Poor man's Powercranks? (PPC)

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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.In the early days we were stuck with anecdotal reports, our own small in-house study, and theoretical benefits to support our claims. All we got was, Where are the studies? Now that there are starting to be studies we are told the same thing, two studies aren't enough, or they are flawed, or they don't comport with my bias, or something else. They are what they are.

We can only put forth the science (studies) as they appear. When other studies become available we will surely let everyone know.

Frank

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.No I don't. It would be unusual that such a result would come from an increased trainng load as most riders see reduced volume when they take up PC's, at least for the first 4-8 weeks or so. I understand the group contained one or two professional cyclists and a bunch of fairly elite amateur cyclists and triathletes but I don't know the specifics of the study as we don't run them.

Frank

No I don't. It would be unusual that such a result would come from an increased trainng load as most riders see reduced volume when they take up PC's, at least for the first 4-8 weeks or so. I understand the group contained one or two professional cyclists and a bunch of fairly elite amateur cyclists and triathletes but I don't know the specifics of the study as we don't run them.

Frank



From the day a rider starts to use PC's, for how long is the hip flexor/thigh pain expected to continue ?

From the day a rider starts to use PC's, for how long is the hip flexor/thigh pain expected to continue ?It depends upon how much effort one makes to adapt and from what point they are starting from. For most it is pretty much gone anywhere from 4-6 weeks, although it will continue as long as one is continually bumping up the mileage beyond what the muscles take reasonably easily.

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

where's the control group?

where's the control group?If there was one they are probably in Canada. :-)

We don't know that there was one but I have been told that there are other valid ways of doing a study that can give statiscally significant results without needing a control group. This study was done by a very reputable group out of Canada so one would assume they knew what they were doing but without access to the protocol and data one cannot know for sure.

Frank

If there was one they are probably in Canada. :-)

We don't know that there was one but I have been told that there are other valid ways of doing a study that can give statiscally significant results without needing a control group. This study was done by a very reputable group out of Canada so one would assume they knew what they were doing but without access to the protocol and data one cannot know for sure.

Frank

Calling Robert Chung... he's our stats man. I can't possibly see how you can have an intervention such as Power Cranks and not have at least one control group. It seems, at first glance, that the methodology is wrong.

And Frank, your spelling is worse than mine.

Ric

Calling Robert Chung... he's our stats man. I can't possibly see how you can have an intervention such as Power Cranks and not have at least one control group. It seems, at first glance, that the methodology is wrong.

And Frank, your spelling is worse than mine.

RicEarly on I had presumed that there was a control group as I, also, couldn't figure out how one could calculate statistical significance without one. But, I have been told there are many ways a study can be designed that doesn't require one or, perhaps the group acted as their own controls. The fact that this well respected group calculated statistical significance suggests they had designed their study in such a way that they could. Unfortunately, they didn't tell us in the abstract how they did that.

Early on I had presumed that there was a control group as I, also, couldn't figure out how one could calculate statistical significance without one. But, I have been told there are many ways a study can be designed that doesn't require one or, perhaps the group acted as their own controls. The fact that this well respected group calculated statistical significance suggests they had designed their study in such a way that they could. Unfortunately, they didn't tell us in the abstract how they did that.

you misunderstand, or perhaps are doing it on purpose.

It isn't the statistical significance i'm worried about per se, it's the fact that the methodology appears incorrect. That is, the point made by Rmur. Perhaps, prior to intervention the group were all doing an hour a week in 39 x 17, while eating chocolate bars, drinking beer and not in the slightest bit interested in their training. They then, did 8 hrs/week for 6 weeks and gained an improvement. well, uhm, what would you expect?

Likewise, i'm expecting a 50% increase in sustainable power from the beginning of the year to sometime by the end of april. Whether i disclose that i had 4 weeks off my bike and ended up horribly detrained you're saying wouldn't matter... I'll have had a significant increase in power...

Ric

you misunderstand, or perhaps are doing it on purpose.

It isn't the statistical significance i'm worried about per se, it's the fact that the methodology appears incorrect. That is, the point made by Rmur. Perhaps, prior to intervention the group were all doing an hour a week in 39 x 17, while eating chocolate bars, drinking beer and not in the slightest bit interested in their training. They then, did 8 hrs/week for 6 weeks and gained an improvement. well, uhm, what would you expect?

