What determines efficiency ???

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More specifically, through what mechanism/ biological adaptions does efficiency increase in response to training? What contributes to differing efficiencies in different athletes at similar work levels ???

More specifically, through what mechanism/ biological adaptions does efficiency increase in response to training? What contributes to differing efficiencies in different athletes at similar work levels ???Taken from here (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=15774697&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum):

"It is hypothesized that the improved muscular efficiency probably reflects changes in muscle myosin type stimulated from years of training intensely for 3-6 h on most days."

I hope it helps, but these hypotheses didn't help me any. :confused:

Thanks, and sorry for the brief and abrupt posting, i was at work and trying to not get caught wasting time.

This (posted above) is one of the few references i have found on the subject, the article has been posted on here a few times, but it seems strange that a variable whch directly correlates to power output is only dealt with in passing. Obviously varying muscle composition is a big contributor to differing efficiencies, but i would love to see an in depth treatment of the subject to help get my head around it all.

It is of slight personal importance as my efficiency is too low, I have a Vo2 max of almost 70ml/kg/m but a PVo2max of only 340 watts.

Thanks, and sorry for the brief and abrupt posting, i was at work and trying to not get caught wasting time.

This (posted above) is one of the few references i have found on the subject, the article has been posted on here a few times, but it seems strange that a variable whch directly correlates to power output is only dealt with in passing. Obviously varying muscle composition is a big contributor to differing efficiencies, but i would love to see an in depth treatment of the subject to help get my head around it all.

It is of slight personal importance as my efficiency is too low, I have a Vo2 max of almost 70ml/kg/m but a PVo2max of only 340 watts. There are lots of things that can potentially affect cycling efficiency. Everything from your muscle fibre type (as hypothesized by Coyle), to cadence, position on the bike, pedaling style, and the condition of your chain and bearings. All of these, except for perhaps muscle fibre type, are potentially optimizable. A nice discussion of most of these can be found in the book Bicycling Science (http://www.amazon.com/Bicycling-Science-David-Gordon-Wilson/dp/0262731541). My product (PowerCranks) has been demonstrated to improve pedaling efficiency in trained cyclists approxiamtely 10% in only 6 weeks. See Luttrell (http://nsca.allenpress.com/nscaonline/?request=get-abstract&doi=10.1519%2F1533-4287%282003%29017%3C0785:EOSTUP%3E2.0.CO%3B2). Another unpublished study by Dixon (http://www.powercranks.com/v4pages/support-manuals.htm) showed similar benefits.

Why Coyle would hypothesize that Lance's documented efficiency changes were due to his changing muscle fibre type without a single shred of evidence while ignoring all other potential explanations is simply bizarre, and boggles my mind.

There are lots of things that can potentially affect cycling efficiency. My product (PowerCranks) has been demonstrated to improve pedaling efficiency in trained cyclists approxiamtely 10% in only 6 weeks.

I can improve pedaling efficiency by, instead of having your thighs do all the work, spreading the power generation and application workload evenly over the upper and lower leg muscles and hips. This has the same effect on the strain on knees and thighs when using high gears as the difference between climbing a stairs one step at a time compared to two steps at a time. How does your PC equipment improve efficiency and why does it take so long ?

I can improve pedaling efficiency by, instead of having your thighs do all the work, spreading the power generation and application workload evenly over the upper and lower leg muscles and hips. This has the same effect on the strain on knees and thighs when using high gears as the difference between climbing a stairs one step at a time compared to two steps at a time. How does your PC equipment improve efficiency and why does it take so long ?Well, we don't know exactly what they do, although we have several ideas. All those that have studied PC's have shown is we do affect efficiency. Someday, we hope they will also try to ask and answer the question: Why? or what are they doing to effect this change?

What we think they do, and they may do any or all of these things in any one person, depending upon their weaknesses.

1. They distribute the work amongst more muscles, keeping all the muscles working in a more efficient range.

2. They affect the pedaling dynamic, especially the direction of the applied forces, such that these become more efficient.

3. They help the user optimize their pedaling cadence to something that is more efficient for them.

There may be other things but I think these are the three major things we do.

And why does it take so long? Well, in my view, improving efficiency 10% in 6 weeks is amazing fast for such an achievement, not slow. Many think it impossible to change this. Greg LeMond told me it took him years of training to learn how to pedal in the PC fashion and that now people can learn it in months. So, to be able to reliably do so in 6 weeks is pretty amazing. But, what do I know?

