The "criticism" you refer to below comes from* Timothy Noakes's excellent "Lore of Running". Much of Lore of Running is explanation, comparison, contrast and refinement of explanatory models for human training and performance, especially running. The entirety of Noakes' criticism (reproduced below) is that Daniels' model doesn't fully explain his own superior results
. Noakes has a first class mind, real curiosity and his writing conveys a humility that surely comes from seeing mental models demolished, year after year, decade after decade. In that sense, he's like any quality scientist, coach or athlete. He's not trying to fit reality to anybody's mental model.
Here is what Noakes actually says:
(Lore of Running, pp 311-2). "as a result of his training in classical exercise physiology, Daniels uses specific physiological terms to describe both the nature of his different training sessions and the physiologic adaptations that will result from those training sessions. The strength of this approach is that it fixes in athlete's minds the exact reason why they are doing a particular workout.
However, the terminology used by Daniels… indicates that <he is a dedicated proponent> of the Cardiovascular / Anaerobic Model. Hence, <he> defines the exercise intensities for <his> different sessions in terms of the different (anaerobic) thresholds that are likely to occur, purely in terms of altering capacities of oxygen delivery to and use by the muscles, with resulting changes in skeletal muscle lactate production.
While these objections may be valid, they do not detract from the clear evidence that Daniels has achieved great practical success with this training method. That he uses an unproven and perhaps dated model to explain the physiological reasons for his success is of no consequence. In time, science will catch up with Daniels and will provide a more correct physiological explanation as to why his methods, field-tested for more than three decades, produce the superior results his athletes have achieved
Noakes then notes Daniels' six physiological adaptations model, continuing with:
"However, to my knowledge, there are no published studies that prove that training at a particular exercise intensity uniquely adapts only one of the six physiological processes listed by Daniels… <it seems likely to me> it may be that the body adapts all these different physiological processes during all training, regardless of its intensity, but that certain adaptations are emphasized at specific running intensities.
<Daniels model> does not acknowledge that adapting the muscles to absorb the shock of running may be another important adaptation for marathon running specifically. Furthermore, consideration is not given to the possibility that training adaptations may also occur in the brain and that these changes could possibly explain how training improves running performance…"
(Lore of Running, pp 591-2): Noakes observes that Daniels' published calculations predicting temperature effects on marathon finish times "appear to be conservative" compared those shown in a chart of results; empirical data compiled by some other researchers. As above, this is hardly a devastating critique.
Interestingly, that chart (reproduced on p. 591) is entitled "The influence of the ambient dry bulb temperature
on the average winning times in the standard marathon". To me it seems silly to ignore humidity and direct radiative (sun) effects only assessing the effects of temperature on athletic performance. Cooling requirements will be determined by (1) ambient air temperature, (2) radiative heat, (3) humidity and maybe even (4) convection. A better model for thermal loads and their effects would incorporate all four.
Why would both Daniel's and these researchers only look at the first of these four factors? Why would they produce such a silly model? My guess: they simply didn't measure the other three.
Curious you mention Jack Daniels, one the criticisms of some of his research was failure to account for other factors beyond the body's pure ability to produce a given effort, things like impact fatigue and thermal stress.
* Likely drawn from the wikipedia article on Jack Daniels.