What determines efficiency ???

acoggan

No, but it is the only one that has been demonstrated, and it's a fairly close relationship at that, so it does make for a plausible explanation for the improvements in efficiency that were observed.



Armstrong wouldn't have had to change his training in the least, all he would have needed to do was keep piling on the miles year after year after year. Indeed, that's essentially all that I have done, and my efficiency has improved much like Armstrong's.



Not in the least. For example, even the type of training performed by match sprinters will induce changes in myosin expression that will favor an increase in efficiency.



Coyle didn't need such data to put forth a plausible hypothesis.




Ironically, I've been sitting here at my desk reading a recent paper in the journal Diabetes (much more high-profile than the Journal of Applied Physiology), trying to figure out how the authors were able to infuse a radiolabeled triglyceride, when triglycerides (fats) aren't soluble in water (and hence can't just be introduced into the circulation). Tracing back through their earlier papers, it turns out that they complexed the tracer with apoprotein E, etc., to make an artificial, chylomicron-like particle. Did this mention this in the Diabetes paper, though? No, they didn't...but clearly that's what they did.

(Translation: Frank, you're an idiot if you truly believe that Ed would overlook something as simple as controling for cadence when assessing efficiency.)




First, there's no data in the paper by Luttrell et al. that would explain the improvements in efficiency that were apparently observed - it just "is" (was).

Second, even if mechanisms other than changes in myosin expression (and position, e.g., saddle height, and cadence, etc.) contribute to or result in changes in efficiency, that doesn't mean that they were operative in Armstrong's case.

Third, to date fiber type is the only factor (other than position and cadence, of course) shown to be associated with cycling efficiency. Most importantly, efficiency is not correlated (in cross-sectional studies) with the pattern of force application at the pedal, and acute modifications in the pattern of force application at the pedal have been shown to DECREASE efficiency.



As I recall the paper, other mechanisms are in fact mentioned, even if Coyle then discounts them (which, as the author of the Discussion, is his right, at least IMO).



I take it you've never spoken with Armstrong? A question like that would be met with a look that would make you believe that he (Armstrong) had just seen a green-eyed Martian, followed quickly by a withering wisecrack along the lines of "what planet are you from, man? I just ride my f***ing bike a lot!!".



That may be a problem for you, as the inventor of PowerCranks, and for the masses, but it's certainly not a problem for Coyle, or for the scientific community.



You need to go back and re-read the paper: the hypothesis is developed in considerable detail, with reference to supporting research findings. If it hadn't been, no reviewer would have accepted the paper.

acoggan

Economy is used to describe the relationship between power (or, for running , swimming, cross-counrtry skiing, etc., pace) and the rate of oxygen uptake.

Efficiency is used to describe the relationship between power and the rate of energy (i.e., ATP) "production".

The rate of oxygen uptake can be used to calculate the rate of energy "production" at the cellular level, so for cycling the two terms are almost completely synonymous. However, since it is very difficult to quantify the rate of power output when running (or swimming, etc.), only economy is readily defined.

n crowley

John979, here is one example of the damage that has been done, these studies are based on the understanding that there are two basic pedalling styles when in fact there are three possible basic styles with the third (unknown to researchers) style the most important of the three. As the old saying goes, " a little learning is a dangerous thing ".

john979

Please provide peer-reviewed evidence.

Fday

Wrong, Luttrell demonstrated the ability to improve cycling efficiency a greater amount than Armstrong improved his in only 6 weeks. Of course, he wasn't dealing with world class athletes. Such an improvement is unlikely from changing fibre type (since it occurred in only 6 weeks) and it could not have come from cadence changes (since he controlled for that). The Luttrell data was published before Coyle published this paper although the mechanism for the improved efficiency was not invesitgated by Luttrell (he was just trying to see if it changed), it did change so there must be another possible mechanism, presuming the data to be confirmed in another experiment. Until Lutrell's data is refuted alternative explanations for efficiency improvement must be considered plausible.


