At least as it pertains to crank length. Hopefully this will lead to an intelligent discussion
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http://www.youtube.com/watch?v=HFxBg7BnFlQ
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http://www.youtube.com/watch?v=HFxBg7BnFlQ
Ok, is this the same Martin Study that has a population size of 16 and concluded:Originally Posted by Fday .
Well, the Martin study was a peer reviewed study. He is a well-known and well-respected researcher in this area. I am simply making inferences from that study and my own experience experimenting with this. I am simply making the argument based upon this study and what is commonly accepted as true. There certainly is no evidence to prove that what I say is wrong.
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I am not ignoring anything. Martin says use of 170 cranks will not SUBSTANTIALLY affect power. Looking at his data it looks like the 170 length gives about a 1% power difference. That would be 2-3 watts at what most here are racing at.Originally Posted by kopride .
Ok, is this the same Martin Study that has a population size of 16 and concluded:
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"These data suggest that pedal speed (which constrains muscle shortening velocity) and pedaling rate (which affects muscle excitation state) exert distinct effects that influence muscular power during cycling. Even though maximum cycling power was significantly affected by crank length, use of the standard 170-mm length cranks should not substantially compromise maximum power in most adults."
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And you apparently ignore a later Martin study where he concludes:
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Determinants of metabolic cost during submaximal cycling. McDaniel J; Durstine J L; Hand G A; Martin J C Department of Exercise Science, University of South Carolina, Columbia, South Carolina 29208, USA JOURNAL OF APPLIED PHYSIOLOGY (2002 Sep), 93(3), 823-8.
The metabolic cost of producing submaximal cycling power has been reported to vary with pedaling rate. Pedaling rate, however, governs two physiological phenomena known to influence metabolic cost and efficiency: muscle shortening velocity and the frequency of muscle activation and relaxation. The purpose of this investigation was to determine the relative influence of those two phenomena on metabolic cost during submaximal cycling. Nine trained male cyclists performed submaximal cycling at power outputs intended to elicit 30, 60, and 90% of their individual lactate threshold at four pedaling rates (40, 60, 80, 100 rpm) with three different crank lengths (145, 170, and 195 mm). The combination of four pedaling rates and three crank lengths produced 12 pedal speeds ranging from 0.61 to 2.04 m/s. Metabolic cost was determined by indirect calorimetery, and power output and pedaling rate were recorded. A stepwise multiple linear regression procedure selected mechanical power output, pedal speed, and pedal speed squared as the main determinants of metabolic cost (R(2) = 0.99 +/- 0.01). Neither pedaling rate nor crank length significantly contributed to the regression model. The cost of unloaded cycling and delta efficiency were 150 metabolic watts and 24.7%, respectively, when data from all crank lengths and pedal speeds were included in a regression. Those values increased with increasing pedal speed and ranged from a low of 73 +/- 7 metabolic watts and 22.1 +/- 0.3% (145-mm cranks, 40 rpm) to a high of 297 +/- 23 metabolic watts and 26.6 +/- 0.7% (195-mm cranks, 100 rpm). These results suggest that mechanical power output and pedal speed, a marker for muscle shortening velocity, are the main determinants of metabolic cost during submaximal cycling, whereas pedaling rate (i.e., activation-relaxation rate) does not significantly contribute to metabolic cost.
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Here is a more recent Martin power point where he again notes that there is no real disadvantage to a 170mm crank for almost any trained cyclist:
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http://www.plan2peak.com/files/32_article_JMartinCrankLengthPedalingTechnique.pdf
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Again, I am very skeptical of your "elite guys at the top" won't change argument. The guys at the top have spend hours in wind tunnels looking for free speed. Shortening cranks by 2.5 cm is nothing earth shattering if it meant real speed increases.
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In addition to what appears to be very selective citation of small studies, adding to my skepticism is the fact that you are really trying to sell a product. . which is your power crank gizmo.
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Well, the second study demonstrates that pedal length doesn't even factor in the regression at all, it's not even statistically significant. Listen, among 16 cyclists, which was the sample size of the study you cited, I could probably show you that there is a 2-3 or 5-10 watt difference between the riders that gave or received oral sex the night before in my cycling group. I'm just not convinced that you can prove anything from such a minor difference in an isolated study. And the first study was max power, not steady state or endurance power over a 40k tt. You want to test your crank length theory and gizmo on multiple studies of sample sizes approaching 1000, then maybe I will be more impressed, but for now, you are presenting very misleading data in support of your theory. The study did not prove, and was not intended to prove, that under every circumstances, with every rider, shorter is better. It simply explored whether there was support for the idea that cranks longer than 170 could produce more power.Originally Posted by Fday .
I am not ignoring anything. Martin says use of 170 cranks will not SUBSTANTIALLY affect power. Looking at his data it looks like the 170 length gives about a 1% power difference. That would be 2-3 watts at what most here are racing at.
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My argument with him is this.
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1. Why would an athlete want to give up any power when nothing need be done to claim the extra power but change the cranks on the bike?
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My second argument goes to the aerodynamic position. Martin did not test in the aerodynamic position. I infer an mechanism to explain his findings that would suggest this difference becomes much larger when in the aerodynamic position.
