Is Running Bad for Your Knees? What Does the Research Say?
By Lachlan Gillies | Physiotherapist & Founder of Rebuild Physio Glenelg
For years, runners have been told that running will eventually “wear out” their knees.
It sounds logical. Running involves repeatedly loading the knee, often thousands of times during a single run. So surely all that impact must eventually damage the cartilage and lead to arthritis?
Fortunately, the research paints a much more reassuring picture.
For most people, recreational running does not appear to increase the risk of developing knee osteoarthritis. Research suggests that our joints are capable of adapting to the loads placed on them.
That does not mean runners never experience knee pain.
They certainly do, and knee pain is one of the common problems I see in runners in the clinic.
The important distinction is that experiencing knee pain from running is not the same thing as running gradually “wearing away” your knee.
So, what actually happens to our knees when we run?
The myth: running wears away your cartilage
One of the common concerns I hear from runners is that repeated impact will gradually wear away the cartilage inside their knees.
But the human body is not a machine with parts that simply wear out every time we use them.
Our muscles, tendons, bones and joints are living tissues capable of responding and adapting to physical load.
Running places significant demands on the body, but appropriately applied load is also one of the things that allows our bodies to adapt.
This is an important concept in running rehabilitation.
Rather than thinking about running simply as something that damages the knee, it can be more useful to think about the relationship between the demands we place on the body and our current capacity to tolerate those demands.
What does the research say about running and knee arthritis?
Research examining recreational runners has generally provided reassuring findings.
A systematic review and meta analysis by Alentorn Geli and colleagues examined the prevalence of hip and knee osteoarthritis in recreational runners, competitive runners and sedentary individuals.
The researchers found that recreational runners had a lower prevalence of hip and knee osteoarthritis than both competitive runners and sedentary controls.
This does not prove that recreational running prevents arthritis. Factors such as previous injury, training exposure, age and body composition also matter.
However, it challenges the idea that recreational running inevitably causes our knees to deteriorate.
Research involving people who already have knee osteoarthritis has also produced interesting findings.
Lo and colleagues followed runners with knee osteoarthritis and found that self selected running was not associated with worsening knee pain or radiographic progression of osteoarthritis.
Again, this does not mean everyone with knee arthritis should simply start running without considering their individual circumstances.
But it provides further evidence against the idea that running automatically damages an arthritic knee.
Does running damage knee cartilage?
Research looking directly at cartilage provides another useful perspective.
Studies using MRI have shown that cartilage can undergo temporary changes following running.
This is important because a change immediately after exercise does not necessarily represent permanent damage.
A systematic review and meta analysis examining the immediate effects of running on knee cartilage in healthy adults found that cartilage changes observed after running appeared to be temporary, with recovery occurring following exercise.
That fits with a broader principle we use regularly in physiotherapy.
The body responds to load.
The goal is not necessarily to avoid load altogether. It is to expose the body to an appropriate amount of load and allow it to develop the capacity to tolerate what we ask it to do.
So why do runners get knee pain?
If running does not simply wear away the knees, why can your knee still hurt when you run?
This is where things become more individual.
Running related knee pain can have a number of potential contributors.
A runner may have recently increased their weekly kilometres, added faster sessions or hills, returned to running after time away, changed their gym training, or simply accumulated more load than their body is currently accustomed to.
Strength and physical capacity may also be relevant, as can previous injury, recovery and the specific demands of the person’s training.
There is not one explanation that applies to every runner.
That is why I do not think the answer to running related knee pain should automatically be:
“Stop running.”
Sometimes temporarily modifying running is useful.
But the bigger question is:
What does this runner need to be capable of doing, and how can we progressively build them towards it?
What if your knee hurts when you run?
Knee pain during running does not necessarily mean you are damaging your knee.
At the same time, persistent or worsening pain should not simply be ignored.
When I assess a runner with knee pain, I want to understand the person in front of me rather than just looking at the painful knee.
