After dragging my brain through 41 pages of research on "The Influence of Frequency, Intensity, Volume and Mode of Strength Training on Whole Muscle Cross-Sectional Area in Humans" guess what the conclusion was on an extensive study designed to figure out the best way/combination of ways to increase muscle mass? Essentially, that all variables are valuable and there is NO ONE SINGLE MAGIC BULLET.
Sometimes - okay, a lot of times - research totally cracks me up. I think I've stated this before. This paper was about 10x longer than most with extreme detail and for what... to confirm something that any experienced strength coach knows:
Regarding progression, we recommend low volumes (e.g. 1–2 sets) in the initial stages of training, when performing eccentric-muscle actions, because low volumes have been shown to be sufficient to induce hypertrophy in the early stages of training and because exercise adherence may be improved if the workout is relatively brief. Also, avoiding unnecessary damage may allow hypertrophy to take place earlier. As the individual adapts to the stimulus of strength training, the overall volume and/or intensity may have to be gradually increased to result in continued physiological adaptations and other strategies (e.g, periodisation) can also be introduced if even further progress is desired.
So, through actual published research (and not the usual anecdotal evidence), it is confirmed that the best policy when progressing an individual for anything - in this case hypertrophy - is always found in moderation.
The next time you're considering ordering any number of TV products promising to solve all your problems or thinking about signing your kid up for training that "guarantees" quick results, I ask that you keep in mind some solid research and accept that anything worthwhile in life takes time, hard work, and guidance.