I recently acquired a pair of Vibram Five Finger shoes. I had no plans on using them for anything other than water shoes. I started wearing them around the house, getting a feel for them, mostly to creep out Mrs Gunbunny. For some reason she has a pathological disorder about the shoes. Last week, the shipment of toe socks I ordered off of Amazon finally arrived from Korea. Feeling more confident not to stink up the house by wearing the shoes without socks, I started wearing them outside while walking. I started hiking while wearing the shoes, and that's when I really noticed a difference. My calves hurt, especially when going down steps. I never had this problem before. My instep hurt from placing my feet on rocks unwisely. You learn pretty quickly when wearing a pair of minimalist shoes where NOT to put your feet. I haven't even begun to run in them. I periodically thought about it, but then put it out of my mind when thinking about how I run with regular running shoes. Thoughts of glass or other sharp objects on the urban trail really make me not want to try it. I haven't even used them when lifting yet, but I was planning on trying it. Seemingly for no reason, my lower back hurt for all day yesterday, mostly gone by this morning, but still partially there. My question is this, am I transitioning my stabilization muscles incorrectly (i.e. too fast) if my back acts up because of these shoes?