Lie on your back with your knees bent and feet flat on the floor.
Position a stability ball on your thighs and place both hands on the ball.
Lift your feet off the floor, bending your hip and knee joints at 90 degrees.
With your arms straight, press your hands into the ball.
You should feel both your abdominal muscles and the muscles around your chest and sides tense.
Hold this position.
Relax, and repeat.
