New study shows leg flexion less efficient than extension.

[sciguy]

Re: New study shows leg flexion less efficient than extensio

Results: Metabolic cost for the four incremental stages was reduced by 1.2±0.1kcal/min (p<0.001) and efficiency was increased from 16.8±2.0% to 18.6±1.8% (p<0.001) when cycling with the counterweight system.

One more question I have regarding this. Why is his efficiency so low? 16.8% is at the very lowest of the cycling efficiency range I have ever seen reported. 18.6% is still very very low when the average cyclist is at an efficiency of 20% and some are 24-25%. I would be very interested in seeing what he is doing at the top and bottom also. Of course, the authors didn't bother to gather that information even though, I suspect, they had the capability to do so. Without information to allow us to understand what the muscles are doing I think such data is almost uninterpretable regarding underlying mechanisms to explain the results.

Frank,

As I understand it, the efficiencies reported in the abstract represent the average over the whole ramp. As you may or may not know, at lower power, cyclist's measured efficiencies will test lower due to the larger fraction of the total metabolic cost used to just stay alive rather than drive the pedals. At the higher end of the power ramp test the efficiency was 20% with the CW and 18.2% without. So there was still a 10% advantage for the extensor amplified regime.

Hugh

 

[CoachFergie]

I F**KING LOVE SCIENCE!!!!

 

[King Boonen]

Re: Re:

OMG Frank has unleashed the fury of caps lock, we're all in for it now.

How else could a person with one leg pedal but by applying force through the whole pedal stroke?

By the same magic that allows one leg on Gimmickcranks to influence the application of force on the other leg.

Pure fantasy.

Frank has now admitted that uncoupled cranks can't transfer power to the other crank.

He has also admitted that this study should show a decreased efficiency because the counterweight can't unweight like a normal two legged cyclist would.

Err... What? So after throwing out insults and talking BS he's now decided to completely change tack? Utterly ridiculous.

 

[JayKosta]

Re: Re:

...
How much, if any, is the improvement of pedalling circles over the standard use of coupled cranks with an emphasis on pushing down? How much energy is lost by the acceleration/deceleration of the crank?

--------
I don't know how much energy is used to compensate for the (minor) accel/decel of the cranks, but it is probably small.
However, in a competitive situation it might make a difference.
From a mechanical point of view, maintaining a constant speed is more efficient than having continual acel/decel that produces the same average speed.

Jay Kosta
Endwell NY USA

 

[JayKosta]

Re: Re:

...
7 years of immersion training in circular pedalling is less efficient and more metabolically costly than riding one legged with a counterweight.

The counter weight acts in the same way as a normal leg.

We saw this in practice with Para riders who all went slower when the rule changed that barred the use of a prosthesis.

Pretty frigging simple, circular pedalling is less efficient and more metabolically costly than mashing.

--------------------------------------
Is it your opinion that use of the counterweight REDUCED the degree of this rider's doing circular pedaling?
I.e., is it your opinion that his technique with the counterweight became more like 'mashing' than circular pedaling?

Also, I'd like to know more about what happened with the Para riders.
What was the before & after situations?
Were they ever allowed to used counterweights?
Was the type of allowable prosthesis changed?
Was there some other accomodation made if/when prosthesis were prohibited?

Jay Kosta
Endwell NY USA

 

[FrankDay]

Re:

You are amazing Frank. You have absolutely zero connection to reality.

You spent a dozen posts arguing that uncoupled cranks transfer power. Now you make it seem like we are the ones who finally understand how it works, when it was you that had no clue.

Show me a single post where I stated that uncoupled cranks can transfer power.

We coined a term for my brother, aggressively incorrect. The more wrong you are, the more you fight back and spin all manner of lies and insults to try and get out without admitting that you're wrong.

LOL.

 

[JamesCun]

Re: Re:

You are amazing Frank. You have absolutely zero connection to reality.

You spent a dozen posts arguing that uncoupled cranks transfer power. Now you make it seem like we are the ones who finally understand how it works, when it was you that had no clue.

Show me a single post where I stated that uncoupled cranks can transfer power.

We coined a term for my brother, aggressively incorrect. The more wrong you are, the more you fight back and spin all manner of lies and insults to try and get out without admitting that you're wrong.

LOL.

