Here is my theory on this from personal exp.:
I don't quite like Pianas way with STILL heavy enough weights. I've watched a bunch of videos too and saw a lot of guys were just overdoing it.
Man, your muscle needs to recover after a heavy ass workout from the gym as it is already on the daily basis.
What I realised by trying things out, the one thing u don't want to do - is break the muscle! <-- And that is the key.
I was using rubber bands. It took me twice to buy the right one. First one I bought later turned to be too hards even though it seemed light in the shop at first. U want superlight, yes -very very light band, just to get the blood pumped in and feed it. If you jerk/curl just empty wrists like 50-70 times you already will get some pump. So imagine just having it that little bit extra tense.
From other point of view - Well, the sensation is awesome, as pump it self is. I must say I was lacking on time to keep it to a decent period to be able to judge about it's efficiency though. But definitely learned that breaking muscle will be a bad way to go, because 1. you will not be ready for your sweet "arms day" (plus some ppl, like my self, manage to do arms twice a week), and 2. that feeding must be, as they claim in the video too - frequent/regular.
Actually I still have a desire to fully test it on my self, IF the time and schedule somehow would alow some day..
