Does running wear out your knees? My grandma used to worry when my dad went running. “That’ll wear out your knees,” she would say. It is one of the most common myths about running, and several recent clinical studies have debunked it. In fact, the evidence suggests running does not wear out your knees, and running may actually help keep them strong and healthy. Here are five proven reasons why, plus what actually causes running and knee pain when it does occur.
1. Your Knee Cartilage Is Built to Handle Compression
People used to think repetitive compression of the joints causes degeneration and pain. Mechanical load does affect the joints, but it does not wear them out the way the myth suggests.
The knee joint is protected by articular cartilage, which reduces friction so the bones move smoothly past each other. Compression from running does temporarily compress the cartilage, but that is exactly what it is designed to do. This compression squeezes interstitial fluid out of the cartilage, which lubricates and nourishes the knee joint.
2. Cartilage Reabsorbs Fluid Like a Sponge
Importantly, this is not a one-way process. Cartilage is porous like a sponge, so the fluid pressed out during running is absorbed back in afterwards. This cycle of compression and reabsorption is part of how healthy cartilage stays nourished, rather than a mechanism of damage.
3. Running Does Not Reduce Cartilage Volume
Recent studies using MRI to measure the thickness and volume of knee cartilage found no significant difference between runners and non-runners. In other words, running was not associated with thinner or reduced cartilage.
There was a short-term rise in cartilage oligomeric matrix protein (COMP), a protein released into the blood after cartilage compression, at 30 minutes after a run. But this returned to normal within an hour. So running had only a brief, temporary effect on COMP and did not change cartilage volume or thickness.
4. Runners Are Not at Higher Risk of Knee Osteoarthritis
Multiple studies have found no significant difference in radiographic knee osteoarthritis between runners and non-runners. This is one of the most reassuring findings for anyone worried that running will lead to knee osteoarthritis down the track.
Recreational running, in particular, is not associated with the joint damage the old wear-and-tear model predicted. If anything, staying active and keeping the muscles around the knee joint strong supports long-term joint health.
5. When Knee Pain Does Happen, It Is Usually Fixable
None of this means running never causes knee pain. It can, but when it does, the cause is usually a manageable factor rather than your knees wearing out. If you get running and knee pain, a physiotherapist can assess a few key areas.
Technique and Biomechanics
The alignment of your hip, knee and ankle joints may be suboptimal when you run, causing knee pain. This can come from muscle weakness or imbalance, habitual movement patterns, or technique.
Muscle Weakness or Imbalance
The glutes, hamstrings, quads and calves all need to be strong for running. Weakness, or a discrepancy between sides, can contribute to running and knee pain. In this case you may benefit from a strengthening programme before building your running volume.
Structural Changes
Several structures can contribute to knee pain, including osteoarthritic changes, meniscus tears, patellar tendinopathy and muscle tightness. These can be diagnosed and treated by a physiotherapist, and they do not necessarily mean you cannot run in the future.
The Bottom Line
The idea that running wears out your knees is a myth that the evidence does not support. Running does not reduce cartilage volume or increase your risk of knee osteoarthritis, and the knee joint is well designed to handle the load. If you do experience running and knee pain, it is usually down to a fixable factor worth getting assessed.
Our general physiotherapy team can assess your knee pain and what is driving it. For runners, our running assessment looks at your technique and strength, and our sports physiotherapy team can build a plan to keep you running comfortably.
Frequently Asked Questions
Does running wear out your knees?
No. Studies using MRI show no significant difference in knee cartilage volume or thickness between runners and non-runners, and no higher rate of knee osteoarthritis. The knee joint and its cartilage are well designed to handle the load of running.
Does running cause knee osteoarthritis?
The evidence does not support this for recreational running. Multiple studies have found no significant difference in radiographic knee osteoarthritis between runners and non-runners.
Why do my knees hurt when I run?
Running and knee pain usually comes from a fixable factor such as technique, muscle weakness or imbalance, or a treatable structural issue, rather than your knees wearing out. A physiotherapy assessment can identify the cause.
Should I stop running if my knees hurt?
Not necessarily. Knee pain is often manageable with a strengthening programme and adjustments to technique or load. A physiotherapist can help you keep running while addressing what is causing the pain.
References
Dhillon J, Kraeutler MJ, Belk JW, et al. Effects of Running on the Development of Knee Osteoarthritis: An Updated Systematic Review at Short-Term Follow-up. Orthop J Sports Med. 2023;11(3):23259671231152900.
Dong X, Li C, Liu J, et al. The effect of running on knee joint cartilage: A systematic review and meta-analysis. Phys Ther Sport. 2021;47:147-155.
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BeFit Training Physiotherapy Edgecliff
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Shop 1/2 Byron Street, Coogee NSW 2034
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