Page 4 - Poor man's Powercranks? (PPC)

20-02.-2007, 09:47 AM

#46

acoggan

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by Fday

it takes a product like PowerCranks to change the pattern. A device that forces the user to use a different pattern and allows them to get enough repetitions that the neuromuscular memory can begin to change.

Quote:

Originally Posted by Fday

Now that it is possible to actually change the pedaling pattern it is now possible to compare the relative merits of the two styles to see which is superior. Any study that has failed to do such a change and comparison cannot, by definition, know which method is better. I know of only two studies that have made this attempt and both of them have shown the PC method of pedaling to be far superior.

1) See above: Cavanagh found no improvements in efficiency or power output as a result of the intervention.

2) You're overinterpreting Luttrel's results (and still haven't provided the other reference). That is, while they observed an apparent increase in efficiency, there was no control group, and also no direct data showing that the subjects altered their pedaling "style" when using normal cranks. Both would be necessary to make the claim that you do above (and even then I wouldn't go so far as to say "far" superior, given that the absolute improvement in power due to the increased efficiency wasn't that great).

20-02.-2007, 09:51 AM

#47

rmur17

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by acoggan

Again, not true: the US team pursuiters trained extensively with biofeedback prior to the 1984 LA Olympics, and by doing so changed their pattern of force application on the pedals (for a few months, anyway).

1) See above: Cavanagh found no improvements in efficiency or power output as a result of the intervention.

2) You're overinterpreting Luttrel's results (and still haven't provided the other reference). That is, while they observed an apparent increase in efficiency, there was no control group, and also no direct data showing that the subjects altered their pedaling "style" when using normal cranks. Both would be necessary to make the claim that you do above (and even then I wouldn't go so far as to say "far" superior, given that the absolute improvement in power due to the increased efficiency wasn't that great).

what % of say FTP power could be attributed to the hip flexor muscle group? (if it's duration dependent and I figure something like a maximal out of the saddle sprint could be different ....)

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20-02.-2007, 09:52 AM

#48

Fday

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by acoggan

Please don't try to put words in my mouth.

And the other one is...?

Again, to what study are you referring?

(BTW, when training untrained subjects we've obtained 10% increases in VO2max in just 10 d, and even in highly trained athletes it isn't uncommon for VO2max to flucuate +/-10% throughout the year. Depending on the experimental design, a15% increase in 6 wk therefore isn't necessarily all that impressive.)

Luttrell is one and Dixon (presented at the CSEP meeting last November I believe) is the other, as I know you have been told before. Since these were reported as statistically significant improvements it seems to me that you should be at least interested, if not impressed.

Frank

20-02.-2007, 10:00 AM

#49

Fday

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by acoggan

How effective was that intervention in changing ingrained habits. Part time biofeedback is not particularly effective in making these changes just as part time PowerCranks use is less effective than full time use in make these changes and improvements. I suspect it wasn't very effective. What was the "biofeedback protocol"? Where is the reference?

Perhaps you should read Luttrell again. I think you are under interpreting it. There was a control group so the efficiency differences were between groups. While there was no direct evidence that the PC group actually changed their pedaling style, it can be inferred, and if they didn't then something has to account for the improvement. Changing pedaling style is the only rational interpretation based upon the study design.

Anyhow, there are a couple of studies underway now that will be gathering EMG evidence along with all the other data such that changes in style will be able to be demonstrated to be compared to the other data changes. I know you can hardly wait.

Frank

20-02.-2007, 10:22 AM

#50

Fday

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by acoggan

Not true. That is, there isn't a single study showing any particular "style" of running to be superior to any other (with the exception of numerous studies showing that self-selected stride length is routinely most efficient).

I would be surprised if the above were true. I will say that 98% of the running coaches I talk to concur that there is an optimum, most efficient, running style and they agree on what it is.

Quote:

On the contrary: we pedal essentially the same we walk or run.

essentially the same is not the same. Cycling is a learned behavior and, despite how good or experienced a runner or walker someone is, the pedaling coordination cannot be "known" without some prior experience of being on a cycle of some sorts. If you have evidence to the alternative I would love to see it.

Anyhow, with running the foot is on its own between footstrikes and the path of the foot differs substantially between people depending upon the muscle coordination pattern and joint construction. In cycling, the footpath is constrained to a circle, and it is the same for everyone despite those same wildly varying muscle contraction patterns.

