These are pretty cool. I had the pleasure of hearing Dr Lieberman from Harvard give a fascinating speech at ACSM last week on the evolution of humans as endurance runners and he's very interested in the effects of shoes on our feet- looks like he's recruiting FF wearers in addition to his barefooters. Between him and Hugh Herr, who's working on understanding feet to create prosthetics and exoskeletons (assisting impairments), I think we're going to see some huge changes in the understanding of what our feet can do and how much our current shoes inhibit them. Maybe someday I'll be lucky enough to work with one of them- they're truly the rockstars of biomechanics.