If Tim Noakes "Central Governor" Model is Correct AND there is NO Lactate Threshold, HOW should this effect my train

sim

if u report a post it gets deleted immediately - just noticed your post has gone

If you're talking greatest runners of all time, surely Javier Gomez has to be up there. As a triathlete he wouldn't be doing many miles, but check out his 10km times.

Thanks for this important question.

In our studies we have athletes do self-paced exercise in ways for which they are not trained and have never experienced. Thus our most helpful model has been to have athletes pace themselves at a fixed rating of perceived exertion (16 - which is quite hard exercise). They are told that they must sustain this RPE for as long as the exercise continues which means that they will reduce the work rate progressively as the exercise progresses.

When they do not know for how long they will exercise (ie they are not given that information before they start the exercise bout) the work rate falls as an absolutely linear function of the exercise duration. Now we expose them to cold or hot conditions. Under those conditions the rate of fall is still linear but it is less rapid in cool conditions than in hot conditions. Furthermore there is a biological factor - the rate at which the body is accumulating heat - that can exactly explain these different responses in the hot and the cold. In other words the rate at which the body accumulates heat appears to be the factor driving the response because it is exactly the same in both conditions.

Thus we feel we are justified to conclude that the rate at which the work rate falls is not controlled consciously but by subconscious controls which are related to the rate at which the body is gaining heat. This then would be a subconscious control which acts in anticipation to insure that the exercise terminates before the body becomes too hot - the opposite of the usual ("peripheral fatigue") model which holds that exercise only ever terminates after the body has already failed (catastrophically).

However when the subjects know beforehand for exactly how long they will be exercising (and if it is for a relatively short time - say 30-45 minutes) they choose a different pacing strategy and will go harder from the start. This you might argue is the result of a conscious override. On the other hand it could still be a subconscious control in that the subconscious brain has calculated that allowing a greater exercise intensity for the (now) known exercise duration would not cause a dangerous elevation in body temperature and so would be acceptable.

Other evidence that the control is subconscious (at least in laboratory experiments) comes from studies (in Wisconsin and Canberra) in which the content of oxygen in the inspired air is changed without the athlete being informed. In all these experiments, within about 15-30 seconds of the oxygen content being reduced (and without the athletes being consciously informed that the change has occurred) the athlete's pace falls. Again most of the subjects are sea level athletes with little exposure to altitude training.

Furthermore the extent to which the fall occurs is a function of the change in oxygen content in the inspired air and is a linear function of the change in the oxygen content in the blood. In as much as we are not consciously aware of the exact amount of oxygen in our blood at any time, one might argue that this control also occurs at a subconscious level.

Finally we found (but have not really followed it up) that when athletes begin exercise with low muscle glycogen content, they BEGIN the exercise at a lower work rate and they pace themselves at a lower work rate for the duration of the exercise. Remarkably we also found that individual athletes stopped exercise at exactly the same glycogen content regardless of whether they began exercise with more or less glycogen in their muscles. This suggested to us that the pacing strategy had been designed to insure that they stopped exercise at the same (but not completely empty) muscle glycogen stores.

Again as we are not consciously aware of what exactly is the content of glycogen in our muscles, this control would likely also be acting at a subconscious level. But these experiments are not as definitive as those showing the effect of a change in conditions DURING the experiment since in those experiments, the athletes begin all the exercise tests in exactly the same condition. Thus they do not begin the exercise knowing that they have for example exercised more the day before this particular trial than before the trial in which they had higher glycogen content (since additional exercise must be performed to lower the muscle glycogen content before the low glycogen trials).

When I began running I could not understand how the winning athletes were able to run the 90km (56 mile) Comrades Marathon so that they ran the final kilometer usually at the same pace as the first few kilometers of the race. I was intrigued because I wondered how they could project forward 5-6 hours and so choose the correct pace right from the start? I knew they were quite unable to run either that speed or distance in training. So how could they ever train themselves so that they consciously knew exactly at what pace they should start the race, at least the first time?

