New study shows leg flexion less efficient than extension.

[acoggan]

Re: Re:

If people are near 100% unweighting at race effort, why is it so hard to adapt to PC and why do people need to use them 100% of the time for at least 6months to get any benefit?

(Quoting/replying to your post 'cause it's easier to drill down to the salient point.)

In his response to your question, Frank left out:

4) 'cause there's a big difference in what our legs have to do between simply unweighting the rising pedal to some degree when using coupled cranks and generating sufficient force/power to have it keep up with the contralateral leg when using uncoupled cranks. However, he can't admit that, because it would emphasize the enormous lack-of-specificity that results from using his product.

 

[acoggan]

Re: Re:

It was originally posted in this thread by a FrankDay...

That would be funny (in a tragic sort of way) if it were simply a mistake. I am sure, however, that the obfuscation is deliberate (which simply goes to show Frank's utter lack of character).

 

[acoggan]

Re: Re:

the evidence upon which I base by conclusions was posted here by Dr. Coggan.

Not to my recollection. (Not that it really matters, since it appears correct...I just don't wish to be inadvertently credited for somebody else's work.)

It was originally posted in this thread by a FrankDay...

For posterity:

viewtopic.php?p=1712616#p1712616

 

[sciguy]

In all fairness to Frank, the slide is one of Jim Martin's. If you inspect the image info you'll see this:

http://i1035.photobucket.com/albums/a434/jimmartin4/Slide4_zpsc2792b74.jpg

Jim originally posted it in the Powercrank thread.

viewtopic.php?p=1571712#p1571712

Hugh

 

[King Boonen]

Re: Re:

the evidence upon which I base by conclusions was posted here by Dr. Coggan.

Not to my recollection. (Not that it really matters, since it appears correct...I just don't wish to be inadvertently credited for somebody else's work.)

It was originally posted in this thread by a FrankDay...

For posterity:

viewtopic.php?p=1712616#p1712616

 

[CoachFergie]

Staggering that Frank thinks we have to disprove his made up claims.

 

[FrankDay]

Re: Re:

the evidence upon which I base by conclusions was posted here by Dr. Coggan.

Not to my recollection. (Not that it really matters, since it appears correct...I just don't wish to be inadvertently credited for somebody else's work.)

Yes, you are correct. My memory let me down. That graph was originally posted by Dr. Martin himself September 9, 2014 in the PowerCranks thread. http://forum.cyclingnews.com/viewto...ng+leg+flexion+is,+in+fact,+positive#p1571712 It seems to me that you posted the vector diagram of this data, although I can't find it for now (edit: found it in the pedaling technique thread: http://forum.cyclingnews.com/viewtopic.php?p=1639586#p1639586), which I think accounts for my confusion. BTW, SCIGUY posted the graph just a couple of posts earlier.

Sorry folks, I can't take credit for any of this work. It isn't my fault that this data, done by others, supports my case.

 

[sciguy]

Re: Re:

Sorry folks, I can't take credit for any of this work. It isn't my fault that this data, done by others, supports my case.

of self delusion??????????????????

So back to the study we're discussing here where we see that an elite athlete who was forced to use his leg flexor muscles in an extremely vigorous way for 7 years suddenly becomes much more efficient when forced to increase the use his extensor muscles in lieu the flexors. Gee whiz, that really makes me think using uncoupled cranks is a total waste of time.

Hugh

 

[acoggan]

Re: Re:

the evidence upon which I base by conclusions was posted here by Dr. Coggan.

Not to my recollection. (Not that it really matters, since it appears correct...I just don't wish to be inadvertently credited for somebody else's work.)

Yes, you are correct. My memory let me down. That graph was originally posted by Dr. Martin himself September 9, 2014 in the PowerCranks thread. http://forum.cyclingnews.com/viewto...ng+leg+flexion+is,+in+fact,+positive#p1571712 It seems to me that you posted the vector diagram of this data, although I can't find it for now (edit: found it in the pedaling technique thread: http://forum.cyclingnews.com/viewtopic.php?p=1639586#p1639586).

