the pump and proper form lol. if you powerlift with improper form your nickname will be cripple . i guarantee powerlifters pay attention to form better than most bodybuilders do.also some of the best all time bodybuilders trained as powerlifters . ronnie coleman even used the powerlifting suits . NOTHING and i mean NOTHING adds mass like heavy lifting , concentrating on the pump is some BULLSHIT propaganda that the muscle rags / magazines use to sell their crap.