> It really depends on running form and individual physiology True enough. I too have read "Born to Run", and would suggest that most modern humans aren't ada

> It really depends on running form and individual physiology True enough. I too have read "Born to Run", and would suggest that most modern humans aren't adapted to it (certain populations certainly, but most not). Although I have hit reasonably good times, I don't count myself among that population. In high school and in my 30's, I certainly was in the 90th percentile of runners, just by the numbers. Individual races, definitely higher. I love to look at the form and economy of top tier runners, and frankly, I'm not built like that; I could never perform like that. I'm bound to break down eventually, and I'm pretty good at running. > on an elliptical machine or something This is not running. This is training for running by not-running. Dress it up how you like, but it's how people like me save the damaging work for races.