Still not entirely correct. The colored diagram is indeed Jim's data, but the "clock" diagram is the classic one from Jeff Broker.

 

[veganrob]

Re: Re:

There is no memory to refresh because you never knew this in the first place.

Thanks for the attempted insult Frank. Does it bother you when people you consider inferior can trip you up so easily?

That wasn't an insult, wasn't even intended to be an insult, simply a statement of what I believe to be a fact. All you need do to prove me wrong is state where it is that you "knew" that typical rider unweights about 90% but you just forgot where that information came from so you asked to be "refreshed" in that regard.

From my perspective, it is what I believe to be a reasonable guess...

I've quoted the relevant text in your post. Thanks for confirming that you have no real data to support that 90% number. Somewhat similar to the 40% efficiency that you talk about as another reason why changing pedaling technique can lead to such massive improvements in power.

So, we are all waiting for you (or anyone else like Dr. Coggan or Dr. Martin) to provide the data that shows that riders unweight some other lesser amount.

So, question for you. If people are near 100% unweighting at race effort, why is it so hard to adapt to PC and why do people need to use them 100% of the time for at least 6months to get any benefit?

There are several reasons. For instance:

1. The study that showed near 100% unweighting at race effort was done in national level riders. They are substantially better than our average customer. But, even they are not uniform in their ability in this area.

2. We don't have the details of that study in that we don't know if their technique was the same at the end of the ride as it was at the beginning. (Further, the technique of the group 2 riders had never been described before so there is also the question as to what was going on to explain this.) The issue with PowerCranks training is not, usually, being able to do the technique (that is pretty simple because, as we have demonstrated here, it is not that far from what they normally do) but, rather, one of endurance in muscles that are being asked to do a little more. It is like improving your marathon pace from 10 min/mile to 9:30 min/mile. It is just a little bit more effort but it may take months of work to achieve that ability. It is the endurance issue (and retraining the unconscious pattern so it stays even when one returns to regular cranks) that takes all the time.

3. Most of our customers are not currently elite level riders. Elite riders seem to adapt a lot faster than "average" riders.

All you guys have to do is to provide some evidence that my way of estimating how much the typical rider unweights is flawed. Of course, you won't be able to do that because such data simply doesn't exist.

Isn't the analogy of a marathoner improving his time with a little more effort be a cyclist just getting stronger and pushing harder on cranks?

 

[JayKosta]

Re: Re:

...
So back to the study we're discussing here where we see that an elite athlete who was forced to use his leg flexor muscles in an extremely vigorous way for 7 years suddenly becomes much more efficient when forced to increase the use his extensor muscles in lieu the flexors. Gee whiz, that really makes me think using uncoupled cranks is a total waste of time.

Hugh

--------------------------------------------------------------------
I look at it slightly differently -

The single-leg rider LEARNED/TRAINED to use the leg flexor muscles in that manner.
And he probably did that training to increase overall power and speed - with less regard about efficiency.

With the counterweight, it's not clear to what extent he had to increase the use (duration, placement, and force) of extensor muscles, because the data was not shown. And similarly, it is not known how the use of the flexor muscles changed.

My guess is that when doing non-counterweighted single-leg pedaling, the rider was producing much more power (and less efficiently) on the upstroke than would be required for 100% unweighting.

The efficiency improvement with use of a counterweight for single-leg pedaling does seem to indicate that this rider was able to improve efficiency by changing the distribution of power production by reducing the use of the flexors and increasing use of the extensors. And that seems to occur because without the counterweight, he is using the flexors to produce significant actual +power on the upstroke - a situation that isn't required with the counterweight or with two-leg pedaling. Which simply indicates that the efficiency of the flexors is reduced when they are used in a highly strenuous manner.

