New study shows leg flexion less efficient than extension.

[CoachFergie]

Re: Re:

Isn't this your basic premise in promoting Powercranks???????????????????? You're forcing athletes to do single legged pedaling albeit both at the same time.

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Yes, interesting observation.
In the test described, the counterweight acted somewhat similar to a full-sized other leg that produced no power and had no drag.
So, for a rider who is (supposedly) skilled in one-leg-pedaling, having a non-productive 'other leg' might also give the observed increase in efficiency.

I don't think it is too much of a 'leap' to suppose that if both legs are similarly skilled in one-leg-pedaling that the combined effect of both legs being used would be even more beneficial.

Jay Kosta
Endwell NY USA

Having worked with Para cyclists there is a distinction between amputation above and below the knee. For above the knee they are not allowed to use a prosthesis and must use a pod to support the stump otherwise those with an amputation high on the leg would be at a disadvantage and those who could ride with a prosthesis could counter weight the leg to balance. As we see in this case study there is a clear advantage to doing this.

Are you sure of those conclusions Jay. Someone trained in single leg, 7 years of immersion training, one leg pedalling reduced metabolic cost and improved efficiency pedalling with a counter weight on the other side in much the same way as everyone else does.

Frank himself has said that after a period of immersion training on Gimmickcranks going back to regular cranks harms their performance. Here we have real, not doctored, data showing a rider who is forced to pedal in a complete circle making instant gains. Be interesting to see the progress they would make training like this for a period of time. Expect that would bring the efficiency back up to what we would normally expect. Also have to go back and look at the efficiency of able-bodied subjects in Jim's first studies with counter weighted pedalling. For Para would be pointless as they have to compete without a counter weight. In much the same way it is pointless to train with a Gimmickcrank when you have to compete on coupled cranks.

We use this with riders to help them maintain riding fitness while they have leg injuries.

 

[CoachFergie]

A Masters Thesis looking at training singled legged with a Counterweight...

http://oatd.org/oatd/record?record=oai%5C%3Aetheses.bham.ac.uk%5C%3A1657

Elmer et al 2013

http://link.springer.com/article/10.1007%2Fs00421-012-2455-0

 

[CoachFergie]

Goes to show that Coyle was right all along in 1991, not with Lance, but can't win em all, and mashing down is the way to go.

Pretty clear data showing that 7 years of immersion training in pedalling in a circle is less efficient and more metabolic costly than counter weighted pedalling. Goes to show that immersion training is only of benefit if it is in the most efficient manner or in the manner with which the athlete has to perform. Pretty much what 100 or so years of sport and exercise science has been telling us all along!

I F**KING LOVE SCIENCE!!!

 

[King Boonen]

Re: Re:

I don't get this. You weight the non-leg pedal and efficiency increases? Surely this is obvious? It doesn't mean that pulling has a negative impact, just that aiding that pulling with a counterweight increases efficiency. Am I missing something?

I assumed the study is trying to test the idea of pushing only vs pedalling circles. Since they have a built in control with a single leg rider, they can add dead weight to see what impact that has. Frank always talks about the negative forces on the upstroke being something you want to eliminate. This is an attempt to see if that theory bears any weight.

Sorry for the late reply, internet is broken at home.

I don't really see how the study actually tests that though. All it seems to show is that assisting the upstroke of single leg pedalling results in increased efficiency, even with the increased cost of moving the weight on the down stroke, which seems obvious. This doesn't negate pulling up from what I can see, just that increasing force on the down stroke is much more beneficial.

I keep away from discussing Frank's theories as much as possible...

 

[JamesCun]

Re: Re:

I don't get this. You weight the non-leg pedal and efficiency increases? Surely this is obvious? It doesn't mean that pulling has a negative impact, just that aiding that pulling with a counterweight increases efficiency. Am I missing something?

I assumed the study is trying to test the idea of pushing only vs pedalling circles. Since they have a built in control with a single leg rider, they can add dead weight to see what impact that has. Frank always talks about the negative forces on the upstroke being something you want to eliminate. This is an attempt to see if that theory bears any weight.

Sorry for the late reply, internet is broken at home.

I don't really see how the study actually tests that though. All it seems to show is that assisting the upstroke of single leg pedalling results in increased efficiency, even with the increased cost of moving the weight on the down stroke, which seems obvious. This doesn't negate pulling up from what I can see, just that increasing force on the down stroke is much more beneficial.

I keep away from discussing Frank's theories as much as possible...

This is a much better explanation by Alex.