Why Coyle would hypothesize that Lance's documented efficiency changes were due to his changing muscle fibre type without a single shred of evidence while ignoring all other potential explanations is simply bizarre, and boggles my mind.

Because:

1) Coyle has previously demonstrated a close relationship between fiber type and cycling efficiency;

2) if significant changes in fiber type are possible, they will tend to occur over a prolonged period of time (i.e., the time course makes sense);

3) there really are no other plausible explanations.

In any case, the Discussion of a paper is where the author(s) have the liberty to speculate, and you can't really criticize a paper on such basis if the speculation is plausible (which it was).

More specifically, through what mechanism/ biological adaptions does efficiency increase in response to training? What contributes to differing efficiencies in different athletes at similar work levels ???

Fiber type (and cadence, of course) is really the only thing that has been shown to correlate well with cycling efficiency. Notably, the pattern of force application at the pedals does not, and acute attempts to "improve" said pattern to result in a more "circular" pedaling style has been shown to reduce efficiency.

Because:

1) Coyle has previously demonstrated a close relationship between fiber type and cycling efficiency;

2) if significant changes in fiber type are possible, they will tend to occur over a prolonged period of time (i.e., the time course makes sense);

3) there really are no other plausible explanations.

In any case, the Discussion of a paper is where the author(s) have the liberty to speculate, and you can't really criticize a paper on such basis if the speculation is plausible (which it was).Oh, phooey. the fact that Coyle has demonstrated a close relationship between fiber type and cycling efficiency doesn't mean that is the only relationship with cycling efficiciency. Further, since the most efficient muscles are the slow twitch muscles, he doesn't explain how a rider like Lance would change his training to increase the proportion of slow twitch muscles to achieve such changes as he documented, let alone document that Lance changed his training in such a fashion. Coyle's explanation is only "plausible" if Lance changed his training in a fashion to encurage such a change. The only way I can envision that someone might make such changes in fiber type would be to do exclusively long slow distance aerobic training. I would suspect high intensity work would be counter productive to this end. I doubt Lance did little high intensity work. Anyhow, there is no documentation that muscle biopsy showed such changes nor that Lance changed his training to encurage such changes so his speculation is hardly plausible.

And, sure there are other possible explanations. Study after study has shown efficiency varies with cadence. Did Coyle control for this? If he did it would seem he would have commented. He did not. further, there have to be other explanations or else the efficiency improvements documented by Luttrell in his study would be impossible, since they occurred over a period of 6 weeks so highly improbable these are due to a change in fiber type so must be due to another explanation (and it wasn't cadence since he controlled for that).

And, sure, I can criticize the paper for his "speculation" as to this being the explanation as to this change (the only significant change seen in Lance over this period of time) without some discussion as to how Lance achieved this change, or discussion of other possible explanations since it was the only really important finding from this analysis. I wonder if Coyle happened to ask Lance how he might explain such a change? Probably not. What would he know about it anyhow? The problem here is Coyle is so highly regarded that shoddy work isn't seen as shoddy so any speculation he puts forth is taken by the masses as having been proven by him. That change was so large and so important to explain Lance's domination (and evidence his domination was not due to drugs) that it certainly need a deeper analysis than a single sentence proclaiming what the author thought was the explanation. His "speculation" in this instance is hardly much more than pure guessing based upon his bias, at least as far as can be determined from the text of the article.

I come from a running background, and find it interesting that we use different terms for the same concept. In running, I think what you're calling efficiency is called economy. Either way, its the same concept - how much useful power output per unit of energy consumption.

To your question, I don't understand what happens at the cellular level to explain an increase in economy. I do know it can be improved by doing hard reps at 98 ~ 100% sprint speed (Daniels, et al)

This is complete amateur speculation, but from a first law perspective, thinking of the body as a closed system, improvements in economy/efficieny could be achieved by minimizing the energy requirements of "auxilliary" systems, e.g. the body's cooling system, and by reducing frictional energy losses in the movements of joints and muscles. That would be a great research area (actually, someone probably already has published some work on that topic).:cool:

The problem here is Coyle is so highly regarded that shoddy work isn't seen as shoddy so any speculation he puts forth is taken by the masses as having been proven by him.
What's shoddy is that you continue to lean upon misleading "the masses" so that you can sell another set of your PowerCranks.
Even a summary review of your posts here shows that they are continually blown apart by those with scientific minds with no financial gain to cloud their statements.

