About one-fourth of all problems treated by orthopedic surgeons involve the knee, according to the American Academy of Orthopaedic Surgeons. Torn ligaments and cartilage are the bulk of the problems, but many knee ailments are lumped under the term "runner's knee," a loose heading for aches and pains involving the kneecap.
Runner's knee, which can strike cyclists, swimmers, basketball and volleyball players, step-aerobics fans, and runners, happens when the tendon below the kneecap becomes irritated from overuse or there is wear or arthritis under the kneecap. Sometimes, in knock-kneed people, leg muscles pull the kneecap out of the groove in which it normally slides up and down, causing painful grating on the cartilage. Flat-footedness also can cause kneecap displacement during exercise.
Note: Women are especially vulnerable to ligament injuries and other knee disorders. A study by Edward Wojtys, M.D., of the University of Michigan Medical School, found that female athletes had more knee laxity, less muscle strength and endurance, and different muscle reaction time than male athletes, even when strength was corrected for body weight. These factors have contributed to a large rise in women's knee injuries, two to eight times the level found in male athletes.
What longtime basketball, volleyball, soccer, or hockey player or runner hasn't twisted an ankle and torn a ligament or tendon? "In my practice, ankle sprains are the most common injury," says Dr. Maharam. Ankle sprains account for one in five sports-related injuries, reports the American Orthopaedic Foot and Ankle Society.
"Shinsplints" is a general term used to describe pain on the inner side of the middle third of the shinbone. Shinsplints can be caused by running or jumping on hard surfaces, wearing worn-out shoes, or increasing intensity too fast while training.
The shinbone is the attachment site for muscles used to help raise the arch of the foot. Insufficient arch support or too-tight calf muscles strain these arch-raising muscles and the attached tendons, causing mild to sharp pain. Shinsplints often occur in people who aren't used to exercise, says Robert Nirschl, M.D., of the Nirschl Orthopedic Clinic at Arlington Hospital in Arlington, Virginia.
While you can tear any muscle tissue during exercise, the most common pulls are to the hamstring, calf (especially in aging tennis players), and groin muscles. Most are caused by weakness, fatigue, inflexibility, or a hasty and improper warm-up.
The good news here is that low back pain is less prevalent among people who exercise regularly. It is a far more serious problem among overweight, sedentary people. Dr. DiNubile cites a study that showed fewer back problems among firefighters as they improved their aerobic fitness.
Low back pain, however, is always lurking around the corner for golfers, tennis players, cyclists, joggers, and baseball and softball players. One hurried warm-up before the first tee can bring any golfer to his or her knees with a backache.
Usually, the problem is the sudden overloading of muscles and ligaments that aren't warmed up or strong or flexible enough to withstand the activity. Back spasms, bulging discs, and sciatica (pain shooting down the leg from the lower back) are less common but more painful.
Runners may be surprised to know their low back pain is usually not related to the above causes. "The most common cause of low back pain in runners is a leg-length discrepancy," says Dr. Maharam, author of Backs in Motion. Repeated and jarring movement with one leg 1/4 inch longer than the other throws the back out of whack.
About 4 million people seek medical help each year for shoulder sprains, strains, and dislocations. Shoulder pain is common in sports that involve excessive overhead motion, such as swimming, tennis, weight training, volleyball, baseball, and softball. Early in the season, too many innings of softball can be hard on winter-softened shoulders.
Most shoulder problems are from overuse. The shoulder is a ball-and-socket joint held together by a group of muscles and tendons called the rotator cuff. Repeated use loosens the rotator cuff, and you feel stiffness, a lack of strength, and slipping in the shoulder, especially as you raise your arm overhead. Impingement is the pain caused by excessive rubbing of the rotator cuff on the top part of the shoulder blade.
When the tendons and muscles on the outside of your elbow are repeatedly overloaded in the backhand stroke in tennis, the result is a tendon degeneration called tennis elbow.
Golf elbow occurs when poor strokes result in jarring divots and when golfers try to "muscle the ball," says Dr. Nirschl, author of Arm Care. Golf elbow can occur on either elbow -- on the outside of the leading elbow (the left arm for right-handers) or the inside of the trailing elbow (the right arm).