This is a question we get here at Optimize all the time: is running bad for my knees? Well, to answer this question we need to make sure we consider REAL research and not just opinions of others that have developed knee pain that they feel is due to running. It’s easy to focus on the negative experiences that accompany any sort of physical activity and injury but remember that those are usually the folks that are most vocal about their experiences. It’s more common to hear “I used to run but it ruined my knees” than it is to hear “I’ve been running for years without any real issue”. Not because one occurs more than the other but because one group is more vocal about it than the other.
Before we dive in, I want to make sure to mention that arthritis does not automatically mean you are going to have pain. There are plenty of people with arthritis out there with no symptoms or decrease in function.
That being said, let’s see what the research says. There have been multiple studies (here and here) that show little to no correlation between recreational running and knee arthritis. The studies also suggest that a sedentary lifestyle is more strongly correlated to knee arthritis than recreational running. One other thing the studies suggest is that competitive running tends to lead to more hip and knee arthritis than recreational running (but that does not mean pain or decreased function/performance necessarily).
Another study implies that running at a self-selected intensity and mileage does not worsen arthritis in people that already have it. This suggests that running can be a healthy exercise option even if you already have arthritis in your knees.
In conclusion, when answering the question the answer is: it depends. It depends on your goals, previous injury history, other health issues, etc. In general though, running has actually been shown to improve knee health in the recreational runner.