Strength training's 7% solution

By Nanci Hellmich, USA TODAY


Strength training increases the number of calories the body burns at rest as much as 7% a day, according to a recently published study, which adds to the evidence that this type of exercise is important for weight loss.


For years, experts have touted the benefits of aerobic exercise for trimming pounds, but now more than ever, experts are putting increased emphasis on strength training, also known as weight and resistance training.


A host of best-selling books push this premise, including Body-for-Life by Bill Phillips and Michael D'Orso; The Business Plan for the Body by Jim Karas and Strong Women Stay Slim by Miriam Nelson and Sarah Wernick.


"Strength training is critical for people with a weight-control problem," says Nelson, director of the Center for Physical Fitness at Tufts University in Boston.


"If you are only doing aerobics, you are missing the boat," says Wayne Westcott, co-author of Specialized Strength Training. "You will lose muscle mass and your metabolism will slow down as you age if you don't strength train."


Become a lean machine


Experts say resistance training, including lifting free weights, working out on weight machines and doing pushups, helps preserve and increase lean muscle, which revs up metabolism and increases the number of calories the body burns at rest.


The reason for the metabolic advantage: Lean muscle is like a car engine. It burns the gas, or in this case calories, and provides the power to get you from one place to another. The bigger the engine, the more fuel the car can burn. The larger the lean muscle mass, the more calories your body burns at work and at rest.


The recent study done at the University of Maryland showed that resting metabolic rate increased by about 7% after six months of very intense weight training. So if a person eats 2,000 calories a day to maintain weight, that would mean the body would burn 140 or more calories a day after muscle mass is increased. Other studies show this kind of exercise may increase metabolism as much as 15%.


Experts say that every pound of lean muscle burns an additional 30 to 50 calories each day. In the Maryland study, exercisers added about three to six pounds of muscle in six months, says Jeffrey Lemmer, now with the Human Nutrition Center on Aging at Tufts.


An exerciser might gain a couple pounds of muscle in five to six weeks of intense exercise, Nelson says. Men build muscle more easily than women, she says.


Her research shows that most people who weight train lose fat as they gain muscle and often drop down a size or two in clothing after they start a program. "Fat takes up so much more space than muscle. It's bulky and less dense. A pound of muscle is about 30% smaller than a pound of fat," she says.


Nelson says weight training is especially important for older people because people lose about one-third of a pound of muscle a year, starting in the mid- to late 30s. That's why many people gain weight at about this time, she says. For those who want to lose weight, aerobics is important, too, she says, because people typically burn about twice as many calories in 30 minutes of aerobics as they do during 30 minutes of weight training.


The dieter's secret to success


Many successful dieters do both types of exercise, say obesity researchers who have studied people who've successfully lost weight and kept it off. They found people who are participating in the National Weight Control Registry burn an average of 2,800 calories a week with exercise. On average, participants use about 1,000 calories a week by walking. They use another 1,800 calories doing activities like weight training, aerobics and biking.


To get the health benefits of physical activity, the government recommends at least 30 minutes of moderate activity most days of the week. For cardiovascular health, the American College of Sports Medicine suggests doing aerobic activity three to five days a week for 20 to 60 minutes, either continuous or intermittent activity. The group says resistance training should include one set of 8 to 10 exercises that condition the major muscle groups. This should be done two or three days a week.


But when it comes to weight control, experts have different ideas on how to allocate exercise time:

  • Nelson says a person should gradually work up to strength training for 45 minutes at a high intensity three times a week. She recommends doing aerobic exercise for 45 minutes three or more days a week.
  • Author Bill Phillips suggests weight training for no more than 46 minutes three days a week and doing 20 minutes of aerobics on the alternate days.
  • Westcott, research director of the South Shore YMCA in Quincy, Mass., says an hour of exercise might be broken down into 30 minutes of aerobics and 30 minutes of strength training and stretching, including warm-up and cool-down exercises. He recommends doing this every other day if the goal is health and fitness. Those who want to lose weight might want to do aerobic exercise six days a week and do a full-body strength training workout three days a week, he says.
  • Author Jim Karas suggests devoting 75% of the workout to resistance training and 25% to cardiovascular exercise. He believes three hours a week of this is enough to achieve significant results.


Strength training can change the way you feel about yourself, Nelson says. "It changes your shape. It makes you feel stronger. And when you are strong, you feel so good about yourself."

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