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PostPosted: Thu Dec 22, 2011 5:20 pm 
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You've only got half a brain, so doing the rest makes sense

Fortunately, studies show that even with my half a brain I produce over seven times the reasoning power per kilogram than you.

:lol:

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Looks like Rick is sold to the pedal based system,...

Not at all.
In fact, if you review the evolution of the thread, you will see that I am not really sold on the pedal based power system. I just don't summarily dismiss it without considering that some people (not necessarilly you or me....certainly not tapeworm) might find it interesting and useful.
I think people started assuming I was defending the pedal-based system. I am not. I am arguing there may be someting to learn from it. Maybe it will be shown to be completely worthless. But I am not willing to assume its worthless until more people have tried it.
One study done on amputees doesn't really convince me of anything one way or the other. I am just surprised at the number of people who claim to already know the answers, when the data is actually extremely sparse. :up:


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Posted: Thu Dec 22, 2011 5:20 pm 


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PostPosted: Thu Dec 22, 2011 6:18 pm 
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Having used a computrainer when i was being coached, a L-R imbalance was pointed out to me during warm up.
After 10 mins or so of warm up before testing began (and trying to "correct" this imbalance..), my coach then stated that once at normal operating speeds etc, the imbalance disappears in 90+% of people...

Therefore my conclusion is you're paying twice what you should be for the system

The Look/Polar pedals seem a tad on the high price to me, and what happens when they wear out, as keo's seem to do quite quickly, and from my experience Polar aint the most robust of stuff. Will parts be available; new bodies etc? and will that big black thing clear your frame?

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PostPosted: Thu Dec 22, 2011 7:54 pm 
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Rick wrote:
I am arguing there may be someting to learn from it. Maybe it will be shown to be completely worthless. But I am not willing to assume its worthless until more people have tried it.
One study done on amputees doesn't really convince me of anything one way or the other. I am just surprised at the number of people who claim to already know the answers, when the data is actually extremely sparse.

The data aren't really all that sparse if you know where to look. I just picked the amputee study because it seemed particularly appropriate. Here is a different ]study that looks at how bilateral asymmetry varies with cadence.

You're getting boxed in. Time to stop saying, "opinions on the shape of the earth differ; I'm not willing to assume it's round until more people have traveled around it in spaceships."


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PostPosted: Thu Dec 22, 2011 8:17 pm 
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Rick wrote:
One study done on amputees doesn't really convince me of anything one way or the other. I am just surprised at the number of people who claim to already know the answers, when the data is actually extremely sparse. :up:


As Mr Chung has pointed out the data and research on this topic is not new nor is it lacking. How hard have you looked?

It all comes back to the fact that the legs do not work in isolation and by merely correcting a power differential in a part will not change the effectiveness of the system. Thus the ability to measure left/right power is a good marketing point, but for a training aspect rather benign.

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"Physiology is all just propaganda and lies... all waiting to be disproven by the next study."
"I'm not a real doctor; But I am a real worm; I am an actual worm." - TMBG


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PostPosted: Fri Dec 23, 2011 12:45 am 
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OK....this is getting fun.

Let me accept your claims that there is LOTS of data showing that assymmetry in leg power makes no difference.
As usual, you are right, and anyone who disagrees is wrong.

So, I would presume that Mr. rchung would cite a study (from the many available) that would clearly support his and your claims.

So, let's look at the abstract of the study:

