Is it true that the "round pedalling stroke" is a myth?



gudujarlson

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Originally Posted by daveryanwyoming .

Many, many ways.

Many folks think that if you can 'pull up' on the backstroke then it's only common sense that you can engage more muscles, share the work and of course your power will increase. Trouble is, it's been shown repeatedly that this common sense theory does not work in practice and efforts to pull up on the back stroke do not lead to increased power sustained for any substantial periods. Classic fail for common sense approaches.
I still contend that it is not common sense that applying torque evening through the cycle is more efficient that applying it unevenly. From a high school physics point of view it very simple to apply the law of conservation of energy to see there is no difference. If there is any difference it must come from some complex physiological mechanisms which are very often contrary to common sense.
 

n crowley

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Originally Posted by daveryanwyoming .

Many, many ways.

Many folks think that if you can 'pull up' on the backstroke then it's only common sense that you can engage more muscles, share the work and of course your power will increase. Trouble is, it's been shown repeatedly that this common sense theory does not work in practice and efforts to pull up on the back stroke do not lead to increased power sustained for any substantial periods. Classic fail for common sense approaches.

Similarly, even if you can apply the same peak torque at a different point in the pedal stroke it is not a given that this translates to either higher sustained power (which is what racers are really after) or higher efficiency for the same power (useful for endurance and fueling strategies but not necessarily faster in most racing situations).

-Dave

When a seated rider pulls up on the backstroke, he is doing it when he is supposed to be applying his greatest down torque. The more a rider concentrates on that pulling up, the more of that down torque he will lose, This is obvious on all of those circular v mashing comparison graphs. The maximal torque at 12 is generated when both legs of natural pedallers are effectively idling and merges with the equal maximal 3 o'c down torque, increasing reduced torque between 1 and 2 to maximal torque in the process, for an extended highly effective power stroke. This is a TT technique, ideal for uninterrupted sustainable high power output and not suitable for the erratic speeds used in road races. Let it rest there until the evidence is made available.
 

gudujarlson

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People have been presenting evidence since at least the 19th century.

http://en.wikipedia.org/wiki/Conservation_of_energy
 

fergie

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Force measuring pedals have been available for years to test Noel's theory. As I recall Noel was invited to travel to California (all costs covered) to test his theory but declined. He now ducks for cover again as Brim Brothers delay the release of their product in the same way as Garmin with their pedal based power meters.
 

n crowley

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Originally Posted by fergie .

Force measuring pedals have been available for years to test Noel's theory. As I recall Noel was invited to travel to California (all costs covered) to test his theory but declined. He now ducks for cover again as Brim Brothers delay the release of their product in the same way as Garmin with their pedal based power meters.

What pedalling advice do you give to young riders ?
 

dominikk85

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Originally Posted by n crowley .



When a seated rider pulls up on the backstroke, he is doing it when he is supposed to be applying his greatest down torque. The more a rider concentrates on that pulling up, the more of that down torque he will lose, This is obvious on all of those circular v mashing comparison graphs. The maximal torque at 12 is generated when both legs of natural pedallers are effectively idling and merges with the equal maximal 3 o'c down torque, increasing reduced torque between 1 and 2 to maximal torque in the process, for an extended highly effective power stroke. This is a TT technique, ideal for uninterrupted sustainable high power output and not suitable for the erratic speeds used in road races. Let it rest there until the evidence is made available.
that is actually a good point. too many studies have concentrated on the pulling up but in fact the 11-1 and 5-7 phases are the weakest phases in the pedal cycle. so getting some propulsion there would make much more sense than at 9 o clock.

I'm not sure however if your method is the best to achieve that. can you create a graphic of the forces in your pedal system?

