Running Won’t Ruin Your Knees
"...there is very little evidence to support the idea that running ruins knees. In fact, some research suggests that the opposite may be true: that, much as lifting weights tears your muscles a little bit and your body builds them back stronger, running may prompt the cartilage in your knees to do the same thing."
In her latest NY Times Phys Ed column, Gretchen Reynolds covered a new study from the University of Maryland in College Park on this topic. She writes:
Using motion capture and sophisticated computer modeling, the study confirms that running pummels knees more than walking does. But in the process, the authors conclude, running likely also fortifies and bulks up the cartilage, the rubbery tissue that cushions the ends of bones. The findings raise the beguiling possibility that, instead of harming knees, running might fortify them and help to stave off knee arthritis.