Awww that's nasty! We don't do our class barefooted thank god, only to kick...definately not the warm-up...yikes, I don't think my poor shins could handle that. What you say is probably right...I only get these pains when I've been doing a lot of roadrunning, like the GNR last weekend...and they only last a week or so. Awww, I really feel for you though, the pain's awful...