A New Study Shows Why Running Won’t Wreck Your Knees
It may actually build cartilage and strengthen your knees
If you’ve spent much time running, you have surely heard the advice that you are destroying your knees. It’s not uncommon to hear this not only from well-meaning friends and family members but also from medical professionals. I once had a physical therapist that was treating me for a back injury tell me I should give up running for some other low-impact sport.
I didn’t listen. The entire reason I was working so hard at my physical therapy was so that I could get back to the trails as soon as possible. That was over ten years ago, I’ve been running ever since, and so far, my knees are doing just fine.
It was unimaginable to me to stop running then, regardless of what it meant for my knees. My instincts told me running was better for me than stopping. And now, luckily for me, I have science on my side.
Running and your knees
Your knees take a pounding when you run. There is no controversy about that. And yet, if running destroyed knees, you would expect most runners to develop knee arthritis as they age.
But most runners don’t. On the contrary, runners may be less likely to develop arthritis than nonrunners. One explanation for this is running helps keep extra weight off, which is beneficial to your joints. But new research shows there may be more going on.
Running strengthens knees
A recent study has shown there may be something else going on as well. Running may be helping to rebuild cartilage in your knees. Researchers determined that running places a high load of pressure on the knees. The amount of strain is so high that if cartilage didn’t repair itself, they argue the knee would not be capable of withstanding the damage for a lifetime.
Experts will tell you that damaged cartilage cannot repair itself. It doesn’t have its own blood supply, and common wisdom says that once you damage or lose cartilage, it’s gone forever unless you receive medical intervention.
So how is it that many people can run for a lifetime with no damaging effects to their knees?
Ross Miller, associate professor of kinesiology at the University of Maryland in College Park, posed this question. Dr. Miller studied animals that run and he wondered if human’s knees might be able to adapt to the constant pounding of running. He thought perhaps the pummeling of the cartilage increases resiliency rather than breaking it down.
Dr. Miller ran models to find out what walking and running every day would do to an individual’s chance of developing arthritis over time. These models were run with the assumption that cartilage could not be repaired but only broken down.
Here is what he found:
- Daily walkers had a 36% chance of developing arthritis by age 55. (With no cartilage repair.)
- Daily runners had it much worse. They had a whopping 98% chance of developing arthritis eventually. (With no cartilage repair.)
But, when Dr. Miller ran the models again, this time adding in the ability of cartilage to repair and adapt, the numbers for both walkers and runners fell to 13%.
The results are clear. Dr. Miller believes that cartilage is malleable. That it rebuilds the damage it receives and becomes stronger. Without this ability, every runner would experience severe knee damage eventually. But we don’t.
“Running places high stresses on cartilage, and in a healthy state these stresses trigger an adaptation response that extends the fatigue-life of cartilage.” — Dr. Miller
This research creates many more questions. More research is needed into how the cartilage behaves this way. What causes it to repair itself, and is it affected by other factors such as genetics, body weight, or nutrition? Answers to these questions could help the many people that suffer cartilage loss and knee pain.
This study, while theoretical, can give runners peace of mind when the next person tells them running wrecks their knees. Without the ability for cartilage to adapt, it’s very unlikely anyone’s knees could survive a lifetime of running. And yet, they do.
So, the next time someone tells you, “running is ruining your knees,” you can tell them, “it’s just the opposite.”
