Could you please give us some exercises to do using the exercise ball that would be good to strengthen the abs? Also, thank you for explaining how to get the most out of doing the crunches by keeping the feet off the floor. I was doing them with my knees bent and close to my buns but feet on the floor. Thanks, Mary Lou

I am so glad you asked this question! In my experience, the large stability ball is the most effective piece of exercise equipment one can use to achieve strong abdominal, back, and leg muscles. And while you are using the ball, you are also working on improving your balance - that's why it is called the "stability" ball.

In this article, I am going to describe several ball exercises and techniques that will not only strengthen the center core of your body - known as the "powerhouse" or "foundation" - but will also work other areas along with increasing balance and proper posture.

Begin using the following tips for continued success and maximum results. Be sure, as always, to check with your physician before starting any exercise program. Clothing that is snug is recommended. You will need space. Remember to breathe normally and also realize that it will take time and experience to become comfortable with and on the ball.

There are three sizes of balls: 45 cm - for under 4'10"; 55 cm - for under 6 feet; and 65 cm for over 6 feet. In general, when seated on the ball, the knees should be even with or slightly above the hips. The firmer the ball, the more difficult most exercises will be, so you might start with a softer ball (let out some of the air).

In the beginning, get used to the ball by sitting on it, rotating, and also walking down the ball, while leaning back. You will feel awkward and challenged, but it won't take long for you to start loving it if you just stick with it. Do what you can and work at your own pace.

You will experience a deeper and more beneficial abdominal workout than ever before. Sit in the middle of the ball with your feet spread out in front of you and wide apart. Drop backward down onto the ball, so that the small of your back is in the middle of the ball. This is the position with the greatest range of motion, but if you start feeling too much strain on your back, come forward a bit on the ball.

You will do curls, supporting, but not pulling on, your head and neck with your hands and arms. Make sure that it is your abdominal muscles that are doing the work. Breathe out as you come up, in and you go back down.

Also, do curls on the diagonal, bringing your rib cage to the opposite leg, keeping your elbows wide - working those obliques. Start with a few in each position and work up to 30 repetitions in each direction.

You will be amazed by how quickly your foundation or trunk will firm up and become strong. When you are ready for a break, just lie back on the ball, spread out your arms, and relax completely. It is not only a wonderful tool for exercising, but the best for stretching also.

Strengthen those all important quadriceps and calves while using the ball against a wall. The quadriceps, muscles on the upper portion of our legs, help protect our knees, so need to be strong. For this exercise, place the ball fairly low on your "buns" between you and a wall. Start with your feet far enough out in front of you, so that as you squat your knees do not protrude out over your toes (this is hard on the knees). Keep your head up, your body erect, and abdominal muscles tight. Squat slowly (the more slowly the better), first with the feet shoulder width apart, then wide apart, and finally together.

As you become stronger and can manage more repetitions, try to hold in the down position for several seconds. Be sure to stretch out those "quads" and then turn around and place that ball in front of you and between you and the wall. Your legs are back far enough so that your heels just touch the floor, feet about six to eight inches apart. Then rise up and down slowly, feeling your calf muscles working hard.

As you progress, place one ankle behind the other and rise on one leg and then switch to the other leg. Take time to give the calves a good stretch. (Note: you will find a stretch in my previous article on muscles.)

Celebrate "buns of steel" by exercising on the ball. One area for me that has always been elusive when it comes to firming is the gluteus maximus, better known as our "buns." Not anymore, now that I use the ball! Start on the floor, kneeling gently behind the ball, take a deep breath, blow out all the air, tighten your abdominal muscles and drape over the ball with your waistline in the middle of the ball and your hands lightly on the floor in front of the ball.

You can keep one foot on the floor - or in the air - as you slowly raise the other leg for at least 20 repetitions. Switch legs. Then, keeping your legs together, raise both of them as often as you can mange. It is OK to make use of a bit of a bounce from the ball (it makes it fun, too).

Realize that there are many, many more routines and exercises using the ball. I have just touched the surface with a few of my favorite ball exercises. Push-ups with your legs on the ball, shins in the center of the ball, will strengthen your shoulders, back, and trunk.

Leg raises while side-lying, draped over the ball, will strengthen your hips and thighs. The dynamic nature of the ball will improve balance, posture, body awareness, and coordination, along with strength and flexibility.

The stability ball is an affordable tool for all ages and fitness levels. I guess that by now you know that I am sold on using the stability ball. Balls are available for purchase in local exercise stores, or you may visit the American Council on Exercise's website at www.acefitness.org to order a ball.

Just remember, the ball can be a challenge, but a worthwhile challenge. Your muscles and body will be saying, "Thank you." And, you will be having fun while getting fit and fitter.