stressing out

Sunday, July 10, 2011

The NBA’s Ming dynasty ended this weekend with the retirement of the 7 ½ foot Houston Rocket due to injury. Yao Ming was unable to recover from repeated stress fractures in his foot that required surgery to attempt to get the bones to heal. He is not alone in suffering from this type of injury but perhaps he is the poster child for what can go wrong when the body cannot adjust to the pressure demanded of it.

When we walk, run or jump, the foot has to be able to absorb the stress of two to four times the body weight with each stride or leap. The arch of the foot has to flex and the muscles of the foot and lower leg need to act as shock absorbers. Other joints are called into play to help with the biomechanics that can protect the body each time a foot hits the ground. The ankles, knees, hips and back play a role in dissipating the force that can occur hundreds of times a minutes with an athletic activity, whether that be walking or playing pro basketball.

Stress fractures are an overuse injury where a bone weakens because of constant pounding. There may be a mechanical flaw that causes a specific bone to weaken but often it is the metatarsals in the foot that take the brunt of the force if the shock absorbers of the leg fail. The metatarsal bones are the five long, thin bones that attach the mid foot to the toes. They occur frequently in people who suddenly increase the amount of walking or running and are often named March fractures because they so often afflict soldiers. In basketball players, the increased activity isn’t as important as the inability for the foot to tolerate hundreds of pounds of force generated with each jump. A 300 pound, 7 foot player might generate over a half tone of force and sometimes their body is unable to deal with the repeated trauma.

The pain of a stress fracture begins gradually; there is no one inciting event. The pain goes away with rest but then returns when the activity resumes. Sometimes, swelling and tenderness may be felt along the injured bone and the diagnosis is often made by history and physical examination. Plain x-rays may take weeks to show the injury, sometimes showing evidence of healing instead of the break itself. Bone scans and MRI are commonly used to confirm the clinical diagnosis.

Treatment is less than satisfying. It begins with stopping the activity and resting for 4-6 weeks. If there is pain with walking, a walking boot or cast along with crutches may be needed. Most fractures heal with time but depending on the location, there may be a higher risk for non-union or failure to heal. Surgery may be needed to repair the injury with hardware (screws or a plate).

Prevention would be ideal but the research is less than satisfying when it comes to stress fracture. One would think that orthotics or insoles would help in cushioning the foot but while some studies support this idea, others find that orthotics make no difference. What does make a difference is muscle strengthening so that the legs can help with the repetitive shock and stress of walking and jumping. And in women, nutrition may play a role with calcium and Vitamin D being important nutrients to adequate maintain bone density.

It seems though, that the benefit of being tall on the basketball court is balanced with the increased risk of injury the taller and heavier one gets. With pre-season and playoffs, an NBA pro can play a hundred games and just as many practices. The ability of the body to adapt may be the reason a dynasty can collapse.

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