In Reply To:
Everything else being the same, HR correlates pretty well with oxgen consumption. I look forward to hearing from you how this is a misconception.
Maybe you can explain how oxygen consumption is a true and accurate measure of efficiency. I am well aware that this is a lost cause, given numerous power cranks threads. And, as is always the case, I would suggest that maybe you do some research that proves that you are correct rather than telling me I should prove you wrong. Generally speaking, utilization of a greater percentage of Type II muscle fibers equates to a lower HR , but that's not the same as efficiency, since it's well documented that Type I fibers respirate more efficiently than type two fibers. Much of the literature that's been around actually defines efficiency by that cadence which maximizes type I fiber recruitment, since they contract the most efficiently. Now I'm not an exercise physiologist, so I am sure I am way oversimplifying things, but I would also say that it's an antiquated theory to equate HR alone and efficiency. I'd argue that BLA is also a relevant metric if you are going to examine oxygen consumption. Because what is more interesting is how the work is being distributed, which BLA will help give you insight about, though even that is not a complete measure. If you are going to use HR as a proxy for O2 consumption, then you could also potentially use BLA as a proxy for fiber type recruitment, though I am sure there are limitations to that, I just don't know enough to the physiology to accurately assess them.
As you said, numerous studies have been done to try and answer why cyclists pick a cadence that is not the most "efficient," defining efficiency according to HR, O2 consumption, or something similar. Maybe that's because that definition of "efficient" is wrong, since once you start to consider muscle fiber recruitment, then the preferred cadence and the most efficient cadence track more closely. But even fiber recruitment isn't necessarily the whole story. As an example, might it not be more appropriate to consider efficiency in terms of damage to muscle tissue, especially for something like Ironman racing? Or what about efficiency defined by most work being done by major muscle fibers with minimal recruitment of smaller stabilizer muscles?
Biologic efficiency is not at all easy to measure. The best cyclists in the world continually choose cadences that those metrics for efficiency tell them are not optimal. Yet they do not change. These are people whose livelihoods depend on winning races. If the more "efficient" cadence worked, they would choose it. The fact that as a group they do not choose it leaves two options - 1) all the best athletes in the world are wrong, which defies the law of large numbers, which is pretty compelling evidence. OR - 2) the way in which efficiency is being defined//measured is wrong, which is supported if you look at the other studies using alternative definitions of efficiency, namely fiber recruitment, since it is well documented that type I fibers are more efficient than type II fibers at contracting, which is what we really care about.
Of course, much of the literature that discusses this type of efficiency with respect to cycling also says that the most effective way to pedal is to simply hammer the downstroke of the pedal cycle and to not worry about anything else, so I can see why you might not want to read them too closely.
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