Millions of older women suffer the pain and stiffness of arthritis, especially in their knee joints, which can severely curtail everyday activities like climbing stairs or getting out of a car. It turns out there may be a way to protect our knees and avoid the discomforts of aging: strong thigh muscles. That's according to a University of Iowa study published this week, which found that women who had the strongest thigh muscles were about 50 percent less likely to develop knee pain compared with those with the weakest muscles. (The study didn't find the same association in men.)
Previous research has shown that strong quadriceps muscles (located in the upper half of the leg) help protect against cartilage loss behind the kneecap and also provide crucial support for the joint. However, strong thigh muscles don't appear to actually prevent osteoarthritis in the knee; about 10 percent of the female participants developed knee arthritis over the 2½-year study, according to X-rays. Even those without symptoms still had signs of arthritis. "But I think these women wouldn't have otherwise known they had arthritis," says study author Neil Segal, "since they wouldn't have gone to doctor with symptoms." The study wasn't designed to see whether building thigh muscles actually prevents painful knee arthritis, but Segal says it's reasonable to assume that it may.
What should you do? You'll probably need more than a basic aerobic workout like brisk walking or biking to avoid age-related muscle loss in your thighs, as my colleague Katherine Hobson recently reported. You need to supplement your regular exercise routine with specific strengthening exercises that target the quadriceps, for about 15 minutes, two or three times a week. (Inspired by this study, I decided this morning to hit the weight machines at my gym adding the leg press and quad extensions to my triceps curls and chest presses.) Here's a basic move you can try in your living room.
And check out our strength-training guide, which includes a set of illustrated exercises for your thighs.