The objectives of this study were to (1) determine whether bilateral asymmetry in cycling changed systematically with pedaling rate, (2) determine whether the dominant leg as identified by kicking contributed more to average power over a crank cycle than the other leg, and (3) determine whether the dominant leg asymmetry changed systematically with pedaling rate. To achieve these objectives, data were collected from 11 subjects who pedaled at five different pedaling rates ranging from 60 to 120 rpm at a constant workrate of 260 W. Bilateral pedal dynamometers measured two orthogonal force components in the plane of the bicycle. From these measurements, asymmetry was quantified by three dependent variables, the percent differences in average positive power (%AP), average negative power (%AN), and average crank power (%AC). Differences were taken for two cases--with respect to the leg generating the greater total average for each power quantity at 60 rpm disregarding the measure of dominance, and with respect to the dominant leg as determined by kicking. Simple linear regression analyses were performed on these quantities both for the subject sample and for individual subjects. For the subject sample, only the percent difference in average negative power exhibited a significant linear relationship with pedaling rate; as pedaling rate increased, the asymmetry decreased. Although the kicking dominant leg contributed significantly greater average crank power than the non-dominant leg for the subject sample, the non-dominant leg contributed significantly greater average positive power and average negative power than the dominant leg. However, no significant linear relationships for any of these three quantities with pedaling rate were evident for the subject sample because of high variability in asymmetry among the subjects. For example, significant linear relationships existed between pedaling rates and percent difference in total average power per leg for only four of the 11 subjects and the nature of these relationships was different (e.g. positive versus negative slopes). It was concluded that pedaling asymmetry is highly variable among subjects and that individual subjects may exhibit different systematic changes in asymmetry with pedaling rate depending on the quantity of interest.

Now, I don't see anywhere in there where it concludes that NO IMPROVEMENT can POSSIBLY come from training the non-dominant leg to be more equal to the dominant leg. Furthermore, since it does state that "the non-dominant leg contributed significantly greater average positive power and average negative power than the dominant leg. " I don't see why it is not at least theoretically possible to improve total effective power by simply concentrating on not creating negative power (improving 'spin' of non-dominant leg).
It seems odd that Mr. Chung would cite a study that seems to support my position if there are so many conclusive studies out there that support your contention that it is completely irrelevant.

So, I am "boxed in". Can you please explain how you reach your conclusion from the study being cited ? :wink:


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PostPosted: Fri Dec 23, 2011 3:44 am 
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Rick wrote:
Let me accept your claims that there is LOTS of data showing that assymmetry in leg power makes no difference.
As usual, you are right, and anyone who disagrees is wrong.

Thanks, but let's not overstate things. First, you keep leaving out the word small as in: there's a lot of evidence that small asymmetries make no difference. Second, not everyone who disagrees with me is wrong -- just you, and just in this case. Unless, of course, you say something else stupid; then I'd disagree and you'd be wrong there, too. Dude, I've already pointed out the basics of the evidence and I'm sensing that you're really not equipped to evaluate it so it's almost surely not going to be fruitful to point to more evidence that you'll also be unable to evaluate. As one of my professors was wont to say, "You can lead a horse's ass to water but you can't make him think." I think it's time for us both to cut our losses.


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PostPosted: Fri Dec 23, 2011 4:39 am 
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Thanks for your insightful additions.

Admittedly, I am not an expert in this field, as you are. So I am disappointed that you have declined to provide further information on the subject.
I am willing to learn, however, so I have found a couple more studies to help with my education.

In 2009, Dr Stephen Cheung, author of this book:
Image
wrote:
"Why does the asymmetry decrease with higher torques and power outputs? Is it because the non-dominant leg becomes more active, or is it because the dominant leg is so “fatigued” by it working harder at lower efforts that it cannot contribute any more when the hammer drops?

Even if it is hard to quantify, I feel that, logically anyway, a more balanced body and pedal stroke can only lead to improved performance and decreased injury. Personally, I have been using PowerCranks or variations since 2005 either continuously or for specific workouts, and I find they have been a useful system and excellent training tool. At the very least, I would encourage you to think about the way you pedal, and not just treat pedaling as a means to an end. "


Now he is obviously simply wrong also. So would be glad to send him an email to help correct his views if you would just kindly point me to any of the mutitude of studies that have shown him to be in error.

I don't really want to have to depend on you for credible information; I know your time is valuable, and it is a real imposition to have to educate less erudite novices like myself, so I have been trying to dig out more info on the subject, but I am really having a hard time. In fact, one of the only other articles I could find was from 2010: Carpes, Mota, and Faria wrote an article for The Journal of Physical Therapy in Sport, entitled "On the bilateral asymmetry during running and cycling – A review considering leg preference."
In that study, they conclude:
"For both running and cycling, few investigations examined the central mechanisms of neuromuscular control, and no study addressed the effect of asymmetry on performance.