Frank

20-02.-2007, 11:33 AM	#51
Paulie-AU Registered User Join Date: Mar 2005 Location: Ahhh...im lost Posts: 275	Re: Poor man's Powercranks? (PPC) Being completely unqualified in this, personally I find in racing if I need to bridge a gap sometimes the only way to do so is to focus on the lift part of my pedal stroke because I really have nothing more to give on the downstroke. Sure I use energy to create the speed (wonderful law of physics), but it seems to be the only way to jump from say 45km/h to 48km/h at the 45min mark of a Crit. The question I have is why would you rely on one muscle set to do all the work, when there is another one that can contribute to help the other? Surely while the enery required to do a speed is going to be the same whether you are using your legs/arms/tounge (all things being equal) there has to be method in sharing the muscle fatigue. I realise that this technique will not increase brute power (apparently AIS measured highest power reading at their track facility from Nathan Rennie (World Cup DH MTB'er) on flat pedals) but surely it would better manage muscle fatigue regardless of fitness. That could only be a plus, especially at the business end of a race.

20-02.-2007, 01:53 PM

#52

Fday

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by Paulie-AU

Being completely unqualified in this, personally I find in racing if I need to bridge a gap sometimes the only way to do so is to focus on the lift part of my pedal stroke because I really have nothing more to give on the downstroke. Sure I use energy to create the speed (wonderful law of physics), but it seems to be the only way to jump from say 45km/h to 48km/h at the 45min mark of a Crit.

The question I have is why would you rely on one muscle set to do all the work, when there is another one that can contribute to help the other? Surely while the enery required to do a speed is going to be the same whether you are using your legs/arms/tounge (all things being equal) there has to be method in sharing the muscle fatigue.

I realise that this technique will not increase brute power (apparently AIS measured highest power reading at their track facility from Nathan Rennie (World Cup DH MTB'er) on flat pedals) but surely it would better manage muscle fatigue regardless of fitness. That could only be a plus, especially at the business end of a race.

Why don't you see increasing the muscle mass by "pulling up" as being compatible with "increasing brute power"? It just so happens to also be compatible with increasing power by improving technique but from a brute power (muscle mass) perspective it is just slightly different than simply pushing harder (which is hard to do when you are pushing as hard as you can).

I guess the question is, if one is able to increase power does it matter if it comes from technique, "brute" power, or both?

Frank

20-02.-2007, 03:05 PM

#53

Paulie-AU

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by Fday

I guess the question is, if one is able to increase power does it matter if it comes from technique, "brute" power, or both?

Frank

Yeah that is true. I was just thinking of the power output of Rennie on flat pedals, and the fact that he beat the AIS track team.

21-02.-2007, 06:03 AM

#54

n crowley

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by acoggan

True.

On the contrary: we pedal essentially the same we walk or run.

And who is responsible for this, Coyle and his colleagues. Common sense has more to offer. Yes you can pedal the same way as you walk/run, you can also walk/run in the same stooped way as a TT rider pedals, but you don't see many doing that. Then scientists are mystified by the prevalence of low back pain in cyclists ?

21-02.-2007, 07:37 PM

#55

squidwranglr

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by Fday

But, pedaling is not "natural". It is somewhat related to walking and running but it is not the same. We must learn how to do it. No one gets on a bike the first time and pedals off without difficulty.

I'll double-check this with my mom tomorrow, but I think I had to learn how to walk, too, at some point. Then again, it may have been different for you. I really don't see how the fact that our neurons had to be wired at some point to coordinate the muscle contraction patterns says anything about whether walking or pedaling is more "natural."

The one thing that I'd like to note here Frank is that in the two and a half years that I've monitored your debates on various forums, you've only been able to name the Luttrell study and the "other" study, while falling back predominantly on anecdotal "results." That just doesn't seem to match the counterpoints which can be offered through scientific methods as to the lack of significant improvements in cycling efficency due to unweighing. You can't offer a single new study that's published in that amount of time for such a revolutionary improvement in cycling?

And as far as your points about various IronMan triathletes having their best bicycle splits on seasons where they've used PowerCranks, can you really separate other aspects of their training regiment from the inclusion of PowerCranks? Were they truly controlled experiments? Even the placebo effect psychological boost of using new equipment and focusing on training more effectively has to be considered.

Berend

22-02.-2007, 04:20 AM

#56

Fday

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by squidwranglr

Of course you had to learn how to walk but I can assure you that you would have "learned" how whether anyone helped you or not. It is ingrained in the genome. Cycling is not even though it is a related activity. Because it is related is probably why most of us learn it faster (and better) than playing the piano.

