Is Running Bad for Your Knees? Not for Most People, Research Finds

“You’ll ruin your knees.”

If you run, someone has probably told you this. It sounds like common sense.

Every stride sends a jolt through the joint.

So surely, after years of pounding, the cartilage wears out?

The research says no. For most people, it points the other way.

Here’s what the biggest studies found, where the real risks are, and what to do if your knees already hurt.

Is running bad for your knees?

For most people, no. The evidence suggests running does not wear out healthy knees.

The biggest review, published in 2017, pooled studies of more than 114,000 people. Only 3.5% of recreational runners had hip or knee arthritis.

Among people who didn’t run, it was 10.2%.

Elite and competitive runners were the exception. Their rate was 13.3%, a little higher than non-runners.

So the worry has some truth at the extreme. But for someone who jogs a few times a week, the studies point to healthier knees, not damaged ones.

Why people think running hurts your knees

The idea comes from a simple picture: the knee as a car part that wears down with use.

Running does put a lot of force through the knee. Each step loads the joint more than walking does.

But cartilage is living tissue, not rubber. Joints seem to adapt to regular load, much like bones and muscles do.

Runners also tend to weigh less. Extra body weight is a well-known risk for knee arthritis.

What the research shows

A 2023 review of 17 studies

The main source here is a 2023 review in the Orthopaedic Journal of Sports Medicine, led by researchers in Colorado and Texas.

It gathered 17 studies covering 7,194 runners and 6,947 non-runners. The runners were 56 years old on average.

The team checked knee X-rays, MRI scans and what people said about their pain.

Most studies found no difference in knee arthritis on X-rays between runners and non-runners. Cartilage thickness on MRI was also similar.

One older study of 81 former elite female athletes did find more bony growths in runners’ knees. Those growths are an early sign of arthritis.

The authors concluded that running is not linked to worse knee arthritis, at least in the short term, and may protect against knee pain.

The best single study: 2,637 Americans

The strongest study in the review came from the Osteoarthritis Initiative, a big US research project on knee health.

Researchers asked 2,637 adults, aged about 64 on average, about every sport they had done in their lives. Of them, 778 had been runners at some point.

Then they compared knee X-rays and pain between runners and people who had never run.

These rates are high because many people in this project were chosen for being at risk of knee arthritis. The comparison is what matters.

People still running after 50 had the least pain and painful arthritis of all. And people who had stopped running didn’t do worse than those who never ran.

After the researchers accounted for age, weight, sex and past knee injuries, runners still had less knee pain. The gap in X-ray arthritis was no longer clear.

One number in the review is wrong

I checked the review’s figures against the original study. The review gives the non-runners’ knee pain rate as 58.8%.

The original paper says 41.1%. The 58.8% is the X-ray arthritis rate, copied into the wrong row.

That error inflates the review’s pooled knee pain result. The conclusion still holds, but the gap is smaller than the review suggests.

Who funded it

For the 2023 review, several authors reported consulting or speaking fees from medical device companies, including makers of knee implants.

The 2017 study was funded by the US National Institutes of Health and the Department of Veterans Affairs. The Osteoarthritis Initiative also had drug company partners.

Is running bad for your knees if you have arthritis?

This is the question many older runners really want answered.

A 2018 study followed 1,203 people over 50 who already had knee arthritis, for four years. About 1 in 9 of them ran.

Running was not linked to faster damage on X-rays. It wasn’t linked to new knee pain either.

Runners were actually more likely to say their knee pain had gone away, though that result was borderline.

The authors were careful. People with arthritis chose for themselves whether and how much to run.

That choice was likely shaped by their knee pain, and may have meant gentler, shorter runs.

Still, the message was clear: running “need not be discouraged” in people with knee arthritis.

How much running is too much?

Nobody knows exactly. The worrying signal comes mostly from elite athletes who ran very hard for many years.

A 2023 review looked at weekly distance in nine studies with 12,273 people. Runners doing 8 to 32 km a week had no more knee arthritis than non-runners.

The same was true at 32 to 48 km. Even above 48 km a week, there was no clear rise.

The authors warned that most of these studies had a high risk of bias. So the honest answer is: high mileage hasn’t been proven harmful, or proven safe.

What earlier research found

Runners needed fewer knee operations

A 2017 review from the University of Nottingham pooled 15 studies on running and knee arthritis.

The results on arthritis itself were mixed. But runners were less likely to need surgery for knee arthritis.

The authors said the evidence was moderate to low quality and couldn’t settle the question.

Cartilage changes faded within an hour

A 2021 review of 15 studies looked at what running does to knee cartilage.

A protein released by stressed cartilage rose right after a run. It was back to normal within an hour.

Cartilage volume didn’t change. The authors suggested running may help push nutrients into cartilage.

Landing softer cut knee injuries

A 2022 review of 30 trials asked how to prevent knee injuries in runners.

In one trial of 320 people, learning to land more softly was linked to a 68% lower risk of knee injury.

Different shoes, exercise programmes and gradual running plans made no clear difference. The certainty of this evidence was low.

How it fits together

Different teams, decades apart, keep reaching the same place. For most runners, knee arthritis risk does not go up.

The open questions are about extreme training and old injuries, not about the weekend jogger.

How much should you trust this?

Promising. The findings agree across many studies and countries. But nearly all of them are observational.

What makes it convincing

• Studies over 30 years point the same way.
• They used X-rays and MRI, not just what people remembered.
• Runners did no worse even when researchers looked at people who already had arthritis.

What makes me cautious

• Nobody has randomly assigned people to run or not for decades.
• People whose knees hurt may stop running, which makes runners look healthier.
• Many studies were small, and some had no comparison group.
• Old knee injuries, like a torn ligament, raise arthritis risk, and runners do get injured.

What this means for you

• Don’t quit running for fear of arthritis. For most people, the evidence says it won’t wear out healthy knees.
• Build up slowly. Add distance gradually, especially if you’re new to running.
• Keep your weight in a healthy range. Extra body weight is a well-known risk for knee arthritis.
• Strengthen your legs. Stronger thigh and hip muscles help absorb the load.
• Try landing softer. Shorter, quieter steps may reduce knee injuries.
• Listen to pain. Mild soreness that settles is normal. Pain that is sharp, swelling or getting worse needs a check-up.
• Had a knee injury or surgery? Ask a physiotherapist or doctor before going back to running.
• Already have arthritis? Gentle running may be fine. If it hurts, try cycling. A 2026 study found 3 to 5 hours of cycling loads the knee about as much as 1 hour of running.

The NHS guide to osteoarthritis treatment explains why exercise is a core treatment, not something to avoid.

If you’re curious how this fits with other activities, we looked at how many steps a day you really need.

In this short video, New York Road Runners and the Hospital for Special Surgery tackle the biggest running myths:

What we still don’t know

1. Is running protective, or do healthy knees just keep running? Long studies that start before people take up running would help.
2. Where is the limit? We don’t know how much elite-level training is too much.
3. Who is at risk? Past injuries, body shape and genes may change the answer for some people.
4. Do shoes or surfaces matter? The trials so far found little difference.

My take: the knees are tougher than the myth

What I like about this evidence is how stubborn it is. Researchers have gone looking for running damage for decades, and keep not finding it in everyday runners.

I’m less convinced by the idea that runners are protected. Some of that gap is surely people with bad knees giving up running.

But “running won’t hurt healthy knees” is a strong enough message on its own.

If you enjoy running, the knee worry is not a good reason to stop. Build up slowly, stay strong, and see someone if pain doesn’t settle.