"Nope, when riding PowerCranks the opposite leg acts as the counterweight. PowerCranks is nothing more than counterweighted single legged pedaling both legs at the same time. "

viewtopic.php?p=1709167#p1709167

 

[FrankDay]

Re: Re:

You are amazing Frank. You have absolutely zero connection to reality.

You spent a dozen posts arguing that uncoupled cranks transfer power. Now you make it seem like we are the ones who finally understand how it works, when it was you that had no clue.

Show me a single post where I stated that uncoupled cranks can transfer power.

We coined a term for my brother, aggressively incorrect. The more wrong you are, the more you fight back and spin all manner of lies and insults to try and get out without admitting that you're wrong.

LOL.

"Nope, when riding PowerCranks the opposite leg acts as the counterweight. PowerCranks is nothing more than counterweighted single legged pedaling both legs at the same time. "

viewtopic.php?p=1709167#p1709167

Nothing says anything about an energy transfer in that statement. Because the driving force with PowerCranks is always positive, the counterweight driving force will always go to the wheel, not to the other crank. That is the case whether the cranks are coupled or uncoupled as long as there is a positive force on the pedals around the entire circle. What is different is the rider doesn't have to push harder (as he does with single legged counter weighted pedaling) because there is no need to push the counterweight up because it (the other leg weight) is actively pulled up by the contralateral muscles. With PowerCranks riding all of the muscle work goes to driving the bicycle and none is wasted pushing the other leg up and over the top.

 

[FrankDay]

Re: Re:

...
7 years of immersion training in circular pedalling is less efficient and more metabolically costly than riding one legged with a counterweight.

The counter weight acts in the same way as a normal leg.

We saw this in practice with Para riders who all went slower when the rule changed that barred the use of a prosthesis.

Pretty frigging simple, circular pedalling is less efficient and more metabolically costly than mashing.

--------------------------------------
Is it your opinion that use of the counterweight REDUCED the degree of this rider's doing circular pedaling?
I.e., is it your opinion that his technique with the counterweight became more like 'mashing' than circular pedaling?

Also, I'd like to know more about what happened with the Para riders.
What was the before & after situations?
Were they ever allowed to used counterweights?
Was the type of allowable prosthesis changed?
Was there some other accomodation made if/when prosthesis were prohibited?

Jay Kosta
Endwell NY USA

Whatever his opinion in this regard is it is either a guess or an assumption because what the rider was actually doing wasn't measured (he points out again).

 

[FrankDay]

Re: New study shows leg flexion less efficient than extensio

Results: Metabolic cost for the four incremental stages was reduced by 1.2±0.1kcal/min (p<0.001) and efficiency was increased from 16.8±2.0% to 18.6±1.8% (p<0.001) when cycling with the counterweight system.

One more question I have regarding this. Why is his efficiency so low? 16.8% is at the very lowest of the cycling efficiency range I have ever seen reported. 18.6% is still very very low when the average cyclist is at an efficiency of 20% and some are 24-25%. I would be very interested in seeing what he is doing at the top and bottom also. Of course, the authors didn't bother to gather that information even though, I suspect, they had the capability to do so. Without information to allow us to understand what the muscles are doing I think such data is almost uninterpretable regarding underlying mechanisms to explain the results.

Frank,

As I understand it, the efficiencies reported in the abstract represent the average over the whole ramp. As you may or may not know, at lower power, cyclist's measured efficiencies will test lower due to the larger fraction of the total metabolic cost used to just stay alive rather than drive the pedals. At the higher end of the power ramp test the efficiency was 20% with the CW and 18.2% without. So there was still a 10% advantage for the extensor amplified regime.

Hugh

One more thing. I notice this is a poster presentation. I have no more information than is in this abstract. Where did you get this "I understand" stuff?

 

[JamesCun]

Re: Re:

Nothing says anything about an energy transfer in that statement. Because the driving force with PowerCranks is always positive, the counterweight driving force will always go to the wheel, not to the other crank. That is the case whether the cranks are coupled or uncoupled as long as there is a positive force on the pedals around the entire circle. What is different is the rider doesn't have to push harder (as he does with single legged counter weighted pedaling) because there is no need to push the counterweight up because it (the other leg weight) is actively pulled up by the contralateral muscles. With PowerCranks riding all of the muscle work goes to driving the bicycle and none is wasted pushing the other leg up and over the top.