That can include considering when the pain occurs during or after running, recent changes in running volume or intensity, strength and physical capacity, previous injuries, gym and sporting load, aggravating activities and the runner’s future goals.
From there, rehabilitation can be individualised.
For some runners, that may involve temporarily adjusting running volume or intensity while maintaining as much running as is appropriate.
For others, improving strength and progressively exposing the knee to greater loads may form an important part of rehabilitation.
As capacity improves, running can then be progressively built towards the person’s normal training and goals.
For runners returning after knee pain or another injury, this progression should be individualised. You can read more about how we approach this in our Return to Running After Injury guide.
The aim is not simply to make your knee feel better while you are in the treatment room. The aim is to help your knee become capable of handling the running you want to do.
Should you stop running if your knee hurts?
Not necessarily.
Whether running needs to be reduced, modified or temporarily stopped depends on the individual problem.
For some runners, continuing to run at a modified level can be appropriate. For others, symptoms may require a more substantial reduction before running is gradually reintroduced.
There is not a universal number of kilometres or pain level that is appropriate for everyone.
This is why rehabilitation should be based on the runner, their symptoms and the demands they are trying to return to.
Building stronger, more resilient runners
One of the reasons I enjoy treating runners is that rehabilitation does not have to finish when the pain settles.
Running places substantial physical demands on the body.
Strength training and progressive loading can therefore be useful tools for developing the physical qualities required for running.
This does not mean every runner needs to become a powerlifter.
It means identifying what that individual runner needs and progressively developing their capacity to tolerate their training.
For someone wanting to run five kilometres comfortably, those requirements may look very different from someone preparing for a marathon or trying to improve their race performance.
The rehabilitation plan should reflect that.
So, is running bad for your knees?
For most recreational runners, the evidence does not support the idea that running simply wears away the knees.
Our joints are living structures capable of responding to load, and recreational running does not appear to inevitably increase the risk of knee osteoarthritis.
But runners can still develop knee pain.
When that happens, the answer is not always to stop running indefinitely.
Understanding the problem, managing training load where appropriate and progressively rebuilding the capacity required for running can help runners work towards getting back to what they enjoy.
Knee pain stopping you from running?
If knee pain is affecting your running, a physiotherapy assessment can help determine the factors contributing to your symptoms and develop an individual plan for returning to running.
I am Lachlan Gillies, Physiotherapist and Director of Rebuild Physio Glenelg. I have a particular interest in running injuries, strength training and helping active people build the capacity to return to the activities they enjoy.
You can learn more about Running Injury Physiotherapy at Rebuild Physio Glenelg or book an appointment with me if you would like help getting back to running.
About the Author
Lachlan Gillies
Founder, Director & Physiotherapist
Rebuild Physio Glenelg
Lachlan is the founder and principal physiotherapist at Rebuild Physio Glenelg, with a strong interest in strength and conditioning, sports injury rehabilitation and helping people achieve their physical performance goals.
His clinical approach combines evidence-based physiotherapy with progressive exercise rehabilitation, helping patients develop strength, improve physical capacity and confidently return to the activities they enjoy.
Based in Glenelg, Adelaide, Lachlan works with patients of different abilities, from recreational runners to competitive athletes.
References
Alentorn Geli E, Samuelsson K, Musahl V, Green CL, Bhandari M, Karlsson J. The association of recreational and competitive running with hip and knee osteoarthritis: a systematic review and meta analysis. Journal of Orthopaedic & Sports Physical Therapy. 2017.
Lo GH, Driban JB, Kriska A, et al. Running does not increase symptoms or structural progression in people with knee osteoarthritis: data from the Osteoarthritis Initiative. Clinical Rheumatology. 2018.
Coburn SL, Crossley KM, Kemp JL, et al. Immediate effects of running on the knee joint cartilage and meniscus in healthy adults: a systematic review and meta analysis. Sports Medicine. 2023.
