“It’s just so hard on the knees.”
You’ve heard it more than once, but running, long thought to cause unnecessary damage to the knee joint from all the pounding and rattling around, actually can have the opposite effect. Running can make your knees stay healthier, longer.
Long-term studies actually indicate that running doesn’t appear to cause much damage at all to the knees, on the contrary, it can strengthen the joint, and it doesn’t look like it increases the risk of arthritis.
There are caveats, though. If you’re overweight or have suffered a significant knee injury, this doesn’t apply. However if you don’t fall under one of those categories, running as a form of exercise is probably a good idea. If weight or injury aren’t an issue, the load on your joints from jogging may be mitigated by other factors.
Ross Miller, Ph.D., authored a study where researchers had adults walk or run on a treadmill that captured data on the amount of force, or load, each step had with the ground over a specific distance. Results indicated that the force exerted on the knees while running was up to three times higher than while walking, but it was offset by the runners’ stride length and the time they spent in the air.
Each step you take walking exerts a load on the knee 2 to 3 times your body weight, he says. The force from running increases that load to anywhere between 5 to 12 times your weight, depending on running speed or form.
“While walking, your foot is on the ground about 60 percent of the time, but in running that’s reduced to about 30 percent of the time,” says Miller. “Even though the load is higher, you don’t experience it for a very long time.” Additionally, because running has a longer stride length than walking, it means fewer steps are required to travel the same distance (source).
Studies also indicate that exercise may stimulate cartilage to repair to minor damage. It’s possible the impact of body weight when the foot hits the ground increases production of certain proteins in the cartilage that make it stronger. This is similar to the way exercise, in particular weight-bearing exercise like jogging, increases bone and muscle mass.
Just like anything else, too much too soon can, and most likely will cause overuse injuries, so if you’re new to running, try walking and running to start and working your way up. If you feel pain, stop. Rest. Take care of yourself. But if you’re already running and healthy (and if you’re reading this, you probably are), don’t listen to the naysayers that tell you you’re wearing out your joints. It’s more likely you’re building up your joints, so you stay healthier, longer.