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Ask the Experts

Why Do Women Have More Knee Injuries?

by Berkeley Wellness  

Q:Why do women tend to have more sports-related knee injuries than men?

A: Anatomy plays a large role—along with some other factors. For one, women have a proportionately wider pelvis, so their thigh bones angle in more sharply from hip to knee, causing greater stress and instability in the knee. And their ligaments tend to be more lax—particularly the anterior cruciate ligament (ACL), which stabilizes the knee by connecting its top and bottom parts.

In addition, they tend to have smaller and weaker leg muscles than men, as well as stronger quadriceps (muscles on front of thigh) relative to their hamstrings (back of thigh), which affects the strain on the ACL. There are also biomechanical differences between men and women in how they land on their feet when running or jumping.

These factors put women at greater risk of developing patellofemoral pain syndrome (“runner’s knee”) and ACL tears. In fact, female athletes are at least twice as likely to injure a knee ligament as male athletes.

Because women are more prone to knee injuries during certain phases of their menstrual cycles, researchers theorize that hormones (namely estrogen) may be involved. Some support for this comes from a University of Texas case control study in Medicine & Science in Sports & Exercise, which found that teenage girls (15 to 19) on oral contraceptives had fewer ACL reconstructions (indicating serious injury) than non-users. What’s more, a study in the journal The Knee that examined the effect of testosterone in male rats suggests that this hormone contributes to the ACL’s ability to withstand loads and thus may also help explain the different ACL injury rates between men and women.

The best way to protect your knees (for both men and women) is to strengthen and stretch your hip and leg muscles (particularly the quadriceps and hamstrings) and do plyometric (jumping) exercises and balance training. Some simple exercises include partial (not full) squats, lunges (don’t go too deep), leg presses and curls, bridges, and squat jumps. Avoid full leg extensions with heavy weights and locked knees; downhill running; cycling with the seat too low or gear too high; and taking large steps on the stairs or on a stair-climbing machine. If you have existing knee problems, it’s best to work with a physical therapist or trainer for more targeted exercises and to avoid further injury.

Also see Don't Ignore Buckling Knees.