"The addition of the counterweight means that a proportion of the work done during a revolution is shifted from the single leg upstroke to the downstroke, i.e. the downstroke has to work harder to lift the counterweight to the same tune that the upstroke is given a reprieve by the counterweight dropping but the net work per revolution is the same.

Same net work per rev but efficiency much higher when the per rev work is moved from upstroke muscles to downstroke muscles. This for an athlete extremely well conditioned to pulling up during pedalling."

 

[King Boonen]

Re: Re:

I don't get this. You weight the non-leg pedal and efficiency increases? Surely this is obvious? It doesn't mean that pulling has a negative impact, just that aiding that pulling with a counterweight increases efficiency. Am I missing something?

I assumed the study is trying to test the idea of pushing only vs pedalling circles. Since they have a built in control with a single leg rider, they can add dead weight to see what impact that has. Frank always talks about the negative forces on the upstroke being something you want to eliminate. This is an attempt to see if that theory bears any weight.

Sorry for the late reply, internet is broken at home.

I don't really see how the study actually tests that though. All it seems to show is that assisting the upstroke of single leg pedalling results in increased efficiency, even with the increased cost of moving the weight on the down stroke, which seems obvious. This doesn't negate pulling up from what I can see, just that increasing force on the down stroke is much more beneficial.

I keep away from discussing Frank's theories as much as possible...

This is a much better explanation by Alex.

"The addition of the counterweight means that a proportion of the work done during a revolution is shifted from the single leg upstroke to the downstroke, i.e. the downstroke has to work harder to lift the counterweight to the same tune that the upstroke is given a reprieve by the counterweight dropping but the net work per revolution is the same.

Same net work per rev but efficiency much higher when the per rev work is moved from upstroke muscles to downstroke muscles. This for an athlete extremely well conditioned to pulling up during pedalling."

Thanks, I get that and totally agree that aiding the upstroke will have a bigger effect, but I still don't think it discounts the effect of pulling up unless they have telemetry data to show normalised power in the upstroke is altered. Basically his pulling movement has been aided, it's not surprising this has a net positive gain, but doesn't mean the pulling up isn't significant (for clarity I don't think it is).

 

[JamesCun]

King Boonen, for the same power output less energy is used when the counterweight is attached. Aiding the upstroke with the counterweight reduced the energy needed to maintain the same power output. What telemetry data would you need to show something different?

 

[King Boonen]

I get that, I'm not contesting it. My contention is that just because the overall efficiency is massively skewed towards the downstroke, that doesn't mean pulling up has no effect (I don't think it does but this doesn't prove it). My contention is that in the first post sciguy implies that this study shows pedalling circles is nonsense but based on the data we have it can't show that.

Now, if you normalise power to take into account the added assistance of the counterweight and have readings from around the whole pedal stroke, that would show if there was a real reduction in pulling forces while still maintaining the same power. This would show that upstroke pulling had negligible influence.

At least, that's how my brain is trying to work it out...

 

[JamesCun]

Re:

Now, if you normalise power to take into account the added assistance of the counterweight and have readings from around the whole pedal stroke, that would show if there was a real reduction in pulling forces while still maintaining the same power. This would show that upstroke pulling had negligible influence.

What do you mean by the bolded part?

Are you suggesting that even though more force is required on the downstroke to lift the weighted 'leg' that the upstroke still had the same amount of pulling forces and somehow that equals out to the same power output as before?

 

[King Boonen]

Re: Re:

Now, if you normalise power to take into account the added assistance of the counterweight and have readings from around the whole pedal stroke, that would show if there was a real reduction in pulling forces while still maintaining the same power. This would show that upstroke pulling had negligible influence.

What do you mean by the bolded part?

Are you suggesting that even though more force is required on the downstroke to lift the weighted 'leg' that the upstroke still had the same amount of pulling forces and somehow that equals out to the same power output as before?

No, I'm saying less upward force will be required to maintain power due to the counterweight, so you would need to normalise for this as some reduction in pulling force would be expected. If this was done I would still expect the reduction in upwards force to be significant and this would indicate it's effect is negligible, but this needs to be measured.

 

[FrankDay]

Re: Re:

I don't get this. You weight the non-leg pedal and efficiency increases? Surely this is obvious? It doesn't mean that pulling has a negative impact, just that aiding that pulling with a counterweight increases efficiency. Am I missing something?

I assumed the study is trying to test the idea of pushing only vs pedalling circles. Since they have a built in control with a single leg rider, they can add dead weight to see what impact that has. Frank always talks about the negative forces on the upstroke being something you want to eliminate. This is an attempt to see if that theory bears any weight.

