Q. Are high-impact activities like running really bad for the knees?
A. Although running puts a great deal of force on the joints, the idea that people who run or play sports recreationally are more likely to develop arthritis hasn’t held up to scientific scrutiny. Research indicates that while the effects of exercise vary, overall it delivers more benefit to joints than harm.
Some studies have shown that professional runners are at higher risk of developing osteoarthritis in the knees and hips, he says, even at a fairly young age. Studies on professional athletes in other high-impact sports, like tennis, suggest a similar story. So there seems to be a difference between recreational running and pushing the knees too far. How much is too much? “I don’t know,” Felson admits. “But I think there probably is some threshold, and it may vary by individual.”
It’s important to consider your own personal tolerance for high-impact activities. While running seems to be fine for healthy knees, people who have had a knee injury or a surgery in the past, Felton says, “already have damaged knees, and running just worsens the damage.” Overweight people are more likely to develop arthritis because of the heavier load on the joints. He advises people with known knee problems to stick to lower-impact activities like swimming or using elliptical machines at the gym.