In addition the longest race that most of the best athletes compete in before the 56 mile race are of about 35 miles. So until they have actually run the 56 mile race, they could not have trained themselves to consciously know how to pace themselves during the race. Clearly athletes tend to become better pacers as they run the race more frequently and usually it takes 2 or more races before the athletes really achieve the best pacing strategy. But is this purely due to changes in conscious pacing strategies?

Roger Bannister was the first to run the mile in under 4 minutes because his coach told him he could run 3:56 on a good day and that under the wet, windy and cold conditions present at the Iffley track on May 6th 1954 he could run 3:59 and if he did not attempt it "he might regret if for the rest of his life". Bannister told me that he also wanted to do something important for England because (of the "chance" event of his birth date) he had been spared fighting in the Second World War.

This theme of being spared exposure to fighting in a World War (and achieving the dreams of those who died in that war) is a central theme of Chariots of Fire in which Harold Abrahams (100m gold medallist in the 1924 Olympic Games in Paris) and his fellow class at Cambridge are reminded that in the First World War " the flower of a generation, the glory of England ... died for England and all that England stands for. And now by tragic necessity their dreams have become yours" so that the students in the first post-war class at Cambridge were exhorted to "examine yourselves. Let each of you discover where your true chance for greatness lies ... And let no power or persuasion deter you in your task".

After he had run six or more miles in 4:01 or 4:02 in 1953/4, Australian John Landy who was one of the two other athletes who might have run the first sub-4 minute mile, said early in 1954 to the effect that the four minute mile is a brick wall and that he would not be able to break the mark although others might be able to. Yet 46 days after Bannister broke the barrier, Landy ran 3 second faster than he had ever before and smashed Bannister's record.

As described in his book In Quest of Gold (pages 15 to 16) Jim Ryun describes how in his high school sophomore year and after he had been running for only 2 years, his coach called him in to his office and asked him how fast he (Ryun) thought he could run when he was a senior. Ryun said he did not know but perhaps 4:10. To which his coach responded "I'm talking about the four minute mile, Jim. No high school boy has ever run one. I think you can be the first". Two years later Ryun, just like Bannister, achieved what his coach said he would achieve.

The stand-out South African marathoner of the past decade Hendrik Ramaala has recently written that: "In my opinion, the person who wins the race has already won it in his head before the start of the race".

The point of course is that if exercise is "limited" by the development of "peripheral fatigue" which is dependent only on the function of the heart and the muscles, then why did Bannister and Ryan have to be told how fast they could run. And why did Landy need first to be told that Bannister had broken the 4 minute mile before he could also do it. And how can the heart and muscles decide before the race begins that together they are going to win the race?

In my opinion, most athletes probably decide how good they are on the basis of what their coach tells them. Then they go out and confirm that opinion. The truly exceptional athletes somehow learn that they can be better than either they or their coach initially believed they were. This then is a conscious decision (which is integrated into the more subconscious control provided by the Central Governor - in my speculative opinion). Since humans always exercise with reserve (according to the central governor model) so if they truly believe they can run (a little bit faster) then they usual will (but up to a limit set by their particular physiology and state of training).

I think the missing variable is intention. It is a quality of the mind and forms the direction and magnitude for our actions. It is prior to action and also prior to thought. It sonnects with with ones emotional energy to charge up the intention capacity of the mind. The folktale of the mother who in deperation to save her son lifts a giant piece of pipe of him. She could not even budge the pipe later on when normal.

I think our intention forms based on the other examples around us. History and present performances, training partners and of course the coach all help form this intention. Ramaala sounds like he knows the intention well.

now i don't even know what is gone. What did i write? :(

;)

Precisely. The traditional teaching in human physiology is that the reason why creatures are successful is because they can regulate the constancy of their internal environment. This then allows them to adapt to many different environments. Reptiles unable for example to control their body temperatures are at a significant disadvantage when it is cold since they become immobilized by the cold. That is why there are no reptiles (to my knowledge) in the polar regions.