Then, why was this result so surprising and remarkable? Why doesn't every pro improve their efficiency every year as they keep piling on the miles. certainly Armstrongs mileage wasn't 3 or 4 times that of his peers. Even Coyle remarked right before he goes into his change in fibre type hypothesis that the reasons for this changes as well as "the stimuli that provoked this adaption" are unclear. If they are so unclear to Coyle, why are they so clear to you?



An 8-9% in efficiency in a world class athlete? Show me a single example of another world class athlete where such changes have been documented over any period of time. Better yet, show me a single example where such changes have been documented and there is muscle biopsey data to prove that the changes occurred from changing muscle fibre type.



I don't disagree that this is a plausible hypothesis and that, at least, some of his improvement might be explained in this way. What bothers me is Coyle himself stated the reasons for this change are unclear then he puts forth this hypothesis, without any supporting data to suggest it actually has a basis in fact, (ignoring the fact that other riders who have trained similarly to Lance, at least mileage and intensity wise have failed to improve similarly) and ignored other potential explanations such that the world now thinks that this in fact occurred in Lance.



Thanks for that example. Such a failure to mention something like that is a deficiency in the paper. That is all I am saying. He may have (probably did) considered such but he didn't mention it. The journal editors should have picked up on that but they didn't. Probably too awed by the name.


Of course not. Luttrell was just trying to see if efficiency changed from using the product. Almost like a pilot study. Now that it is demonstrated that it does, then it would be reasonable to design a study to try to answer the question, why?

No, but since the physiologic mechanisms (as well as the stimulus for these changes) were stated by Coyle to be unclear to him, it seems that all of the potential mechanisms for such a change should have been part of the discussion rather than simply the first one he could think of. This was the major change noted that could account for Lance's dominance. It was deserving of a deeper discussion.

Well, of course the studies that have asked participants to consciously change their pedaling pattern or force applicaiton from what they usually train would show a decrease in efficiency. Both under trained muscles and unfamiliar coodination patterns would be necessary. Unless one is comparing equivalently trained people using different patterns such data is worthless. I am surprised you haven't figured this out yet. That is what is so interesting about the Luttrell study. Once the participants had enough time learning a new pedaling style and getting the new muscles up to some reasonable state of aerobic fitness their is a demonstrable increase in efficiency.



Well, I didn't see them. I am sure you have access to this paper. Shouldn't take you long to find where all these other mechanisms are mentioned.


I do know of one of my customers who spoke with Armstrong at a book signing. He asked him, "What do you think of PowerCranks?" After a period of time going back and forth with his agent he turned back to my customer and said "Whatever improves your efficiency!" The customer felt very good about his purchase. Hmmmm. I wonder what Armstrong meant about that efficiency remark? could he actually have put more thought into this bike riding than just simply riding the bike. Of course, if one doesn't ask him, one will never know.



My problems with the paper stand. That fact that no one else will read Coyles work critically doesn't bother me. At least Coyle did state that he didn't know what was going on. But, from his "discussion" everyone takes from it that he did understand and no other alternative explanations could exist.

acoggan

But the Luttrell study provides no data re. possible mechanisms. It would therefore be relevant to the discussion at hand (and the Discussion of Coyle's paper) if Armstrong had used PowerCranks.



The half-life of the myosin protein is measured in days, so significant changes in fiber SUB-type that could contribute to an improvement in efficiency can indeed happen in just a few weeks. (Of course, since Luttrell did little or nothing to accomdate the subjects to the laboratory setting, the improvement in efficiency may not even be real.)



As you admit, the Luttrell study did not collect any data that would shed light on possible mechanisms, so why should it have been cited? To do so would have been the epitome of speculation!



How do you know that they don't? Certainly, the performance of cyclists (and other endurance athletes) tends to continue to improve long after VO2max and LT have plateaued.



I would have written what Coyle wrote: the mechanisms responsible for Armstrong's apparent (I would have tossed that word in since this was an unplanned, uncontrolled case study) are unclear. That said, it certainly is possible to put forth a plausible hypothesis, i.e., that it was the result of a gradual change in myosin expression.



