There is a great deal of evidence that humans not only can run long distances, but have evolved to do so. The idea is that before primitive weapons (bow and arrow or whatnot), this is how we caught food -- by simply running it down.<p>From other sources:<p>"Biomechanical research reveals a surprising key to the survival of our species: Humans are built to outrun nearly every other animal on the planet over long distances."<p><a href="http://discovermagazine.com/2006/may/tramps-like-us" rel="nofollow">http://discovermagazine.com/2006/may/tramps-like-us</a>