Strengthening knees
Illustration: Leif Parsons
Talk about a gender gap: Simply being female means we are up to eight times more likely to suffer a severe knee injury than we would be if we had a Y chromosome. Researchers believe a woman's wider hips place the thighbone at a more extreme angle where it meets the knee, putting strain on the anterior cruciate ligament (ACL); female hormones that keep connective tissue pliable may also weaken the knee. Now it looks as if an exercise regimen developed by the Santa Monica Orthopaedic and Sports Medicine Research Foundation and tested by the CDC's Injury Center may offer women real protection.

The regimen is called PEP (prevent injury and enhance performance). It targets the hip and thigh muscles as well as those in the abdomen and lower back and takes just 15 to 20 minutes, three times a week. A study of 1,435 women soccer players—published last year in the American Journal of Sports Medicine—found that those who followed the exercise plan had 41 percent fewer ACL injuries than players who didn't.

Here are six essential moves from PEP to get you started. 

The rest are at aclprevent.com/pepprogram.htm