Here's the thing. There have been many bodybuilding systems over the years, and all of them work, for a while. The fact is, any given system only works so long because your body becomes habituated to the system and you will stop gaining. The way the muscles gain is by shocking them. Once they become habituated, you have to change the routines so that they can be shocked again. My own favorite system was the 100 rep system. You start with just an empty bar, and do 100 reps. Once you can do 100 reps without strain, you add a pound. When there's no strain with that, you add another pound. And so on. You do a workout every day, but you only work that one muscle a day. It's highly effective, it does spur growth, but even that system will only last so long before habituation sets in and you have to change to something else. The reason I liked this system so much is because along with muscle work, it also greatly strengthened the tendons and ligaments, which is something I find a lot of bodybuilders neglect, and pay for with with injuries.