The second point is that creatures modify their behaviors when exposed to challenging environmental conditions and in this way we further maintain our homeostasis. But the behavior is regulated to insure that the homeostasis is regulated.

But the key point of the Hill "peripheral fatigue" model is that fatigue develops AFTER homeostasis has been lost. Thus if true, it means that exercise is a special physiological case in which the normal rules of human physiology are ignored and for some reason homeostasis is allowed to be lost. If this is indeed the case, then this special case must have developed because it gave humans an evolutionary advantage some time in our past.

(There may indeed be examples in which a temporary loss of homeostasis might be helpful. For example the point at which the cheetah terminates its chase of an antelope is homeostatically regulated to insure that the cheetah does not overheat. But the antelope it is chasing would be helped if it could just run another hundred metres and so outlast the cheetah even if during that 100m the antelope was temporarily out of homeostasis. This is because the cheetah needs about an hour to lower its body temperature to the point at which it would again be able to chase the antelope. During that time the antelope would be able to recover and escape).

But there is no reason to suspect that this loss of homeostasis model ever developed in humans. Rather it seems that we evolved to run long distances at a moderate pace chasing large antelope to their exhaustion in very hot conditions. Since we still had to take the meat back to our families (usually at least 20 km away) it would have been useless to catch the antelope at the same time that we were exhausted. Rather the human had to evolve the capacity always to finish exercise with reserve.

What we have said is that we cannot find evidence that the human body ever loses homeostatic control during exercise. Always the regulation appears to have occurred and homeostasis has been retained. (Of course there are individual cases in which homeostasis is lost - death from overdrinking during exercise is one example as is the development of heat stroke - but these can usually be explained by abnormal behaviors associated with genetic predisposition - in my view).

Then we have been able to show that a key defender of this homeostasis is behavior change (ie athletes slow down) that occurs during exercise and this then insures that homeostasis is retained. Since this behavior change also occurs during competitions in which there would be lucrative rewards for over-riding the control (ie keep running fast to win the money or gold medal) then the control has to be acting predominantly at a subconscious level.

The conclusion is that humans are not designed purely to produce a maximal athletic performance regardless of the cost. Rather the primary goal will be to allow only those behaviors that do not threaten homeostasis.

Of course the greater the athletes biological capacity, the faster and further he or she will be able to run without threatening that homeostasis.

I have no answer except to state the obvious - the level of arousal and expectation BEFORE the event influences the outcome.

This cannot be easily explained by a model in which the regulation is in the muscles (as a result of peripheral fatigue) which would then always cause you to be tired at exactly the same effort.

On the other hand if humans are designed always to exercise with reserve and this is regulated centrally in the brain, then there will be times when you can access more of that reserve. And conversely there will be times when you can access less of that reserve because you are less "motivated".

For example if you were told on the way to the race that some tragedy had befallen your family or a friend, would you still produce a best effort? It cuts both ways.

If the regulation of exercise performance was purely peripheral, you would always produce the same performance regardless of your state of mind before the race.

Possibly homeostasis has thresholds within it. The first one is when we go outside out daily comfort zone. Like when our breath first starts to draw beyond resting rate. There definitely seems to be one through which we cannot go. The survival threshold of homeostasis. Possibly there is another one which exists between where the aerobic is the main energy source and the anaerobic becomes the main energy source. From there we have limited time left. Before that threshold we can run ultra marathons if we spent the time training.

The two factors that seem to be at the center of this debate are akin to conscious control and sub conscious control. I believe it is generally accepted that what is contained in the subconscious previously existed in the conscious. Survival as a sub-conscious drive drive was developed far back in our evolutionary history. Further back than breathing to be sure.

