It is interesting how many questions concerning abdominals I am asked in my classes and through this column.

I once took a fitness seminar where the leader referred to our obsession with abdominals. He told us that flat abs for women and the six-pack look for men has been so hyped that millions of dollars are spent annually just on this one area alone.

He suggested that if we could only convince the public that the elbow is the most beautiful part of the anatomy, we could probably start a whole new trend in exercise equipment and sales.

I am not in any way taking away from the importance of the abdominals. As I have mentioned before, from just below our breasts and down to the pelvic region - the whole circumference - is our "powerhouse." All movement is generated here, and this area sets our posture and is important for the body's total strength.

Q. I read your article about flat abs, or rather, strong abs and I have a question about the stability ball. Can you give me a detailed description on how to perform abdominal exercises on it with the most effectiveness?

A. I am pleased that you qualified your question with the word "strong" for that is our goal - to have strength in our core - our powerhouse. And you are also wise to be using the stability ball. Almost every exercise performed using the ball will achieve this goal, but I will describe some of the moves that target the abdominal area most effectively.

Start by sitting on the ball with the feet spread wide and in front. Lie back, so that the small of your back is centered on the ball. Then perform crunches - the more slowly you come up and the longer you hold the upright position, the better. You may support your head and neck with your hands (keeping elbows wide), but do not pull on them.

Breathe out as you come up, tightening the pelvic area, pulling in on the abdominals, and then breathe in as you come back down. Vary with doing repeats on the diagonals - bringing your rib cage toward the opposite leg - feeling the movement in the oblique abdominals.

The other, and challenging, abdominal exercise can be performed lying on your back (supine) on a mat. Grab the ball with your feet on both sides. Then, as you perform crunches slowly raise the ball in the air toward you, always tightening your abdominals as you move. And, again, be sure to breathe out as you raise the ball and in as you lower it.

Another great strengthening exercise is to sit on the ball. Walk forward until your head is in the middle of the ball, shoulders are resting on the side of the ball, and feet (about shoulder width apart) are out in front of you, far enough so that your legs are at a 90 degree angle.

Now, form a strong bridge with your body, tightening every part so tight that you can imagine someone being able to walk across you. Now, tighten even more, up and down, breathing out and in. You will feel this in your whole core, and your buns and hamstrings besides.

Q. I am constantly working out my abs and my lower abdomen still bulges out a bit. I am only a size 5 but it feels as if my belly is not under control. Do you have any suggestion? Lisa

A. It doesn't sound like you are carrying around extra fat. I have overweight students who may have strong abdominals (the good news) but have a layer of fat hiding them (the bad news). There are several reasons, however, you could be noticing a bulge.

First of all, if you are doing lots of abdominal work, you may be making a common mistake with your form. As you work those abs, make sure that you are always "sucking them in." It is so easy to let them "pooche" out. When you do this, the abs will get hard, but they will be bulging out.

One way to check this is to place your hand on your abdominals as you crunch and feel if they are coming up as you move. The latest fitness phrase is "navel to the spine." I've watched numerous people doing this, and their abs bulge.

Secondly, and not as easy to remedy, we all have the body types we are born with. No matter how thin or heavy we are our shapes are relatively fixed. If you carry your weight in your belly, it might be generic. You can strengthen it, but not necessarily flatten it.

Thirdly, you may have a condition like I have. Even though I am slim, fit and have a small percentage of body fat, I have a bulge in my belly. It turns out that it is a slight hernia (probably a result of having five children).

The doctor says that as long as it isn't giving me any problems to leave it alone. They could operate to pull it together, but that doesn't appeal to me in the least. So, I just do lots of abdominal work to keep my core and powerhouse as strong as possible.