DEAR DR. DONOHUE: I would like your advice on weight lifting for young children. I have a 7-year-old boy who begs me to let him lift weights. He has two older brothers, 14 and 17, who have turned our garage into a gym, and he wants to join them. Is 7 too young for this kind of exercise? I have heard that weight lifting can stunt growth if it’s begun before puberty. True? – M.D.

ANSWER: Weight lifting by children who have not yet reached puberty used to be thought of as dangerous. There was fear that young children would hurt their growth plates. Growth plates are cartilage sections of young bones that allow bones to grow longer. If a growth plate is injured, the bone might not reach it full length. Weight lifting is no more dangerous to growth plates than any other childhood activity.

It was also thought that weight lifting would not benefit a child before puberty. Experts told us that testosterone was necessary to make strength gains, and prepubertal children have little testosterone. However, it’s been demonstrated that weight lifting definitely increases the strength of young children. They might not see great gains in muscle size – something that happens with the onset of puberty – but they do develop stronger muscles.

This exercise increases bone strength and prevents injuries that can happen to any child playing any sport. It provides insurance against osteoporosis at later ages. It’s a good way to fight childhood obesity. It enhances a child’s movements in all sports.

Young children need strict supervision. A young girl or boy should be able to lift a weight 10 to 15 times, take a rest, lift another 10 to 15 times, take another rest and repeat a third set of 10 to 15 lifts. Children can do this only if they are lifting light weights. They should not increase the weight until they can perform 15 lifts, three times, comfortably. When they can, they can increase the poundage by 5 percent to 10 percent and start all over.

Children should lift only three times a week, with 48 hours of recovery between lifting sessions.

DEAR DR. DONOHUE: Does coffee provide energy for sports and exercise? I hear that it does. How does it work, how much do you have to drink, and when should you drink it? Do sports authorities test for caffeine, and can it disqualify a person from competition? – R.W.

ANSWER: Caffeine appears to improve endurance for prolonged exercises like distance running and to provide stamina for short, intense exercise like sprinting.

A past explanation on how it does this was the theory that it broke down fats, which then became sources of fuel for exercising muscle. The fat spared the body’s main fuel source, glycogen-stored muscle carbohydrate. A newer explanation says caffeine interacts with brain chemicals to quell the sensation of fatigue.

Blood caffeine level peaks at one hour after drinking it. Therefore, the ideal time to take it is an hour before you are scheduled to perform or exercise. The blood level dips to almost zero by six hours.

If you’re not a coffee drinker, you are going to be quite sensitive to caffeine, and it most likely will make you shaky and temporarily increase your heart rate. It takes a little while to get used to it.

Two cups is enough to give you caffeine’s benefits.

If you drink 6 cups, that’s enough to disqualify you for an Olympic event. Are you an Olympian?

DEAR DR. DONOHUE: I’m a 72-year-old woman who started an exercise program of stretching and lifting weights two years ago. I found I could not lift a coffee cup without pain, so I stopped my exercises. A doctor told me I had tennis elbow. My arm is still weak, and my exercise has fallen by the wayside. Is there something I can do at this late date to repair the damage? – R.D.

ANSWER: It’s not too late to have a doctor examine your arm and elbow and give you a definite answer on your injury and its treatment. If the arm is weak but not painful, then the weakness might only be from lack of exercise. You could safely try to resume exercise. Stop if it hurts.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.