To your question, I don't understand what happens at the cellular level to explain an increase in economy. I do know it can be improved by doing hard reps at 98 ~ 100% sprint speed (Daniels, et al)
True for running, maybe, but alas, not true for cycling, which appears to have almost no significantly trainable "skill" element. In cycling, the only differences which have been demonstrated to alter efficiency are metabolic and cellular. Tho' there's apparently money to be made trying to convince cyclists otherwise...

Notably, the pattern of force application at the pedals does not, and acute attempts to "improve" said pattern to result in a more "circular" pedaling style has been shown to reduce efficiency.

Incorrect, leaving the circular style aside, the correct unweighting technique improves efficiency. In my opinion Coyle did more damage to the advance of cycling (pedalling) science than any other scientist.

Incorrect, leaving the circular style aside, the correct unweighting technique improves efficiency. In my opinion Coyle did more damage to the advance of cycling (pedalling) science than any other scientist.Please provide some evidence instead of your opinion. Keep in mind that if you read Dr. Coyle's complete body of work carefully, you will find that early on he was under the belief that a rounder pedaling style was better. One good thging abou him, he isn't trying to sell you something...

actually, it's 'economy' in cycling too..some posters are just using the term to include things that aren't really efficiency.

I come from a running background, and find it interesting that we use different terms for the same concept. In running, I think what you're calling efficiency is called economy. Either way, its the same concept - how much useful power output per unit of energy consumption.

To your question, I don't understand what happens at the cellular level to explain an increase in economy. I do know it can be improved by doing hard reps at 98 ~ 100% sprint speed (Daniels, et al)

This is complete amateur speculation, but from a first law perspective, thinking of the body as a closed system, improvements in economy/efficieny could be achieved by minimizing the energy requirements of "auxilliary" systems, e.g. the body's cooling system, and by reducing frictional energy losses in the movements of joints and muscles. That would be a great research area (actually, someone probably already has published some work on that topic).:cool:

Oh, phooey. the fact that Coyle has demonstrated a close relationship between fiber type and cycling efficiency doesn't mean that is the only relationship with cycling efficiciency.

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.

Further, since the most efficient muscles are the slow twitch muscles, he doesn't explain how a rider like Lance would change his training to increase the proportion of slow twitch muscles to achieve such changes as he documented, let alone document that Lance changed his training in such a fashion. Coyle's explanation is only "plausible" if Lance changed his training in a fashion to encurage such a change.

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.

I would suspect high intensity work would be counter productive to this end.

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.

there is no documentation that muscle biopsy showed such changes nor that Lance changed his training to encurage such changes so his speculation is hardly plausible.

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


there are other possible explanations. Study after study has shown efficiency varies with cadence. Did Coyle control for this? If he did it would seem he would have commented. He did not.

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.)


further, there have to be other explanations or else the efficiency improvements documented by Luttrell in his study would be impossible, since they occurred over a period of 6 weeks so highly improbable these are due to a change in fiber type so must be due to another explanation (and it wasn't cadence since he controlled for that).

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.

And, sure, I can criticize the paper for his "speculation" as to this being the explanation as to this change (the only significant change seen in Lance over this period of time) without some discussion as to how Lance achieved this change, or discussion of other possible explanations since it was the only really important finding from this analysis.

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 wonder if Coyle happened to ask Lance how he might explain such a change? Probably not. What would he know about it anyhow?

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!!".

The problem here is Coyle is so highly regarded that shoddy work isn't seen as shoddy so any speculation he puts forth is taken by the masses as having been proven by him.

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.

That change was so large and so important to explain Lance's domination (and evidence his domination was not due to drugs) that it certainly need a deeper analysis than a single sentence proclaiming what the author thought was the explanation. His "speculation" in this instance is hardly much more than pure guessing based upon his bias, at least as far as can be determined from the text of the article.

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.

actually, it's 'economy' in cycling too..some posters are just using the term to include things that aren't really efficiency.

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.

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.






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, 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 ".
Please provide peer-reviewed evidence.

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.
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.


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.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?



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.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.



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



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.)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.


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). 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?

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.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.

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. 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.


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).
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 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!!". 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.



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.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.