I'm skeptical as it seems like nothing but broscience to me. I've never been an advocate of "chasing the pump". In my opinion, and experience, hypertrophy occurs when heavier and heavier loads are placed on the muscle forcing it to have to adapt (grow). Over the last 30 years of training I've done both high and low rep work and I've only observed growth during my heavier weight/lower repetition cycles. Granted, even my higher rep work didn't go to the extremes that Rich is advocating, but higher rep work for me only allowed me to maintain muscle size, not increase muscle size. Seems like these days with the internet and our access to so much information everyone has a philosophy about what they think works and they attach a fancy title or acronym to it and call it their own, such as FST-7, DOGGCRAPP, HIIT, Mountaindog, to name a few. I believe in the basics and I feel a lot of people make hypertrophy more complicated than it really is.