If we had a fast-twitch muscle fiberfor every time we've heard "running will ruin your knees," we'd beable to out sprint Usain Bolt. And our knees would feel good while we did so,because despite what your potentially well-meaning but definitely ill-informedneighbors, co-workers, and relatives may have told you, there's no evidencethat regular running damages knees.
That's not to say that no runners' kneesever bother them. But many knee problems in runners are the result of thingsgoing on elsewhere in the body, and most can be overcome with some simplechanges.
Here are five things all runners shouldknow about knees.
Runners don't get arthritis in their knees more often than nonrunners
Those are the facts. Period. If anything,long-term studies have found that runners have less incidence of kneeosteoarthritis. One study that followed runners and nonrunners for 18 yearsfound that, while 20% of the runners developed arthritis during that time, 32%of the nonrunners did. A large study that looked at runners and walkers foundthat regular runners had roughly half the rate of arthritis as regular walkers.In that second study, the runners with the highest regular mileage had thelowest rate of arthritis.
The above is true regardless of your age
Some medical experts have said that lossof cartilage, including in the knees, is a natural part of aging. But there'sno evidence that running accelerates that loss. In fact, at least one studyfound that when people who were at risk of developing arthritis began amoderate running program, the health of their cartilage improved, while thecartilage of a group of similar people who didn't start running didn't improve.
Supplements won't re-grow knee cartilage
Despite ad claims, no dietary supplementshave been proven to increase knee cartilage. The most popular such supplement,glucosamine, may help with knee osteoarthritis by protecting the articularcartilage, which, among other roles, helps to lubricate the knee joint. A studythat looked at vitamin D supplementation in people who had knee arthritis foundthat they had the same levels of pain and loss of cartilage after two years asdid people with arthritis who didn't take vitamin D.
Runner's knee is usually caused by issues elsewhere
The most common knee injury among runnersis runner's knee. Known clinically as chondromalacia patella or patellafemoralpain syndrome, it's inflammation of the cartilage under your kneecap. There'sincreasing consensus among sports medicine professionals that many people withrunner's knee have a few common biomechanical problems. These include weak hipsand glutes, which introduce instability further down the legs; weak quadriceps,which can make it difficult for the kneecap to track properly; and tighthamstrings, which shift some of running's impact to the knees.
There are some simple ways to keep your knees happy
As noted above, weakness and/or tightnesselsewhere in your legs can mean trouble for your knees. So get stronger.
Extra weight places tremendous strain onyour knees. The American College of Sports Medicine has said that eachadditional pound of body mass puts four extra pounds of stress on the knee.Running's long-term effect on keeping weight lower is thought to be a keyreason why, as we saw above, runners might have less incidence of kneearthritis.
Run on level ground to lessen the torqueon your knees.
If you have a history of knee pain,including from accidents or other sports, consider switching to more of aforefoot strike. One recent study found that more impact force affects theknees in rearfoot strikers, while forefoot strikers have more impact forces intheir ankles.