When an athlete runs a long race i see both the sub-conscious survival mechanism controlling things and the conscious decision making as also controlling things. There is another category that involves the recent crossover from conscious to sub-concious and that is the learning about running and racing that has occurred over their lifetime. I don't know whether you would include the inital movement patterns we took on when beginning to crawl and then walk and then run as children or not. Do precise definitions exist for this stuff? Sub-conscious, conscious as well as subconscious learned as children and sub-conscious learned as adults. Possibly sub-conscious prior to being able to learn consciously versus sub-conscious after being able to learn consciously. Dunno.

Homeostasis is something that surrounds us like a bubble. We are kept safe within in. It has gravity so if we attempt to travel too far the gravitational suction prevents us from continuing. In a three dimensional perspective it would look like a bubble that can expand and contract or like a pulsar, a sun that is pulsating. Optimal arousal would see this maximal pulsation. Optimal arousal could see a potential increase in the maximal size of the pulsation. It has been stretched. We have been stretched.

It is difficult to think in three dimensions so i will try with 2. Homeostasis is a ceiling applying pressure downwards. The further from the ceiling we get the less pressure there is. Eventually there is no pressure and we call this our comfort zone, where we exist in daily life.

Arousal is the bell shaped curve we travel along as we discover the optimal way to apply effort. As this curve/meteor path we have launched ourselves on approaches this ceiling we find increasingly more pressure preventing our increased elevation. The pressure is akin to reverse gravity. Icarus is a good image for this one.

Our arousal curve can only travel as high as this ceiling allows. In many sedentary people the ceiling is probably quite low. The image of the heart attack business man victim red faced and unable to breath as he dies shows a case where the ceiling was quite low and the business man got too aroused. Those women of the night can do that.

In highly trained athletes the ceiling is quite high and it requires extended training to continue to raise it. But this is the purpose of elite track and field is it not!

as we find the optial way to apply effort and fall away from and then fall away from as we try too hard. Ideal arousal (the apex of the curve) comes in contact with this ceiling and can pressure ti upwards in reverse

ignore the last paragraph please it was meant to be discard stuff

Now we are getting into a very interesting topic here (or have we been already...???). There are indeed tons of examples like that. One of my favorites is the one of Dick Quax. When they had this international competition in NZ back in, I believe, 1975, he ran 5000m against some of the best runners in the world including Henry Rono and Nyambui. After winning the race, he was asked when he thought he could win (expecting the answer like a lap to go or at 2/3 of the way...); he replied, "Last night!"

Coach Koide kept telling the eventual Olympic marathon champion, Naoko Takahashi that she could be an Olympic champion almost every single day. She said, after winning the marathon, that you would soon start to believe if someone tells you that you're going to be an Olympic champion. A similar thing; it was Arthur Lydiard, disregarding what Peter Snell thought, who told Snell that he would break the world record at the rate he was improving. Peter wasn't quite sure but it was Arthur who absolutely convinced him that he would.

As a coach, I always, ALWAYS, try NOT to get any seed of negativity in the athlete's head particularly before the competition. One time this girl I'm coaching was doing the strides into the wind 5 minutes before her race. I made a mental note to tell her that it'd be better to do them with the wind LATER. I didn't want her to think like "Oh, my God, I've been doing these strides all wrong all this time!" during the race. Of course, this local coach rushed to her to tell her she shouldn't do that into the wind and ruined it! ;o) Unless it's urgent ("Get the hell off the road; the semi is trying to storm past you!!!"), I usually try to make a mental note and tell them at the right momemt about a crooked foot or landing hard on their heel or stuff like that. Any negative thought COULD grow during the moment of the truth; "No wonder I'm losing the ground...with my crooked foot!" and use THAT as an excuse to let it go. I think Frank Shorter's analogy about Viren and Quax at Montreal is right; if Quax believed Viren blood-doped, who knows, that negative thought was enought to let him go in the final 100m; "Well, there's no way I can beat him with that extra blood...!" We would never know but if Quax hadn't heard anything about that rumour... Hey, maybe the rumour was started by Viren himself to mess with his opponets' mind??? ;o)

