A meta-analysis found no link between knee osteoarthritis and either the amount or duration of routine exercise.
As someone who has good knees and has run many marathons, I’m happy to read this.
From the Press Release »
“Knowing that the amount of physical activity and time spent doing it is not associated with the development of knee osteoarthritis is important evidence for both clinicians and the public who may need to consider this when prescribing physical activity for health,” said co–lead author Thomas Perry, BSc, PhD, of the University of Oxford, in the UK.
Age is the largest risk factor for osteoarthritis, along with others like sex (women report it more often), genetics, and weight, since it can put more stress on the knees. Physically stressful jobs that require lots of heavy lifting and knee-bending have been linked to osteoarthritis as well. It’s less clear whether physical activity outside of work can cause or worsen knee osteoarthritis, though it’s certainly a common fear that exercises like running will eventually ruin your knees.