New study shows leg flexion less efficient than extension.

[sciguy]

Several pedaling technique studies done in the past have shown that cyclists become less efficient when they intentionally alter their peddling to increase the utilization of the flexor muscles of the leg. Even Frank Day the inventor and promoter of Powercranks who espouses the circular peddling technique recently admitted

Further, most see a drop in power the first 6 weeks or so (at least when on PowerCranks).

It's Frank's contention that previous pedaling technique studies have been flawed because they didn't last long enough for a full adaptation of the flexor muscles as well as reprogramming of the nervous system to fire the muscles with optimal timing.

Which brings us to the recent study carried out at the University of Utah, Salt Lake City, UT. In this study the metabolic cost and efficiency of an elite amputee cyclist was carefully measured both with and without the addition of a 25.5lb counterweight to the unused crank arm. Addition of the counterweight allowed energy to be stored from leg extension to be used utilized throughout the whole pedal cycle decreasing the demand for power from leg flexion. The upshot was that when using the counterweight system, the athlete was 10.7% more efficient than without.

So after 7 years of full immersion in the pedal circles technique, the cyclist still proved to be substantially more efficient when he was enabled to “just push harder”.

Here is the first author in action - https://www.flickr.com/photos/lacrepat/6270632877

Presentation Abstract             
 
Session:           B-41-Sports Equipment
            Wednesday, May 27, 2015, 1:00 PM - 6:00 PM
Presentation:   914 - A Counterweight Improves Efficiency for an Amputee Cyclist
Location:         Exhibit Hall F, Poster Board: 310
Pres. Time:      Wednesday, May 27, 2015, 2:00 PM - 3:30 PM
Category:        0402. Biomechanics and Neural Control of Movement - sport biomechanics
Keywords:      cycling; efficiency; amputee
Author(s):        Brett A. Weitzel1, Daniel S. Nelson1, Steven J. Elmer2, Jim C. Martin, FACSM1. 1The University of Utah, Salt Lake City, UT. 2Michigan Technological University, Houghton, MI. (Sponsor: Jim C. Martin, FACSM)
Abstract:         Cycling technique is steeped in cultural lore. One deeply held belief is that pedaling techniques which increase the pulling action (muscular leg flexion) will improve efficiency. In contrast, research indicates that cycling efficiency is reduced when cyclists increase leg flexion power. These previous studies used acute interventions that may not have allowed sufficient time to adapt to and refine the technique. Single-leg amputee cyclists must produce substantial leg flexion power to lift the leg and thus have likely optimized the pulling action. The cyclist who volunteered for this investigation is a 4 time U.S. National Champion in road and track events who has performed single-leg cycling for 7 years. Thus, he should have a fully adapted and refined pulling technique. Purpose: To evaluate the effect of a counterweight system, which reduces the requirement for muscular leg flexion, on the metabolic cost and efficiency of a single-leg amputee cyclist. Methods: The cyclist performed two incremental cycling trials (100W + 35W/5min); one with and one without an 11.6kg counterweight on the unused crank. Expired gasses were measured and data from the last minute of each stage were used to calculate metabolic cost and efficiency. Differences in metabolic cost and efficiency for the four stages were evaluated using separate paired Student’s t tests. 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. Conclusion: A counterweight system, which reduced the requirement for muscular leg flexion, decreased metabolic cost and increased efficiency even in this amputee single-leg cyclist who must pull up substantially during his normal cycling. The changes observed in this individual were similar to those observed during previous acute double- and single-leg interventions suggesting that previous results were not confounded by lack of practice. Rather, it appears that pulling up during cycling is inherently more metabolically costly and less efficient than pushing down. These data suggest that cyclists should not adopt pedaling techniques which increase the pulling action. Finally, a counterweight system may increase performance and enjoyment for amputee cyclists.
Disclosures:      B.A. Weitzel: None.



My thought is that this nicely bears out what so many of us have seen and thought all along. As Dave Luscan, an excellent time trialest recently said

"Pedaling" and "technique" should rarely be used together. "Pedaling technique" starts with a bike fit, including attention to all four planes of cleat alignment. Next you ride a lot. That's pretty much it.

Scraping mud, powering the upstroke and spinning perfect circles are all ideas mired in the myth and lore of cycling. Say it with me, "The bicycle IS the circle. We just push"

Let's save the LOLs for the 14 year old girls and self comparisons to Einstein for the megalomania forum.