Can we agree that there is some level of leg flexor usage that is typically 'most beneficial' for two-leg pedaling?

Jay Kosta
Endwell NY USA

 

[FrankDay]

Re: Re:

So back to the study we're discussing here where we see that an elite athlete who was forced to use his leg flexor muscles in an extremely vigorous way for 7 years suddenly becomes much more efficient when forced to increase the use his extensor muscles in lieu the flexors. Gee whiz, that really makes me think using uncoupled cranks is a total waste of time.

Hugh

Really, total waste of time despite the last several pages of discussion on this topic? LOL

There are only a few problems with your analysis which have previously been pointed out but which you seemed to ignore.

1. In this study both conditions, the one legged pedaling condition and the counterweighted one-legged pedaling condition, resulted in pedaling efficiency substantially lower than the average bilateral pedaler. So, even though there is a substantial improvement in efficiency going from one legged (16.8%) to counterweighted one legged (18.6%) in this instance the best result is still substantially less than the typical bilateral rider sees (20%). both results are inferior to what we would expect to see if we also tested bilateral pedaling. This is not discussed and is being ignored by you folks who are wanting the result to support what you believe.

2. The author doesn't actually measure pedaling technique between the two methods so one is forced to assume what the real differences between the pedaling techniques are and how they compare to typical bilateral pedaling.

3. You people are still considering counterweighted single legged pedaling to replicate bilateral pedaling but as posted earlier in this thread http://forum.cyclingnews.com/viewtopic.php?p=1722203#p1722203] they are not. Yet, bilateral pedaling has even higher efficiency (20%), on average, than demonstrated by either tested condition here. This discrepancy needs to be explained if one hopes to understand what is going on here.

4. The title of this thread reads too much into these results. The author got it right because all this study showed is "A Counterweight Improves Efficiency for an Amputee Cyclist" Other than that, not much more can be taken from this study without a lot of inference and supposition. While it is possible to theorize why these results occurred it is left for other research to fully explain the findings.

5. Lots of other studies exist with seemingly different results. How does one explain Luttrell, who demonstrated an improvement in efficiency from 20 to 22% by seemingly changing pedaling technique (although, admittedly, he didn't measure technique either) that didn't involve one legged pedaling?

 

[FrankDay]

Re: Re:

Isn't the analogy of a marathoner improving his time with a little more effort be a cyclist just getting stronger and pushing harder on cranks?

The analogy applies to any endurance athlete/muscle. Improvement in aerobic capacity comes slowly. The better any particular muscle is the slower further improvement will come and the harder it will be to attain.

 

[sciguy]

Re: Re:

The efficiency improvement with use of a counterweight for single-leg pedaling does seem to indicate that this rider was able to improve efficiency by changing the distribution of power production by reducing the use of the flexors and increasing use of the extensors. .

I totally agree

Which simply indicates that the efficiency of the flexors is reduced when they are used in a highly strenuous manner.

Which is what Frank wants us to do.

Can we agree that there is some level of leg flexor usage that is typically 'most beneficial' for two-leg pedaling?

Yes I would, but would also contend that cyclists are all ready doing that amount without any specialized training.

 

[FrankDay]

Re: Re:

The efficiency improvement with use of a counterweight for single-leg pedaling does seem to indicate that this rider was able to improve efficiency by changing the distribution of power production by reducing the use of the flexors and increasing use of the extensors. .

I totally agree

Which simply indicates that the efficiency of the flexors is reduced when they are used in a highly strenuous manner.

Which is what Frank wants us to do.

Nope! What Frank wants you to do is to increase the use of those unweighting muscles slightly, to become more balanced when compared to the "pushing" muscles, a 10-20% increase but not "in a highly strenuous manner." Plus, I would like for people to do more over the top, to generate some power in the most underutilized portion of the stroke.

Can we agree that there is some level of leg flexor usage that is typically 'most beneficial' for two-leg pedaling?

