It is very difficult to measure perceived effort I agree, but not fiber recruitment also known as motor unit activation for the 'science' guys. I'll post a quote from this guy Carpinelli on how this is done:
"Motor unit activation level (AL) can be measured by comparing voluntary and induced response. “During an MVC [maximal voluntary contraction], a supramaximal [greater than maximum] electrical stimulus is superimposed with surface electrodes onto a muscle or its nerve,” Carpinelli explains. “When the superimposed twitch technique is applied properly, the electrical stimulus fully activates all the motor units in the pool. If all the motor units have been recruited [voluntarily] and are firing at optimal frequencies, no additional force will be detected [as a result of the electrical stimulus].”
Motor unit activation studies, writes Carpinelli, “strongly support” the size principle. “It is the intensity of effort that determines the AL of motor units and the resultant force output. A greater effort produces greater motor unit activation. Maximal effort produces maximal, or near maximal, activation of motor units. The resultant force, which is the dependent variable—not the independent variable—is a maximal force produced in a specific individual for a specific exercise. It is entirely dependent on the intensity of effort. However, it is important to recognize that none of the [AL] studies speculate on a minimal recruitment threshold for strength gains…A maximal effort only insures maximal voluntary motor unit activation.”
IMO, the bottom line is progressive overload, always striving to lift a little heavier or more reps over time. Training with close to max efforts may be more effective at inducing hypertrophy due to the increased fiber recruitment or motor unit activation.
My point with all of this is that 'heavy' as in low reps is not needed and that high reps work just as well, because it is progressive overload and degrees of effort that matter.
I've read Carpinelli's stuff. I like the way he lays out his toughts.
But nothing he says disagrees with what I said. In fact, what I said is pretty much a simple derivation of what he's said.
Carpinelli is telling us that at a maximal voluntary contraction, which requires the highest intensity level (which he defines at %1RM in his papers), the entire pool of motor units is recruited, and hence, the fibers ascribed to those motor units contract. All of them. In accordance with the size principle, of course. Therefore, past the level intensity that triggers a maximal voluntary contraction of the entire motor unit pool in a muscle, you can't recruit more muscle fibers. You've already recruited all the ones you can ever recruit. And the force output you get out of maximal recruitment is a defined factor (i.e. the dependent variable). You apply more intensity, you get more recruitment, you get more force out of the muscle via contracting more fibers.
I don't want to assume I know what you're trying to tell me, but I think I have an idea. We're probably saying the same things, just that we disagree on the terminology. Plus, it's Friday end of month, and I've done my mandatory 5 posts on training science for the month per my contract with Ron, so I'm going to back out now. I talk a big game on the science of training because it's my educational background.
In reality, 95% of your results come from picking up something heavy and lifting it a lot. The other 5% comes from knowledge of training programs and how to cycle them. If you're an elite athlete, it matters. If you just want to get bigger and stronger for whatever reason, it doesn't matter that much. Until you get older and want to prevent injuries. Then it matters a bit more. But not too much.
I like to talk about training modalities, only because I have shit genetics, and I studies it a ton in school hoping that knowledge would help me overcome shitty genetics. It does not. I've told a million stories about guys who eat/train like shit who look way better than I ever could, all while I was studying under Tudor Bompa.