Hugh

 

[King Boonen]

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?

 

[FrankDay]

Re: New study shows leg flexion less efficient than extensio

Several peddling technique studies done in the past have shown that cyclists become less efficient when they intentionally alter their peddling to increase the utilization of the flexor muscles of the leg. Even Frank Day the inventor and promoter of Powercranks who espouses the circular peddling technique recently admitted

Further, most see a drop in power the first 6 weeks or so (at least when on PowerCranks).

It's Frank's contention that previous peddling technique studies have been flawed because they didn't last long enough for a full adaptation of the flexor muscles as well as reprogramming of the nervous system to fire the muscles with optimal timing.

Which brings us to the recent study carried out at the University of Utah, Salt Lake City, UT. In this study the metabolic cost and efficiency of an elite amputee cyclist was carefully measured both with and without the addition of a 25.5lb counterweight to the unused crank arm. Addition of the counterweight allowed energy to be stored from leg extension to be used utilized throughout the whole pedal cycle decreasing the demand for power from leg flexion. The upshot was that when using the counterweight system, the athlete was 10.7% more efficient than without.

So after 7 years of full immersion in the pedal circles technique, the cyclist still proved to be substantially more efficient when he was enabled to “just push harder”.

Here is the first author in action - https://www.flickr.com/photos/lacrepat/6270632877

Presentation Abstract             
 
Session:           B-41-Sports Equipment
            Wednesday, May 27, 2015, 1:00 PM - 6:00 PM
Presentation:   914 - A Counterweight Improves Efficiency for an Amputee Cyclist
Location:         Exhibit Hall F, Poster Board: 310
Pres. Time:      Wednesday, May 27, 2015, 2:00 PM - 3:30 PM
Category:        0402. Biomechanics and Neural Control of Movement - sport biomechanics
Keywords:      cycling; efficiency; amputee
Author(s):        Brett A. Weitzel1, Daniel S. Nelson1, Steven J. Elmer2, Jim C. Martin, FACSM1. 1The University of Utah, Salt Lake City, UT. 2Michigan Technological University, Houghton, MI. (Sponsor: Jim C. Martin, FACSM)
Abstract:         Cycling technique is steeped in cultural lore. One deeply held belief is that pedaling techniques which increase the pulling action (muscular leg flexion) will improve efficiency. In contrast, research indicates that cycling efficiency is reduced when cyclists increase leg flexion power. These previous studies used acute interventions that may not have allowed sufficient time to adapt to and refine the technique. Single-leg amputee cyclists must produce substantial leg flexion power to lift the leg and thus have likely optimized the pulling action. The cyclist who volunteered for this investigation is a 4 time U.S. National Champion in road and track events who has performed single-leg cycling for 7 years. Thus, he should have a fully adapted and refined pulling technique. Purpose: To evaluate the effect of a counterweight system, which reduces the requirement for muscular leg flexion, on the metabolic cost and efficiency of a single-leg amputee cyclist. Methods: The cyclist performed two incremental cycling trials (100W + 35W/5min); one with and one without an 11.6kg counterweight on the unused crank. Expired gasses were measured and data from the last minute of each stage were used to calculate metabolic cost and efficiency. Differences in metabolic cost and efficiency for the four stages were evaluated using separate paired Student’s t tests. 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. Conclusion: A counterweight system, which reduced the requirement for muscular leg flexion, decreased metabolic cost and increased efficiency even in this amputee single-leg cyclist who must pull up substantially during his normal cycling. The changes observed in this individual were similar to those observed during previous acute double- and single-leg interventions suggesting that previous results were not confounded by lack of practice. Rather, it appears that pulling up during cycling is inherently more metabolically costly and less efficient than pushing down. These data suggest that cyclists should not adopt pedaling techniques which increase the pulling action. Finally, a counterweight system may increase performance and enjoyment for amputee cyclists.
Disclosures:      B.A. Weitzel: None.



My thought is that this nicely bears out what so many of us have seen and thought all along. As Dave Luscan, an excellent time trialest recently said

"Pedaling" and "technique" should rarely be used together. "Pedaling technique" starts with a bike fit, including attention to all four planes of cleat alignment. Next you ride a lot. That's pretty much it.

Scraping mud, powering the upstroke and spinning perfect circles are all ideas mired in the myth and lore of cycling. Say it with me, "The bicycle IS the circle. We just push"

Let's save the LOLs for the 14 year old girls and self comparisons to Einstein for the megalomania forum.

