|Love my Kinvaras!|
I get really cranky and exasperated when someone says to me, "Aren't you worried that all that running will wear out your knees?" or "I don't run because running wears out your knees." Running does not wear out your knees people! Simply the use of a body part does not wear it out. Our body was designed to function better when used more. That's what makes the human body so mind-blowingly amazing. Does more core exercise wear out your core? Does breathing more wear out your lungs? Does cardiovascular exercise wear out your heart? It's simply ridiculous to say that using your knees for an activity that is as basically human as breathing will wear them out. It's amazing to me that this archaic myth is still believed by many people.
If one takes time to look (with a simple google search), there is a large body of evidence to support the opposite. In fact, running can actually protect you from osteoarthritis, the medical word for "wearing out" your knees. In fact, one well designed long-term study of the general population called the Osteoarthritis Initiative from the Baylor College of Medicine in Texas showed that runners were less likely to develop arthritis than non-runners, by between 16 and 29 percent (Runners World).
Our knees are a relatively simple hinge joint built to support the load of our body weight. Ideal function of the knee joints happens under the assumption that we are asking them to support optimal body weight (not the weight equivalent of 1.5-2 people) with the support of a strong muscular system in a biomechanically optimal manner. Running under these conditions may even promote cartilage thickening and prevent the loss of cartilage proteoglycans, as evidenced by research and the undeniable fact that many top placing ultra-runners are in their 5th and 6th decades and have been running for years. Quite happily and successfully I might add.
A much stronger association exists between non-optimal body mass index (BMI) and knee osteoarthritis than between running and knee OA. One study publish in 2013 in Medicine and Science in Sports and Exercise concluded that "running significantly reduced OA and hip replacement risk due to, in part, running's association with lower BMI, whereas other exercise increased OA and hip replacement risk. This study did not specify what "other exercise" was other than non-running or walking. The study highlights several other interesting factors that increase or decrease risk of OA and hip replacement and can be read here.
What does tend to stress the knees is asking them to do more with less: to support more weight than they are built for, with weak muscular support, poor alignment and poor biomechanics. Gravity works. It works with every footstep. Don't ask your knee joints to support 3-5G's with each foot strike with little muscular support or proper time to develop adequate connective tissue strength. If you've gained weight or carry heavy gear while running, your muscular system needs to be that much stronger and your connective tissue will need longer to adapt.
There ARE people who shouldn't run - those with pre-existing traumatic injuries or with already present degenerative conditions that require caution. But aiming to "protect your knees" by not running is the worst thing you can do. Become inactive, gain weight, get weak, and you are almost guaranteed joint problems in the future. No one likes to hear it, but it's true.
Now that you know the facts, don't judge me. And if you don't want to run, don't make excuses based on myth. Just say, 'running is not my thing.' That's O.K. Then go find some other way to move your body.