If you love regular fun runs, then this news is for you. Moderate levels of recreational running may be the sweet spot for healthy knees and hips, according to a new scientific review in the Journal of Orthopedic & Sports Physical Therapy. Compared with people who ran competitively or not at all, middle-of-the-pack athletes had lower rates of osteoarthritis over time.
The meta-analysis, which combined data from 17 previous studies involving a total of 114,829 people, also concluded that running at a casual level for up to 15 years—and possibly longer—is safe for healthy individuals.
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Overall, the international team of researchers found that only 3.5% of recreational runners developed hip or knee arthritis over the periods they were monitored for their studies. This was true for both male and female runners who reported running in amateur, non-professional contexts. People who reported not running at all had a 10.2% chance of developing hip or knee arthritis. Meanwhile, those who were classified as elite or professional runners, or who competed internationally, had a 13.3% chance.
Research on running and joint health has, not surprisingly, delivered mixed results. But many studies have suggested some protective effects. A 2016 report from Brigham Young University, for example, found that running for 30 minutes reduced inflammatory markers around the knee joint.
The new meta-analysis didn’t group runners by mileage or intensity, because the definitions for recreational versus competitive varied between studies and were not always quantified with these measures. But in other research, they note, logging more than 57 miles per week has been linked to an increased risk of arthritis in these same joints.
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The findings are good news for the majority of runners, say the authors. “Running at a recreational level can be safely recommended as a general health exercise, with the evidence suggesting that it has benefits for hip and knee joint health,” the wrote. That evidence is particularly strong in people who have run for 15 years or less, they say; there weren’t enough relevant studies to determine safety or joint-health benefits for people who had run for longer periods.
The authors also could not determine the amount of running that is safe for weight-bearing joints, and they warn that their findings should be “interpreted with caution” due to limitations in the research, such as an inability to factor in potential factors such as obesity or prior injury.
Despite these limitations, the authors say their investigation provides valuable information for doctors, physical therapists, and other health professionals who might prescribe running to patients for athletic training or for general health. Plus, they wrote, the findings are also “of general health interest, given the high popularity of running worldwide.”