The pedaling technique thread

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Sep 23, 2010
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JamesCun said:
So, are you going to stop using the variance in efficiency shown in the studies as evidence of pedalling technique having huge room for improvement? Pretty weak argument on your part if a key point you've made is so easily shown to be well accounted for in the research.
Sure I will stop using that variance for this argument. I simply used that as I was unaware that muscle type could account for that amount of variance (almost). Of course, it doesn't account for it all so it is up to you to let us all know where the other variance comes from as I suspect some of it has to do with pedaling technique even though they didn't find that to be the case to a statistically significant level.
You are massively overstating the losses that might exist. Would you invest as much time it is was a 1-2% change vs the 100% you claim theoretically possible?
If I were serious about racing I wouldn't give up on a 1-2% improvement. Why would you?

Further, I am not massively overstating the losses. Lets assume muscles can optimally contract at an efficiency of between 30 and 40% and we measure at the wheel an efficiency of 16-26%. We see a 10% range at both ends but there is a 14% drop in between. Perhaps 5% of that drop can be accounted for chain, bearing and tire losses. This still leaves 9% drop unaccounted for. That is a pretty big loss since we are talking about this being a loss from the energy expenditure point of view, not the power at the wheel point of view. So, 200 watts at the wheel and at a 20% efficiency requires energy equivalent of 1000 watts at the input to the muscle. 9% of that is 90 watts. Are you willing to give that potential up simply because you can't explain them? Now, I don't believe all of those 90 are recoverable but I suspect 40-50 of them are.

Even if I were "massively overstating" the losses can you at least admit that there are losses here? Are you willing to pass on those improvements simply because you think them small (say just 10 watts or so)?

From a scientific perspective all of the losses need to be accounted for so, from a scientific perspective, one can know where to best approach potential improvement. What can be done? What is not being addressed? No one has done that that I can find. Coggan and Martin (the known researchers who hang out here) sure are being quiet or have you not noticed. You guys can't do that even from a theoretical basis. I believe I can but what I can't do is quantitate the various losses due to pedaling technique that I see. Someone should do that work.
 
Sep 23, 2010
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coapman said:
How does one get an accurate value of the potential best muscle power output.
That is done in isolated muscle preparations on the laboratory bench (but not usually done in human muscle). I posted a link earlier to a study that did something like this that showed a 35-50% highest efficiency range in various leg muscles. Even Dr. Coggan has posted that skeletal muscle can contract at an efficiency of the best electric motors. What Dr. Coggan has not attempted to do is tell everyone where the losses occur to account for all the drop between the muscle and the wheel. Guess he can't bring himself to say he doesn't know.
 
Mar 10, 2009
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FrankDay said:
That is done in isolated muscle preparations on the laboratory bench (but not usually done in human muscle). I posted a link earlier to a study that did something like this that showed a 35-50% highest efficiency range in various leg muscles. Even Dr. Coggan has posted that skeletal muscle can contract at an efficiency of the best electric motors. What Dr. Coggan has not attempted to do is tell everyone where the losses occur to account for all the drop between the muscle and the wheel. Guess he can't bring himself to say he doesn't know.

The answer can be found in the gym, how does the efficiency of the leg press man compare with that of a cyclist ?
 
Sep 23, 2010
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coapman said:
The answer can be found in the gym
NO it can't. To find the efficiency of a specific muscle that muscle needs to be isolated so the energy in and energy out can be quantified.
 
Sep 23, 2010
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Here is one example of how efficiency is affected by pedaling technique. I consider the chosen cadence as part of pedaling technique. Cadence affects efficiency. This is a well known effect. The reasons for this are two. cadence affects muscle shortening speed and force, both of which can affect muscle contractile efficiency. Further, cadence affects energy losses associated with making the legs go up and down while the feet to go around and around (this loss cannot be fully recovered but can be minimized). Many cyclists choose to ignore this scientific fact because, well because they don't think what the science shows applies to them.
 
Jun 1, 2014
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You numbers are again skewed to show your bias. How do you know if it is 30 or 40%...that is a huge difference. The 16-26 is likely to be muscle fibre as a key factor. You are assuming that the 16 and 30 go together and 26 and 40 go together. Changed completely if those assumptions are wrong.

