A Little Back Pain...

Well I started another cycle of Mass Assault today and needless to say I finished my 4th round with two more to go and could feel my lower back tighten up. I told my self to stop and I actually listened! I knew this feeling from when I injured my back quite a while ago with conventional weight training. It's a bit sore right now but nothing a few days of intu-flow and rest wont help. I think I injured it doing too aggressive on the swing portion of the training so I have to be careful.