The Pre-exhaust system has been around since the 60's & probable before. Doing an extension exercise before the bigger push/pull exercise. With flys you want to tire the pecs to their limit, than switch to the bench (or incline/dips, etc) and with the help of the triceps and delts , push the pecs to work even more.
Good theory for BB'ing. Some confuse Pre-exhaust with SS's. But a lot of different training systems can go by different names today.
Can do quads with with leg extensions first than squats. Delts: lateral raises (strict) with press behind neck. Lats: straight arm pullover than lat pull down/rows/etc. Lots of combo's. Surprised it's not used than much now. BB'ing is very trendy, so maybe it will come back big time again. Good Luck.
Side Bar: Got ya, Evo!