What is the most efficient exercise to lose fat on abdominal area? - K.F.

Next to "How can I lose weight?" that's probably the most-asked fitness question. Lisa Talbott, who teaches "The Abdominal Connection" classes for women at North Lake Physical Therapy in Seattle, prefaced her advice by saying, "Aerobic conditioning probably is the best thing to do to keep fat down on all parts of the body." While 20 minutes a day, three to five times a week, may be enough for health benefits, Talbott says to lose weight (and thus fat) she recommends weight-bearing aerobic workouts 45 minutes a day, five times a week.

Targeting the abdominal muscles doesn't help lose fat, but does change the tone of those muscles, often giving a firmer feel and tighter look. Talbott says the main idea is to identify the muscle targeted and make sure it's contracting. Many people who do crunches (mini-sit-ups) are working only the washboard-like rectus muscles, which run vertically down from the ribs. Below those are the obliques, which bend and twist the torso. Deepest is the transverse abdominis, which flattens the abdomen the most, but usually is the least exercised.

"When you suck in your stomach, like when you're putting on a pair of jeans, that's the transverse muscle," Talbott says. "You don't need that muscle to do a sit-up." This is why many ab exercises begin with pulling in the stomach, as if bringing the belly button toward the spine: so the transverse muscles are being worked the whole time. For normal crunches, put hands either behind the head or, if that pulls the neck, crossed in front to the shoulders. Keep the small of the back on the floor (so the pelvis doesn't tilt. Go slowly, so the muscles do the work, not momentum, and go up just far enough so the shoulder blades leave the floor. Fifty good crunches like that each day work much better than hundreds of poor-form ones, Talbott says.

Still, she adds, we need realistic expectations: "Even if we're doing all the right things, everyone's built differently." Her two-hour classes (next on Jan. 24 and Feb. 19) are $25; for information: 206-361-4745.

I am female, 64, with low to moderate risk of developing osteoporosis. I want to do more exercises to help to slow down bone loss. Can you advise me exactly what to do and how much weight is necessary to see result of gaining bone mass? - W.L.C.

"Boning Up on Osteoporosis: A Guide to Prevention and Treatment" recommends varying exercise depending on activity and fitness levels and bone health, but in general call for weight-bearing activity 30 minutes a day (all at once or in 10-minute sessions) at least four times a week. For resistance training, it suggests two to three times a week, at 80 percent effort (usually one weight lifted 8 to 10 times, increasing the weight as you can reach 10 easily), three sets, resting 1 to 5 minutes between sets. The 70-page guide is $3 through the National Osteoporosis Foundation, 1150 17th St. N.W., Suite 500, Washington, D.C. 20036.

I am 62, weigh 120 and am 5-foot-7. I take two- to three-mile fast walks daily. At least half of that time, I develop moderate pain from my ankles upward for about 6 inches on my lower legs. There is no swelling or pain after I slow down or stop altogether. I wear well-fitting and extremely comfortable running shoes, and walk on sidewalks or asphalt paving most of the time. I attend aerobic classes twice a week and never experience this pain while exercising and moving vigorously indoors on wood flooring. Is this pain shin splints? How can I prevent this pain, and what exercises will strengthen this part of my legs? - C.M.

It sounds a lot like the shin splints I'm all too familiar with, and Bill Welch agreed. A physical therapist at Pacific Physical and Sports Therapy in Renton, Welch said you could try some typical shin-splint advice and if that doesn't help, then check with your doctor. He suggests stretching your calf muscles, using the stretch that looks like you're trying to push down the wall: Front leg bent, back one straight with heel on the ground to stretch the calf. One strengthening exercise: Turn your foot inward and up, so the bottom of the foot is trying to face the other leg. An isometric exercise: Push the ball of the foot against an immovable object. You might also want to try orthotics, perhaps starting with over-the-counter arch supports.

A new book with an overview of shin splints and other common recreational-athlete injuries is "The Return to Glory Days" ($14, Pocket Books) by Morton Dean and Benjamin Gelfand.

Molly Martin is assistant editor of Pacific Northwest magazine.

-------- Notebook --------

No-stress shopping

Can't find any more Tub Tea? Looking for a computerized punching bag? Need a few womb sounds to help you sleep? The Stress Less catalog (800-555-3783) assembles products to help counter the strains of daily living. At its website http://www.stressless.com you can take a short stress-assessment test and find tips on stress-reduction skills.

Weight belt blues

It's an ongoing debate in weight rooms: Does wearing a weightlifting belt ward off injury and improve performance? A study in a recent issue of Spine magazine (reported in the FitnessZine, http://www.fitnesszone.com) found the belts led to weaker back and abdominal muscles, and less lifting capacity. Proper technique was recommended instead of belts, but those already wearing belts are advised to check with their doctors before switching to beltless training.

Carbo-addicts alert

Fans of Drs. Rachael and Richard Heller and their "Carbohydrate Addict's Diet" books can get social and dietary support by joining the e-mail list: e-mail listserv@maelstrom.stjohns.edu and put in the body of the post: subscribe CADIS (your whole name). Once signed up, follow the directions to request the digest, which compiles the daily postings (which can number 40 or more) under one e-mail.

Ask again

Questions on training, equipment or nutrition? Send them to Ask Molly, On Fitness, Pacific Northwest magazine, Seattle Times, P.O. Box 70, Seattle, WA 98111, e-mail mmar-new@seatimes.com or call 206-464-8243.