(copy that image http://www.nettally.com/palmk/crankset.gif
with right click, paste it into power point and then insert arrows as force vectors then upload with something like tinypic or so)

here is how I understand the models
2e5sjuv.jpg


the left is the classic round pedal model and the right seems to represent the study results. Is that correct?
 

alienator

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gudujarlson said:
I still contend that it is not common sense that applying torque evening through the cycle is more efficient that applying it unevenly. From a high school physics point of view it very simple to apply the law of conservation of energy to see there is no difference. If there is any difference it must come from some complex physiological mechanisms which are very often contrary to common sense.
First, those complex physiological mechanisms are not contrary to common sense. To have common sense about these mechanisms you have to have knowledge of them. There are many things in science which appear to violate common sense, but they only seem so because people aren't informed about those processes. As for applying torque evenly through a cycle, someone has already posted a report (I think it was daveryanwyoming) that showed that when the subject (or subjects) pedaled using the cadence style that nearly everyone uses average power was higher than it was when the subject (or subjects) tried to pedal all the way around the circle. Other studies have shown that when when riders try to apply equal torque around the circle, one leg frequently opposed the other in terms of the direction of force from each leg. It should also be obvious that given the muscle structure and geometry of the leg, there will be a direction in which the force applied is maximum, and likewise there will a direction in which force applied is minimal. It might be a decent first though or hypothesis that applying even torque around the circle would be optimal, but there don't appear to be any studies that support that conclusion. That is significant. As for any "linear" technique, the terms don't even apply.
 

fergie

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Originally Posted by n crowley .



What pedalling advice do you give to young riders ?
In twenty years of coaching I have never had to give advice to anyone about pedalling.

Actually no, I have given evidence based advice to you and Frank Day that your crackpot theories are unproven/img/vbsmilies/smilies/smile.gif
 

fergie

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Originally Posted by dominikk85 .

that is actually a good point. too many studies have concentrated on the pulling up but in fact the 11-1 and 5-7 phases are the weakest phases in the pedal cycle. so getting some propulsion there would make much more sense than at 9 o clock.
And you have missed the very good and very clear advice provided by Dave and others that trying to pedal harder in one part of the circle means you lose power in another and don't end up with any extra power overall. That is what coaches and riders are concerned about. No evidence yet that any attempt to change the application of force around the pedal stroke = higher power whether that is toe clips or clipless, independent cranks or fixed cranks are just trying to apply force in a different manner.
 

frost

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Oct 25, 2007
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Originally Posted by alienator .


First, those complex physiological mechanisms are not contrary to common sense. To have common sense about these mechanisms you have to have knowledge of them. There are many things in science which appear to violate common sense, but they only seem so because people aren't informed about those processes.
As for applying torque evenly through a cycle, someone has already posted a report (I think it was daveryanwyoming) that showed that when the subject (or subjects) pedaled using the cadence style that nearly everyone uses average power was higher than it was when the subject (or subjects) tried to pedal all the way around the circle. Other studies have shown that when when riders try to apply equal torque around the circle, one leg frequently opposed the other in terms of the direction of force from each leg. It should also be obvious that given the muscle structure and geometry of the leg, there will be a direction in which the force applied is maximum, and likewise there will a direction in which force applied is minimal.
It might be a decent first though or hypothesis that applying even torque around the circle would be optimal, but there don't appear to be any studies that support that conclusion. That is significant.
As for any "linear" technique, the terms don't even apply.
I think you have to re-read... /img/vbsmilies/smilies/smile.gif

Originally Posted by gudujarlson

I still contend that it is not common sense that applying torque evening through the cycle is more efficient that applying it unevenly.
 

n crowley

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Originally Posted by fergie .


And you have missed the very good and very clear advice provided by Dave and others that trying to pedal harder in one part of the circle means you lose power in another and don't end up with any extra power overall.
That is a nonsensical statement because that is what you and all other cyclists do when pedalling, you pedal harder between 1 and 5 o'c, where do you lose the power when you increase the force?. Now I understand why you don't give advice on pedalling.
 

alienator

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n crowley said:
  That is a nonsensical statement because that is what you and all other cyclists do when pedalling,  you pedal harder between 1 and 5 o'c,  where do you lose the power when you increase the force?. Now I understand why you don't give advice on pedalling.
You've misinterpreted what he's said. Read daveryanwyoming's posting of a study that showed a decrease in average power when cyclists under study used a angular power output different than what is typical. It would be wise, if you're going to persist you're hypothesis, that you read literature on power output vs crank angle. That is S.O.P. when formulating and presenting hypotheses.
 

n crowley

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Originally Posted by alienator .


