips and torso parallel with the floor. Avoid the tendency to let your hips drop down. Push your feet into the floor and hips towards the ceiling to help maintain stability and control. Inhale and hold this position briefly before rotating to the opposite side.
Exercise Variation: As you learn to perform this exercise with good form, you can increase the exercise challenge by moving your feet together or adding resistance in the form of holding a medicine ball or cable.
Controlling your balance over the ball is critical for your safety. Avoid fast or bouncy movements that can cause you to lose control and fall.