Hugh

LOL. I am not sure this study proves or disproves anything. Let me rephrase his conclusion to correspond more to my current belief. "A counterweight system, which better balanced the leg flexion and extension work done, decreased metabolic cost and increased efficiency even in this amputee single-leg cyclist who must pull up substantially during his normal cycling." Further, without actually measuring pedal forces during this test it is a matter of pure supposition as to how the cyclist changed his technique. And, without measuring pedal forces it is not possible to actually know how the actual muscle work was distributed differently between the two trials.

In my opinion it is the imbalance between the pushers and the pullers (doesn't matter which one is greater) that decreases efficiency. This study seems to reinforce that view. Thanks for that.

 

[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.

 

[JamesCun]

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.

 

[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.

The problem, of course, is it was a poor study design as pedal forces were not measured so one can only guess as to what changes occurred between the two conditions.

 

[JamesCun]

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.

Do you think it's possible that being forced to use the smaller muscles on the upstroke is a negative in terms of efficiency? Maybe having two legs and being able to recovery on one while the other is pushing is more efficient

 

[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.

Do you think it's possible that being forced to use the smaller muscles on the upstroke is a negative in terms of efficiency? Maybe having two legs and being able to recovery on one while the other is pushing is more efficient

It doesn't matter if one is using one leg or two, the "pushing muscles" recover on the upstroke regardless of whether the antagonist muscles are pulling a lot or a little. There are two muscles across a joint, when one is contracting the other is, usually, resting and recovering. And, it is debatable how much "smaller" the "pulling" muscles are.

 

[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.

The problem, of course, is it was a poor study design as pedal forces were not measured so one can only guess as to what changes occurred between the two conditions.

It still shows the output, which is a key component of racing faster

Interesting how any study that goes against your theories is flawed and any study that supports your theories is adequate. Bit of a double standard. You would have more credibility if you were more balanced in your judgements. Just a little tip.

 

[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.

The problem, of course, is it was a poor study design as pedal forces were not measured so one can only guess as to what changes occurred between the two conditions.

It still shows the output, which is a key component of racing faster

Interesting how any study that goes against your theories is flawed and any study that supports your theories is adequate. Bit of a double standard. You would have more credibility if you were more balanced in your judgements. Just a little tip.

This study is flawed whether it goes against my beliefs or not. They found a difference but they gathered no information (information that is relatively easy to obtain) that might allow them to explain the difference without guessing.

 

[JamesCun]

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.

Do you think it's possible that being forced to use the smaller muscles on the upstroke is a negative in terms of efficiency? Maybe having two legs and being able to recovery on one while the other is pushing is more efficient

It doesn't matter if one is using one leg or two, the "pushing muscles" recover on the upstroke regardless of whether the antagonist muscles are pulling a lot or a little. There are two muscles across a joint, when one is contracting the other is, usually, resting and recovering. And, it is debatable how much "smaller" the "pulling" muscles are.

I said legs. And it isn't debatable. The muscles that pull up, or work from 6-12 are smaller than the muscles that push down.

 

[Alex Simmons/RST]

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?

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.

 

[JamesCun]

Re: Re:

This study is flawed whether it goes against my beliefs or not. They found a difference but they gathered no information (information that is relatively easy to obtain) that might allow them to explain the difference without guessing.

If you say so...

I'd take this info over your Rodriquez 'data' any day of the week. At least we know the methods here and know that a reputable group did the study. There was a control and a valid comparison made. None of that is flawed. If you want to say that they are jumping to conclusions, that is fine, not sure you can back that up, but you can certainly make that claim.

 

[FrankDay]

Re: Re:

There was a control and a valid comparison made. None of that is flawed. If you want to say that they are jumping to conclusions, that is fine, not sure you can back that up, but you can certainly make that claim.

There was a control? Must have missed that. Perhaps you can point it out to me. The design looks a little bit like the Dixon study to me except the Dixon study involved 8 cyclists and not just one.

Anyhow, it isn't a claim. It is a fact. They demonstrated a difference. The only way they can come up with a mechanism to explain the difference is to make assumptions because they didn't collect the data to allow them to do anything more. They assumed he had optimized his stroke in 7 years. No one knows what an optimized stroke looks like but they assumed he had done so. Is an optimized stroke for single legged pedaling the same as the optimized stroke for two legged pedaling? No data to support that assumption that I know of. This study backs up my theory just as well as it does yours. It all depends upon what actually happened and NOBODY knows that.

