Well, I practice my serves while at work (I know, dream jo, but only for this summer). When I'm at work I'm wearing my shallow soled skate shoes and I was hitting my serve pretty good. When I go to a court and play a match I wear my Nike cross-trainers whoch have a different sole. Well, it took me two outings to getused to serving in my Nikes, everything felt different when I wasn't wearing my skate shoes. Does this make sense? Can changing shoes actually effect your serve? Don't get me wrong I won't be wearing my skate shoes to play any time soon, I was just really surprised at how much of an effect this seemed to have on my serve.