Warning: super long, rambling post about hypertrophy.
In the spring I had a really good exchange with Ron (NWLifter) concerning hypertrophy stuff, and my thoughts lately have often drifted back to that exchange, including the idea of "novelty" in terms of stimulation to muscle tissue, RBE, and the whole shebang.
In that sense, I've been going over the questions and steps that led Bryan to develop HST in the first place, remembering some of the original discussions back in 2002, which is why this thread jogged my thoughts.
Along those lines, I honestly feel there's a very definitive pattern people's training careers follow. During one's initial training years, a lot of gains in both strength and size are made. Assuming you push yourself to lift heavier objects in general and eat enough, a lot of one's results happen during this time period.
However, at SOME point, a pattern seems to emerge in most trainees. That pattern, which has been the object of my obsession, is this dilemma:
During one's initial years, growth very much seems to follow increases in training load, and those increases in training load are a direct result of getting stronger. Your "strength ceiling" is raised over time by an accumulation of muscle tissue, and people will generally notice that any changes in strength are relatively permanent.
However, at some point, the fun and games seem to stop and people plateau. Now, plateaus are a reality of training at all levels, and people will tend to accumulate more strength/muscle here and there, but more intermittently past that noobie stage.
MANY people, however, eventually end up in kind of an odd, vicious cycle. I've found myself in this cycle and am still attempting to escape it.
The cycle is basically characterized by an inability to add muscle mass WITHOUT resorting to chronic overeating, an inability to RETAIN increases in strength post training cycle, and an inability to hold more muscle mass when actually lean. I believe all of these are related to the same fundamental problem.
That fundamental problem, I think (i.e. this is all just my humble opinion), is that, for one reason or another, our TRAINING is not actually making us grow, is at best providing somewhat better partitioning when purposefully overfeeding.
So what happens is that we wind up in a bizarre cycle of strength and weight gain and loss if we actually try to stay lean. Some compensate by not worrying about the lean part - if you get indefinitely fatter, you will allow yourself to get indefinitely stronger, providing the illusion of unlimited progress. If/when they actually decide to get LEGITIMATELY lean again, many are surprised that most/all their gained muscle and strength seems to disappear.
Now, getting fatter will in and of itself add muscle tissue, and training alongside this will likely help partitioning. So your "ceiling of strength" can increase as a direct consequence of this. But if you are driving muscle gain with food intake, then there does seem a certain logic/symmetry to these gains dissipating when you attempt to diet back off the fat, and this seems to track extremely well with people's experience.
Additionally, our gains in strength from a given training cycle (5 x 5, HST, or whatever) WITHOUT the above occurring (i.e. even if you don't purposefully drive strength with food intake) tend to wind up neural in nature. As Siff points out in Supertraining, strength gains that occur alongside structural (muscle) gain tend to be far more long lasting than strength gains that are largely due to neural magic. If you have ever experienced very rapid losses in strength from a break, SD, or whatever you'd like to call it, I have a sneaking suspicion you fall into the above category.
So what is the "fix?" Do SOMETHING in our training that directly results in an increase in muscle mass without RELYING on excess food intake. Yes, you have to eat enough no matter what, but when you attempt to make your progress drive adaptation (i.e. if I eat enough and keep slapping weight on the bar, good things are bound to happen), I believe the above scenario tends to play out for many, many, many trainees.
What is that something that actually allows training to induce the necessary changes? I don't know, but I do think Bryan was attempting to answer that question by introducing strategic deconditioning and relating it to the RBE. Ignoring terminology for a second, muscle tissue is, first and foremost, tension-sensitive, so the idea was that chronically exposing a muscle to a similar stimulus (in this case, persistently similar levels of tension) will quickly eliminate its ability to respond and restructure itself. As Bryan himself put it many years ago, he needed a way to grow bigger without first getting stronger. Why? To avoid the vicious cycle above, I think, to allow adaptation to drive progress instead of the other way around. If this works, you WILL get stronger anyways, but as a direct consequence of holding more contractile tissue - the whole "ceiling of strength" thing described above.
In this case, SD was the answer of taking the "protective coating" off of muscle, and the rapidly escalating loads were the "novelty" that would, in principle, keep triggering growth over and over again. The frequency recommendations were based on attempting to provide an optimal backdrop for this process to occur.
So, 5 years later, was Bryan's answer correct? I honestly still don't know. While a lot of people do find success with the default HST template, I've seen Bryan drop "hints" that I think would be more fully fleshed out in his book that higher volume for more advanced/trained individuals would be of great utility.
Bryan, for example, follows a 6 day a week upper/lower split. Why? More total volume per body part, both acutely and weekly. It's not implausible that Bryan could have been right all along, but a lot of people aren't being "wowed" because they aren't doing enough on a per-session basis to actually trigger growth.
So yah, there's a whole heaping helping of thoughts on the topic of muscle growth and the state of HST.
