Originally Posted by
blowdpanis
Howdy Mark,
To focus on one point and simplify the jist of what I'm saying, I'm going to offer a thought experiment.
If, for the sake of argument, you were creating your own study/trial/whatever to determine the "optimal" rep range for hypertrophy, would you be inclined to believe that "higher reps" would be more advantageous IF we held volume (total reps) approximately constant in our comparison groups?
Example groups and the sets/reps they'd use in our pretend study:
2 sets of 12
3 sets of 8
4 sets of 6
5 sets of 5
All groups are approximately equal volume (24-25 reps), with the difference being the potential loading. I.e. 2 sets of 12 might allow a ~14-15 RM at one end of the spectrum, whereas 5 sets of 5 might be something like a 7-8 RM at the other end.
My personal guess is that, all else constant (e.g. volume and frequency), heavy will always "win" or at least tie for growth. And when I say growth, I mean growth of actual contractile tissue, just to clarify.
The point of this illustration, I guess, is to show that the reason higher rep sets might be conducive to hypertrophy isn't necessarily the high reps per se, but rather the total volume you can safely squeeze in at the load required to use higher reps. For example, you can probably squeeze in ~50-60 total reps a pop with something like 10-15 RM across multiple sets, but as you approach, say, a 5 RM, you're looking at a level of volume that may be unrealistic when trying to avoid overtraining/injury (like 17-20 sets of 3 or something insane).
As for a discussion on sarcoplasmic hypertrophy and how fatigue affects that, that's kind of its own conversation, but my personal opinion is that you can't really separate myofibrillar from sarcoplasmic hypertrophy, the idea that, for example, bodybuilders' muscles are like these inflated balloons without much contractile tissue as a result of their higher rep training, I think, personally, is bunk.