Thanks Tim. I too think my Option 2 is the only one likely --but you have to agree that this pretty much means that even if the CG does exist knowing this is essentially useless in improving performance. It is altering other factors through training that is the real limitor (ie, maintaining homeostatis at a higher speed/energy output)
"In the laboratory I believe we study subconscious controls when we have subjects do activities with which they are unaccustomed (exercising at a fixed rating of perceived exertion) and we expose them to changes in the oxygen content of the inspired air which they have usually not ever experienced before. I would not understand how under these conditions, the changes that occur in their exercise performance are due to conscious controls. But again I may be wrong. Similarly when they exercise in the heat or the cold, we are able to explain (ie predict) why they change their exercise performance on the basis of biological signals that I don't think are being perceived at a conscious level by the subjects. I do not know that we consciously know how quickly our bodies are heating up - this is the biological signal to which the brain is responding under these conditions."
The conclusion that this must be regulated by the brain is not necessarily correct. It could be regulated metabolically as energy demands can no longer keep up. For instance, reducing oxygen leads to a reduced ability to maintain the same level of aerobic energy production. Without energy, muscles don't work and pace must slow.
"but I also learned, especially in the 56mile Comrades marathon, that if you went too fast early on in the race, sooner or later the "bear" would jump on my back and I would "hit the wall" and whatever I might consciously wish to happen would simply not happen, however hard I willed it to happen, or prayed for assistance, or whatever. At the time I believed that this "fatigue" was due to changes in my muscles - "peripheral fatigue". Now on the basis of what we have found - in particular the finding that under these conditions we are activating less than perhaps 40% of the fibers in our active muscles - it seemed more likely that our effort was being regulated centrally in the brain. Because if it were not, the brain would logically recruit progressively more muscle fibers until all were active at which time and only then would we be exhausted."
So the CG is in place to protect us, yet we can override it at will? What purpose does it serve then? Honestly it seems to me that you are twisting your theory any way that you need to in order to avoid having physical observations contradict it. What evidence do you have that we can override it, or that there is a reserve when it kicks in? One time you tell us it is there to protect us, now in this thread you tell us we can "flog a dead horse" and you've driven yourself past it many times. Seems to me this is evidence it isn't really there. As for assuming the brain will keep recruiting more fibers, I believe that conclusion is too simplistic. There could be a multitude of reason more fibers are not recruited.
"This endspurt taught me that the cause of my fatigue could not have been "peripheral fatigue" since it was reversible at least for a short time. And if exercise was regulated only by "peripheral fatigue" why was it necessary also to prepare my brain for the last month (at least)?"
This ignores metabolism. Your body is always trying to prepare for "fight or flight". During endurance races, you are primarily running off aerobic sources. You have anaerobic metabolism, either through lactate production or creatine, ready to supple short bursts. You could just as easily be leveraging these energy sources to fuel the burst. Increases in lactate levels demonstrate that this isn't just the brain willing you faster.
"During those runs I also learned that it requires all your conscious effort just to MAINTAIN your pace; it was quite impossible to will yourself to speed up, except in the last mile or so. "
I could will myself to blow up at any point during the race.
"But there has to be more to it than that since it seems that the governor is conservative and it does insure that there is quite a large reserve."
If such a large reserve exists, why? What adaptive purpose does that serve if your theory is correct and the governor is there to protect us yet you said you can override it at will?
"Thank you for agreeing that the Hill model is fatally flawed since it absolutely does not allow for the brain to influence the exercise performance."
You're welcome, as I said I have no horse in this race. But I don't think your model is any more correct and honestly probably worse if you do not accept the conclusions that come with my Option 2.
"In contrast we have provided irrefutable evidence that exercise performance is regulated by a complex intelligent system and we have published that work in a number of peer-reviewed journals."
Which I have read, and you have discussed here, and as I have pointed out are far from irrefutable.
Thanks for the discussion. I'd appreciate hearing how you resolve in your mind the contradictions pointed out above -- that the CG is there to protect us, yet we can override it whenever we want, etc.