1. Not on my end. (Logged in from home, not signed in to my university or society accounts.)
2. Because the study reported the largest ever increase in mitochondrial marker enzyme activities ever observed in a longitudinal study (minimizing genetic advantages), to match the two-fold higher values found in elite athletes, despite the fact that the participants only trained 4 h/wk. (Apparently you've never encountered the classic 1964 paper in *Science* on "strong inference", one major point of which is that scientific progress is most rapid when you focus on *disproving* hypotheses.)
3. No one has said that larger volumes aren't necessary/beneficial - it is just to the extent that they are, *it's not because of some unique ability of "zone 2" training to alter muscle respiratory capacity" as you have claimed*.
4. *Of course* the results are partially because the individuals were initially untrained. But, that's the whole point, because that is the reference condition when evaluating the muscle respiratory capacity of highly trained individuals.
5. There are numerous studies in the literature of both rats and humans showing a high correlation between mitochondrial enzyme activities and performance, mostly dating back to the late 1960s to early 1980s. For rats, see studies from Holloszy's lab. For humans, see Sjodin's work with marathoners.
*However, this is really just a red herring. You claimed (and continue to claim) that when it comes to mitochondria/metabolism, there is something special about lower intensity, "zone 2" training. As that classic study by Gollnick et al. so aptly demonstrates, there isn't. You therefore need to find another way of rationalizing your belief system with respect to optimal training, because your hypothesis about being about mitochondria is flat-out wrong *
6. There is no LT1 or LT2, or really even an LT - lactate increases continually albeit not linearly as a function of intensity. The way to shift that curve is obviously to train with some combination of intensity and vi, but science can't tell you what is optimal, especially for any given individual.
More importantly, focusing on attempting to improve physiological responses/adaptations is a mistake. What you should focus upon is improving actual *performance*, and just let the physiology sort itself out. Otherwise, you will find yourself going down stupid rabbit holes, like doing "over-unders" to try to improve lactate clearance (which is irrelevant), or obsessively measuring lactate concentrations during almost every workout, in the mistaken belief that "intensity control" is critical to improvement.
