So I went to the physio today and was chatting about boxing/kickboxing/mma etc, and when I mentioned what type of training I'd been doing he said that crunches and sit-ups were essentially useless. His reckoning went like this. Crunches build up a mass of muscles that are effective in protecting your internal organs from blows, but they are not really useful when it comes to delivering power. If you want to hit with the full force of your body weight you have to have a really strong lower back, obliques, upper back (core) and neck area so that the energy isn't dissapated and absorbed back into your body before the actual punch/kick lands. So with that in mind, does anyone know of, or anyone do any killer lower back, core, etc exercises?