So, 30% to 26% minus your 5% losses shows that cycling is actually more efficient that it theoretically should be ;)
 
FrankDay said:
Further, I am not massively overstating the losses. Lets assume muscles can optimally contract at an efficiency of between 30 and 40% and we measure at the wheel an efficiency of 16-26%.
Well these folks in New Zealand would disagree with you by a large margin.



That's cutting your losses down to nil;)

Hugh
 
Sep 23, 2010
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sciguy said:
Well these folks in New Zealand would disagree with you by a large margin.



That's cutting your losses down to nil;)

Hugh
Or this analysis (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144848/) of human muscle contractile efficiency, placing it at 68%, increasing my estimates of potential gain substantially. 40% efficiency is a generally accepted skeletal muscle efficiency number in medicine and unless we have incontrovertible evidence of another number perhaps we should be using that as a starting point for discussion.

The problem with your paper, as I see it, is it stems from their inability to reconcile the measured efficiency of the cyclists with the measured efficiency of in vitro muscle preparations of other species.
So, it remains difficult to reconcile the cycling human with expectation based on data from isolated muscle
So, because they cannot reconcile the difference, they make a bunch of assumptions that allow them to conclude that human muscle evolved to be only about half as efficient as most of the other animal world. I guess that is possible but seems highly unlikely to me
 
Sep 23, 2010
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JamesCun said:
You numbers are again skewed to show your bias. How do you know if it is 30 or 40%...that is a huge difference. The 16-26 is likely to be muscle fibre as a key factor. You are assuming that the 16 and 30 go together and 26 and 40 go together. Changed completely if those assumptions are wrong.

So, 30% to 26% minus your 5% losses shows that cycling is actually more efficient that it theoretically should be ;)
Ugh, the Coyle paper demonstrated there was a high correlation between muscle efficiency and cycling efficiency. It defies logic to then say that the 30% muscle can result in a 26% overall cycling efficiency while the 40% efficient muscle would result in the 16% efficiency based upon that paper.
 
FrankDay said:
Or this analysis (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144848/) of human muscle contractile efficiency, placing it at 68%, increasing my estimates of potential gain substantially. 40% efficiency is a generally accepted skeletal muscle efficiency number in medicine and unless we have incontrovertible evidence of another number perhaps we should be using that as a starting point for discussion.
Frank, I see you're still confused on this topic. The 68% efficiency they quote is based on the use of ATP which we have already shown you is formed from glucose with an efficiency of only 39% So once again using those numbers its back to .68 X .39 = 26% Hmmmmmm that number seems familiar. You're absolutely full of crap regarding skeletal muscle being 40% efficient in terms of converting glucose to useable work and have yet to provide any evidence for that even though you say it's common knowledge.

A value of 0.68 for the efficiency of force production and activation (contraction-coupling efficiency) was recently reported for a human muscle (Jubrias et al., 2008). This value was calculated from the change in ATP per change in work over several work levels (so-called delta efficiency) (Gaesser and Brooks, 1975).

So will you for once admit that you're wrong about this? You do see that they are talking about ATP in the link you cited?

You're the one who always tells us you're willing to learn and admit your mistakes.

Hugh
 
Sep 23, 2010
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sciguy said:
Frank, I see you're still confused on this topic. The 68% efficiency they quote is based on the use of ATP which we have already shown you is formed from glucose with an efficiency of only 39% So once again using those numbers its back to .68 X .39 = 26% Hmmmmmm that number seems familiar. You're absolutely full of crap regarding skeletal muscle being 40% efficient in terms of converting glucose to useable work and have yet to provide any evidence for that even though you say it's common knowledge.

A value of 0.68 for the efficiency of force production and activation (contraction-coupling efficiency) was recently reported for a human muscle (Jubrias et al., 2008). This value was calculated from the change in ATP per change in work over several work levels (so-called delta efficiency) (Gaesser and Brooks, 1975).

So will you for once admit that you're wrong about this? You do see that they are talking about ATP in the link you cited?

You're the one who always tells us you're willing to learn and admit your mistakes.

Hugh
And, the paper you posted involved a lot of guesses to get to a number that felt right to them. There is zero experimental data to support their supposition.