You've misinterpreted what he's said. Read daveryanwyoming's posting of a study that showed a decrease in average power when cyclists under study used a angular power output different than what is typical. It would be wise, if you're going to persist you're hypothesis, that you read literature on power output vs crank angle. That is S.O.P. when formulating and presenting hypotheses.

I read it as a viewer who reads only Fergie's post. I believe in keeping things simple.(eg) When seated you can't increase power output by trying to apply effective torque with both legs at the same time. All available pedalling research literature is based on variations of the basic natural pedalling style, all of them giving the same sinusoidal graph. What is there to be gained from reading that or from power output vs crank angle data when it should be obvious to most people that the more tangential the force you apply to the crank, the greater your torque will be. Am I missing something.?
 

frost

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Oct 25, 2007
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Originally Posted by n crowley .



I read it as a viewer who reads only Fergie's post. I believe in keeping things simple.(eg) When seated you can't increase power output by trying to apply effective torque with both legs at the same time. All available pedalling research literature is based on variations of the basic natural pedalling style, all of them giving the same sinusoidal graph. What is there to be gained from reading that or from power output vs crank angle data when it should be obvious to most people that the more tangential the force you apply to the crank, the greater your torque will be. Am I missing something.?
Yes, you are missing the biochemical process that produces the energy to the pedalling.
 

dominikk85

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Oct 29, 2012
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Originally Posted by n crowley .



I read it as a viewer who reads only Fergie's post. I believe in keeping things simple.(eg) When seated you can't increase power output by trying to apply effective torque with both legs at the same time. All available pedalling research literature is based on variations of the basic natural pedalling style, all of them giving the same sinusoidal graph. What is there to be gained from reading that or from power output vs crank angle data when it should be obvious to most people that the more tangential the force you apply to the crank, the greater your torque will be. Am I missing something.?
yes only tangential force counts and the more degrees of tangential force you can apply over a rep the more mechanically efficient your pedalling will be. studies confirm that.

however those studies also found out that mechanical efficiency goes down as power goes up. that doesn't make sense when you first look at it but it seems that the biological situation is more important than the mechanical situation.

I think the problem is that the legs have a hard time being constantly contracted.the muscles might need a phase of relaxation and the question is whether you take that break in the sweetspot of the stroke or in the parts that are less efficient anyway.
 

frost

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Originally Posted by dominikk85 .

I think the problem is that the legs have a hard time being constantly contracted.
Haven't tried but I would imagine it'd become quite painful after say couple of hours /img/vbsmilies/smilies/rolleyes.gif
 

alienator

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n crowley said:
 I read it as a viewer who reads only Fergie's post. I believe in keeping things simple.(eg)  When seated you can't increase power output by trying to apply effective torque with both legs at the same time. All available pedalling research literature is based on variations of the basic natural pedalling style, all of them giving the same sinusoidal graph. What is there to be gained from reading that or from power output vs crank angle data when it should be obvious to most people that the more tangential the force you apply to the crank, the greater your torque will be. Am I missing something.?
Yes you are. You're missing how the biomechanics of the human body, specifically the leg and its parts, work with the bicycle. You are not turning pedals with 3 link mechanical system powered by an independent power source whose output can be ramped up as needed. It's certainly not as easy as just applying the maximal force normal to the crank.
 

fergie

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Originally Posted by n crowley .

That is a nonsensical statement because that is what you and all other cyclists do when pedalling, you pedal harder between 1 and 5 o'c, where do you lose the power when you increase the force?. Now I understand why you don't give advice on pedalling.
Coming from the 2nd biggest crackpot on the cycling forums that is highly amusing. I have always understood why people don't buy your unproven theory on pedalling.