The text below is all from an anonymous commenter’s notes on this post discussing the theory of supercompensation. Many thanks to this person for the detailed and thoughtful comment, which is a good follow-up on the note above about Scooby. In fact I thought that the comment might have been from Scooby; but I don’t think so. My additions are within “[ ]”. While the comment is there under the previous post for everyone to see, I thought that it deserved a separate post.
I love this subject [i.e., strength training]. No shortages of opinions backed by research with the one disconcerting detail that they don't agree.
First one opening general statement. If there was one right way we'd all know it by now and we'd all be doing it. People's bodies are different and what motivates them is different. (Motivation matters as a variable.)
My view on one set vs. three is based on understanding what you're measuring and what you're after in a training result.
Most studies look at one rep max strength gains as the metric but three sets [of repetitions] improves strength/endurance. People need strength/endurance more typically than they need maximal strength in their daily living. The question here becomes what is your goal?
The next thing I look at in training is neural adaptation. Not from the point of view of simple muscle strength gain but from the point of view of coordinated muscle function, again, something that is transferable to real life. When you exercise the brain is always learning what it is you are asking it to do. What you need to ask yourself is how well does this exercise correlate with a real life requirements.
[This topic needs a separate post, but one can reasonably argue that your brain works a lot harder during a one-hour strength training session than during a one-hour session in which you are solving a difficult mathematical problem.]
To this end single legged squats are vastly superior to double legged squats. They invoke balance and provoke the activation of not only the primary movers but the stabilization muscles as well. The brain is acquiring a functional skill in activating all these muscles in proper harmony and improving balance.
I also like walking lunges at the climbing wall in the gym (when not in use, of course) as the instability of the soft foam at the base of the wall gives an excellent boost to the basic skill by ramping up the important balance/stabilization component (vestibular/stabilization muscles). The stabilization muscles protect joints (inner unit vs. outer unit).
The balance and single leg components also increase core activation naturally. (See single legged squat and quadratus lumborum for instance.) [For more on the quadratus lumborum muscle, see here.]
Both [of] these exercises can be done with dumbbells for increased strength[;] and though leg exercises strictly speaking, they ramp up the core/full body aspect with weights in hand.
I do multiple sets, am 59 years old and am stronger now than I have ever been (I have hit personal bests in just the last month) and have been exercising for decades. I vary my rep ranges between six and fifteen (but not limited to just those two extremes). My total exercise volume is between two and three hours a week.
Because I have been at this a long time I have learned to read my broad cycles. I push during the peak periods and back off during the valleys. I also adjust to good days and bad days within the broader cycle.
It is complex but natural movements with high neural skill components and complete muscle activation patterns that have moved me into peak condition while keeping me from injury.
I do not exercise to failure but stay in good form for all reps. I avoid full range of motion because it is a distortion of natural movement. Full range of motion with high loads in particular tends to damage joints.
Natural, functional strength is more complex than the simple study designs typically seen in the literature.
Hopefully these things that I have learned through many years of experimentation will be of interest to you, Ned, and your readers, and will foster some experimentation of your own.