Conclusions

Collectively, the volume of studies supporting symmetry is small and to a large extent research considered unilateral assessment. Preferred limb performance can differ from the contralateral limb. In the context of biomechanical and physiological investigations, we believe that further studies should address the role of lower limb symmetry on human motor performance and injury risk focusing on the energetic cost, muscle efficiency and the neuromuscular aspects such as muscle activation and motor units firing rate.
"

Now these guys are also apparently unaware of the near-conclusive evidence that has been elucidated since 2010, and that you are apparently in possession of, so that article is probably just plain obsolete also.

....I'll keep looking. But you know how hard it is with my limited intellectual ablities. So it may take some time.
Thanks. Ill try to be less irritating to you in the future.


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PostPosted: Fri Dec 23, 2011 5:02 am 
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Has anyone heard of this guy: Dr. Edmund Burke ??!?

Anyway, he says:
"Most cyclists are not symmetrical in the application of power to the pedals, favoring one leg over the other, and exert more force on the pedal with this leg. The result is asymmetrical pedaling, which leads to loss of power.

To alleviate this problem, try this exercise: Place one foot on a 16- to 18-inch box. With the other leg, force yourself to pedal smooth circles for 5 to 10 minutes. This technique will improve your ability to apply power over a longer portion of the crank circle because you do not have the inertial support of the other leg. After several weeks of alternating work with both legs, slip the trainer into a very low gear and, using both legs, attempt to pedal with a smooth application of power. This is what professional cyclists refer to as pedaling with suppleness."


I am trying to find the info that shows that symmetry is irrelevant to power production. Instead, I just keep coming up with these deluded morons. I this some sort of internet conspiracy to hide the truth ?

I'll keep plugging along; but I am starting to get tired. :cry:


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PostPosted: Fri Dec 23, 2011 5:56 am 
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And what is the reason or reasons why asymmetrical peddling leads to loss of power?

Consider this study and tell us the what can be concluded from this:-
http://www.ncbi.nlm.nih.gov/m/pubmed/21330612/

_________________
"Physiology is all just propaganda and lies... all waiting to be disproven by the next study."
"I'm not a real doctor; But I am a real worm; I am an actual worm." - TMBG


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PostPosted: Fri Dec 23, 2011 5:24 pm 
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And what is the reason or reasons why asymmetrical peddling leads to loss of power?

I don't know.
And I don't pretend to know.
That is why I am willing to entertain the idea that further study might be of benefit. :)
Quote:
Consider this study and tell us the what can be concluded from this:-


Well, here is the abstract:

"Single-leg cycling may enhance the peripheral adaptations of skeletal muscle to a greater extent than double-leg cycling. The purpose of the current study was to determine the influence of 3 wk of high-intensity single- and double-leg cycle training on markers of oxidative potential and muscle metabolism and exercise performance. In a crossover design, nine trained cyclists (78 ± 7 kg body wt, 59 ± 5 ml·kg(-1)·min(-1) maximal O(2) consumption) performed an incremental cycling test and a 16-km cycling time trial before and after 3 wk of double-leg and counterweighted single-leg cycle training (2 training sessions per week). Training involved three (double) or six (single) maximal 4-min intervals with 6 min of recovery. Mean power output during the single-leg intervals was more than half that during the double-leg intervals (198 ± 29 vs. 344 ± 38 W, P < 0.05). Skeletal muscle biopsy samples from the vastus lateralis revealed a training-induced increase in Thr(172)-phosphorylated 5'-AMP-activated protein kinase α-subunit for both groups (P < 0.05). However, the increase in cytochrome c oxidase subunits II and IV and GLUT-4 protein concentration was greater following single- than double-leg cycling (P < 0.05). Training-induced improvements in maximal O(2) consumption (3.9 ± 6.2% vs. 0.6 ± 3.6%) and time-trial performance (1.3 ± 0.5% vs. 2.3 ± 4.2%) were similar following both interventions. We conclude that short-term high-intensity single-leg cycle training can elicit greater enhancement in the metabolic and oxidative potential of skeletal muscle than traditional double-leg cycling. Single-leg cycling may therefore provide a valuable training stimulus for trained and clinical populations."


