EDITOR'S NOTE: Washingtonian Denise Austin is the resident fitness expert on NBC's "Today" show, author of Denise Austin's 1-Minute Exercises, star of exercise videos and ESPN's "Getting Fit With Denise Austin." She is also known as proud owner of one of the world's hardest ("firm" doesn't do it justice) tummies. You'll have to take our word for that, but starting today you can take her words for the rest -- as she begins a new exercise and fitness column for Weekend.

DEMONSTRATING my tummy exercises on the "Today" show, I received more than 25,000 letters from men and women wanting tummy tips -- that's a lot of stomachs crying out in need!

There is no reason why every one of you, by performing my abdominal exercises for just a few minutes a day, every day, cannot achieve a super stomach.

Did you know that 80 percent of Americans who suffer from lower-back pain have weak abdominal muscles? By strengthening them you'll keep your back healthy and improve your posture. After head colds, backaches are the biggest cause of time lost from work.

Did you also know that doing a sit-up with your feet hooked under a couch is not working your abdominal muscles effectively? Instead you're doing most of the work with your leg muscles and hip flexors.

TUMMY TIPS

Never do a sit-up with straight legs. Always bend your knees to relax your back and relieve strain on your lower back.

While performing a sit-up, press the small of your back flat into the floor, pressing the navel down as well. To keep those tummies from protruding, they should be deflated and abdominals contracted.

Proper breathing is important. Exhale on the effort of any exercise; that is, exhale as you sit up, inhale coming down.

A few slow sit-ups are better than a lot of fast ones. Holding the lift requires you to use your strength rather than momentum.

Doing a sit-up with elbows and chin tucked to chest concentrates the work in the upper abdominals; keeping elbows out to the sides and chin up works the entire rectus abdominus -- both upper and lower areas.

Posture plays a key role in keeping your tummy flat. When you slouch forward it has nowhere to go but out. Always make a conscious effort to keep your back upright and tummy tucked in where it belongs!

Hard to believe, but even people who aren't overweight still have potbellies. Excess weight increases one's chances, but a potbelly can happen to anyone who neglects abdominal strength.

To lose inches from your spare tire you not only need to do these specific exercises to zero in on what's weak, but you also must eat less and do an aerobic exercise three to four times a week.

EXERCISES

Here are a few of my favorite one-minute tummy exercises. Do these just a few minutes a day, every day, and you'll start seeing results in about six weeks.

ONE-MINUTE TUMMY TIGHTENER --

Lie on your back with your knees bent. Place a foot on the opposite knee. Clasp your fingers behind your head and press the small of your back against the floor. Lift your head and shoulders slowly, at least 4 inches, using your abdominal muscles. Keep your chin up, elbows back and eyes fixed on the ceiling. Exhale through your mouth as you lift -- don't hold your breath. Hold for 10 seconds. Relax. Repeat twice. Switch legs and repeat.

Benefit: Works the entire abdominal region, including the rectus abdominus, the long muscle running vertically along the abdominal wall from your chest to your pubic bone.

ONE-MINUTE SIDE TUMMY TRIMMER --

Lie on your back with knees bent as above. Lace your fingers behind your head. Slowly raise your head and shoulders from the floor. Exhale and twist to the right from your waist. Try to touch your left elbow to your right knee. Keep your right elbow on the floor. (Don't fret if you can't touch your knee; reaching toward it works your tummy muscles plenty.) Slowly lower your head and shoulders to the floor. Continue lifting, twisting and lowering for 30 seconds. Release. Switch sides and repeat, reaching your right elbow to your left knee.

Benefit: Tones and strengthens your internal and external obliques, the muscles along the sides and front of your abdomen; trims your waistline.

ONE-MINUTE LOWER ABS FLATTENER --

For more concentration in the lower abdominal region, do the same position as the tummy tightener but this time tilt your pelvic area up with your buttocks lifted off the floor.

CLASSIFIED SIT-UPS --

Here's a secret tummy-tightener that's inconspicuous and can be done anywhere. Sitting or standing, tighten your abdominal muscles for 10 seconds; that's equal to one sit-up. To do this effectively, visualize getting socked in the stomach and contract your abdominals in defense, tucking your navel back into your spine. You can be doing sit-ups without anyone knowing it. I'm tucking in my tummy as I write this. If you could do this every hour on the hour, you'll have done fifteen sit-ups without changing into your workout clothes! So the next time you're stuck in a Beltway back-up, waiting for the Metro, or in the Safeway checkout line . . .

Write to Denise Austin c/o Weekend, 1150 15th St. NW, Washington DC 20071.