Levine’s comments seem to be a bit of a strawman of Noakes’ position… though, based on your second quote, he may also be a strawman of himself.
A subject can elect to simply stop exercising on the treadmill while walking slowly because they don’t want to continue; no mystical ‘central governor’ is required to hypothesize or predict a VO2 below maximal achievable oxygen transport in this case.
Whether sub-maximal oxygen transport ever occurs is entirely beside the point; the implication of the central governor model would be that maximal oxygen transport (or maximal muscle contraction, or whatever) occurs only under extreme circumstances, because the brain subconsciously detects potential for damage to the body and reduces exercise effort. A VO2 max is generally determined by running some exercise test “until exhaustion”, with no mechanism in place for knowing how hard the athlete is trying. Presumably the only motivation is “this doctor just told me to keep going until I’m tired” or maybe “I want a good test score for bragging rights”. It’s definitely not “baby trapped under the car”. In this situation the evidence for Noakes’ hypothesis would be something like, measure VO2 max again while being chased by a bear (or during some kind of competition, if the IRB doesn’t like the bear thing) and it should be higher the second time. If you can improve performance through increased motivation, up to the highest levels of motivation you’re willing/able to measure, then common sense would say you still probably haven’t reached the actual “maximum”. Anecdotally, in at least one instance of extreme motivation I’ve been able to cycle so hard that in a period of about 30 seconds I gave myself a nasty cough lasting several days; I am unable to repeat this under normal circumstances.
Whether the performance limitation occurs primarily through pain or whether there’s also some kind of hard limit is unclear. Limitation of exercise performance by fatigue is familiar to anyone who’s tried running a mile in gym class. On the other hand, I’ve read that major league pitchers are often limited in pitching speed by the stress on their elbow ligaments, rather than by the ability of the muscles to contract harder. If true that means the brain is detecting potentially injurious muscle contractions and putting a damper on them, but without necessarily causing pain.
Following up on this because what I said about VO2 max is misleading. I’ve since learned that VO2 max is unusually useful as a measure of fitness specifically because it bypasses the problem of motivation. As effort and power output increase during the test, VO2 initially increases but then plateaus even as output continues to increase. So as long as motivation is sufficient to reach that plateau, VO2 max measures a physiological parameter rather than a combination of physiology and motivation.
Levine’s comments seem to be a bit of a strawman of Noakes’ position… though, based on your second quote, he may also be a strawman of himself.
Whether sub-maximal oxygen transport ever occurs is entirely beside the point; the implication of the central governor model would be that maximal oxygen transport (or maximal muscle contraction, or whatever) occurs only under extreme circumstances, because the brain subconsciously detects potential for damage to the body and reduces exercise effort. A VO2 max is generally determined by running some exercise test “until exhaustion”, with no mechanism in place for knowing how hard the athlete is trying. Presumably the only motivation is “this doctor just told me to keep going until I’m tired” or maybe “I want a good test score for bragging rights”. It’s definitely not “baby trapped under the car”. In this situation the evidence for Noakes’ hypothesis would be something like, measure VO2 max again while being chased by a bear (or during some kind of competition, if the IRB doesn’t like the bear thing) and it should be higher the second time. If you can improve performance through increased motivation, up to the highest levels of motivation you’re willing/able to measure, then common sense would say you still probably haven’t reached the actual “maximum”. Anecdotally, in at least one instance of extreme motivation I’ve been able to cycle so hard that in a period of about 30 seconds I gave myself a nasty cough lasting several days; I am unable to repeat this under normal circumstances.
Whether the performance limitation occurs primarily through pain or whether there’s also some kind of hard limit is unclear. Limitation of exercise performance by fatigue is familiar to anyone who’s tried running a mile in gym class. On the other hand, I’ve read that major league pitchers are often limited in pitching speed by the stress on their elbow ligaments, rather than by the ability of the muscles to contract harder. If true that means the brain is detecting potentially injurious muscle contractions and putting a damper on them, but without necessarily causing pain.
Following up on this because what I said about VO2 max is misleading. I’ve since learned that VO2 max is unusually useful as a measure of fitness specifically because it bypasses the problem of motivation. As effort and power output increase during the test, VO2 initially increases but then plateaus even as output continues to increase. So as long as motivation is sufficient to reach that plateau, VO2 max measures a physiological parameter rather than a combination of physiology and motivation.