[undersuit]

Our anatomy evolved to work on almost all surfaces. The early homo erectus that could not run on a surface was genetically less fit. Our gait changes slightly depending on what surfaces we run on; loose rock, sand, packed dirt, or concrete. Not being able to run on concrete would mean our ancestors would have avoided rocky areas... which they did not.

[anonymousDan]

Not convinced. I highly doubt there is any evidence of our ancestors running barefoot for long distances over rocky areas. From what I know the primary reason our running abilities evolved was to allow chasing grazing animals over long distances on grasslands. Be interested to see any evidence otherwise though!