Top Ten Runner’s Mistakes

Running is a cheap and easy exercise. "You don't need anything other than a good pair of shoes and somewhere safe to run," says Dr. Margot Putukian, director of athletic medicine at Princeton University. And with all the health benefits of a good jog, it's no wonder that nearly 12 million Americans do it regularly and more than 37 million lace up their track shoes at least once a year. Running helps prevent obesity, diabetes, hypertension, high cholesterol and heart disease. It helps with mental health while burning between 450 and 1,400 calories an hour, depending on a runner's speed and size. Just 30 minutes of cardiovascular exercise three times a week can increase longevity by six years, says Dr. Tyler Cooper, a physician at the Cooper Clinic in Dallas and co-author (with his dad, Dr. Kenneth Cooper) of the new book "Start Strong, Finish Strong."

But even if running seems like the most intuitive exercise you can do, runners still develop some ill-advised habits that can cost them when it comes to their health. Here are 10 of the most common mistakes and how to avoid them:

1. Footwear
Folly Wearing old shoes, or ill-fitting ones, can lead to problems with your feet, ankles and knees. Replace your shoes every 500 miles or so. Cooper recommends buying two pairs of shoes and alternating. "It gives the shoe time to rebuild the cushioning and expand back," he says.

2. Overdoing It
Don't be a weekend warrior. Many people fall victim to the too's—"too much, too soon, too hard," says Dr. William Roberts, medical director for the Twin Cities Marathon in Minnesota. Start slowly, running half a mile, then walking half a mile—or walking a block, then running a block. And take at least one day a week off. People who do too much too quickly can develop musculoskeletal problems like tendinitis in their heels or knees. For physical fitness, just a half hour five times a week is plenty.

3. Skimping on the Stretching
It's most important to cool down after the run. Stretching before the run is OK too, but do it lightly and avoid the "bouncy, ballistic" stretching, says Putukian. Instead, do a "slow, steady stretch," she says.

4. Postponing a Doctor Visit
"People are notorious for trying to run through their pain," says Cooper, a five-mile-a-day runner who admits that he falls into this category himself. "Be proactive. Go to the doctor before it gets bad. A lot of times just putting some orthotics in your shoe can change everything." If you don't take care of a problem, you may end up with chronic tendinitis or shin splints.