obviously ROM matters, those people who just look like they are bouncing the rig up and down a few inches are not getting optimal muscle stress and contraction
if you are doing this, and are not able to slowly unrack the weight................ta ke in down slowly reasonably deep................stop ..................and fully extend back up...................you r most likely using WAY too much weight
also, using too much weight, and and bouncing, and using Poor ROM........is a good way to hurt yourself................ when i was dumber a few years back i herniated some discs in my back leg pressing like an asshole
