Letsrun.com I wanted to add this note that Tim Noakes wanted posted to the site. Below is a copy & paste of his Email to me:
Dear John,
Perhaps you could add the following comments to the site.
I really appreciate the attention that has been spent on the Central
Governor Model. It is however clear that very few have read the full
exposition of the model in a series of articles in the British Journal
of Sports Medicine in 2004 and 2005. Some of those articles can be
accessed for free and it might be helpful if any one who believes he or
she is an expert on the Central Governor Model to first read those
articles. To base an opinon on a brief description in a book that was
written 5 years ago does not seem a good idea. Ideas evolve and my
understanding of the Central Governor Model is very different today from
what it was in 2001 and 2002.
The statement is frequently made that there is no evidence for this
model. This is quite incorrect. There are now a host of studies which
can only be interpreted according to the Central Governor Model and
which absolutely are incompatible with the traditional peripheral
fatigue model. There are 2 crucial findings. First that any exercise
performance is regulated "in anticipation" so that the brain adjust the
behaviour during exercise (usually by slowing down) well before harm
develops. It is clear that only an intelligent complex system is able to
modify behaviour in a predictable way in anticipation of what might
happen if no such behaviour change were to occur. So the brain does
not allow the body simply to continue to exercise until some catastrophe
(exhaustion or extreme fatigue) occurs. Your readers might wish to read
our recent (2006) paper in the Journal of Physiology, authored by Ross
Tucker. This study clearly shows that the perception of fatigue is used
by the brain to modify exercise behavior specifically to insure that
harm does not occur sometime in the future (of the exercise bout).
The second point that is not compatible with the traditional model is
the finding that not all the muscle fibers are ever active during any
form of exercise. If not all the fibers are active during exercise, then
the brain regulates the exercise performance (as fully argued in the
BJSM articles). For if peripheral fatigue was the regulator, why does
the brain not simply activate more muscle as so continue to exercise
until all the muscle fibers were exhausted? The answer is that if this
were to occur, no one would survive a single exercise bout.
Those who focus only on the VO2max and oxygen delivery to muscle as
evidence for against this model ignore all the evidence from other
studies showing that the traditional model simply does not explain
enough to be considered a realistic explanation of what happens during
exercise and the nature of the controls that determine our exercise
behaviours.
The Central Governor Model is not perfect but it is currently the only
model that can reasonably explain so many of the most obvious features
of running including the fact that we start at different paces when we
run races of different distances; why we can produce an end-spurt when
we are the most exhausted (near the end of a race); why drugs like
amphetamines can improve performance remarkably even though they do not
act to prevent "peripheral fatigue" - Amphetamines clearly show that we
all run with a biological reserve that can be (very easily) accessed
when we interfere with the higher brain control mechanisms; and why
fatigue is never absolute. Even the most exhausted marathon runner can
still walk to his car etc.
I remain astonished that some can believe that the control of exercise
performance lies with the heart and the muscles and that the brain can
play no part. That seems far more unrealistic than anything I have ever
proposed.
Best wishes and keep the debate going,
Tim Noakes.