The prediction of the coach, the trusting coach, can mean huge to the athlete. Of course, you, as a coach, can't just drop a number or whatever. That trust has to be nurtured and earned. Making a prediction and hopefully it happens the way you predicted can be a powerful tool but you have to be pretty close otherwise it could backfire! ;o)

With the same token, the athlete has to know exactly what he/she is doing in order to have that sort of positive mind. I mean, I see so many young talented kids who would talk like they would blow the rest of the world away but they haven't done the "homework(=physical training)" and done it "correctly" and consequently they never achieve what they could have or should have.

An interesting example here is Al Salazar. I remember this very well--I was in the US when he emerged as a young marathon phenome, setting the debut marathon record of 2:09:41 on his first marathon at mere 21 years of age, smashing Derek Clayton's world record which stood more than 12 years (of course, now we know the course was slightly short but I still believe he would have broken it anyways), winning Boston in the epic "Duel in the Sun" against Beardsley a week after battling against Henry Rono in 10000m race... Now he came into Fukuoka, saying that he's in the best shape in his life, in a shape to break the WR again... In other words, he had already "won" in his head. What happened? He finished 5th. What particularly shocking to him, I'm sure, was the fact that ALL 3 Japanese representative to LA Olympics beat him (with Ikangaa also beating him). It wasn't like one Japanese, one Tanzanian, one Ethiopian, and another German...something like that. I don't think he had ANY excuse that day, like he had cold or sore foot or anything. He was clearly the winner in his head; and time wasn't out of his reach either. I see many like that, particularly in America.

I clearly remember this argument I had with a friend of mine in high school in Japan. The movie, Rocky, just came out (no...I was in middle...kindergarten...yeah, that's it; I was fi...three years old...!). She argued that it was his positive thinking (and, of course, LOVE) got him go the distance. I said bullshit; he wouldn't have lasted a round without getting up at 4:40 in the morning and running up and down the stairs (I don't know about egg drinking though...) that made him possible to go the distance. Too many young people, unfortunately, skip that "homework" part and think, by being coockie, they can be a good runner; by thinking tough and training tough, they can be a good runner. But it's actually slog of pounding on the pavement that builds the foundation. So with that, I would still go back to Lydiard's argument--"Don't just look at what Kenyan world record holder does in training, look at what he did 10 years ago (when he was building the foundation)..."

Timothy Noakes wrote: I have no answer except to state the obvious - the level of arousal and expectation BEFORE the event influences the outcome.

...

If the regulation of exercise performance was purely peripheral, you would always produce the same performance regardless of your state of mind before the race.

OK, I'll buy that. Thanks.

Thanks also for contributing your thoughts here directly. I don't know how familiar you are with the dynamics of message boards (and this one in particular), but this place is more like a locker room than a lecture hall. This has some tremendous advantages (lots of interesting discussion, some of it very funny, some of it very informative), and some minor disadvantages. Expect (and ignore) some heckling and petty bullshit, and you'll get along fine. And while anyone can express disagreement openly and without fear of reprisal, intelligent readers are able to sift through what's written and make good decisions about what to believe and what to disregard. I'm sure I'm not the only one who is enjoying the contributions of a small number of posters in this thread, and I hope you'll continue to engage in the discussion.

I agree completely but would argue that this sort of attitude and its influence on performance can be affected by factors other than a coach telling an athlete they\'re good enough to win. There are of course, examples of athletes who are told by coaches or even parents that they\'ll never amount to anything and who decide to \"sow\" those people how wrong they are. And there undoubtedly aer athletes who believe they\'re mid to back packers and who would simply shrug off a coach who predicts greatness for them.

Also, as Nobby points out, there needs to be other things working for the athlete than just an uncompromising belief that they\'ll win. If you read Ron Hill\'s autobiography you know that he went to Munich sure he\'d win the marathon and was well into the race before it occurred to him that he wasn\'t going to. But in general I think we agree here.

