Is running bad for your knees? What the research shows

Running puts repeated impact through the hips and knees, and the idea that it wears joints out is one of the most familiar warnings in fitness. It seems intuitive: more pounding, more wear.

The research mostly points the other way for recreational running. Large reviews find less hip and knee osteoarthritis in recreational runners than in people who do not run. The picture is less clear for years of high-volume competitive running, and all of the evidence comes from observational studies rather than trials.

What knee and hip osteoarthritis is

MedlinePlus describes osteoarthritis as the most common type of arthritis, affecting joints such as the hands, knees, hips, neck and lower back. In a healthy joint, cartilage pads the ends of the bones. With osteoarthritis, the cartilage breaks down and becomes rough, and sometimes wears away so that bone rubs on bone.

MedlinePlus lists several things that make it more likely, including aging, being overweight, a past injury or surgery on a joint, and a family history of the condition. It also lists activities that overuse the joint, including sports with a lot of jumping, twisting, running, or throwing. That is part of why the question about running persists.

What studies show about running and arthritis

The largest summary is a 2017 review in the Journal of Orthopaedic and Sports Physical Therapy. It gathered 25 studies of 125,810 people and pooled 17 of them, covering 114,829 people, comparing hip and knee osteoarthritis in runners and in sedentary non-runners.

Osteoarthritis affected 3.5% of recreational runners, 10.2% of non-runners and 13.3% of competitive runners, defined as professional or elite athletes or people who raced internationally. Recreational runners had a lower occurrence of OA compared with competitive runners and controls, the authors wrote, with OA standing for osteoarthritis. People who had run for less than 15 years also had less arthritis than non-runners.

The authors read this as two risks at either end: a sedentary lifestyle on one side, and long exposure to high-volume or high-intensity running on the other, were both linked with hip and knee osteoarthritis. They noted that they could not tell whether these links were causal or confounded by other risk factors, such as previous injury.

What a US study of runners found in their knees

A study from the US Osteoarthritis Initiative looked at people’s knees and their lifetime running history at one point in time. About 29.5% had run at some point in their lives. Current and past runners had no more knee pain, x-ray signs of osteoarthritis or painful osteoarthritis than people who had never run, and on some measures they had less.

The authors concluded there is no increased risk of symptomatic knee OA among self-selected runners compared with non-runners. In people without osteoarthritis, they wrote, running does not appear to be detrimental to the knees.

What marathon runners report about their knees

A 2018 survey in the Journal of Bone and Joint Surgery reached 675 active marathon runners who had completed at least five marathons and still ran at least 10 miles a week. On average they were 48, ran 36 miles a week, had been running for 19 years and had finished 76 marathons.

Nearly half reported hip or knee pain, but only 8.9% reported arthritis. Among the US runners, arthritis prevalence was 8.8%, against 17.9% in a matched group from the US population. Arthritis was not linked to how far, how fast or how long they had run, or how many marathons they had completed. Age, family history, and surgical history independently predicted arthritis.

What health sources say about exercise and osteoarthritis

For people who already have osteoarthritis, exercise is part of standard care rather than something to avoid. MedlinePlus says treatment usually begins with exercises to improve strength, flexibility and balance, along with weight loss if needed and braces or shoe inserts. We covered a 2026 trial of high-impact exercise in people who already had knee osteoarthritis in a separate article.

Why the running and knee research is hard to interpret

Every study here is observational. The biggest problem is who keeps running. People whose knees hurt tend to stop, so surveys of current runners, especially long-time marathoners, are filled with people whose joints have held up. Runners also tend to be lighter, and extra weight is a known risk for osteoarthritis.

The competitive group was small and mixed, studies defined arthritis in different ways, from x-rays to self-report, and many relied on people remembering how much they had run over decades. Past injuries, which raise arthritis risk, are hard to separate from running itself.

What the running research cannot tell us yet

No trial has assigned people to run or not run for decades and then checked their joints, and none is likely to. The studies cannot say how much running is too much, whether the answer differs for people with earlier knee injuries, or how running affects people who already have osteoarthritis over the long term.

What the running evidence adds up to

Across more than 100,000 people, recreational running has not been linked to more hip and knee osteoarthritis, and runners often have less of it than non-runners. Years of high-volume competitive running may carry more risk, though the evidence is limited and could reflect injuries.

The studies cannot show cause and effect. For any one person, joint risk also depends on age, weight, past injuries and family history.