DEAR DR. DONOHUE: I’m an on-again, off-again racquetball player. Mostly I’m an off-again player because of my hamstring muscles. I have played for about five years. Every year, the muscles on the back of my thigh, either on the left or right, begin to hurt so much that I have to give up the game. One doctor told me I pulled my hamstring muscles. What is a hamstring pull, and what can I do to avoid it? – J.K.

Hamstring pulls happen in every sport. The hamstring muscles are the ones on the back of the thighs. They bend the knee in such a way that the foot comes off the ground upward and toward the buttocks. They also straighten the hips. These are only two of the movements that the hamstrings take part in.

A hamstring pull is a muscle strain, and a muscle strain is a tearing of muscle fibers. Strains, like ligament sprains, come in three degrees. A third-degree sprain is one in which many muscle fibers are torn with a gap between the torn fibers. Sprinters, because of the great force imposed on hamstrings in fast running, often tear their hamstrings. So do athletes who have to make sudden stops.

The hamstring muscles are not as strong as the muscles on the front of the thigh, and that strength difference is one reason why they tear. Prevention of pulls centers on strengthening the hamstrings. Leg curls are the perfect exercise, but you have to have a machine to do them. However, you can perform the same motion with weighted boots. The knee is bent while you draw the heel toward the buttock. You must, of course, support yourself while doing this exercise.

Warming up before playing is another important preventive measure. Warming up is not the same as stretching. Running in place is an example of a warm-up exercise.

Stretching, I’m told, might prevent hamstring pulls. Put one leg on a table that’s slightly lower than your waist. Bend down in a motion that brings your head toward the stretched-out leg. Hold the stretch at least 10 seconds and then switch legs.

DEAR DR. DONOHUE: I am a 68-year-old male who runs about 30 miles a week and participates in numerous races from 5Ks (1 kilometer is .62 mile) to marathons. I ran in a 15K race last weekend. At about the 7-mile mark I got a sharp pain in my right side, similar to ones I remember getting as a child when I ran too far and fast without much prior training.

Since I have been running long distances, I have never experienced this type of pain. When I slowed down, the pain left after about a mile, and I finished the race. What causes such a pain when running? – R.M.

I believe you’re talking about a side stitch. All runners have had one at some point in their career. It’s a sharp pain, more often felt on the right side, just below the bottom of the rib cage.

Theories about the cause of side stitches abound. One has it that they are cramps in the diaphragm – the large muscle that stretches across the abdomen and separates it from the chest. It’s the main breathing muscle. Another theory says it comes from the intestines pulling on their ligament supports.

Remedies for side stitches are as numerous as theories about their cause. One is to lean forward, while contracting the stomach muscles and pushing in at the painful site with the fingertips. Another says to breathe out forcefully through pursed lips. A third remedy is to exhale forcefully when the foot strikes the ground. If the pain is on the right side, exhale forcefully when the left foot hits the ground.

DEAR DR. DONOHUE: I am 67 and have high blood pressure, high cholesterol and arthritic knees. Walking was my favorite exercise, but knee pain now prevents that. What exercise would be best for my knees? – R.C.

Swimming would be the ideal exercise. Even if you don’t know how, 67 is not too old to learn. You could also do water aerobics – exercising in the water. Water provides buoyancy that protects your knees.

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

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