I've got a pair of Vibram Five Fingers Sprints. I love them. I use them hiking in dirt and sprinting in the grass fields near my house. Today I was out running (in normal running sneakers) and a man (very likely 50 lbs heavier than me, both in strength and stature) bounced past me in a pair of Vibram KSOs! We were running on a lengthy concrete path and it was a rather unpopulated portion of the path so I presume that he wasn't doing "sprints." He was likely out for a reasonably lengthy run.
So here's my question:
If being barefoot is natural, and Vibrams (plus other minimalist footwear) mimic the natural movement of the foot, are we sure it is okay to wear them (or be barefoot) on non-natural surfaces?
I can understand wearing minimalist footwear on grass or dirt or sand; but on concrete? Hardwood? Asphalt? Surely the modern and harsh nature of the modern surfaces counteracts the natural strength of the foot in some way... Or not? What say ye?