Yes I would, but would also contend that cyclists are all ready doing that amount without any specialized training.

Yes, as I pointed out before, uncoupled pedaling is closer to what people already do on the backstroke than either one-legged pedaling or counterweighted one legged pedaling.http://www.sciencedirect.com/science/article/pii/S0021929099001001From this abstract.

There was no negative muscular crank torque generated at 60 rpm and negligible amounts at 75 and 90 rpm.

. Going from small or negligible negative work to zero negative work is not a huge "highly stenuous" change. Your problem is you simply do not understand what I am talking about so you make stuff up.

 

[JayKosta]

Re: Re:

Can we agree that there is some level of leg flexor usage that is typically 'most beneficial' for two-leg pedaling?

Yes I would, but would also contend that cyclists are all ready doing that amount without any specialized training.

----------------------------
I understand your view, but I think it's doubtful that the typical recreational cyclist, or beginning or low category racer, is doing (or training for) the optimal amount of flexor usage. I base this doubt on the amount of attention paid to training cyclists about optimal pedal cadence, body positioning for aerodynamics, nutritional concerns, power meter use for pacing, etc.

If we only look at high-level amateurs, elite cyclists, professionals, etc. - then possibly 'yes' they didn't need specialized training. Not because it's 'natural for everyone', but luckily for them it did come natural - and having that trait contributed to them advancing to become high performing cyclists. The cyclist who could have benefited from specialized training didn't receive it, so they were stuck at a lower performance level.

Jay Kosta
Endwell NY USA

 

[sciguy]

Re: Re:

Can we agree that there is some level of leg flexor usage that is typically 'most beneficial' for two-leg pedaling?

Yes I would, but would also contend that cyclists are all ready doing that amount without any specialized training.

----------------------------
I understand your view, but I think it's doubtful that the typical recreational cyclist, or beginning or low category racer, is doing (or training for) the optimal amount of flexor usage. I base this doubt on the amount of attention paid to training cyclists about optimal pedal cadence, body positioning for aerodynamics, nutritional concerns, power meter use for pacing, etc.

If we only look at high-level amateurs, elite cyclists, professionals, etc. - then possibly 'yes' they didn't need specialized training. Not because it's 'natural for everyone', but luckily for them it did come natural - and having that trait contributed to them advancing to become high performing cyclists. The cyclist who could have benefited from specialized training didn't receive it, so they were stuck at a lower performance level.

Jay Kosta
Endwell NY USA

Jay, how do you know they do it more than novices and if they actually do pull up slightly more than novices what makes you believe it comes naturally to them rather than just being acquired through cycling a few thousand kilometers?

One would think if the tendency to pull up did prove advantageous more elite riders would show it in spades and yet they don't.

 

[FrankDay]

Re: Re:

Which simply indicates that the efficiency of the flexors is reduced when they are used in a highly strenuous manner.

Which is what Frank wants us to do.

One more thought here. Here you are arguing that strenuous use of the hip flexors is inefficient when compared to stenuous use of the hip extenders (the pushing muscles), which counterweighted one legged pedaling forces the rider to do. But, both conditions show less efficiency than one would expect of a bilateral pedaler. Therefore, it can be argued from this data, that "stenuous use" of ANY MUSCLE is less than optimum from an efficiency viewpoint which makes perfect sense since STRENUOUS USE involves more of the less efficient fast-twitch fibers in the muscle. This goes to my argument that balanced use of all the muscles is the ideal we should be looking for. Is it better when pedaling to use one group, the pushers, at 80% of its capability while another group, the lifters, is at 40% for instance? I would argue that it would be best if all muscles involved in powering the bike were working at say 70% of their capability, if that were possible, which I believe it is. If the rider used their muscles this way it seems to me they should theoretically have both more power and more endurance, two qualities every racer craves.

 

[FrankDay]

Re: Re:

Can we agree that there is some level of leg flexor usage that is typically 'most beneficial' for two-leg pedaling?