Likewise, i'm expecting a 50% increase in sustainable power from the beginning of the year to sometime by the end of april. Whether i disclose that i had 4 weeks off my bike and ended up horribly detrained you're saying wouldn't matter... I'll have had a significant increase in power...

Ric
It is not possible to know if the methadology is incorrect without knowing what the methodology is. If they chose the correct test for their methodology then it is relevant if the results were statistically significant. If there are many ways to do something then it is not necessarily deficient if it is an acceptable way but not the way you would have chosen.

Why would you would think this group would choose to do a study in which they took riders and put them on enforced bedrest and fed them chocolate for 6 weeks then started PC training? I guess it is possible if someone wanted to make the cranks look good but it has been my experience that most researchers don't believe our claims so they make their protocol as rigourous as possible to try to minimize the PC benefit. The cranks look pretty good despite this.

So, your presumption is one I don't think is fair to make even though I also would be much happier if we had all the data. I accept the fact that without the protocol and the raw data to check one cannot "know" how good the study was. But, the authors put their name to this study. If they did crap work it will come out. I understand these authors have an excellent reputation such that I doubt they would put their name to it and present it at a national meeting if they knew it was crap work. So, for you to assume it was a piece of crap just because you don't like the results is a little to much for me.

Anyhow, take your beef up with the authors. I can only present the data I have.

BTW, I wouldn't call someone, who has an excellent base like yourself, who takes 4 weeks off their bike, "horribly detrained". A better term might be fully rested and reinvigorated.

it has been my experience that most researchers don't believe our claims so they make their protocol as rigourous as possible to try to minimize the PC benefit. The cranks look pretty good despite this.


think about it like this: if you wanted to trial an ergogenic aid intervention (e.g. caffeine), you'd need to use a randomised, placebo, double-blind crossover methodology, to see how it worked and whether there was a learned effect (e.g. if you always did the caffiene trial last, you could attribute the increase in performance - if there was one - to a training effect). Now, while you can't do a double-blind crossover study with Power Cranks, there are other ways to make the testing more rigorous, because without a control group, the study is a joke.

For e.g., you could have a contol group doing the same training after initially matching the control group with the test group to make sure that both groups were as fit as each other and doing the same training. then one group would do the new training with power cranks, and the other group would do the exact same training without the power cranks.

Here would be a much better example of a training study, with a control group http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=12439086



BTW, I wouldn't call someone, who has an excellent base like yourself, who takes 4 weeks off their bike, "horribly detrained". A better term might be fully rested and reinvigorated.

Detraining occurs rapidly, such that my FTP has dropped significantly by ~ 100 W and my map by ~ 70 W. It may also be that performance decline isn't helped by my 'disability' (although i have only anecdotal data on that score).

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=11252068&query_hl=6&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=11474330&query_hl=6&itool=pubmed_docsum

Ric

you misunderstand, or perhaps are doing it on purpose.


No, Frank misunderstands. That is, despite (or perhaps because of?) his background it is clear from his comments that he has, at best, a very rudimentary grasp of experimental design and statistics. It is therefore a waste of time to discuss such issues with him, because he quite simply doesn't "get it".

Anyhow, take your beef up with the authors. I can only present the data I have.

If you're not willing or able to discuss the strengths and limitations of this (or any other) study involving your product, you shouldn't try to use them to support your claims.

I understand these authors have an excellent reputation

Dr. Stephen Cheung would be the most senior individual. A search of PubMed reveals that he has published one to two papers per year for the past ~15 y, almost entirely in the area of thermoregulation. Analysis of his publication record using the ISI Web of Knowledge indicates that these papers have been cited a sum total of 236 times, or an average of 9.08 times each, with his 'h index' being 8. So, while I don't know him and can't comment on the quality of his work (which AFAIK is excellent), it would appear that it has yet to have a significant impact even in his sub-speciality. I'd therefore say that it is yet another 'Dayism' to claim that he/his coauthors have quite the reputation that you repeatedly cite.

If you're not willing or able to discuss the strengths and limitations of this (or any other) study involving your product, you shouldn't try to use them to support your claims.I am more than willing to discuss the strengths and weaknesses of any study I have knowledge of. I would ask that you do the same for the studies that you cite, most specifically the Coyle study that you and others repeatedly cite as having "proven" that just pushing harder is the superior pedaling technique. In the past when I have brought up "weaknesses" in the studies you cite you simply ignore me. How about a discussion, or are you not willing or able to discuss the strengths and limitations of studies that you claim support your poit of view?

