Muscle Tone a Key to Knee Health

The joint won't be jumping if your knees aren't up to it. There won't be much running, walking, dancing, skipping or hopping, either.

For all these motions, you need your knees, but they can pay a painful price.

"Their main function is mobility, and there's an inverse relationship between mobility and stability," says Michael McKeough, a professor of physical therapy at California State University, Sacramento.

In other words, the more you move, the greater the risk of tweaking, twisting or otherwise stressing the knee joints that keep you going.

McKeough knows about this personally as well as professionally. A gymnastics injury in the 1960s led to surgical removal of the meniscus in both knees. The meniscus is a piece of cartilage that acts as a sort of pad between the thigh bone (femur) and the shin bone (tibia).

He was told to expect arthritis and having to use a cane. But, at 59, he has managed to stay active biking at least 100 miles a week, skiing every year. (He gave up running at 55.) And he does these comfortably.

"I've not had one day of knee pain," he says of his current regimen.

His secret: Keeping his leg muscles "really strong."

"You can increase stability with muscular strength," he explains. His favorite exercises are lunges and wall squats, which work the quadriceps.

The muscles that most influence knee function are the quadriceps (which run on the front of the thigh) and the hamstrings (which run along the back of the thigh). Other muscles that get in on the act include the hip abductors (on the outer thigh) and the hip adductors (on the inner thigh).

Slow Degradation

Imbalances of muscular strength and flexibility can lead to knee problems. McKeough says that men are more likely to suffer from overly tight hamstrings, while women are more likely to suffer from weak quadriceps.

Although McKeough's knee injuries were of the traumatic variety, the usual knee story is of a slow-and-steady degradation from osteoarthritis, the most common type of arthritis, which affects about 21 million Americans. It generally develops between the ages of 40 and 50 and is more prevalent in women.

It can result from injury, being overweight or simply aging, and causes swelling and pain of joints, most commonly in hands, knees, spine and hips.

Osteoarthritis breaks down cartilage, the slippery tissue that covers bones in a joint. When it wears down enough, bones rub together and can be further damaged.

But osteoarthritis is no excuse to stop moving. In fact, a recent large-scale study following 1,279 participants (or more than 2,500 knees) over nine years found that exercise did not exacerbate or reduce the risk of developing osteoarthritis. (The study was published in the February 2007 issue of Arthritis Care & Research.)

The moral of this story: Get moving, and pay attention to the joints that keep you going.

As McKeough puts it: "You need to listen to your knees."