Look, it doesn't matter, for the purposes of this discussion, what the efficiency of the muscle is. All that does is set the maximum efficiency possible for the cyclist if there were no losses downstream from that point. All I am concerned about here are the losses between this point and to where the losses as part of the bicycle begin. We know that cadence alone involves a loss because changing cadence changes efficiency (both too low and too high decrease overall efficiency). Mechanical engineering principles also stipulate there will be additional losses from non-optimal vector forces which have been documented, that is the direction of applied muscle forces do not line up with the direction of the pedal motion. The question is not whether there are losses due to these things but, rather, the size of the losses and how much can be recovered if cadence and applied force were optimal for that individual and power. Can you at least admit that these losses exist and that some moderation is possible?
 
Jun 1, 2014
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sciguy said:
Frank, I see you're still confused on this topic. The 68% efficiency they quote is based on the use of ATP which we have already shown you is formed from glucose with an efficiency of only 39% So once again using those numbers its back to .68 X .39 = 26% Hmmmmmm that number seems familiar. You're absolutely full of crap regarding skeletal muscle being 40% efficient in terms of converting glucose to useable work and have yet to provide any evidence for that even though you say it's common knowledge.

A value of 0.68 for the efficiency of force production and activation (contraction-coupling efficiency) was recently reported for a human muscle (Jubrias et al., 2008). This value was calculated from the change in ATP per change in work over several work levels (so-called delta efficiency) (Gaesser and Brooks, 1975).

So will you for once admit that you're wrong about this? You do see that they are talking about ATP in the link you cited?

You're the one who always tells us you're willing to learn and admit your mistakes.

Hugh
Frank has a scary lack of knowledge on a subject that is central to his entire 15year crusade agains mashers. Hard to believe that he hadn't learned anything about cycling economy over all that time.

Thanks for sharing these very relevant docs and info. I'm glad the educated crowd can still muster the interest in 'discussing' these things with Frank.
 
Sep 23, 2010
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sciguy said:
Well these folks in New Zealand would disagree with you by a large margin.



That's cutting your losses down to nil;)

Hugh
I just took another look at this. Do you agree with their assessment from the experimental data they mention in the first paragraph that the efficiency of the exercising cyclist is greater than the efficiency of the contraction of human muscle?
The efficiency of a human riding a bicycle is about 0.2, and it could be reasonably assumed that the efficiencies of the exercising muscles alone would be somewhat higher than this value. do results of studies of isolated muscle (Table 3) support this idea ? The data upon which the comparison should be based are those of the efficiency calculated from the oxygen uptake over complete cycles of contraction and relaxation. The range of values of experiments meeting these criteria 0.1 0.2 (Table 3). That is, contrary to expectations, even the highest value scarcely match the human cycling efficiency.
There you have it. According to the data of these authors something between the muscle and the bike qualifies as a perpetual motion machine. Even more reason to look at this area. Where does the energy get added? My assumption there have to be losses there is clearly wrong. Good find SciGuy.
 
FrankDay said:
I just took another look at this. Do you agree with their assessment from the experimental data they mention in the first paragraph that the efficiency of the exercising cyclist is greater than the efficiency of the contraction of human muscle? There you have it. According to the data of these authors something between the muscle and the bike qualifies as a perpetual motion machine. Even more reason to look at this area. My assumption there have to be losses there is clearly wrong. Good find SciGuy.
Frank,

That was a couple of paragraphs from a 60+ page document. If you read the whole document the absolute maximum muscle efficiency one might imagine is 27%. I'd be glad to share the whole thing with you. It might help get you a bit more "up to speed" on the topic.

Hugh
 
Sep 23, 2010
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sciguy said:
Frank,

That was a couple of paragraphs from a 60+ page document. If you read the whole document the absolute maximum muscle efficiency one might imagine is 27%. I'd be glad to share the whole thing with you. It might help get you a bit more "up to speed" on the topic.

Hugh
LOL. That first paragraph says it all. Their absolute maximum of 27% doesn't allow for any losses (ok, 1%), including chain, bearing, or tire losses, in the 26% efficient cyclist. And you believe this BS when there are plenty of other papers out there with different data.

Send me the entire paper. I will be happy to tear it apart, not that you would believe my assessment. Why anyone experienced in the area would want to wade through this thing past the first page would baffle me. Your holding this paper out to support your argument says all we need to know about your position.