 

[JamesCun]

Re: Re:

There was a control and a valid comparison made. None of that is flawed. If you want to say that they are jumping to conclusions, that is fine, not sure you can back that up, but you can certainly make that claim.

There was a control? Must have missed that. Perhaps you can point it out to me. The design looks a little bit like the Dixon study to me except the Dixon study involved 8 cyclists and not just one.

Anyhow, it isn't a claim. It is a fact. They demonstrated a difference. The only way they can come up with a mechanism to explain the difference is to make assumptions because they didn't collect the data to allow them to do anything more. They assumed he had optimized his stroke in 7 years. No one knows what an optimized stroke looks like but they assumed he had done so. Is an optimized stroke for single legged pedaling the same as the optimized stroke for two legged pedaling? No data to support that assumption that I know of. This study backs up my theory just as well as it does yours. It all depends upon what actually happened and NOBODY knows that.

LOL...this isn't even remotely close to the Dixon 'study'. The cyclist here acted as their own control. This wasn't a pre/post training intervention like the Dixon 'study'. It was the same as testing an aero helmet on a rider, one trial with helmet A and another with helmet B. Dixon would be like having all of the riders use helmet B and assuming that you knew the speed they would go with helmet A.

You can talk around in circles all day, but there is no way this backs up any theory that you have presented.

 

[sciguy]

Re: Re:

There was a control and a valid comparison made. None of that is flawed. If you want to say that they are jumping to conclusions, that is fine, not sure you can back that up, but you can certainly make that claim.

There was a control? Must have missed that. Perhaps you can point it out to me.

Please tell me you're joking that you don't see the control here.

The design looks a little bit like the Dixon study to me except the Dixon study involved 8 cyclists and not just one.

In the Dixon study the Powercrankers underwent several weeks of intense training and improved their fitness. No big surprise there to anyone who has done some interval training. The lack of control in that exercise was that there wasn't a second group of fixycrankers doing the same thing to see how much they would improve.

Is an optimized stroke for single legged pedaling the same as the optimized stroke for two legged pedaling? that.

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

 

[FrankDay]

Re: Re:

There was a control and a valid comparison made. None of that is flawed. If you want to say that they are jumping to conclusions, that is fine, not sure you can back that up, but you can certainly make that claim.

There was a control? Must have missed that. Perhaps you can point it out to me.

Please tell me you're joking that you don't see the control here.

It is the same control as Dixon used, the cyclists acted as their own controls. You have repeatedly denied that Dixon had controls so why do you accet this control? One question, how on earth did Dixon calculate probability values without a control?

The design looks a little bit like the Dixon study to me except the Dixon study involved 8 cyclists and not just one.

In the Dixon study the Powercrankers underwent several weeks of intense training and improved their fitness. No big surprise there to anyone who has done some interval training. The lack of control in that exercise was that there wasn't a second group of fixycrankers doing the same thing to see how much they would improve.

Is an optimized stroke for single legged pedaling the same as the optimized stroke for two legged pedaling? that.

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

Well, yes... counterweighted single legged pedaling, the optimum result here. Like I said, this study supports my thesis just as well as it does yours.

 

[JamesCun]

Frank, this would be covered in any first year university course. A 6 weeks intervention means the cyclists can't act as their own control. They can be pre/post results, but you aren't able to determine anything at all from those results. In this case, the intervention is immediate and reversible, like switching equipment. See my helmet example above...

 

[Alex Simmons/RST]

Re: Re:

Well, yes... counterweighted single legged pedaling, the optimum result here. Like I said, this study supports my thesis just as well as it does yours.

Frank, it wouldn't matter what evidence you were presented with. In your universe everything supports your beliefs, even when they clearly and directly contradict them. The level and consistency of cognitive dissonance you display is remarkable.

 

[sciguy]

Re: Re:

It is the same control as Dixon used, the cyclists acted as their own controls. You have repeatedly denied that Dixon had controls so why do you accet this control?

Well Frank if the Dixon experiment had been "does working intensely for 6 weeks improve fitness" then I would agree with you that the athletes could be their own controls. The fact that you have attempted to imply the intervention with Powercranks was superior to doing the same workouts without Powercranks makes changes the situation. In this case the subjects cannot act as their own controls.

One question, how on earth did Dixon calculate probability values without a control?

