Awesome discussion! There is some great insight in this thread. I just want to add the idea for those not sure how to frame this discussion in their minds, that biological tissue is "fuzzy" in the way they used to say "fuzzy logic". From Wiki, "Fuzzy logic is a form of many-valued logic in which the truth values of variables may be any real number between 0 and 1 both inclusive. It is employed to handle the concept of partial truth, where the truth value may range between completely true and completely false." "By contrast, in Boolean logic, the truth values of variables may only be the integer values 0 or 1." The reason I bring this up is that there is a temptation by thinking lifters to define the ideal set using boolean logic, instead of fussy logic. It is tempting to try to prescribe the ideal number of reps, or weight, or time under load, etc. When in reality, as a biological system with both mechanical and chemical components, there will never be a fixed quantity of any of the variables involved that will always be true or "ideal". It is fuzzy, there is a range of possible quantities that will work for stimulating a system that has a range of possible "states". It is for this reason that we have the HST principle which states, "The effectiveness of any load-stress depends on the condition of the tissue at the time the load-stress is applied." And the condition or "state" of the system is dependent on what load-stress it has been most recently and chronically exposed to. Additionally, it is difficult to say what RPE is ideal without considering the fact that we have a moving target with mechano-sensing cellular protein structures such as costameres, intregrins, and adhesion GPCRs fluctuating in sensitivity all while the chemical milieu within the cell is ever changing. Now I'm not saying discussions like this are futile, on the contrary, they are great and certainly do a lot to help lifters understand what they are shooting for when executing a set. All I'm saying is that, like an electron, we can't ever say for sure where it is at any given time, at best all we can say with some certainty is where (a range) it should be. Ok, back to the discussion!