Sorry for the late reply, internet is broken at home.

I don't really see how the study actually tests that though. All it seems to show is that assisting the upstroke of single leg pedalling results in increased efficiency, even with the increased cost of moving the weight on the down stroke, which seems obvious. This doesn't negate pulling up from what I can see, just that increasing force on the down stroke is much more beneficial.

I keep away from discussing Frank's theories as much as possible...

James (and some others) seem to think that just adding a counterweight suddenly means that this cyclist, who has been pedaling 1 legged for several years, suddenly stops doing anything on the upstroke reverts to just relaxing and does all the work on the downstroke. While I suppose that might have occurred I would be surprised but, either way, BECAUSE THEY DIDN'T MEASURE PEDAL FORCES IT IS NOT POSSIBLE TO KNOW HOW HE CHANGED. My best guess is he was still pulling up on the backstroke, just not as vigorously. And, it is this better balance that is responsible for the efficiency improvement. But, because of the inadequate study design, it is not possible to answer the question from their data.

 

[JamesCun]

Re: Re:

...seem to think that just adding a counterweight suddenly means that this cyclist, who has been pedaling 1 legged for several years, suddenly stops doing anything on the upstroke reverts to just relaxing and does all the work on the downstroke. While I suppose that might have occurred I would be surprised but, either way, BECAUSE THEY DIDN'T MEASURE PEDAL FORCES IT IS NOT POSSIBLE TO KNOW HOW HE CHANGED. My best guess is he was still pulling up on the backstroke, just not as vigorously. And, it is this better balance that is responsible for the efficiency improvement...

Who said anything about there being no pulling up on the backstroke. Hyperbole much??

It is not better balance compared to having no counterweight, it is worse balance. More on the downstroke and less on the upstroke is not better balance, if we are looking at balance meaning the amount of force at any given time.

 

[FrankDay]

Re: Re:

...seem to think that just adding a counterweight suddenly means that this cyclist, who has been pedaling 1 legged for several years, suddenly stops doing anything on the upstroke reverts to just relaxing and does all the work on the downstroke. While I suppose that might have occurred I would be surprised but, either way, BECAUSE THEY DIDN'T MEASURE PEDAL FORCES IT IS NOT POSSIBLE TO KNOW HOW HE CHANGED. My best guess is he was still pulling up on the backstroke, just not as vigorously. And, it is this better balance that is responsible for the efficiency improvement...

Who said anything about there being no pulling up on the backstroke. Hyperbole much??

It is not better balance compared to having no counterweight, it is worse balance. More on the downstroke and less on the upstroke is not better balance, if we are looking at balance meaning the amount of force at any given time.

I guess you didn't pay much attention to my video where what is going on with pedal forces is explained. http://youtu.be/1KR5OO7AJcI The forces on the pedals have little relationship to what the muscles are doing. For instance, the counterweighted pedal has lots of forces on it yet that crank is doing zero total work. The better balance I refer to refers to better muscle balance. Better pedal force balance is meaningless and not worth worrying about.

 

[JamesCun]

Re: Re:

I guess you didn't pay much attention to my video where what is going on with pedal forces is explained...SPAM... The forces on the pedals have little relationship to what the muscles are doing. For instance, the counterweighted pedal has lots of forces on it yet that crank is doing zero total work. The better balance I refer to refers to better muscle balance. Better pedal force balance is meaningless and not worth worrying about.

Yes, better muscle balance without the counterweight. With the counterweight, the downstroke has more muscular work done and the upstroke has less, compared to the non-counterweighted trial.

Care to explain how more muscular activity on the downstroke and less on the upstroke is better balanced?

 

[sciguy]

Re: Re:

I guess you didn't pay much attention to my video where what is going on with pedal forces is explained...SPAM... The forces on the pedals have little relationship to what the muscles are doing. For instance, the counterweighted pedal has lots of forces on it yet that crank is doing zero total work. The better balance I refer to refers to better muscle balance. Better pedal force balance is meaningless and not worth worrying about.

Yes, better muscle balance without the counterweight. With the counterweight, the downstroke has more muscular work done and the upstroke has less, compared to the non-counterweighted trial.

Care to explain how more muscular activity on the downstroke and less on the upstroke is better balanced?

During my morning ride, I came to the conclusion that Frank must be envisioning the counterweight strapped on the pedal that's being powered as that's the only way I can see he might be so bollixed up.

Hugh

 

[CoachFergie]

Bad study Frank?

It's an excellent case study, some excellent work from Jim and his team.

Show some respect to people who actually do research rather than make up data, charts or video to support their pathetic marketing claims!

