June 17, 2002 -- It usually starts when a woman enters her mid-30s. Muscles begin to fade. A quarter to a third of a pound of muscle is lost per year — every year.
"Women become disabled. We get osteoporosis, diabetes, and obesity largely because we're losing this muscle," Miriam Nelson, an associate professor of nutrition at Tufts University, told ABCNEWS' John McKenzie.
But recent research assures women that they need not give in to aging. Pumping iron is now a proven prescription.
A recent study, published in the Journal of the American Medical Association, found that post-menopausal women can reduce their body fat, increase muscle mass, build up their bones, and improve their balance by lifting moderately heavy weights on a regular basis.
"Biologically, these women were about 20 years younger then they were at the start of the year," says Nelson, expert and lead author of the study.
Experts say the benefits of weight training are now indisputable, to both prevent the effects of aging in pre-menopausal women and reverse the effects of aging in post-menopausal women.
To find out how women can get the most out of weight-training sessions, ABCNEWS.com asked three exercise experts — Johanna Hoffman, an exercise physiologist at the Johns Hopkins Weight Management Center in Lutherville, Md.; Dr. Edward Laskowski, co-director of the Mayo Clinic Sports Medicine Center in Rochester, Minn., and a specialist in physical medicine and rehabilitation; and Dr. Paul D. Thompson, director of preventive cardiology at Hartford Hospital in Hartford, Conn. — their top training tips. Here are their top 12 tips:
1) Set a Goal. Decide what you want to get out of your workout. Are you after Jennifer Aniston's arms or a job with World Wrestling Entertainment? Are you lifting weights to improve function, health, appearance, or sports performance? Once this has been determined, you can better tailor your routine, choosing exercises that will target the proper muscles.
2) Be Consistent. Once you commit to weight training, stick with it. True, a long day at work doesn't provide much inspiration, but resist the urge to skip sessions. "If you can't do a lot, do a little," recommends Thompson. "Something is better than nothing."
3) Learn Proper Form and Technique. "Exercise is like medicine," says Laskowski, "it's based on science." If you have no experience with weights, experts recommend investing in a couple of sessions with a personal trainer. One thing to keep in mind is to avoid hyper-extending or locking out any joints. This allows the muscle to relax, which is counterproductive. Also, be sure that your whole body is properly aligned in order to protect the lower back.
4) Get Tired. While many theories exist on the best ways to build muscle, recent research indicates that a single set of 12 repetitions with the proper weight can build muscle just as efficiently as three sets of the same exercise — good news for people trying to squeeze weight lifting into a busy schedule. Laskowski recommends a single set of exercises using a weight heavy enough to tire the muscles after a dozen repetitions. "When you work a muscle to fatigue, you are releasing factors that build endurance and strength," adds Hoffman.
5) Muscles Are Sexy. Many women avoid weight lifting because they are afraid of looking too buff and muscular, opting instead for the treadmill or the elliptical machine to burn calories. In truth, weight training converts fat into lean muscle. Lean muscle burns more calories, aiding in weight loss. "It's like having a V-8 engine instead of a 4-cylinder. You have a bigger engine to burn more calories because it takes calories to keep that engine running," explains Laskowski.
6) Vary Your Exercises."You can fall in love with your trainer but don't fall in love with any one exercise," says Thompson. If you repeat the same exercise, you will overdo a particular muscle group. Everyone undoubtedly has a particular asset they may want to develop, but don't overdo it. Use a full variety of exercises, machines and resistances. Try lifting free weights, water, household items, and even your own body weight. Changing it up will shock the muscles, challenging them to lift the weight.
7) Move Slowly. Don't cheat by racing through your exercises. Remember, it only takes one set so be sure to get the most out of your time in the gym. Take one to two seconds to contract the muscle, hold the contraction for half a second, and then lengthen the release to three or four seconds. You are 20 percent to 40 percent stronger on the way down so following this time breakdown will maximize strength gain.
8) Work Balanced Muscles Groups. People generally work out only what they can see, says Laskowski, "it's as if they have a 'Cadillac in the front, and a Volkswagen in the back.'" But too much time devoted to one side may create posture problems. Since, every muscle has an opposing muscle, be sure to work the entire pair. For example, follow stomach crunches with back extensions and bicep curls with tricep kickbacks.
9) Find Female-Focused Exercises. Women should pay particular attention to building strength in the upper back and shoulders. This will protect against poor posture later in life, a common problem related to osteoporosis. And don't neglect your lower body — females are five to six times more likely to suffer a knee ligament tear. To protect against knee injury, focus on building the hamstring muscles.
10) Choose a Get-Buff Buddy. A lifting partner is helpful not only for spotting but for motivation as well. When your arms are feeling like Jell-O and you think you've got nothing left to give, a little encouragement from a friend may be all you need to push out that final rep.
11) Drink Caffeine Before Lifting. Although optional, a little caffeine may give you an extra boost of energy to lift after a long day. You may be surprised by the effects a cup of coffee or can of soda can have on your performance.
12) Be Patient. "Rome wasn't built in a day; you won't be either," says Thompson. It takes time to incorporate the benefits of weight lifting. Changes in muscle fiber won't show until four to six weeks, but in the meantime, your muscles are learning how to act more efficiently.
ABCNEWS' John McKenzie contributed to this resort.