Afraid my personal take on this is not very optimistic. I respect people's desire to want to revert to the caveman or the lesser primitive way of doing things, including barefoot walking and running. The truth is, our ancestors did not live very long, have tons of health issues (often result in painful deaths). Additionally, their activities were much different than ours (probably no tennis). The environment they lived in were also different. So what make us think that a caveman could survive the modern world better than the modern version?