And regarding studies, there are exactly ZERO studies that demonstrate that traiing with PC's is not superior to training without them. So, the fact there are only two studies demonstrating effectiveness SO FAR is hardly a reason to discount them. If there were two studies showing benefit and 10 or 20 studies showing no benefit then there would be substantial doubt. Anyhow, I think both the Luttrell (a statistically significant 10% increase in cycling efficiency in 6 weeks) and Dixon (a statistically significant 11% increase in power and 15% increase in VO2 max in 6 weeks) study demonstrate revolutionary change, but that is up for debate. We will just have to wait for further studies (several are in the pipeline) to see if they continue to demonstrate effectiveness over traditional training methods or not.

The anecdotal reports are not "proof" of anything, I agree. However, they are consistent with both Luttrell an Dixon which would offer some support that the changes reported are real and due to the PC's.

Frank

22-02.-2007, 04:27 AM

#57

ric_stern/RST

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by Fday

So, the fact there are only two studies demonstrating effectiveness SO FAR is hardly a reason to discount them. Anyhow, I think both the Luttrell (a statistically significant 10% increase in cycling efficiency in 6 weeks) and Dixon (a statistically significant 11% increase in power and 15% increase in VO2 max in 6 weeks)

What is the Dixon study? In a *brief* search of Pub-Med i can't find this study. Can you point me to the study?

Ric

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22-02.-2007, 05:07 AM

#58

daveryanwyoming

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by Fday

.... there are exactly ZERO studies that demonstrate that traiing with PC's is not superior to training without them...

When engaging in a paradigm shift or selling a new and innovative product the burden of proof is clearly on your shoulders. You can't say lack of published peer reviewed contradictory studies is proof that your concept actually works. You've repeatedly offered the Luttrell study which has been extensively questioned and you've been pretty vague about the Dixon study. Is Dixon an employee of PowerCranks? Has the Dixon work been peer reviewed (no, not hand picked peers) or published?

If you want to market your product by saying "we really think these are great and some racers are very happy with them" then fine, that's marketing. But if you want to use science to sell your product your methods have to hold up to scientific scrutiny and peer review. When you dance around the questions of study design and peer review you really open yourself up for criticism. We've all seen snake oil sold in the form of dietary supplements and quick fix fitness programs. Vendors claiming an upcoming study or an unnamed study show how great their product is are understandably viewed with suspicion.

22-02.-2007, 05:25 AM

#59

Fday

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by ric_stern/RST

What is the Dixon study? In a *brief* search of Pub-Med i can't find this study. Can you point me to the study?

Ric

The Dixon study was presented at the last CSEP meeting last November. It has yet to make it into publication. The abstract of the presentation is available at my web page. But, in case you can't find it, here it is.

Physiological responses to training using PowerCranks on trained cyclists Stephen J. Dixon, Michael F. Harrison, Kenneth A. Seaman, Stephen S. Cheung and J. Patrick Neary

University of New Brunswick, Fredericton, NB; Dalhousie University, Halifax, NS; University of Regina, Regina, SK

PowerCranks™ are cycling cranks that are independent of each other, requiring force application throughout the pedal stroke, theoretically increasing muscle recruitment and stimulus in the legs. This study examined the physiological adaptations to PowerCranks, and the time course of responses in maximal and submaximal cycling performance. Eight Trained cyclists (35.1 ± 6.8 yr) participated in 6 wks of 100% immersion training using solely PowerCranks, consisting of ~8 h/wk of aerobic and anaerobic (~80:20) cycling training. A continuous incremental cycling test to exhaustion (50 W increase every 2 min) was performed prior to and following the training program using normal cranks. In addition, 10 min of submaximal cycling (70% of VO2max wattage) were performed with both normal cranks and PowerCranks at an approximate cadence of 85 rpm, pre and post training. VO2max increased 15.6% (58.1 ± 5.8 to 67.3 ± 6.6, P=0.013). Maximum power increased 11.6% (316.7 ± 25.8 to 358.3 ± 20.4, P=0.011) following PowerCranks training. In summary, our data suggest that PowerCranks increased maximal aerobic capacity and power in trained cyclists. Supported by NSERC

22-02.-2007, 06:14 AM

#60

rmur17

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Re: Poor man's Powercranks? (PPC)

Quote:

Originally Posted by Fday

Do you know the training load/state of the riders just prior to the study? Or their previous PB's for Vo2max and MAP? Those are great improvements but not if coming off a period of rest/detraining.

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