Hah, I think I need to buy a pair of real running shoes, because right now I work out in a pair of Nike Frees. When I bought them I figured that the light, thin, flexible shoe would allow more motion of my foot and therefore work my calves more, but right now i'm rethinking that as my legs end up sore after running a quick mile. Can't tell if its a good thing from the muscles getting worked or if I'm putting too much stress on my shins and ankles!