DEAR DR. DONOHUE: My son entered high school this fall, and to the surprise of me and my husband, he tried out for the junior-varsity football team. He made it, and, even more surprising, he is one of the best players. He never did anything athletic before.

We got a note from his coach asking us about his health. He said that the boy coughs a lot when playing, and he would like us to get a doctor’s opinion. He has always been healthy. He doesn’t cough at home. What could this be? Is it the end of his athletic career? – J.J.

ANSWER: It could be exercise-induced asthma. That’s asthma that comes on during periods of intense exertion. Some people with asthma will have an attack while exercising. But others who never had an asthma attack before come down with one while exercising.

Asthma is a sudden constriction of the bronchi (the airways) along with inflammation of the bronchial lining. Signs of asthma can be one or more of the following: shortness of breath, wheezing and coughing. The affected person often complains of chest tightness.

You or your husband could watch your son while he’s practicing and see if he has any of these asthma symptoms. Better yet, get him to the doctor, who can test him for asthma.

If he does have exercise-induced asthma, he doesn’t have to stop playing sports. Medicines in pill or inhaler form usually can quickly terminate an asthma attack. And inhalers or pills can prevent attacks.

Some have found that specific training can lessen the number of exercise-induced asthma attacks. The program goes something like this: People warm up for 10 minutes, and then for the following 35 minutes go through physical activities that alternate between low-intensity exercises for a minute and a half followed by high-intensity exercise for 20 seconds. Then there’s a rest break that lasts until the person’s heart rate drops to 130 beats a minute. This is getting ahead of things. First, the boy needs a diagnosis.

DEAR DR. DONOHUE: Partly from reading what you have to say and partly from listening to my doctor, I have taken up weightlifting. I am 86. I don’t lift heavy weights. I started with 1 pound; I now use 5 pounds. I feel much stronger. My question has to do with how fast one is supposed to lift the weight. Is there a rule about this?

ANSWER: You really don’t have a big concern. Lifting is fine regardless of timing.

However, standard instructions say to lift the weight in two seconds and lower it in four.

Some now favor faster lifting for older people. Faster lifting builds power. Power and strength are not the same. Power means exerting force in as minimal amount of time as possible. Power declines more rapidly with age than does muscle size and muscle strength. Power is what keeps people from falling.

To increase power, lift the weight up as fast as possible. Pause for one second in the lifted position. Then lower the weight in two seconds.

Don’t get all bent out of shape trying to do this. What you’re doing on your own is fine.

DEAR DR. DONOHUE: The latest fad in the gym I use is sit-ups on a huge ball. I watch people doing it and wonder if they know something I don’t. What is the advantage of doing sit-ups in this way? – R.K.

ANSWER: That huge ball is a stability ball and is used in many exercises. When the ball is positioned under the lower back, abdominal muscles get a more intense workout when people do sit-ups on it. The ball requires a person’s muscles both to keep the ball from rolling and to keep the body from tumbling off it. That gets more muscles into the act, and the muscles that are used in a regular sit-up are exercised more rigorously.

Try it. You might learn to like it.

DEAR DR. DONOHUE: I was involved in a car accident two and a half years ago. My knee was injured and lacerated. I was told I have prepatellar bursitis. What can be done for it? – Anon.

ANSWER: Bursas are thin disks placed between tendons and bones to reduce friction. Bursitis is inflammation of those disks. The inflammation causes swelling. Your disk is located in the region of the knee. It’s a frequent site for bursitis. If rest and anti-inflammatory drugs like Advil or Aleve do not relieve the inflammation, a doctor can drain the fluid with needle and syringe and then instill a cortisone drug to prevent fluid from coming back.

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