Ed Ayers was an editor for Running Times for many years. He's contributed a very interesting read on the front page called Toes, Heels, and Human Evolution By Ed Ayres.
A most excellent article from Ed Ayers. Not only do I feel much better about the stubby toed blocks I've been perched on for 45 years, but it's nice to know that the longing to just run and run and run is likely natural. Next time my dog wants to chase down a prey animal, I might just join her.
Nature has a funny sense of humor though - could it be that the ability to run sustained distances is in part what led to our success as a species and has led us to our sedentary liffestyle?