Anyhow, I believe we have had quite a discussion before on the Luttrell study. I am more than willing to do so again. I am unable to discuss the Dixon study since the only specific information I have about it is contained in the abstract, which is poorly written if one wants to know anything about the specific protocol.

Frank

think about it like this: if you wanted to trial an ergogenic aid intervention (e.g. caffeine), you'd need to use a randomised, placebo, double-blind crossover methodology, to see how it worked and whether there was a learned effect (e.g. if you always did the caffiene trial last, you could attribute the increase in performance - if there was one - to a training effect). Now, while you can't do a double-blind crossover study with Power Cranks, there are other ways to make the testing more rigorous, because without a control group, the study is a joke.

For e.g., you could have a contol group doing the same training after initially matching the control group with the test group to make sure that both groups were as fit as each other and doing the same training. then one group would do the new training with power cranks, and the other group would do the exact same training without the power cranks.

Here would be a much better example of a training study, with a control group http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=12439086




Detraining occurs rapidly, such that my FTP has dropped significantly by ~ 100 W and my map by ~ 70 W. It may also be that performance decline isn't helped by my 'disability' (although i have only anecdotal data on that score).

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=11252068&query_hl=6&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=11474330&query_hl=6&itool=pubmed_docsum

RicEvery study has flaws and weaknesses, especially if it involves human subjects. The fact that a study has flaws does not necessarily make it invalid. Take out of it what you can. Some may take more than others. That is your (and my) choice.

From one of your cites: "Fiber distribution remains unchanged during the initial weeks of inactivity, but oxidative fibers may decrease in endurance athletes and increase in strength-trained athletes within 8 wk of training stoppage. Muscle fiber cross-sectional area declines rapidly in strength and sprint athletes, and in recently endurance-trained subjects, whereas it may increase slightly in endurance athletes. Force production declines slowly and in relation to decreased EMG activity."

I guess peoples definition of "horribly detrained" can vary.

Frank

Dr. Stephen Cheung would be the most senior individual. A search of PubMed reveals that he has published one to two papers per year for the past ~15 y, almost entirely in the area of thermoregulation. Analysis of his publication record using the ISI Web of Knowledge indicates that these papers have been cited a sum total of 236 times, or an average of 9.08 times each, with his 'h index' being 8. So, while I don't know him and can't comment on the quality of his work (which AFAIK is excellent), it would appear that it has yet to have a significant impact even in his sub-speciality. I'd therefore say that it is yet another 'Dayism' to claim that he/his coauthors have quite the reputation that you repeatedly cite.I was simply told by a researcher in Australia that he had an excellent reputation for doing good work. It doesn't matter. His work in this instance will either stand or fall on its own. Having published a lot or being cited a lot is not a very powerful tool for measuring quality of subsequent papers, in the academic publish or perish atmosphere.

Frank

I was simply told by a researcher in Australia that he had an excellent reputation for doing good work.

Undoubtly someone whose expertise lies in thermal physiology, because it's high unlikely they would have heard of Dr. Cheung otherwise (I know that I would not be aware of him if I weren't a cyclist).

It doesn't matter.

On the contrary, it matters a fair bit, because 1) until the actual study is published, all we really have are tidbits of information to go by (including who performed the study), and 2) you keep touting the research as being performed by some high-powered scientists (which it clearly was not).

His work in this instance will either stand or fall on its own.

Indeed, that is the beauty of the scientific process (vs., say, overly-stated claims made on the web).

Having published a lot or being cited a lot is not a very powerful tool for measuring quality of subsequent papers, in the academic publish or perish atmosphere.

Did you really just say that? :eek:

On the contrary, it matters a fair bit, because 1) until the actual study is published, all we really have are tidbits of information to go by (including who performed the study), and 2) you keep touting the research as being performed by some high-powered scientists (which it clearly was not).Might I remind you Dr. Coggan that you just recently referred to two studies to make your point. One that was PRESENTED at the ACSM, a similar situation as the Dixon study but for which not even an abstract was given nor available to anyone, apparently, to anyone who was not at the meeting and another which you stated is IN PRESS. Very useful to make your point.

Thanks for keeping me honest. Let the discussion of the merits of the various articles as they relate to PowerCranks, or anything else, begin.

Frank

Indeed, that is the beauty of the scientific process (vs., say, overly-stated claims made on the web).You mean you didn't get all that knowledge from Wikipedia?!! :D