 

[JayKosta]

Re: Re:

...
Care to explain how more muscular activity on the downstroke and less on the upstroke is better balanced?

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My view of 'better balance of muscle usage' is adjusting the forces on the pedals so that the instantaneous rotational speed of the crank arms is constant (to avoid the extra force necessary for continual cyclic acceleration/deceleration of the cranks arms and the entire bicycle) - AND to provide the desired amounts of power and efficiency.

I don't see any need for the amount of 'muscle activity' or 'generated muscle force' to be 'balanced' in of itself.

As I understand it, the goal of 1-leg pedaling exercises is to improve the ability to 'pedal in circles', and to maintian a constant spindle rotational speed. Apparently the use of a counterweight makes that easier (more efficient).

Jay Kosta
Endwell NY USA

 

[JamesCun]

Re: Re:

...
Care to explain how more muscular activity on the downstroke and less on the upstroke is better balanced?

----------------------------------
My view of 'better balance of muscle usage' is adjusting the forces on the pedals so that the instantaneous rotational speed of the crank arms is constant (to avoid the extra force necessary for continual cyclic acceleration/deceleration of the cranks arms and the entire bicycle) - AND to provide the desired amounts of power and efficiency.

I don't see any need for the amount of 'muscle activity' or 'generated muscle force' to be 'balanced' in of itself.

As I understand it, the goal of 1-leg pedaling exercises is to improve the ability to 'pedal in circles', and to maintian a constant spindle rotational speed. Apparently the use of a counterweight makes that easier (more efficient).

Jay Kosta
Endwell NY USA

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?

 

[CoachFergie]

Re: Re:

My view of 'better balance of muscle usage' is adjusting the forces on the pedals so that the instantaneous rotational speed of the crank arms is constant (to avoid the extra force necessary for continual cyclic acceleration/deceleration of the cranks arms and the entire bicycle) - AND to provide the desired amounts of power and efficiency.

I don't see any need for the amount of 'muscle activity' or 'generated muscle force' to be 'balanced' in of itself.

As I understand it, the goal of 1-leg pedaling exercises is to improve the ability to 'pedal in circles', and to maintian a constant spindle rotational speed. Apparently the use of a counterweight makes that easier (more efficient).

Did you look at the study Hugh posted?

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.

 

[FrankDay]

Re: Re:

My view of 'better balance of muscle usage' is adjusting the forces on the pedals so that the instantaneous rotational speed of the crank arms is constant (to avoid the extra force necessary for continual cyclic acceleration/deceleration of the cranks arms and the entire bicycle) - AND to provide the desired amounts of power and efficiency.

I don't see any need for the amount of 'muscle activity' or 'generated muscle force' to be 'balanced' in of itself.

As I understand it, the goal of 1-leg pedaling exercises is to improve the ability to 'pedal in circles', and to maintian a constant spindle rotational speed. Apparently the use of a counterweight makes that easier (more efficient).

Did you look at the study Hugh posted?

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

I wouldn't call how this guy pedals the same as what I call circular pedaling. Of course, I am guessing here BECAUSE THEY DID NOT MEASURE HIS PEDAL FORCES SO NO ONE KNOWS HOW HE PEDALS NORMALLY NOR HOW HE CHANGED WITH THE COUNTERWEIGHT.

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

Not in the least. The counterweight makes things more "normal" on the upstroke but worse on the downstroke because normally most riders unweight 90-95% on the upstroke whereas the counterweight is unweighted ZERO.

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.

If you say so. All you have to do is show me that what he was doing in either case constituted circular pedaling in that the muscular work was distributed equally about the circle. Of course you can't BECAUSE THEY DID NOT MEASURE HIS PEDAL FORCES SO NO ONE KNOWS HOW HE PEDALS NORMALLY NOR HOW HE CHANGED WITH THE COUNTERWEIGHT. This is a worthless study for deciding anything about pedaling technique.

 

[CoachFergie]

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.

 

[JamesCun]

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.

 

[FrankDay]

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.

That is correct. That is the special power of them. Glad you finally seem to realize that. Of course, that doesn't mean they can't "help" each other. At any given power the more work one crank does the less work the other has to do.

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.

Huh? I have theorized that this might be a reason the efficiency of this cyclist was so low. Of course, without knowing what he was actually doing on those pedals everyone is guessing here!!! It is an awful study if one wants to learn anything about pedaling technique.

 

[JamesCun]

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.

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.

 

[twothirds]

Someone get Frank a shovel. He's REALLY digging in. Actually, get him a backhoe.