Now you're arguing in circles: the reason that Coyle's data was of sufficient interest to be published is because data on world class athletes (esp. of Armstrong's stature) are lacking. IOW, it's very uniqueness is what made it worthy of publication.



Then what are you whinging on about???



But ypu have no right to be bothered: Coyle was fully within his rights as an author to write his Discussion the way he did.



The supporting data that makes Coyle's hypothesis plausible are properly cited in the Discussion.



Again, how do you know that other individuals also don't experience gradual improvements in cycling efficiency when prolonged and intense trainng is performed for years on end? I certainly have, despite the fact that 1) I was biased towards the slow-twitch side from the git-go (thus minimizing the potential for further changes, and 2) I never trained as much as someone like Armstrong did. Furthermore, the fact that VO2max and LT tend to reach a plateau after just a few years of trraining, yet performance doesn't peak (for men) until they are in their late 20s or early 30s provides indirect evidence that efficiency continues to improve over time in any endurance athlete who "keeps their nose to the grindstone".



That's the world's fault, not Coyle's.



Unfortunately for you and your business, your opinion of Coyle's paper counts for naught to members of the scientific community.

Fday

Approximately 20-25 people have told us that Lance did use PC's in training. Of course, we have no proof. When asked (such as the example I gave earlier) he has never admitted same but he has also never denied it. If he did use them, he didn't get them from us (although we did provide many of his training partners with them in the very early days). That being said, I think it is a smoke screen for this discussion because it is clear to me that it is possible (albeit very hard) to learn to pedal in the PC fashion (or, perhaps, some other more efficient fashion) without training with PC's - it is just a lot harder. So, perhaps Lance improved his efficiency, to an amount that Coyle found remarkable, in some other way other than PC's. Wouldn't you like to know how he did it?


Do you mean we should be able to turn a world class sprinters legs into those of a world class marathoner in "days" if we can find the proper stimulation to change those fibers? Wow!!! Do you have a reference for that? Maybe there is hope for me on the basketball court, maybe I can learn to jump more than 6 inches off the ground.

If failure to "accomodate to the laboratory" was the supposed reason his study resulted in such improvement, why didn't it occur to the control group? So, maybe Luttrell's noted improvement in efficiency is not real, but until his experiment is repeated and proven to be flawed, the data exists and has been published. Scientists found a need to reproduce the "cold fusion" experiment when that result was published because it was published for two reasons. 1. it might be true and if it were it would require basic changes to all sorts of theories and, 2. if it isn't true it should be debunked asap.




It did not need to be cited. However, it is part of the milleau of knowledge that suggests that other mechanisms might exist to explain efficiency gains such that, if this was known about, one has to wonder why Coyle chose this one mechanism (changing fibre type) as the only one to wax on about when he already stated he didn't know how the improvement occurred.


Show me the data. I am sure Lance is not the only cyclist who has been followed for many years. I mean, if such improvements are commonplace, why on earth did Coyle comment on Lance's improvement and state he didn't know what the stimulus was to cause it to occur?




I don't have any objection to such a statement. I would have an objection to that being the only hypothesized possible mechanism. And, Why would you hypothesize it was a gradual expression? Above you stated such changes can occur in days.

I concur. What bothered me about the paper was the discussion. The data itself is very valuable. As I said, I think it gives evidence that can explain Lance's domination for all those years with resorting to drugs. Lance was able to improve his efficiency when others were not able to. It should lead researchers to try to figure out how he did so. No one seems the least bit interested. I guess they think they already know.




Becuase the discussion was incomplete and has led unsophisticated (most) readers to conclude this "is" the only plausible explanation. It is not.


Of course he was, just as I have a complete right to criticize (be bothered by) what he did not say.


Yes. Except, like I said above, if this mechanism were in play such changes should be commonplace in almost all professional cyclists. I am not aware of any data to suggest it is. Are you?


Hey, show me the data? The book "Bicycling Science" by Whitt and Wilson, which has examined much of the data regarding cycling efficiency certainly does not remark on this. If they did, I missed it.