With that, I would argue that this belief system functions as a \"central governor\" would. But I\'d think of it more as a process than as a thing.

Going back to your post regarding what it would take to prove the CGM and move it beyond theory, I think that is a decent list.

A few other questions. You earlier stated that you do not believe it is important whether it is conscious or unconscious that controls exercise limits. Yet you now focus on the CGM mainly as subconscious, it appears. Which is it? The fact that consciousness can impact how hard we work is blindingly obvious and I want to believe you're better than to think even Hill really thought that our consciousness did not regulate how hard we run; we don't sprint at top speed until we fall over regardless of the distance to be run, which is the logical extension of that model.

Second, as you stated with the quote from Hawking, a theory that it inconsistent with observation should be abandoned. Correct me if I am interpreting wrong, but I recall that the theory says that the unconscious Governor limits us to keep us from over-exerting and exceeding our limits, leading to heart damage. If this is true, how do you incorporate training? There are two possibilities: 1) you train your body to ignore or "reset" the Governor, thereby allowing you to work harder. The logical extension of this is that you exceed your limits and we'd see elite athletes dying during races at increasingly high numbers the faster we look. 2) Training alters the body and it's ability to produce energy in such a way that we can work harder without hitting the point where the CG slows us down.

I don't see how #1 can be the case, a CG that can be reset to dangerous levels seems maladaptive to me, and we'd see evidence that we are over-exerting and people would be injuring/killing themselves during races.

#2 can be discussed. It does not exclude the fact that there could be a subconscious controller. However, it does indicate that, for all practical purposes, knowing whether there is one is useless and the CG would NOT be the determiner of athletic performance. It would simply be the last link in the process. The actual bottleneck would be earlier in the process, somewhere buried in all of the factors including aerobic capacity etc etc that are classically considered to be the limiters of performance. The CG would sit there unchanged and untrainable.

While I still do not believe there is any real evidence for the CG as you describe it, as I said #2 above does not exclude it from existing but only indicates that from a training perspective it is completely useless. However, it is important to note that most of your "evidence" for the existence of the CG relies on trying to say that all the other classical performance limitors we talk about are incorrect or unimportant.

In summary, the Hill model is fatally flawed if it makes no allowance for conscious thought to influence performance. Likewise, the CG model is fatally flawed if A) you try to say that training resets it, or B) supporting it relies on saying all the classical limiters are wrong or not important (without them, training only affects the CG and we are back to case #1 above)

Please discuss.

spaniel wrote:

Please discuss.

This is much better worded than my earlier attempt, simply asking what value the CT theory presents because either, by defintion, you may not be able to override it and that you probably shouldn't even if you could.

Side note, how does Dr. Noakes determine the CG is attempting to prevent damage. Has it been demonstrated that exceeding the limits the CG theoretically controls actually results in damage/death? Or is this apparent reason for the CG's existence simply posited?

Tim, thanks for your posts. In one of them you mentioned the phenomenon of super-contractility (as I'm going to call it) whereby and athlete runs much faster than normal and much more economically.

This is obviously one of the main contributors to the outstanding performances of the World's best runners.

I experienced this myself recently, where I was running without any expectations (no preset training plan) because I had done a very hard session two days before I was unsure about my recovery. But during the run I was moving along at an incredible pace, with no fear of fatigue or injury, but I was hardly breathing. My stride felt incredibly powerful, thus saving the oxygen cost greatly, despite the very high pace.

Of course I was excited about re-creating this feeling in my next race and of course I failed to get anywhere near. I had the usual pre-race fear of failure mixed with confidence in my recent training, but my muscle contractions were laboured and of course my cardiovascular stress during the race was considerable.

Would things have been different if I had trained hard two days before the race, something we often are told not to do?

