Bad Break The injury that last week sidelined Washington Redskins lineman Jon Jansen downs weekend athletes, too. Rupture of the Achilles tendon -- which attaches the calf muscle to the heel bone -- isn't common (fewer than 5,000 cases were reported in the United States in 2002). But it can be a hazard, particularly for men aged 30 to 50 who play stop-and-start sports -- such as football, basketball or tennis -- that involve random, quick motion and calf muscle contraction.

The Fix Surgery is standard for young, active types like Jansen. Most can resume sports in four to six months following rehab. Less-active folks can opt instead for a cast for eight to 12 weeks, but the risk of re-rupture is greater with this option.

Better Yet Many people prone to injury can avoid the problem, say sports doctors. "Often, tendons that rupture are in people with weakened tendons or those with repetitive bouts of Achilles tendinitis" -- an inflammation of the tendon from overuse, worn shoes or running on hard surfaces -- said Nicholas DiNubile, a spokesman for the American Academy of Orthopaedic Surgeons. Chronic Achilles tendinitis can lead to rupture by weakening the tendon. Stretching and strengthening calf muscles make the tendon more durable.

But Wait Didn't a recent study show that stretching doesn't prevent injury? Yes, said DiNubile, but only in a healthy population; no study has examined stretching's impact on injury-prone people, plus one study isn't enough to settle the matter. Stretching is particularly important for people not naturally flexible, he said. For a healthy Achilles, stretch both the upper and lower calves by placing feet flat on the floor and leaning the elbows against a wall 18 inches away, then raising one leg and bending the raised knee. Strengthen the calves by standing feet flat, then rising on the toes, then lowering slowly.

-- Heidi Splete