Yes I would, but would also contend that cyclists are all ready doing that amount without any specialized training.

----------------------------
I understand your view, but I think it's doubtful that the typical recreational cyclist, or beginning or low category racer, is doing (or training for) the optimal amount of flexor usage. I base this doubt on the amount of attention paid to training cyclists about optimal pedal cadence, body positioning for aerodynamics, nutritional concerns, power meter use for pacing, etc.

If we only look at high-level amateurs, elite cyclists, professionals, etc. - then possibly 'yes' they didn't need specialized training. Not because it's 'natural for everyone', but luckily for them it did come natural - and having that trait contributed to them advancing to become high performing cyclists. The cyclist who could have benefited from specialized training didn't receive it, so they were stuck at a lower performance level.

Jay Kosta
Endwell NY USA

Jay, how do you know they do it more than novices and if they actually do pull up slightly more than novices what makes you believe it comes naturally to them rather than just being acquired through cycling a few thousand kilometers?

One would think if the tendency to pull up did prove advantageous more elite riders would show it in spades and yet they don't.

Ugh, Hugh, while that difference looks substantial to you statistically there was no difference between these groups in this area. Stop claiming there is. They both pedaled essentially the same except one group was more powerful. There were statistically significant differences between these groups though that could explain this difference. Group 1 had 3 years more training experience, a higher capillary density, and a higher percentage of type 1 slow twitch fibers.

 

[sciguy]

Re: Re:

One would think if the tendency to pull up did prove advantageous more elite riders would show it in spades and yet they don't.

Ugh, Hugh, while that difference looks substantial to you statistically there was no difference between these groups in this area. Stop claiming there is. They both pedaled essentially the same except one group was more powerful. There were statistically significant differences between these groups though that could explain this difference. Group 1 had 3 years more training experience, a higher capillary density, and a higher percentage of type 1 slow twitch fibers.[/quote]

Frank,

1. This is the slide of the two groups pedaling at the same power.
2. Are you saying that the Group 1 folks are pushing down harder and pulling up less hard because they had a higher capillary density and a higher percentage of type 1 slow twitch fibers? I would agree with your assertion that it's probably because they had 3 years more training experience that lead them to find the most efficient way to pedal

Hugh

 

[FrankDay]

Re: Re:

One would think if the tendency to pull up did prove advantageous more elite riders would show it in spades and yet they don't.

Ugh, Hugh, while that difference looks substantial to you statistically there was no difference between these groups in this area. Stop claiming there is. They both pedaled essentially the same except one group was more powerful. There were statistically significant differences between these groups though that could explain this difference. Group 1 had 3 years more training experience, a higher capillary density, and a higher percentage of type 1 slow twitch fibers.

Frank,

1. This is the slide of the two groups pedaling at the same power.
2. Are you saying that the Group 1 folks are pushing down harder and pulling up less hard because they had a higher capillary density and a higher percentage of type 1 slow twitch fibers? I would agree with your assertion that it's probably because they had 3 years more training experience that lead them to find the most efficient way to pedal

Hugh

Nope, not saying that. I am saying is that the difference you see can be explained due to random variation. There was a wide range in pedaling types in both groups which would make the standard deviation fairly large and difficult to achieve statistical significance with such low numbers. In the slower group there were even a couple of really bizarre pedaling types that are really hard to explain and are probably responsible for the small difference you do see and if they had divided the groups more realistically there would probably be almost zero difference. The whole reason to do a statistical analysis is to try to separate out random variation from real differences. In this case there isn't enough there to draw the conclusion the difference you see is real. But, that is what you are trying to do.

 

[JayKosta]

Re: Re:

...
I would agree with your assertion that it's probably because they had 3 years more training experience that lead them to find the most efficient way to pedal

Hugh

----------------------------------------------------
So it does take considerable training experience to find the most effective way?
If that's the case then perhaps some training/coaching about efficient pedaling would shorten the learning curve.

