If you’ve ever experienced knee pain while running, you’re in good company. There’s even a common name for the condition: “runner’s knee.” It’s a repetitive-use injury that can technically be caused by more than just running — basketball, skiing and cycling can all be culprits — and is often associated with poor tracking of the kneecap or an irritated IT band. But, it turns out, there’s more to the story — and running might not be the knee-attacking scourge we once thought.
A 2016 Brigham Young University study published in the European Journal of Applied Physiology found inflammatory molecules in the knee joint actually decreased after running — basically the exact opposite of what you’d think. In the study, researchers measured inflammation markers in the knee joint of healthy participants aged 18–35 by testing blood and synovial fluid before and after running. Although anecdotal evidence would suggest knee inflammation increases after pounding the pavement, 30 minutes of running reduced inflammation in the runners’ knees.
Interestingly, the knee joints of the non-running control group showed a higher concentration of one of the inflammatory molecules. So, sitting for 30 minutes actually did more harm to the study group’s knees than running.
“It flies in the face of intuition,” said Matt Seeley, PhD, a professor of exercise science at BYU. “This idea that long-distance running is bad for your knees might be a myth.”
A more recent study from Queen Mary University of London produced similar findings. Though not focused solely on running, researchers studied the impact of exercise on cartilage and how that affects osteoarthritis, a painful condition where cartilage wears down over time. They found that, during exercise, joint cells experience certain mechanical forces that suppress inflammatory molecules. This helps prevent cartilage degradation, which, in turn, keeps osteoarthritis at bay. This is good news because, according to the National Osteoporosis Foundation, osteoarthritis affects more than 200 million people worldwide.
According to Seeley, distance runners are no more likely to get osteoarthritis than any other person. “Instead, this study suggests exercise can be a type of medicine.”
Other research supports this idea, finding that high-impact sports, like running, are associated with better bone mineral density. A University of Missouri study discovered that, just like resistance training causes your muscles to break down and rebuild, running causes bones to adapt, repair themselves, become stronger and, eventually, form new bone tissue.
And, because runners tend to have lower body mass than the general population, their knees don’t have to carry around as much weight — another factor associated with reduced incidence of knee pain and osteoarthritis.
THE BOTTOM LINE
This research seems counterintuitive to anyone who experiences knee pain during or after running. And something is causing that discomfort. But if you’re young and healthy, running seems to create an anti-inflammatory environment in the knee that may benefit your long-term joint health.