The idea that running is bad for your knees is a popular fitness myth. Contrary to popular belief, running does not cause arthritis or osteoarthritis later in life. The biggest risk factor for developing osteoarthritis is age and heredity, running or not.
Running and vigorous sports activities do in fact increase the risk of knee trauma and injuries, which in turn are known risk factors for knee arthritis. Alternatively, running reduces body weight and promotes cartilage thickening, both known as protective for arthritis.
These positive effects seem to actually offset in part its pro-arthritic effects, resulting in diminished arthritis risk or even protection.
Current evidence suggests that running does not increase the risk of arthritis, including participation in marathon races, and, in fact, subjects that ran longer distances are at significantly lower risk for both arthritis and hip replacement.
There are ways to be cautious with your joints and maximize the running benefits, the most popular one being strength training 2-3 times a week to build core strength. Running is a high-level physical activity, so your back, abs, and legs need to be strong to handle the impact of running.
That’s why building good core strength is essential for all but especially for runners. The stronger your muscles, the less impact on your joints and the lower your chance will be for injury or damage. Strength training will otherwise increase your overall performance in long distance runs.