"Running over 30 miles a week for probably my first five, six years on Tour pretty much destroyed my body and my knees,” Tiger Woods said.

So in 4 years it might be really bad? Be careful.

Just running 30 miles a week is not enough to cause damage in most people. Tiger was also doing hours of professional-level golf training every day at the same time.

7 miles/week vs. 30. And this doesn't count all the other physical stresses Tiger put on his body, like the insane torque he was able to generate swinging a club.

Even if the poster walked a mile day, that's only 20 minutes and barely hits the recommended exercise time.

I feel like anytime these threads pop up about someone staying physically healthy a bunch of people come out the woodwork to make it sound like they are hurting themselves. I'm not really sure why.