Edit: I might add that these authors seem to have discovered an instance in the world where both the 1st and 2nd laws of thermodynamics are violated, that is, between the muscles of the cyclist and the wheel of the bicycle. A Noble Prize sure to come their way for such a discovery.
 
Mar 10, 2009
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FrankDay said:
NO it can't. To find the efficiency of a specific muscle that muscle needs to be isolated so the energy in and energy out can be quantified.
I am referring to loss in possible pedal power. How would you explain the difference between the force a leg press man's right leg can apply to the foot plate and what the same leg and muscle can apply to the pedal in a locked 3 o'c position.
 
Sep 23, 2010
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coapman said:
I am referring to loss in possible pedal power. How would you explain the difference between the force a leg press man's right leg can apply to the foot plate and what the same leg and muscle can apply to the pedal in a locked 3 o'c position.
That is easy.

The weight lifter has weight on his shoulders (increasing resistance) and only has to contract once and the movement is in a single direction (down). The cyclist has no weight on his shoulders (such that if he presses down more than his body weight will come off the saddle (which does work but doesn't drive the bicycle forward) but more importantly has to press down 60-90 times a minute for a couple of hours or so, limiting the force he can apply and continue to apply and the direction keeps changing.
 
FrankDay said:
LOL. That first paragraph says it all. Their absolute maximum of 27% doesn't allow for any losses (ok, 1%), including chain, bearing, or tire losses, in the 26% efficient cyclist. And you believe this BS when there are plenty of other papers out there with different data.

Send me the entire paper. I will be happy to tear it apart, not that you would believe my assessment. Why anyone experienced in the area would want to wade through this thing past the first page would baffle me. Your holding this paper out to support your argument says all we need to know about your position.
Frank the paragraphs are from 29 pages in. You have no clue as to what the rest of the paper has to tell you.

Please show us a single paper that supports 40% value you keep espousing. The most recent one only supports a 27% glucose to work efficiency despite you believing 68%. It's pretty simple math there.

Hugh
 
Sep 23, 2010
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sciguy said:
FrankDay said:
LOL. That first paragraph says it all. Their absolute maximum of 27% doesn't allow for any losses (ok, 1%), including chain, bearing, or tire losses, in the 26% efficient cyclist. And you believe this BS when there are plenty of other papers out there with different data.

Send me the entire paper. I will be happy to tear it apart, not that you would believe my assessment. Why anyone experienced in the area would want to wade through this thing past the first page would baffle me. Your holding this paper out to support your argument says all we need to know about your position.
QUOTE]

Frank the paragraphs are from 29 pages in. You have no clue as to what the rest of the paper has to tell you.

Please show us a single paper that supports 40% value you keep espousing. The most recent one only supports a 27% glucose to work efficiency despite you believing 68%. It's pretty simple math there.

Hugh
My friend, I already linked a paper that measured 35%, 40% and 50% efficiency in different muscles. (see post 721) Perhaps you missed it. I don't care what page that crap is on or how many pages they wrote. What they wrote there violates the laws of thermodynamics. I will wait until they are awarded the Nobel Prize for their discovery before I try to get up to speed on their view. Perhaps you should rethink how much you want to rely on what they say.
 
FrankDay said:
sciguy said:
My friend, I already linked a paper that measured 35%, 40% and 50% efficiency in different muscles. Perhaps you missed it.
and once again you're mixing up the fact that those studies were done looking at ATP not glucose so really we're talking about 14%, 16% and 20%. Wow I'm so impressed.

Hugh
 
Sep 23, 2010
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sciguy said:
FrankDay said:
and once again you're mixing up the fact that those studies were done looking at ATP not glucose so really we're talking about 14%, 16% and 20%. Wow I'm so impressed.

Hugh
So, you believe that cyclists can achieve an overall cycling efficiency greater than individual muscle contraction efficiency? Is that correct?
 
FrankDay said:
sciguy said:
So, you believe that cyclists can achieve an overall cycling efficiency greater than individual muscle contraction efficiency? Is that correct?

No I don't. I imagine that the post ATP production value is somewhere between the 60% Andy mentioned and the 68% value both you and I have found. Corrected for the ~60% loss from ATP production that must take place before a twitch can even begin to happen, that works out to and efficiency of 24 to 27%. That's without taking into account all the work necessary to provide blood and oxygen to those muscles as well as support the pedaling athlete..................... So not a whole lot of loss between the muscles and pedals. Certainly not remotely on the order of what you've postulated.

