Mike was not training rear delts. He was in fact bowing down to worship Arnold when Arnold came into the gym. You just don't see Arnold.
Hit can be used when you are short on time and don't want to miss a workout. But you are NOT going to gain much if any size doing it all the time. At best you might maintain what you built by training the right way and at worst you will lose what you did make and cause other body issues ( it takes a toll on your nerves mind heart etc) So train the right way and get results. getting stronger does NOT mean you grew muscle. !! That is one of the biggest mistakes methead did was think if you lifted heavier that you grew muscle. It does NOT work that way!! Lots of skinny guys are strong and lots of big guys are weak. Lifting heavy is good but not all the time. Going to possitive failure is good but not all the time. Pre exhaust is good but not all the time. Supersets are good but not all the time. Do you methead lovers understand that your idol was wrong about almost everything! The fool lost his mind and his body and then his life because he just wouldn't admit he was wrong. Hell even his diet advice was dead wrong. Mike got built training the right way yand then pushed his hit crap but never really trained that way himself. Neither did his brother or casey or Dorian. There has NEVER been a bodybuilder who has EVER gotten big and muscular training with " heavy duty" ( hit) and never will be.
Girls and sons who have not been loved by their fathers seek attention once teens and adults to compensate for what they didn't have originally. Fathers either left them alone, or were distant most of the time and not encouraging them. Some even despised them which would shape their personality and the way they interact with others for the rest of their life. They are extremistic in everything they do, always looking exaggeratly for attention (Hello Goodrum), and have troubles adapting to society's rules, because they also have troubles defining their own identity and respecting authority and hierarchy.
Also boys who got picked on by others during childhood and adolescence -often sons without a father figure- try to compensate by lifting weights, to develop muscles and survive in ther male world. They're insecure because they're girly, childish, feminine having been raised by a single mom. They lift obsessively hoping it will transform them into men, to compensate for their lack of influence from a father figure that was not there. Unfortunately they can get as big as they can but it doesn't cure their insecurity and who they truly are, how they grew up being raised by a single mom. They're not as manly as other men whatever they do, and they often have a big lack of masculine presence they don't know how to balance, hence often being borderline homosexuals while trying to get their manhood back through various manly activities (MMA, cars, weight lifting etc.).
They are often the ones that, in order to get respect from other males, will go the steroids route to get even "bigger", attempting to cure their insecurity, but being natural not being "enough", they still feel "too small", insecure, amongst other males. The lack of a father figure also often means they didn't have guidance to continue studies and are often working shitty manual jobs.