It is shocking how dense you are. I have to assume that is on purpose because you can't really have those degrees you talk of if you were that dense.

There is no counterweight when you are using powercranks. With powercranks you are always required to maintain positive forces on the pedals...ie you must always lift the full weight of the leg. In a counterweighted situation, or with fixed cranks, you aren't required to lift the full weight of the leg since the power is transferred through the crank as one leg lowers the other raises.

You're initial premise has a fatal flaw, you feel that it saves energy to pull up on the leg rather than lifting it by pushing down on the other leg. You feel that it is wasted energy to use big powerful muscles to lift the leg vs lifting it with relatively weak muscles.

 

[sciguy]

Re: New study shows leg flexion less efficient than extensio

Results: Metabolic cost for the four incremental stages was reduced by 1.2±0.1kcal/min (p<0.001) and efficiency was increased from 16.8±2.0% to 18.6±1.8% (p<0.001) when cycling with the counterweight system.

One more question I have regarding this. Why is his efficiency so low? 16.8% is at the very lowest of the cycling efficiency range I have ever seen reported. 18.6% is still very very low when the average cyclist is at an efficiency of 20% and some are 24-25%. I would be very interested in seeing what he is doing at the top and bottom also. Of course, the authors didn't bother to gather that information even though, I suspect, they had the capability to do so. Without information to allow us to understand what the muscles are doing I think such data is almost uninterpretable regarding underlying mechanisms to explain the results.

Frank,

As I understand it, the efficiencies reported in the abstract represent the average over the whole ramp. As you may or may not know, at lower power, cyclist's measured efficiencies will test lower due to the larger fraction of the total metabolic cost used to just stay alive rather than drive the pedals. At the higher end of the power ramp test the efficiency was 20% with the CW and 18.2% without. So there was still a 10% advantage for the extensor amplified regime.

Hugh

One more thing. I notice this is a poster presentation. I have no more information than is in this abstract. Where did you get this "I understand" stuff?

I was able to communicate with one of the authors. Unlike you with the Dixon study where you saw fit to leave the details unexplored, I asked questions.

Hugh

 

[FrankDay]

Re: New study shows leg flexion less efficient than extensio

Results: Metabolic cost for the four incremental stages was reduced by 1.2±0.1kcal/min (p<0.001) and efficiency was increased from 16.8±2.0% to 18.6±1.8% (p<0.001) when cycling with the counterweight system.

One more question I have regarding this. Why is his efficiency so low? 16.8% is at the very lowest of the cycling efficiency range I have ever seen reported. 18.6% is still very very low when the average cyclist is at an efficiency of 20% and some are 24-25%. I would be very interested in seeing what he is doing at the top and bottom also. Of course, the authors didn't bother to gather that information even though, I suspect, they had the capability to do so. Without information to allow us to understand what the muscles are doing I think such data is almost uninterpretable regarding underlying mechanisms to explain the results.

Frank,

As I understand it, the efficiencies reported in the abstract represent the average over the whole ramp. As you may or may not know, at lower power, cyclist's measured efficiencies will test lower due to the larger fraction of the total metabolic cost used to just stay alive rather than drive the pedals. At the higher end of the power ramp test the efficiency was 20% with the CW and 18.2% without. So there was still a 10% advantage for the extensor amplified regime.

Hugh

One more thing. I notice this is a poster presentation. I have no more information than is in this abstract. Where did you get this "I understand" stuff?

I was able to communicate with one of the authors. Unlike you with the Dixon study where you saw fit to leave the details unexplored, I asked questions.

Hugh

Re: Dixon, I also asked questions and just like you I was unable to get any answers. Re: this study, since one of the authors posts here it would seem more useful if he would come here and give us all access to all of the data and discuss this study. But, alas, he leaves it up to you to transmit what you (or he) thinks pertinent while keeping the rest of us in the dark.

 

[JamesCun]

Re: New study shows leg flexion less efficient than extensio

One more thing. I notice this is a poster presentation. I have no more information than is in this abstract. Where did you get this "I understand" stuff?

I was able to communicate with one of the authors. Unlike you with the Dixon study where you saw fit to leave the details unexplored, I asked questions.

Hugh

Quite a weak attempt by Frank to discredit this, only to have it come back as egg on his face. He simply refuses to accept anything that fits outside of his sales pitch.

