Very good point.
Nelson Montana said:There are so many variables. "Failure" is an inderterminante phrase. Pushing until you can no longer complete a rep isn't more "failure" than resting a second and doing another -- or doing partials -- or more reps with a lighter weight.
If there were a "science" to reps we'd all know it by now.
Strength training is something altogether different. You can get stronger and not more muscular.
Plus -- everyone reacts differently to different stimulus. Even cliches' like "compound movements build mass" aren't entirely accuarate.
Didn't mean to get off topic. It's just one of those things that can be analyzed to death yet never really explained.