After trying all the new and "improved" ways to train years ago, I came to the conclusion that lifting heavier weights than the last time was responsible for the best hypertrophy possible. I'd use magnets, and work my way up to adding a 5lb plate, and so on and so forth. Anytime I'd train with one of the big boys, I can point out the one thing they all had in common was hoisting very heavy iron. Sure, it's done in a certain rep range, but ALL of these guys trained very heavy. When this is done, constant nutrients are consumed/flowing through the blood stream, and proper sleep is incorporated, the muscle simply has to grow. It really is that simple.*
* I will note that increasing weights lifted each session doesn't keep going, and going. Oh no... I do this for 8-10 weeks, then "cruise" for 2-3 weeks using the same weights, and straight sets. Injuries are VERY serious, and at 41, are my biggest concern going forward.