 

[JamesCun]

Re: New study shows leg flexion less efficient than extensio

Re: Dixon, I also asked questions and just like you I was unable to get any answers.

We got lots of answers from Hugh. He found out that many of your assumptions were flat out wrong and the 'study' was virtually worthless except to support the long understood fact that training works. We also found out that you made virtually zero effort in the last 5+ years to get any additional information. You obviously had no incentive, since with your incorrect assumptions it supported your sales pitch.

 

[FrankDay]

Re: Re:

Nothing says anything about an energy transfer in that statement. Because the driving force with PowerCranks is always positive, the counterweight driving force will always go to the wheel, not to the other crank. That is the case whether the cranks are coupled or uncoupled as long as there is a positive force on the pedals around the entire circle. What is different is the rider doesn't have to push harder (as he does with single legged counter weighted pedaling) because there is no need to push the counterweight up because it (the other leg weight) is actively pulled up by the contralateral muscles. With PowerCranks riding all of the muscle work goes to driving the bicycle and none is wasted pushing the other leg up and over the top.

It is shocking how dense you are. I have to assume that is on purpose because you can't really have those degrees you talk of if you were that dense.

There is no counterweight when you are using powercranks. With powercranks you are always required to maintain positive forces on the pedals...ie you must always lift the full weight of the leg. In a counterweighted situation, or with fixed cranks, you aren't required to lift the full weight of the leg since the power is transferred through the crank as one leg lowers the other raises.

Let me correct the above for you. In a counterweighted situation, or with fixed cranks, you aren't required to lift the full weight of the leg since the power can be transferred through the crank as one leg lowers the other raises. However, nothing prevents the rider from lifting the full weight of the leg in this situation where this portion of the stroke will behave identically.

You're initial premise has a fatal flaw, you feel that it saves energy to pull up on the leg rather than lifting it by pushing down on the other leg. You feel that it is wasted energy to use big powerful muscles to lift the leg vs lifting it with relatively weak muscles.

Well, it does seem to me a waste of energy to divert energy to simply get the other leg over the top when other muscles can do that job and all the pushing energy can be used to drive the bicycle.

One more question since you seem to think there is no counterweight when riding PowerCranks, why do you think the authors chose the counterweight they did? Why didn't they choose 5Kg, 25Kg 100Kg? Any thoughts there?

 

[JamesCun]

Re: Re:

Nothing says anything about an energy transfer in that statement. Because the driving force with PowerCranks is always positive, the counterweight driving force will always go to the wheel, not to the other crank. That is the case whether the cranks are coupled or uncoupled as long as there is a positive force on the pedals around the entire circle. What is different is the rider doesn't have to push harder (as he does with single legged counter weighted pedaling) because there is no need to push the counterweight up because it (the other leg weight) is actively pulled up by the contralateral muscles. With PowerCranks riding all of the muscle work goes to driving the bicycle and none is wasted pushing the other leg up and over the top.

It is shocking how dense you are. I have to assume that is on purpose because you can't really have those degrees you talk of if you were that dense.

There is no counterweight when you are using powercranks. With powercranks you are always required to maintain positive forces on the pedals...ie you must always lift the full weight of the leg. In a counterweighted situation, or with fixed cranks, you aren't required to lift the full weight of the leg since the power is transferred through the crank as one leg lowers the other raises.

Let me correct the above for you. In a counterweighted situation, or with fixed cranks, you aren't required to lift the full weight of the leg since the power is transferred through the crank as one leg lowers the other raises. IRRELEVANT DIVERSION DELETED.

You're initial premise has a fatal flaw, you feel that it saves energy to pull up on the leg rather than lifting it by pushing down on the other leg. You feel that it is wasted energy to use big powerful muscles to lift the leg vs lifting it with relatively weak muscles.

Well, it does seem to me a waste of energy to divert energy to simply get the other leg over the top when other muscles can do that job and all the pushing energy can be used to drive the bicycle.

Frank, fixed you error. Please don't waste our time with pointless diversions.

How does the counterweight in an elevator work, or in a lift bridge? One goes up, the other goes down. They are always connected as one system and have a direct transfer of energy. Please explain how anything involving powercranks can look the same as that counterweight example???

