The best way to train your ABS: Should I be doing crunches, sit-ups or something else? … and more of your questions answered here - Fitness Q & A

Shape, March, 2002

Q I know that the old-fashioned sit-up is considered obsolete because it engages the hip flexors. But why is that such a bad thing if it's also strengthening the abs? On the recommendation of an ex-Marine, I added sit-ups to my workout and find them very challenging. I can easily do 300 crunches, but I have a tough time doing 50 full sit-ups. Why are we being taught to avoid them?

A "Full sit-ups are just wasted effort," says Palm Springs, Calif., trainer Scott Cole, co-creator of the Best Abs on Earth video. "You're only working your abs in the first 30 percent of the movement." If you can perform 300 crunches, you're probably crunching too quickly, relying on momentum rather than muscle power. Or perhaps you're using your arms to fling your neck forward rather than lifting from your torso. "You should be able to isolate your abs in 20 crunches or less," he says.

Crunches are a better use of your time than sit-ups, Cole says, but even when performed properly, they're not the most effective way to train your abs. In real life, your abs work with other muscles - your back and gluteal muscles - to stabilize your spine. So it makes more sense to train them in conjunction with these muscles than to isolate them with a movement, such as the crunch, that is foreign to daily life or sports. "Crunches don't allow your abs to lengthen fully," Cole says. "If you watch Marion Jones sprinting, you'll see her abs lengthening and contracting as they stabilize her torso. Athletes don't do 800 crunches or have Ab Rollers. The people who have great abs take a multidimensional approach." Cole suggests tai chi, kickboxing or a power-yoga class (see "Power Up Your Yoga" on page 136) that emphasizes core-focused exercises.

Q My husband and I have been exercising for eight months and are thrilled that we have each lost more than 20 pounds. At first I could barely last five minutes on our treadmill, but now run 30 minutes a day and lift weights every other day. However, we are both so exhausted all the time. Why is this? We eat lots of veggies and lowfat foods and limit our calories to 1,300 a day.

A "You're tired because you're not eating nearly enough calories to fuel your daily activities, let alone your workouts," says San Diego sports nutritionist Karen Freeman, M.S., R.D. The typical woman needs about 2,000 calories a day and the average man needs about 2,500 calories -- considerably more if you exercise regularly. Your precise calorie needs depend on several factors, including your body size, muscle mass and activity level. A registered dietitian can make recommendations that suit you and your husband as individuals. To find a local nutritionist, go to eatright.org, the Web site for the American Dietetic Association. In the meantime, gradually increase your calories by adding more fruits, vegetables, whole grains and other nutritious foods. Your fitness and weight-loss achievements are impressive, Freeman says, "but it's not enough to be at your ideal weight if you have no energy."

Q I'm 5 feet 7 inches and 230 pounds, and I've last 20 pounds by walking and lifting weights. I'd like to start running, but because of my weight I'm concerned about stress on my joints. Should A trim down by lower-impact means before I take up running?

A Yes. "Because of your weight, you're at added risk for developing stress fractures, tendinitis and other problems with your knees, ankles and feet," says Gary Brazina, M.D., an orthopedic surgeon at Cedars-Sinai Medical Center in Los Angeles. Lower-back problems also may crop up because your weight will place excess stress on your vertebral disks.

For now, Brazina suggests, stick to walking and other low- or no-impact forms of cardiovascular exercise, such as biking, swimming or low-impact aerobics. Once you weigh less than 200 pounds, try a walk/run program. For instance, jog for one minute and walk for five, gradually increasing your jogging intervals until they are equal to your walking stints. Be sure to wear stable running shoes with good arch support. Also, be sure to continue the strength-training part of your workout program. The extra muscle can boost your metabolism and help you lose weight. Stronger leg muscles also will help reduce the stress to your knees during both walking and jogging.

Q want my muscles to look defined and toned, not bulky. Should I lift lighter weights and do more repetitions or lift heavier weights and do fewer repetitions? I have been training with weights that are very difficult to lift at the end of a 15-repetition set. Is this about right?

A First, realize that muscle definition depends largely on your body composition. "You can have very toned and firm muscles, but if there's a lot of fat on top of them, you won't see it," says Los Angeles fitness trainer Ken Alan. How much fat you carry depends, of course, on your genetics and your eating habits, as well as your exercise program.

As for your strength routine, you're at the upper end of the repetition range generally recommended, It's great that you're pushing to "failure" -- the point at which the last repetition is so difficult that you can't do one more. "Most people stop at 15 whether they're tired or not, so they're cheating themselves out of the benefit of the set," Alan says.