The probability calculated is that of the athletes showing that much improvement by random chance alone. Once again, with the hard training they did it's no surprise that the group showed improvement.

Have you actually communicated with any of the group members yet. I've been in contact with 3 of the 5 authors while you seem to have completely dropped the ball on follow up. Then again the details seem rather unimportant to you.

Is an optimized stroke for single legged pedaling the same as the optimized stroke for two legged pedaling? that.

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

Well, yes... counterweighted single legged pedaling, the optimum result here.

and yet counterweighted single leg peddling minimizes use of the leg flexors, transferring a large part of their workload to the leg extensors. When that was done efficiency was greatly improved.

Like I said, this study supports my thesis just as well as it does yours.

No it doesn't in the least and you've yet give a shred of evidence to the contrary.

 

[FrankDay]

Re: Re:

and yet counterweighted single leg peddling minimizes use of the leg flexors, transferring a large part of their workload to the leg extensors. When that was done efficiency was greatly improved.

Your quotes got out of whack on your last response. I will only respond to this.

You don't have a clue what counterweighted singled legged pedaling or what PowerCranks do for the rider. The counterweight only means that to get the leg up on the backstroke one only need to put in enough energy to increase the potential energy in the leg, that is, to fully unweight the pedal to maintain pedal speed. Isolated leg training requires putting much more force into the pedal on the backstroke to maintain pedal speed. They may look similar to the outside observer but they are horses of a completely different color. Riding PowerCranks is like riding counter balanced single legged riding as in this experiment (the weight of the other leg provides the counter balance). You are apparently speaking loudly about which you seeming know nothing. This study supports my thesis as well as, if not better than, yours. You can't understand that because you don't seem to understand anything I have been saying.

 

[JayKosta]

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.

------------------------
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

 

[CoachFergie]

Re: Re:

and yet counterweighted single leg peddling minimizes use of the leg flexors, transferring a large part of their workload to the leg extensors. When that was done efficiency was greatly improved.

Your quotes got out of whack on your last response. I will only respond to this.

You don't have a clue what counterweighted singled legged pedaling or what PowerCranks do for the rider. The counterweight only means that to get the leg up on the backstroke one only need to put in enough energy to increase the potential energy in the leg, that is, to fully unweight the pedal to maintain pedal speed. Isolated leg training requires putting much more force into the pedal on the backstroke to maintain pedal speed. They may look similar to the outside observer but they are horses of a completely different color. Riding PowerCranks is like riding counter balanced single legged riding as in this experiment (the weight of the other leg provides the counter balance). You are apparently speaking loudly about which you seeming know nothing. This study supports my thesis as well as, if not better than, yours. You can't understand that because you don't seem to understand anything I have been saying.

No, we understand the laws of physics quite well enough in this case.

Good luck finding people dumb enough to believe your snake oil salesmanship version of reality.

 

[CoachFergie]

Re: New study shows leg flexion less efficient than extensio

Several peddling technique studies done in the past have shown that cyclists become less efficient when they intentionally alter their peddling to increase the utilization of the flexor muscles of the leg. Even Frank Day the inventor and promoter of Powercranks who espouses the circular peddling technique recently admitted

Further, most see a drop in power the first 6 weeks or so (at least when on PowerCranks).

It's Frank's contention that previous peddling technique studies have been flawed because they didn't last long enough for a full adaptation of the flexor muscles as well as reprogramming of the nervous system to fire the muscles with optimal timing.

Which brings us to the recent study carried out at the University of Utah, Salt Lake City, UT. In this study the metabolic cost and efficiency of an elite amputee cyclist was carefully measured both with and without the addition of a 25.5lb counterweight to the unused crank arm. Addition of the counterweight allowed energy to be stored from leg extension to be used utilized throughout the whole pedal cycle decreasing the demand for power from leg flexion. The upshot was that when using the counterweight system, the athlete was 10.7% more efficient than without.

So after 7 years of full immersion in the pedal circles technique, the cyclist still proved to be substantially more efficient when he was enabled to “just push harder”.

