My spine hurts from watching this video. Normally though the guys I see jerking their backs like that with every rep have a bandanna on their head and something sleeveless (to show off their spring break tattoo, usually their frat letters).
They train hard, that's for sure. Still, terrible form, a lot of useless curls followed up with half pullups and half chinups. Can't argue with what works, I just wouldn't put my body through that type of shit that would inevitably leave me injured a few years down the road.