Hug
 
Sep 23, 2010
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sciguy said:
FrankDay said:
No I don't. I imagine that the post ATP production value is somewhere between the 60% Andy mentioned and the 68% value both you and I have found. Corrected for the ~60% loss from ATP production that must take place before a twitch can even begin to happen, that works out to and efficiency of 24 to 27%. That's without taking into account all the work necessary to provide blood and oxygen to those muscles as well as support the pedaling athlete..................... So not a whole lot of loss between the muscles and pedals. Certainly not remotely on the order of what you've postulated.

Hug
And, not remotely related to reality. LOL. You might want to check with Dr. Coggan. He has come here and stated that muscles can contract with the efficiency of a high efficiency electric motor. That is substantially higher than 27%. Further, the link I gave you compared "(positive work done divided by the energetic equivalent of the oxygen consumed). (wonder if this study made table 3 of the paper you posted.) This is an energy out divided by the energy in direct measurement of muscle contractile efficiency measured over both the contraction and relaxation cycle and doesn't need any correction. It is how muscle contraction efficiency is measured in vitro. The correction you apply makes the work out greater than the energy in, again violating the laws of thermodynamics. Let's try to keep this real can we. You might try a PM to Dr. Coggan to let him set you straight before you embarrass yourself again.

Anyhow, why are we arguing the efficiency of muscle contraction here when we are supposed to be discussing the losses associated with pedaling. The laws of thermodynamics say there must be losses in this transfer of energy. All we have to determine is why and how they occur and how large those losses are. Then, we can argue whether any can be recovered. Arguing that there are no losses (or negative losses as your paper does) is a waste of time because it simply isn't true unless you can prove it then you will be up for a Nobel Prize.
 
Regarding energy efficiency from glucose, and ATP -
I found this info in a college chemistry textbook -

Fundamentals of Chemistry
General, Organic, and Biological
H.Stepehn Stoker
Edward B. Walker
2nd edition, 1991

Chapter 27, Mitochondrial Oxidation and Phosphorylation Pathway,
page 702

"
Let us briefly consider the efficiency of total glucose oxidation from glucolysis through oxidative phosphorylation. If we seledt liver tissue, where the malate shuttle predominates, we gain 38 moles of ATP from the oxidation of 1 mole of glucose. With 7.3 kcal/mole of free energy stored in each ATP bond, this represents a total of 38 ATP X -7.3 kcal/mole (-277.4 kcal) of free energy captured for use. If we recall that the 'delta G' for the direct combustion of glucose to CO2 is -686 kcal/mole, we can calculate the efficiency in capturing this fee energy.
energy stored in 38 ATP high-enery bonds -> -277 kcal
free energy from combustion of glucose -> -686 kcal
= 40%
"

Is this helpful, or relevant?

Jay Kosta
Endwell NY USA
 
Sep 23, 2010
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For those who are proposing a maximum muscle contraction efficiency of 27% resulting in cyclist overall efficiency of up to 26% I am wondering how you account for chain losses of 2-7%? I think many accept 5% loss as being typical good estimate of chain loss at average power (150-200 watts) for the condition most chains are in.

Further, I take it you are not advocates of "the aggregation of marginal gains" advocated by British Cycling and Team Sky mentioned in the link above, not that they are any good.

When we add wheel bearing losses of about 1% and rolling resistance losses of 10% or more (although rolling resistance losses are probably not part of many cycling efficiency calculations unless the output is measured on an ergometer like the Computrainer) See this model published by Martin et al

edit: Oh, and I forgot, those 16-26% efficiency numbers are usually Gross efficiency, which includes basic maintenance oxygen consumption in the energy cost camp. This means the actual muscle efficiency, the net efficiency, is much higher. Hence, a max muscle efficiency of 27% cannot result in a gross cycling efficiency of 26%. Impossible.

There are losses in transferring energy from the muscles to the bicycle. Losses are dictated by the laws of thermodynamics. Understanding how those losses occur might lead to methods to minimize or eliminate such losses for performance improvement even if the perceived benefit is small. Hiding one's head in the sand and denying even the possibility will not lead to any improvement in this area, guaranteed!
 

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