Lie flat on your back. Bring your knees up to your chest. Place your arms over your knees, and pull your thighs toward your chest. Hold your knees in place for 20 to 30 seconds while breathing deeply. Release your knees.
Lie flat on your back, then bring your knees to your chest. Tilt your knees to the right as far as possible without becoming uncomfortable. Hold your knees in place for 30 seconds, then return them to your chest. Tilt your knees to the left, then hold them in place for 30 seconds. Return your knees to your chest.
Get down on your hands and knees. Put your hands straight under your shoulders, and keep your knees hip-width apart. Arch your back toward the ceiling while pulling in your abdominal muscles. Hold this position for a few seconds. Then push your abdominal muscles toward the floor, and invert your back. Hold this for a few seconds, and then return to the starting position.