Jay Kosta
Endwell NY USA

 

[JamesCun]

Re: Re:

Which simply indicates that the efficiency of the flexors is reduced when they are used in a highly strenuous manner.

Which is what Frank wants us to do.

One more thought here. Here you are arguing that strenuous use of the hip flexors is inefficient when compared to stenuous use of the hip extenders (the pushing muscles), which counterweighted one legged pedaling forces the rider to do. But, both conditions show less efficiency than one would expect of a bilateral pedaler. Therefore, it can be argued from this data, that "stenuous use" of ANY MUSCLE is less than optimum from an efficiency viewpoint which makes perfect sense since STRENUOUS USE involves more of the less efficient fast-twitch fibers in the muscle. This goes to my argument that balanced use of all the muscles is the ideal we should be looking for. Is it better when pedaling to use one group, the pushers, at 80% of its capability while another group, the lifters, is at 40% for instance? I would argue that it would be best if all muscles involved in powering the bike were working at say 70% of their capability, if that were possible, which I believe it is. If the rider used their muscles this way it seems to me they should theoretically have both more power and more endurance, two qualities every racer craves.

Care to explain how anything you described would lead to more power AND more endurance? I can see it leading to more power and LESS endurance.

What does strenuous mean? At normal race outputs, all muscles are performing well below max values. You talk about the adaptation period where most riders get slower with PC, how is that possible if you are just slightly increasing the upstroke effort of muscles that are already unweighting the leg at 90%? If you aren't advocating 'strenuous' use of the flexor muscles, how can you possibly think that would result in a 40% increase in power, on AVERAGE.

 

[FrankDay]

Re: Re:

One would think if the tendency to pull up did prove advantageous more elite riders would show it in spades and yet they don't.

Ugh, Hugh, while that difference looks substantial to you statistically there was no difference between these groups in this area. Stop claiming there is. They both pedaled essentially the same except one group was more powerful. There were statistically significant differences between these groups though that could explain this difference. Group 1 had 3 years more training experience, a higher capillary density, and a higher percentage of type 1 slow twitch fibers.

Frank,

1. This is the slide of the two groups pedaling at the same power.
2. Are you saying that the Group 1 folks are pushing down harder and pulling up less hard because they had a higher capillary density and a higher percentage of type 1 slow twitch fibers? I would agree with your assertion that it's probably because they had 3 years more training experience that lead them to find the most efficient way to pedal

Hugh

I have been thinking about this a bit. There is another huge problem with this analysis. This is a total force graph but the total force graph involves 3 forces that have nothing to do with what the power and that vary substantially with cadence (and somewhat with the size of the rider). "Normalizing" is a misnomer here because they aren't normalizing the muscular/power effort even though they say they are. Further, this is a torque graph but torque is changed by cadence but they are normalizing to power. Then, the last thing, is their selection of the two groups. Their group selection is crazy if they wanted to compare the fast riders to the slow. The best break would have put 6 in the fast group and 9 in the slow. If that were the case the "pushing" difference shown in this graph between the groups is cut in half.

There is just so much wrong here but people will continue to look at this stuff and draw conclusions that aren't warranted.

 

[sciguy]

Re: Re:

...
I would agree with your assertion that it's probably because they had 3 years more training experience that lead them to find the most efficient way to pedal

Hugh

----------------------------------------------------
So it does take considerable training experience to find the most effective way?
If that's the case then perhaps some training/coaching about efficient pedaling would shorten the learning curve.

Jay Kosta
Endwell NY USA

Did you missed the ? I'd contend that it's very natural to "find" one's one efficient technique rather quickly with very little if any to gain via specific interventions into technique. The fact that a good number of very inexperienced cyclists exhibit efficiencies very close to the maximum conceivable of ~25% tells me that factors other than technique such as fiber composition are responsible for the variation one sees in cyclists GME.

Hugh