With powercranks, you must always lift 100% of the weight of the leg, the other crank can offer no assistance in this movement.

 

[acoggan]

Re: Re:

One more question since you seem to think there is no counterweight when riding PowerCranks, why do you think the authors chose the counterweight they did? Why didn't they choose 5Kg, 25Kg 100Kg? Any thoughts there?

You're confusing "counterweight" with plain ol' "weight".

 

[acoggan]

Re: New study shows leg flexion less efficient than extensio

Re: this study, since one of the authors posts here it would seem more useful if he would come here and give us all access to all of the data and discuss this study.

I suspect that Jim is just sitting on the sidelines laughing his ass off...

 

[JayKosta]

Re: New study shows leg flexion less efficient than extensio

...
I suspect that Jim is just sitting on the sidelines laughing his ass off...

----------
Quite likely !

My guess is that he is thinking -

"This was a simple little 'educational exercise' to construct a test that would give a simple answer to the question of whether using a counterweight has any effect. We didn't bother to collect power distribution data because we knew it would just complicate the analysis and would make it more difficult to arrive at an easy to understand answer.
And all these guys are trying to glean meaning out of vapor in order to draw conclusions about things we never intended to investigate -- ha ha ha !"

Jay Kosta
Endwell NY USA

 

[FrankDay]

Re: New study shows leg flexion less efficient than extensio

Re: this study, since one of the authors posts here it would seem more useful if he would come here and give us all access to all of the data and discuss this study.

I suspect that Jim is just sitting on the sidelines laughing his ass off...

or not. My guess is he knows this study is purdy worthless for what he hoped to "prove". If he thought it really useful and not just a bunch of assumptions he would be here correcting my misconceptions. Instead, he has minions acting on his behalf.

 

[acoggan]

Re: New study shows leg flexion less efficient than extensio

We didn't bother to collect power distribution data because we knew it would just complicate the analysis and would make it more difficult to arrive at an easy to understand answer.

Jim told me about the study a while back. I don't remember whether he mentioned collecting inverse dynamics data or not, but I don't know why he wouldn't.

Regardless, the fact that it's not in the abstract says nothing. It could be that data hadn't been analyzed at the time the abstract was written and submitted, and/or it could be that they couldn't squeeze it in.

 

[JamesCun]

Re: New study shows leg flexion less efficient than extensio

Re: this study, since one of the authors posts here it would seem more useful if he would come here and give us all access to all of the data and discuss this study.

I suspect that Jim is just sitting on the sidelines laughing his ass off...

or not. My guess is he knows this study is purdy worthless for what he hoped to "prove". If he thought it really useful and not just a bunch of assumptions he would be here correcting my misconceptions. Instead, he has minions acting on his behalf.

Frank, you have taken to attacking others and avoiding the glaring errors in your previous comments.

Here is the question again: How does the counterweight in an elevator work, or in a lift bridge? One goes up, the other goes down. They are always connected as one system and have a direct transfer of energy. Please explain how anything involving powercranks can look the same as that counterweight example???

 

[acoggan]

Re: New study shows leg flexion less efficient than extensio

My guess is he knows this study is purdy worthless for what he hoped to "prove". If he thought it really useful and not just a bunch of assumptions he would be here correcting my misconceptions.

Yes, because Jim's raison d' etre in life is correcting your numerous misconceptions.

 

[FrankDay]

Re: New study shows leg flexion less efficient than extensio

We didn't bother to collect power distribution data because we knew it would just complicate the analysis and would make it more difficult to arrive at an easy to understand answer.

Jim told me about the study a while back. I don't remember whether he mentioned collecting inverse dynamics data or not, but I don't know why he wouldn't.

Regardless, the fact that it's not in the abstract says nothing. It could be that data hadn't been analyzed at the time the abstract was written and submitted, and/or it could be that they couldn't squeeze it in.

Without the entire study what he did or didn't do is all supposition except for what is in the abstract. This is also the case for Dixon. I don't care what he told you, myself (and the rest of the world) only have the abstract to go by here. You are accepting of his findings and so am I. Where we differ is in what those findings mean. Similar case with Dixon, wouldn't you say. There is one difference though, Martin posts here. Dixon (nor any of the other authors) do as far as I know, do not. Martin should be here explaining what he did and what he found (or giving us a link to the submitted paper). He is not.