Here is the first author in action - https://www.flickr.com/photos/lacrepat/6270632877

Presentation Abstract             
 
Session:           B-41-Sports Equipment
            Wednesday, May 27, 2015, 1:00 PM - 6:00 PM
Presentation:   914 - A Counterweight Improves Efficiency for an Amputee Cyclist
Location:         Exhibit Hall F, Poster Board: 310
Pres. Time:      Wednesday, May 27, 2015, 2:00 PM - 3:30 PM
Category:        0402. Biomechanics and Neural Control of Movement - sport biomechanics
Keywords:      cycling; efficiency; amputee
Author(s):        Brett A. Weitzel1, Daniel S. Nelson1, Steven J. Elmer2, Jim C. Martin, FACSM1. 1The University of Utah, Salt Lake City, UT. 2Michigan Technological University, Houghton, MI. (Sponsor: Jim C. Martin, FACSM)
Abstract:         Cycling technique is steeped in cultural lore. One deeply held belief is that pedaling techniques which increase the pulling action (muscular leg flexion) will improve efficiency. In contrast, research indicates that cycling efficiency is reduced when cyclists increase leg flexion power. These previous studies used acute interventions that may not have allowed sufficient time to adapt to and refine the technique. Single-leg amputee cyclists must produce substantial leg flexion power to lift the leg and thus have likely optimized the pulling action. The cyclist who volunteered for this investigation is a 4 time U.S. National Champion in road and track events who has performed single-leg cycling for 7 years. Thus, he should have a fully adapted and refined pulling technique. Purpose: To evaluate the effect of a counterweight system, which reduces the requirement for muscular leg flexion, on the metabolic cost and efficiency of a single-leg amputee cyclist. Methods: The cyclist performed two incremental cycling trials (100W + 35W/5min); one with and one without an 11.6kg counterweight on the unused crank. Expired gasses were measured and data from the last minute of each stage were used to calculate metabolic cost and efficiency. Differences in metabolic cost and efficiency for the four stages were evaluated using separate paired Student’s t tests. 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. Conclusion: A counterweight system, which reduced the requirement for muscular leg flexion, decreased metabolic cost and increased efficiency even in this amputee single-leg cyclist who must pull up substantially during his normal cycling. The changes observed in this individual were similar to those observed during previous acute double- and single-leg interventions suggesting that previous results were not confounded by lack of practice. Rather, it appears that pulling up during cycling is inherently more metabolically costly and less efficient than pushing down. These data suggest that cyclists should not adopt pedaling techniques which increase the pulling action. Finally, a counterweight system may increase performance and enjoyment for amputee cyclists.
Disclosures:      B.A. Weitzel: None.



My thought is that this nicely bears out what so many of us have seen and thought all along. As Dave Luscan, an excellent time trialest recently said

"Pedaling" and "technique" should rarely be used together. "Pedaling technique" starts with a bike fit, including attention to all four planes of cleat alignment. Next you ride a lot. That's pretty much it.

Scraping mud, powering the upstroke and spinning perfect circles are all ideas mired in the myth and lore of cycling. Say it with me, "The bicycle IS the circle. We just push"

Let's save the LOLs for the 14 year old girls and self comparisons to Einstein for the megalomania forum.

Hugh

What an excellent case study. Well done Jim Martin and your team. Hopefully you can put together a study with more subjects to confirm the generalizability of this data, but in this subject it clearly shows what those of us, who don't have a product to sell, and have foregone the lure of marketing special pedalling technique coaching revenues, have been trying to say all along.

Sport Science 1 : Bullswaste Marketers 0!!!

 

[JamesCun]

Re: Re:

and yet counterweighted single leg peddling minimizes use of the leg flexors, transferring a large part of their workload to the leg extensors. When that was done efficiency was greatly improved.

Your quotes got out of whack on your last response. I will only respond to this.

You don't have a clue what counterweighted singled legged pedaling or what PowerCranks do for the rider. The counterweight only means that to get the leg up on the backstroke one only need to put in enough energy to increase the potential energy in the leg, that is, to fully unweight the pedal to maintain pedal speed. Isolated leg training requires putting much more force into the pedal on the backstroke to maintain pedal speed. They may look similar to the outside observer but they are horses of a completely different color. Riding PowerCranks is like riding counter balanced single legged riding as in this experiment (the weight of the other leg provides the counter balance). You are apparently speaking loudly about which you seeming know nothing. This study supports my thesis as well as, if not better than, yours. You can't understand that because you don't seem to understand anything I have been saying.

No, we understand the laws of physics quite well enough in this case.

Good luck finding people dumb enough to believe your snake oil salesmanship version of reality.

Haha. Frank has really gone for it now. Rewriting exercise physiology, physics and a number of other fields. Somehow a leg that is attached to an uncoupled crank provides a counterweight. Amazing twist of physics there.