Does Running Actually Wear Out Your Knees?
What the Research Says
If you’ve ever told someone you enjoy running, chances are you’ve heard some version of this: “Be careful. You’re going to ruin your knees.”
It’s a common belief that running gradually wears away knee cartilage and eventually leads to arthritis. But is that actually what the research shows? The answer might surprise you.
Your cartilage is designed to handle movement
Cartilage is the smooth tissue that covers the ends of bones within your joints. It helps distribute forces and allows your joints to move smoothly.
Like other tissues in the body, cartilage responds to mechanical loading. Running temporarily compresses cartilage, causing small changes in its thickness and fluid content. However, this doesn’t necessarily mean damage is occurring.
A 2022 systematic review published in Sports Medicine examined how running affects cartilage. Researchers found that changes in cartilage following a run were generally temporary, with cartilage recovering after exercise. In other words, a temporary change in cartilage thickness on an MRI doesn’t automatically mean you’ve damaged your knees.
What about developing arthritis?
Research comparing runners and nonrunners has generally found that recreational running does not increase the risk of developing knee osteoarthritis.
A 2023 systematic review involving more than 14,000 participants found no meaningful worsening of radiographic knee osteoarthritis or patient-reported outcomes among runners compared with nonrunners. Some research has even suggested that recreational runners may experience less knee pain than people who don’t run.
That doesn’t mean running is risk-free. Previous knee injuries, excessive training loads, inadequate recovery, and individual health factors can all influence joint health.
How can you protect your knees?
Rather than avoiding running out of fear, focus on building your body’s capacity to tolerate it.
- Increase weekly mileage gradually, ~10%
- Incorporate strength training, particularly for your quadriceps, hamstrings, hips, and calves.
- Allow adequate recovery between demanding workouts.
- Pay attention to persistent symptoms rather than every temporary ache.
- Adjust training when your body isn’t recovering appropriately.
The bottom line
Your knees are not fragile structures that inevitably wear out from running. They are living tissues designed to adapt to appropriate loading.
If you enjoy running, there’s no good reason to give it up simply because someone told you it will destroy your cartilage.
The goal isn’t to avoid loading your joints. It’s to build the capacity to handle it. Keep moving. Keep getting stronger. Your knees are more resilient than you might think.
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