I accept the findings exactly as stated.
How is this relevant to asymmetries occuring during two-legged cycling ?
I think it has been long suspected that single-legged exercise is beneficial. This study seems to suggest that it is even more important than previously recognized.
So isn't that an argument that knowing the power output of both legs *is* important ?
I don't see how anyone could infer from this study that asymmetries are unimportant.

But apparently you do think it shows asymmetries are unimportant. So I would be glad if you would explain why you conclude that from this study. And I really mean that. Just explain, and I will try to understand. :thumbup:

But I also have to wonder: is this the most conclusive data you have to support the idea that asymmetry is unimportant ?!?!?!


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PostPosted: Fri Dec 23, 2011 8:49 pm 
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Unless these pedal based power systems can tell me which leg has a greater capillary density, more efficient oxygen transport and higher mitochondrial density, I somehow don't believe they have any advantage over a standard power measurement system.

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PostPosted: Fri Dec 23, 2011 9:38 pm 
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The point of the study was that even by increasing the individual power output of the legs in isolation the OVERALL power did not increase. So it would have very possible to do these drills with one leg in order to match the individual leg outputs to be near identical but the total power output is still unchanged. The limits of the SYSTEM cannot be overridden (pun intended) but that of an individual part. So if your FTP is 300watts and the left leg gives 160 and the right 140 by increasing the power output of the right leg will only result in the left leg putting out less power because the system cannot hold any more than 300watts. This is due to a large number of factors but things like processing of metabolites and thermal stress to name a couple.

As I stated earlier, all humans are asymmetrical. A differential is expected. By forcing what we think is an "ideal" power or pedaling technique may not be best for the body in question. This is why, yet again, a professional fitter is crucial to on-bike performance. If there are biomechanical issues for this power differential ie: rocking hips, knee extending too much/too little etc then this is how to best address it.

Hence why there is no contradiction in the fact that one may have differing leg power outputs and still be solid as a rock in terms of te biomechanics. One is mechanical the other is chemical.

I know the books you stated say different but then there is a Dr Frank Day who says his special cranks give you a 30% power increase too...

Keep reading and researching and I guess you have to use you own findings. I have and that's why I don't care about a slight power imbalance. BUT I have had some very good fittings. YMMV.

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"Physiology is all just propaganda and lies... all waiting to be disproven by the next study."
"I'm not a real doctor; But I am a real worm; I am an actual worm." - TMBG


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PostPosted: Sat Dec 24, 2011 5:50 am 
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The point of the study was that even by increasing the individual power output of the legs in isolation the OVERALL power did not increase. So it would have very possible to do these drills with one leg in order to match the individual leg outputs to be near identical but the total power output is still unchanged. The limits of the SYSTEM cannot be overridden .....


That is your interpretation...and you are entitled to it.
But let me just point out that the study does not say anything like that. Your interpretation involves a lot of insertion of your own extensions of logic.
What they actually say is:
Quote:
Training-induced improvements in maximal O(2) consumption (3.9 ± 6.2% vs. 0.6 ± 3.6%) and time-trial performance (1.3 ± 0.5% vs. 2.3 ± 4.2%) were similar following both interventions. We conclude that short-term high-intensity single-leg cycle training can elicit greater enhancement in the metabolic and oxidative potential of skeletal muscle than traditional double-leg cycling. Single-leg cycling may therefore provide a valuable training stimulus for trained and clinical populations."

So the facts are:
1. Both groups did improve. The improvement was "similar", but not "identical".
2. Single legged cycling may provider greater enhancement of certain measures of the muscular potential

Note that it does not say that asymmetry cannot be improved upon, and that it would not improve power. Nor did they really study asymmetry at all. They were just comparing the effect of single leg exercise. Both single leg exercise and dual leg exercise lead to similar improvements. But there was simply no study of how improving the symmetry of the power production would effect overall power in any way. All your assumptiuons are merely projections of your opinion.
Note that I am willing to entertain the idea that you may actually be correct, but they are still just your opinions at this point because the study does not address the issue at all.
It bears repeating that I am not saying you are wrong.
I am not arguing that the opposite is true.
I am just pointing out that this study does not really support your assertions.
Quote:
Hence why there is no contradiction in the fact that one may have differing leg power outputs and still be solid as a rock in terms of te biomechanics. One is mechanical the other is chemical.

