Does marathon-running wear out the knees?
Logically, you’d think it could. Osteoarthritis, after all, is what happens when the protective cartilage on our bones gets worn away. That’s why you sometimes hear it called “wear-and-tear arthritis”. Put your joints through miles of road running and you’ll lose the cartilage even more quickly, won’t you?
Well, not necessarily.
Last month, a new study in the US found that amateur marathon runners actually weren’t more likely to develop hip or knee osteoarthritis, however far, fast or frequently they ran. The project surveyed 3,804 runners who took part in the 2019 and 2021 Chicago Marathons. The researchers wanted to see if the runners’ chances of arthritis rose alongside the number of miles they covered, among other things.
In the end, they couldn’t find an obvious connection. “There was no identified association between cumulative running history and the risk for arthritis,” the authors concluded.
Clearly, most of us aren’t track-pounding ultra-athletes! But are there things we can all learn from this research? Here are three thoughts.
It’s encouraging for runners
The idea that long-distance running inevitably leads to long-term joint damage seems wide of the mark. That may be because we sometimes underestimate the powers of cartilage. Joint cartilage is an amazingly resilient substance. Its constituent tissues are simultaneously energy-absorbing, friction-minimising and flexible. In normal, injury-free circumstances, it can handle a lot of repetitive impact without falling apart. To quote Dr Vehniah Tjong, one of the study’s authors: “Runners should be encouraged by our results. They refute the current dogma that long-distance running predisposes an individual to arthritis of the hip and knee.”
It needs to be put in context
Before we all race off to run 26.2 miles before lunch, however, it’s worth noting that the survey respondents were experienced runners. Sure, there was a range of abilities. But the average was just under 44 years old, ran around 27 miles per week and had been running for circa 15 years. In other words, many were likely fit, had a decent running style, and had generally avoided injury (though 36% did admit that knee or hip pain had prevented them from running in the past year). So we shouldn’t automatically assume their experience applies to everyone everywhere. After all, other factors play a part in cartilage deterioration – not just things like age and weight, but also genetic disposition and malalignment (such as knock knees and bow legs). This was something the researchers acknowledged in their report.
It’s ultimately about your own pace
If there’s a simple takeaway from this research, it’s that our bodies respond well to exercise. Which you probably knew already, didn’t you! But how much is right for your own body? That’s an important question, because rocketing straight into endurance exercise without any build-up is really asking for trouble (something we see time and again here in clinic). In truth, exercise is highly individual. So if you are planning to up your output as the summer draws on, the best advice is to build up gradually. Consider talking to a physiotherapist or medical expert first. Look to improve your leg-muscle strength (this will support your knee joints). Make sure you’re investing in decent shoes. Don’t be tempted to overdo it. And ease back or stop completely if you start to feel pain. As lead study author Dr Matthew James Hartwell puts it: “Take it slowly and make sure you have the proper gear when you’re out running. And listen to the signs your body is telling you.”