It isn’t (or at least shouldn’t be at this point) a secret to anyone how early bodybuilders and same era “strongmen” used to train to develop their physique.
As the need for a spectacularly detailed muscle-structure wasn’t there, and people didn’t even know the extent of the development the human body was capable of, everybody went for sheer strength and thus a low-set approach.
Being strong back in those days meant a lot more than being cut and well defined.
Despite the fact that this way to train did lay the foundations of a very solid muscular development it lacked the tools to sculpt it into a competition-fit physique by today’s standards.
Over the years - through the infallible trial and error method- two things have become obvious for bodybuilders who trained intelligently:
1) The further one progresses as a bodybuilder the harder it becomes to squeeze in more development. The body uses all its resources to resist further growth, thus one needs to cheat it.
2) In order to achieve this one needs to subject different muscle-groups to workloads and efforts absolutely unheard of. It isn’t enough though to simply continue the piling on of the weight as obviously there’s a physical limit to how far one can go in this respect. The workout of any target muscle-group has to be done from all possible angles as well, otherwise perfect definition and development is practically impossible. Put two and two together and you’ll realize that the very thing that can achieve both continuous overload and a thorough all-round workout, is the high number of sets per body-part.
As it’s been discussed on other pages of this site the concept of a “high number of sets” differs from one muscle group to the other and is dependant on the size of the latter.
For a small muscle-group (like the biceps) a relatively low number of sets/exercise (4) is sufficient. However, even so it needs to be hit by a number of exercises to achieve any efficient development. Even if one keeps the number of exercises down to about 3 for the biceps (inner area, outer area and thickness) you do realize that already means 3X4 = 12 sets per a small muscle-group.
Bigger muscle-groups, like the back, need to be worked out from far more angles, thus, even if keeping the number of sets/exercise down to an ideal 4, the total number of sets employed for the muscle-group in question will skyrocket.
No question about it, many of the old time greats, would probably have achieved far more spectacular results, had they been in possession of information available today to anyone.