Hi barefoot runners: Just finished my 5k easy run on a treadmill today, feet feels ok, no discomfort except for the plastic side rubbing against my arch (I have pretty flat feet). Going to stretch out the plastic a little bit. Then I put my old Rider back for 1/2k cool down and I thought the Mizuno was SO heavy Good experience so far. Plan to use them for barefoot training on soft ground such as sand or grass. Next morning, I felt that I used different parts of my calve muscles because of the Vibram. Feedbacks and suggestions welcomed on how I can use them more effectively...P.S. Right after I got down from the treadmill, a foreigner came to me and asked where I got the shoes, good way to start a conversation I guess