I agree that there is no contradiction.
But that is a different question, almost completely unrelated to the one at hand.
The question is simply "Can improvements in symmetry lead to overall increase in power."

Which leads me to ask (quite sincerely) again: is this the most convincing study that you are basing all your assertions on ?!?!?
That seems like very flimsey evidence.

And considering that I have been personally insulted numerous times in this thread for my ignorance and lack of intellectual ability....and told there were many studies proving that asymmetry makes NO difference, aren't I entitled to at least see some credible evidence ?

At this point, I don't even really care. I am having fun pointing out how "experts" on the internet are often just arrogant assholes completely fill of $hit. :beerchug:
Not YOU, of course...just "often". :lol:


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PostPosted: Sat Dec 24, 2011 6:40 am 
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Rick wrote:
So the facts are:
1. Both groups did improve. The improvement was "similar", but not "identical".
2. Single legged cycling may provider greater enhancement of certain measures of the muscular potential


Did you read the part about how power output for the individual legs exceeded that of half the power of both legs?

Why do you think this is?

Quote:
Note that it does not say that asymmetry cannot be improved upon, and that it would not improve power. Nor did they really study asymmetry at all.


I didn't say they did. But you did understand the parts about training the leg in isolation, yes? So, once again, how would you train one leg to balance the power, what would be the ramifications to other leg you don't train and how would that compare to the above study in terms of absolute power output?


Quote:
But there was simply no study of how improving the symmetry of the power production would effect overall power in any way. All your assumptions are merely projections of your opinion.


No, they are based on the facts presented and the data gained from the study. Not assumptions.

Quote:
Which leads me to ask (quite sincerely) again: is this the most convincing study that you are basing all your assertions on ?!?!?
That seems like very flimsey evidence.


Only if you don't understand the mechanisms. And no, its not the only study.

Quote:
And considering that I have been personally insulted numerous times in this thread for my ignorance and lack of intellectual ability....and told there were many studies proving that asymmetry makes NO difference, aren't I entitled to at least see some credible evidence ?

At this point, I don't even really care. I am having fun pointing out how "experts" on the internet are often just arrogant assholes completely fill of $hit.


You've also done a good job of demonstrating that ignorance is not a blessing.

Another question. Why do you think I give the advice I do and assert the things I do on this forum? (this is a rhetorical question BTW, laager). Is it because I like being "right"? That I spend all this time tapping away to prove a point? Or is it that I actually like helping people? Think about it. What am I advocating? That people focus on a good fitting and training hard with a structured plan? Or that they need a new power meter and need to focus on power balance and smooth peddling with special cranks and "suppleness" blah blah blah.

Cycling is a great sport but far too many want to think that there are magic pills, secret training methods or yet undiscovered techniques which will yield a power boost. I am quite passionate about sport science and the one thing which is a common and proven theme is that what works is a shite load of hard work in the chosen sport. In this case, cycling. A lot. Now you can claim there are no direct studies looking at correcting power balance between the legs, true enough. But there is enough data surrounding the mechanisms in the body which allow this to be explained as to why or why not it would improve overall power output (we agree this is the general goal behind training I assume?).

It is good that you question. But you question without basis. It seems like a good idea, and you've quoted two Drs who think it's a good idea as well. But none have come up with any feasible reason WHY. A few of us here have explained why it won't make a difference. I am not sure whether you chose to ignore the evidence or don't understand it.

But keep at it. Who knows, as per my sig line this could all be undone with the next study around the corner....

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"I'm not a real doctor; But I am a real worm; I am an actual worm." - TMBG


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PostPosted: Sat Dec 24, 2011 5:16 pm 
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Another question. Why do you think I give the advice I do and assert the things I do on this forum? (this is a rhetorical question BTW, laager). Is it because I like being "right"? That I spend all this time tapping away to prove a point?


Sorry, but I think I am finished discussing this.
I have produced numerous references that directly discredit and contradict your assertions, and despote my numerous requests you produce only one study that does not support your assertions except through your own convoluted logic.

If you have any credible studies or information, I will be glad to consider it.
Unbiased readers can easily review the evolution of this thread and decide who is ignorant and insulting. :beerchug:


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Posted: Sat Dec 24, 2011 5:16 pm 


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