5 D. Hurst / Alamy

If you’re prone to plantar fasciitis or Achilles tendinitis, don’t spend your summer in flip-flops, says sports podiatrist Stephen Pribut, D.P.M. For starters, flimsy flops offer no arch support. And having to clench your toes to hold your foot in place can cause Achilles tendinitis. But most worrisome: “The repeated rise of your heel off the back of the flip-flop can alter your gait when you walk—and possibly when you run,” says Pribut.

Look for sandals with a molded arch or strap to secure your heels. If your feet or ankles hurt, wear more supportive shoes.

The FDA recently issued stronger warnings about a class of antibiotics—fluoroquinolones (which includes Cipro and Levaquin)—linked to an increased risk of tendon tears. “Fluoroquinolones affect proteins that regulate tissue repair—and can be directly toxic to tissue, especially tendons,” says Susan Joy, M.D., director of Community Sports Health Network at the Cleveland Clinic.

Tips to Help You Sidestep Injuries.

A Scandinavian study reports that runners can lower their injury risk by rotating between two or more pairs of shoes. “Changing footwear alters your running pattern and varies the forces on your legs,” says study author Laurent Malisoux, Ph.D.

Wear a more supportive, cushioned shoe for distance runs and a lighter, flexible shoe for speedwork. Bonus points for picking up a third: “The more shoes in your rotation, the better,” he says.

Our Shoe Finder tool can help you find the perfect pair.

“Iron plays an essential role in shuttling oxygen to muscles,” says Connie Diekman, R.D., of Washington University in St. Louis. Having low levels can hurt your muscles’ ability to repair themselves.

Women need 18 milligrams per day, while men need eight milligrams. Iron-rich foods include lean red meat, fish, dark poultry, and beans (talk to your doctor before taking a supplement). If you experience ongoing fatigue or a sudden decrease in running performance, ask your doc to check your stored iron levels.

Taking a few swigs before a summer run is a no-brainer, since dehydration can up your risk of heat-related illnesses. But fluids are essential for all physical reactions—including muscle functioning and joint cushioning, says nutritionist Marni Sumbal, R.D.

Women should take in 91 fluid ounces per day and men should get 125, which can come from water, sports drinks, and water-rich fruits and veggies.