Exercising with the Ball
The following exercises can be done briefly, to give you a break from sitting, or can be done as part of a workout. For more advanced exercises, consult a physical trainer.
Back Extensions
Lay on top of the ball, face down, with your toes on the ground and the ball under your hips. Place your hands behind your head or back, and roll your upper body down toward the ground. Pause, then lift your chest up off the ball until your body is in a straight line.
Butt Lifts
Lay on the ball, face-up, with your shoulders and neck supported by the ball, your knees at a right angle, and your feet firmly planted on the ground. Slowly lower your butt about halfway to the ground without rolling the ball, then bring it back up until your body is in a straight line.
Body Twist
Assume a pushup position on the floor, with your feet supported by the ball. Your ankles should be about two feet apart and "hugging" the ball. Make sure your back is straight, then slowly twist the ball to the left and right while keeping your shoulders level.
Half-Bird Posture
This one is a little more challenging. Lay face-down with the ball supporting your hips and your fingers and toes on the ground for balance. Raise your feet off the floor while reducing the pressure on your fingers, straightening your back in the process. You will need to roll a little forward or back to keep balanced. When you feel stable, raise one arm out to the side, and hold that posture for 20 or 30 seconds. Repeat with the other arm.
Ham Roll
Lay on the ground, face up, with your heels on top of the ball. Keeping your shoulders on the ground, lift your hips until your body is in a straight line. Then, press your heels into the ball and roll it toward you. This will activate your hamstring muscles (the long muscles on the back of your legs). Be careful not to exert yourself too much, otherwise you may pull a hamstring.
Wall Squats
Back up to a wall and hold the ball against it with your lower back. Move your feet forward about one foot, then slowly lower your body until your knees are bent at a right angle. Hold that position for about 20 seconds, then go back up again. For an added challenge, raise one foot off the ground while you are in the low position.