Coyle contributed to it. If he had only written, "one possible explanation, albeit there might be others, is . . ." I would have had no problem with his discussion. He did not. I found his discussion, for someone of his stature, and for such an important finding, woefully lacking.

If you say so.

n crowley

The "peer reviewed" evidence can be found in books throughout the world. This third style was demonstrated and studied (peer reviewed) for about 15 years during the fifties and sixties and the general consensus was that it was the most stylish and most powerful of all time trial pedalling styles, the like of which had never been seen before and has not been seen since. Like the Fosbury flop, when you have the perfect style the results supply the evidence, no scientific evidence is required. But unlike Armstrong's ? , the explanation for Anquetil's power is easily explained, max power through 12 o'c and the ability to combine upper and lower body muscles and all of this from a simple change in the pattern of power application to the pedals.

john979

Please provide the exact references that I can examine. Title, year, author, publisher, ...

Fday

Don't holdyour breath. I have been trying to understand what he his talking about for years without success. He may be on to something but he sure cannot communicate what it is all about in terms I understand.

n crowley

That does not surprise me, first you have got to understand and explain where the advantages of your own expensive equipment lie, maybe then you will get a better understanding of the technique which I refer to. In both cases the advantages can be got from the same source, mental concentration instead of stomping blindly on the pedals but in your case PC's force a rider to do what could be done naturally if he knew what his objective was.

11ring

Speaking of efficiency, I just read a newspaper article reporting that according to an article published in Nature Genetics all ancient humans possesed a "sprint" gene responsible for promoting fast twitch muscle development by producing alpha-actin-3 protein in fast twitch muscle fibres. Apparently all sucessful sprint runners have this gene, but a small percentage of the population, approximately one in five have an inactive gene which ends up biasing the person towards slow twich fibre production. Apparently the inactive gene spread amongst asians and europeans during the last ice age 15-30,000 years ago as it was an advantage to have more efficient muscles in a period of restricted food supply.

The scientists in the stude created mice without the inactive gene and found they could run 1/3 as long as normal mice and had a more efficient metabolism.

11ring

Here it is in full


Endurance, not speed, key to spread of human race

Sydney Morning Herald, Date: September 11 2007


Deborah Smith Science Editor


MANKIND's switch from sprinter to endurance runner began in earnest in Europe and Asia during the last Ice Age, Sydney scientists have discovered.

And the explanation could be that having more efficient muscles helped people survive the cold, harsh climate when they moved to areas outside Africa.

Kathryn North, of the Children's Hospital at Westmead, said a common genetic variation influenced whether people were "sprinters or stayers".

All Olympic sprinters tested so far have an active form of a gene, which produces a protein called alpha-actinin-3 in the fast-twitch muscle fibres responsible for explosive bursts of power.

About 99 per cent of African people still have this original sprinters' gene, she said. "It's the normal ancestral state."

More than a billion people worldwide, however, have an inactive version of the gene and do not produce the muscle protein, Professor North has estimated.

This includes one in five Australians,she said.

This inactive version of the gene is more common among endurance athletes such as marathon runners and rowers, her team has shown.

For their latest study the researchers wanted to find out when the endurance version of the gene became so common, and what was the evolutionary advantage of losing the sprint gene.

They created mice without the gene and discovered they could run for about a third as long as normal mice with the sprint gene before becoming exhausted. They also found their muscle metabolism was more efficient.

To put a date on the spread of the inactive endurance version of the gene the team analysed DNA samples from 96 people from around the world.

The results, published in the journal Nature Genetics, showed the inactive form of the gene began to rapidly increase in frequency in Europeans and Asians about 15,000-33,000 years ago, during the last Ice Age.

Professor North said that having the endurance gene and more efficient muscles could have been an advantage in a cold climate where food was scarce. "It may have allowed them to adapt to the more hostile environments of Eurasia."

She said that having the inactive form of the gene might not be a benefit now. In a world where food is plentiful and fewer people exercise, slower muscle metabolism could possibly contribute to obesity.

Piotr

Here's an oldie, but goodie.

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