Sit on top of a Swiss ball with your feet flat on the floor and hands by your ears. Slowly lean back and roll yourself along the ball until your torso is parallel to the floor.

Slowly curl yourself up, letting your shoulders and upper back lift off the ball and slightly twist your right shoulder towards your left hip. Focus on keeping the ball from moving. Lower yourself back down, then curl up again, twisting your left shoulder towards your right hip. Lower back down and repeat the exercise for as many repetitions as possible.

As you curl and twist to the left, raise your left knee. Bring your left foot back down as you lower yourself down on the ball, then repeat as you curl to the right, raising your right knee up to meet your left elbow.