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If you want to give up 2-3 watts for the kind of racing you do I guess that is your choice. But, for those doing TT type racing I would guess the difference is more on the order of 5-10 watts and you would be giving up substantial aerodynamic benefits also. Even if there is no power advantage, there are clearly substantial aerodynamic advantages to shorter cranks. Why anyone would willingly give these up when the "fix" is so simple is beyond me but I fully expect lots to come here and argue it is not necessary to change. You are simply the first.
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The point is there is a theoretical advantage to making this change and people should not be afraid to experiment to see if it works for them.
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Well, first of all, you don't cite the study for a TT pace which is the second Martin study concerning sub maximal efforts, and which found that pedal cranks did not even contribute to the regression model. . in other words, pedal cranks were not statistically significant in submaximal, i.e. time trial pace. . instead, you cite the 16 person study for max power, which is completely irrelevant to a TT. And which in no way concludes that cranks shorter than 170 mm are better than 170 mm cranks for even max power.Originally Posted by Fday .
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Your problem, as I see it, is you are focused on the power issue alone. If we were simply arguing power I wouldn't have much to stand on, even though I believe the data would be much more convincing if the study were to be repeated with the riders in the TT position (or comparing the two positions). As I said, even if the power didn't change at all, which you argue, it doesn't matter to my argument because the aerodynamics will change. And for TT type efforts that is a big deal, in case you haven't figured that out yet. There are well established principles regarding aerodynamic drag. I mention them an show how shorter cranks allow the rider to present a smaller frontal area. All else being equal a smaller frontal area will have less drag resistance than a larger frontal area. If you don't care about that type of racing feel free to ignore this. But, if you want to address the point of the video you have to counter my point about the aerodynamics also.
Well, Martin was not willing to make them because the study didn't support the conclusions you want to draw. He was doing an academic study and you are trying to promote your product. If you want to promote your product with science, then hire a researcher like Martin and have him test your theory. Don't use academic papers like a Chinese menu and pick and choose portions to promote a product, and ignore or discount findings which do not support your theory, or offer a theory as to why the other more relevant studies do not support your theory, which is what you did to "make a convincing argument."Originally Posted by Fday .
I certainly am drawing conclusions and making inferences that Martin was not willing to make because I am trying to put incomplete data together to improve outcome and Martin was writing a scientific paper and such inferences are inappropriate for such papers. I suspect that Martin's TT effort data didn't show differences because we would expect the absolute differences to be even smaller at that lower power level. His max power study didn't even show statistical significance between 170 and 145. What I am looking at is the trend line (and the spread for each length, which was very consistent) and concluded that with a larger group the difference between 145 and 170 probably would have eventually reached statistical significance with enough people. If he had done that I suspect his conclusion would have been quite different. It would take a very large cohort to show the same at lower power levels. Sometimes it is important in interpreting scientific papers to understand what was not done and what the inferences of the data might mean if the study was done differently.
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I may not be correct but I think I make a pretty convincing argument. I have made my case and I think it is a very good case. Feel free to ignore it if you wish.
I'm with Frank on this one, ie, even if the effect of receiving oral sex before a competition cannot be statistically proven to exist, a rider would be crazy to ignore the advantage, however small, that it could provide. I'm going to try to incorporate this into my competition regimen effective immediately.Originally Posted by kopride .
I could probably show you that there is a 2-3 or 5-10 watt difference between the riders that gave or received oral sex the night before in my cycling group.
Shortening cranks would have other 'fun' implications. Just imagine all the extra cornering clearance you'd get... that'd be worth it if you were a crit guy or just fancied putting guys through hell on a technical road course. You lower the weight of the cyclist and you get other 'cornering' benefits too. Less weight too - if you're a weight weenie - shorter cranks, shorter seat tubes, less frame material... all dependant to what extremes you take it too.Originally Posted by kopride .
Well, first of all, you don't cite the study for a TT pace which is the second Martin study concerning sub maximal efforts, and which found that pedal cranks did not even contribute to the regression model. . in other words, pedal cranks were not statistically significant in submaximal, i.e. time trial pace. . instead, you cite the 16 person study for max power, which is completely irrelevant to a TT. And which in no way concludes that cranks shorter than 170 mm are better than 170 mm cranks for even max power.
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Second, shortening the cranks increases seat height and also affects aero positioning in lots of subtle ways. That may or may not make a rider slippery. I'm not saying that an individual rider who experiments in a wind tunnel might not find that shorter cranks are better for his set up. It's possible. . . for that rider. But your inferences about shorter cranks may not pass scientific scrutiny. And my guess is that if they did, we would see TT riders racing on 140 mm cranks, or at least 165 as standard.
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My point is that you are making conclusions about power and crank length that Martin was not willing to make; and are proposing an aero theory that is completely untested; and in fact, the existence and prevalence of wind tunnel testing suggests either that your broad conclusions are not true; or aero experts assisting these elite riders are idiots and refusing to adopt a very easy beneficial change.
ÂOriginally Posted by frenchyge .
I'm with Frank on this one, ie, even if the effect of receiving oral sex before a competition cannot be statistically proven to exist, a rider would be crazy to ignore the advantage, however small, that it could provide. I'm going to try to incorporate this into my competition regimen effective immediately.
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You could always get Zinn to build you some cranks... and there's a few companies that will shorten various models of cranks too. It's not like you HAVE to buy PowerCranks to try this stuff.Originally Posted by kopride . Â
In addition to what appears to be very selective citation of small studies, adding to my skepticism is the fact that you are really trying to sell a product. . which is your power crank gizmo.
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