Some body builders lift weights for more than six hours a day, but you don't have to waste that much time to become very strong. Training for weight lifting is done in sets. A set of ten means that you lift and lower a heavy weight ten times continuously before you rest. If you repeat these sets of ten three times with a rest period between each set, you have done three sets of ten.

Pick 6 to 10 weight-machine exercises and do them in three sessions a week. In each exercise, try to lift the heaviest weight that you can lift comfortably ten times in a row without hurting yourself. When an exercise becomes easy, increase the weight. In five months, you should be able to increase your strength significantly and be proud of your larger muscles.

You now decide that you want to become even stronger. Would you increase your strength more by increasing the number of repetitions or by increasing the weight that you lift? For example, should you try to do three sets of ten for each exercise or stay at one set of ten, just try to lift a heavier weight once a week? Dr. Michael Pollock of the University of Florida in Gainesville divided recreational weight lifters into two groups. In one group, they tried to do three sets of 10 three times a week. In the other group, they did just one set of 10 three times a week, but tried to lift progressively heavier weights. Those who did one set of ten with heavier weights three times week were stronger than those who did three sets of ten without increasing the weight.

The single stimulus to make muscles larger and stronger is to stretch them while they contract. When you try to lift a heavy weight, your muscles stretch before the weight starts to move. The greater the stretch, the greater the damage to the muscle fibers and when they heal after a few days, the greater the gain in strength. The results of this study give a clear message. You become stronger by lifting heavier weights, not by exercising more. If you do too much work, you can't lift very heavy weights and you do not become stronger. When it comes to becoming very strong, less is more.

Most competitive bodybuilders spend hours trying to do many sets over and over again. You don't need to do that. Various studies show that you can gain up to 80 percent of your maximum strength by picking out four to eight specific lifts, lifting one set of ten of the heaviest weight in each, and repeating your program twice a week. The reduced workload causes fewer injuries and leaves you with a lot of extra time to do other things.

Lowering a weight slowly, called negative lifting, is a greater stimulus to make you stronger than raising it. You can lower much heavier weights than you can lift. As you raise a weight, you have to slow down because gravity works against you so that the weight feels heavier as you continue to raise it. On the other hand, when you lower a weight, you tend to move faster as gravity works with you and the weight feels lighter.

This negative lifting workout should be done only by experienced lifters not more often than once a week. Pick 10 to 15 lifts that you do regularly. Start out by lifting the heaviest weight that you can lift ten times in a row. You will struggle to get through the last three or four lifts. Then add five to 15 pounds, which may be too heavy for you to lift. Two spotters should lift the weight for you and you try to lower it six times. You'll really hurt and you may want to quit. Add another ten pounds and try to lower the weight three times. Then pick your arms off the floor, replace them on your shoulders and take at least two days off.

Lifting weights enlarges your muscles and makes you stronger, but it does not make you fit. Fitness refers to your heart and is gained by exercising in an activity where you move continuously, such as running, cycling, skating, dancing, walking or swimming. A complete exercise program should include lifting weights two or three times a week and doing a continuous sport three times a week. Alternating your activities gives your muscles a chance to recover and helps to prevent injuries.

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Dr. Gabe Mirkin has been a radio talk show host for 25 years and practicing physician for more than 40 years; he is board certified in four specialties. For more information and hundreds of fitness and health reports, visit http://www.DrMirkin.com

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