“Even more important is the effect heavy presses have on your torso strength. Imagine stabilizing 500 pounds overhead, even for a couple of seconds. Imagine the long trip the bar takes from your shoulders to lockout, and what your whole body has to do to make this happen.”

Swiss ball sit-ups, Swiss ball alternate-arm seated 3-pound dumbbell presses, Swiss ball prone alternate-leg alternate-arm ipsilateral raises, and anything else done on a Swiss ball may be really great for your “core” (the C-word, and I don’t usually use it at all – I’m above that). A bodyweight+ press is a huge stress on the whole man, and the response to this stress in every single muscle from your head down to your toes is a stronger everything, not just a few muscles on either side of the spine.

“Because getting your press up is a worthy goal in and of itself, even if it costs you some bench press” (which it probably won’t, and if it does, the universe will forgive you)

http://www.t-nation.com/free_online_article/most_recent/get_your_press_up