You've seen them, the stiff-kneed former athletes, veterans of countless surgeries to repair the damage done by too much time squatting at the plate, zig-zagging across the football fields or pulling up short to hit the jumper.
Watching them hobble along, the signs of knee arthritis are obvious and painful, and it's enough to make you glad you never made it past your varsity squad.
But what about those folks who remain active all their lives? Are they at risk of developing debilitating knee arthritis too?
Not according to a recent study from researchers in the U.K., which looked at the relationship between moderate exercise and knee osteoarthritis.
Lead researcher A.J. Sutton and colleagues from the University of Leicester gathered information on 216 patients who had experienced arthritis after age 40. This data was then compared to a larger group that did not have arthritis.
While a previous knee injury did appear to signal a higher risk of knee arthritis, this was not the case for moderate activity.
''Our data does not support the suggestion that increased use of the knee joint through moderate sporting and exercise participation wears out the joint and therefore increases the risk of knee osteoarthritis,'' writes Sutton in the August issue of Annals of Rheumatic Diseases.
Instead, they argue, the potential benefits of regular physical activity, such as reduced risk of heart disease and diabetes, ''greatly outweigh'' the risk of developing knee arthritis. And, protective measures such as warming up and learning proper technique can help lessen the risk of sports injuries that may cause problems later in life.
Source:Annals of Rheumatic Diseases 2001, 60, 756-764