It's something I've heard for years: "All of that running is going to kill your knees. You should find some other lower-impact exercises instead." Although it's a common perception that running will negatively affect your knee joints and likely leave you hobbling around in your later years, does research support that idea? Not necessarily.
A study published in the journal Skeletal Radiology examined runners knees before and after a marathon, and then again 10 years later. They found no new damage to the knee joint after 10 years, and even concluded that continuous exercise (such as running) might be more protective than damaging to the knees. Would you have thought that running might actually help your knees?
A Stanford University study followed distance runners for a period of 20 years. They found the runners' knees were healthier and less arthritic than the control group. An additional study in The Journal of Joint and Bone Surgery concluded that "by moving and loading your knee joint, as you do when walking or running, you “condition” your cartilage to the load. It grows accustomed to those particular movements." This conditioning might actually help protect against arthritis.
The best way to prevent knee problems is to avoid injury in the first place. Previous injury significantly increases the chance of injury in the future. You can help prevent injury by avoiding overtraining, increasing mileage slowly, and strength training regularly.
So far, I've been lucky enough to avoid serious injuries in my running career. I always joke that if I'm still running when I'm 60 (which I intend to be), I've got a chance to qualify for the Boston Marathon. (The qualifying time for a 60-year old woman is 4 hours and 30 minutes.) The results of these studies give me hope that I won't have to find a new passion when my body decides it's had enough pounding on the pavement.
What do you think? Do the results of these studies surprise you?