There is this myth that distance running is likely to contribute to the development of arthritis because it involves high impact joint loading. However, a new study entitled, “Why Don’t Most Runners Get Knee Osteoarthritis?” by researchers at Queen’s University in Kingston, Ontario, demonstrated no evidence that running increases the risk of osteoarthritis, including participation in marathons. On the contrary, the runners in the study had less overall risk of developing arthritis than people who were less active. How can running combine high impact loading of knee joints with a low risk for arthritis? Researchers looked more closely at what happens, biomechanically, when we run and how those actions compare with walking. Using specialized motion-capture cameras and body markers investigators found that running produced pounding of knees and other joints. In general, the runners hit the ground with about eight times their body weight while running, which was about three times as much force as during walking. However, they struck the ground less often while running, for the simple reason that their strides were longer. As a result, they required fewer steps to cover the same distance when running versus walking. Additionally, runners experienced knee pounding for a shorter period of time than walkers, because their feet contacted the ground more briefly with each stride. Thus it seems that running and walking are essentially indistinguishable in terms of wear and tear they may inflict on knees. Overall, it seems that any physical activity is healthy and that running is at least not more damaging than walking, meaning if you have healthy knees, use them including running or walking. Otherwise, find something else to do that doesn’t aggravate your knees.
Effects of running and walking on osteoarthritis and hip replacement risk. Williams PT.
Med Sci Sports Exerc. 2013 Jul;45(7):1292-7.