Insanity AM or during the day Kickboxing.
Sure am happy Friday is an 'off' day because I hurt my back again during kickboxing! I think it has to do with the size of the room! On Mondays we are in a small room and are all sardined in. But Thursdays we are in a bigger room and I think there are less people. I think I am hyper-extending, especially when kicking backwards, which is causing me SEVERE back pain!!