How do we get into this state of super-contractility for our races? The best runners rarely fail to achieve this.

Is it all in our heads. Before all of my best races, I have had very low levels of fear, which could be termed negative arousal and high levels of happy excitement which could be termed positive arousal. Is this due to optimum levels of both adrenalin which excites us in the right amounts and makes us anxious if we produce too much, and noradrenalin, which calms us and helps us to improve our judgement in times of extreme stress?

HRE and Nobby,

for me the two of you are presenting the broadest viewpoints of the thread. The simple idea that the mind is more important than the body in the process of training is something that most people resist. In general though i think it is becoming more widely accepted. I think Tim's work is attempting to bring the mind into the physiological picture more than it has been. How is the mind(brain) acting to limit the upper end of performance. I think this can be answered when homeostasis is more accurately identified.

This isn't exactly what you two guys (and others) are exactly getting at though. The mind is more than just a sub-conscious controller. That is one of it's functions for sure but not the only one. The mind can also think consciously. It can use rational or intuitive thought. It can access the past through memories or project into the future through fantasy. It can be solid (ie strong), fluid (ie flexible and adaptable), liquid (ie flowing) or firey (ie explosive) and it can cause the body to react in all of these ways. It can be energized by other parts of oneself such as the vital (your physical center where survival instinct drive comes from) the heart energy (where passion comes from, the following of dreams) or even from divine energy (where we don't have to provide our own source of intention, it is provided for us)

So the last one may be a bit contentious but Sri Chinmoy might agree with it.

The point is the mind has so many qualities and is so difficult to describe in its entirety. It is difficult to just say the mind as meaning just one thing. It is a multi dimensional super computer for the lack of a better description.

HRE, if a process of the mind becomes a process that the body adapts to. Does that process then become a thing?

I can't believe I'm doing this, but... what the heck. For a while this discussion was moving along nicely with lots of dicussion of "evidence" and/or research, but somehow it has once again moved into the realm of anecdotes and supposition.

With regard to your comments about your own performance, I would argue you really don't *know* what the heck was going on regarding "super-contractility" or the "oxygen cost" of your running stride because you didn't measure any of it. If you had a good performance, congrats, you had a good performance, but you really don't know *why* that was.

Is it all in our heads? Some, but certainly not all.

The primary reason I'm responding to this though is your commment about training hard two days before the race, and this is often argued against by many coaches. I would argue that if your "fitness" is high due to sufficiently intense training in preparation for an event, a "hard" training session might be good a couple days before. It also depends on what you have done in the days leading up to that point; it's a big picture question. We can look to the studies of Mujika, in particular, as well as some others who have demonstrated that the best way to prepare for a priority performance is to taper substantially in the weeks leading up to the event, but taper the volume, not the intensity. Again, this is one of those inextricable things about performance, that the traditional view would be that a well rested athlete should perform best on "game day", but as many athletes and coaches know through experience, the athlete often loses the "feel" of the activity. So, in running, since technique is part of the performance equation, some tuning up in the day or two before the race is in order. Maybe to maintain feel, maybe something else. How much tuning up though is the question. It likely depends on how tapered you are, and how fit you have been. Since many coaches might try and maintain the training stimulus as late as possible in preparation for the event, a hard day 2 days before the race might be the kiss of death, whereas, if the training load has been substantially reduced in the recent weeks, then a "hard" session two days before might be good to keep the athlete "open". Further yet, if the taper has been too long, and the athlete has lost "fitness" as a result, the hard effort may be too fatiguing. A delicate balancing act, and one that is easy to get wrong.

Unfortunately, your experiences are presented out of context with regard to the overall training picture, so, it's difficult to say what the great performance, or the so so performances can be attributed. Again, I'm not sure if this has anything to do with the CGM though. The problem with the CGM as far as I can tell is that you can attribute everything to it, and/or nothing. It's nebulous enough that you can transfer your own belief systems onto it as you like, whatever they may be.

Steve