The Powercrank Thread

[FrankDay]

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CoachFergie,

Is the above comment about 'PCs harming performance when regular cranks are used', that you mention quite often?

I don't recall Frank actually saying that .... , only that power when tested on PC is higher than when tested on regular cranks, BUT that the power on regular cranks IS an improvement over pre-PC training (which I agree can't be DIRECTLY attributed to the PC training, but 'is what it is').

Jay Kosta
Endwell NY USA

You are correct Jay. Fergie likes to misrepresent what is said by me so he can continue to make negative comments that have no basis.

The whole idea is to train onself to use a more efficient and more powerful coordination when on the bicycle. This takes a lot of time to change what one has been doing for years to something else that they do without thinking for hours. The PowerCranks force the needed coordination. In the beginning, when the new muscles being trained are inadequate the PowerCranks slow the rider down. But, as soon as they start to develop this basic coordination and reasonable endurance (about 6 weeks in most) they start seeing speed improvement. But, in these early stages the new coordination isn't ingrained and the endurance is pretty marginal. So, when a rider goes back to regular cranks they will partially revert back to their old, less efficient and less powerful, coordination, especially after they start to get tired. This results in a loss of power compared to when they are on the PowerCranks but it is still more powerful than what they were doing before. Fergie likes to jump on the "Franks says people lose power when they go back to regular cranks" as if that is a bad thing. It isn't because they don't go back completely to their previous level so all it means is they have more work to do regarding endurance in the new muscles as the goal is to get to the point there is no drop in power when they do back to regular cranks, and that takes a lot of time for most. If one is properly and completely PowerCranks trained it shouldn't matter what cranks they race on as the power should be the same on PC's or PowerCranks and it should be a lot more powerful and efficient than where they would be if they hadn't trained on them. Dixon and Luttrell both demonstrate this potential.

 

[FrankDay]

Where exactly in the pedalling circle is this timing being used.

Everywhere! That is the point.

 

[coapman]

=================
If you are only interested in 'the leg muscles', then probably little.
But for actual cycling performance, timing and coordination would be a starting point.

Jay Kosta
Endwell NY USA

Actually, if you are only interested in 'the leg muscles' then they still do a lot. Try doing 5,000 reps an hour, for x hours, of extensions/curls in a gym.

So, you using PowerCranks one is training the muscles not only for a better coordination but also the endurance to maintain that coordination for as many hours as necessary for the kind of racing one does.[/QUOTE]

Endurance and coordination will not generate crank torque, only your muscles can do that.

 

[FrankDay]

Frank, stop. You are making an even bigger fool of yourself than you already have.

To have acted as their own control and for p-values to be calculated based on such a control, then the same riders would also have needed to perform the same training on regular cranks under the same conditions, from the same level of training/fitness etc.

My friend, that was the construct of the Dixon study. He started it at the end of the racing season when he expected his subjects would be at their peak form and further training, not preparing for a race, would do no more than maintain their current condition.

Yet this data does not exist.

Yes it does, that is the construct of the Dixon study.

Hence p-values were not calculated based on comparison with a control. It's simply before and after results v null hypothesis (i.e. that training would not have an impact).

My friend, P-values are calculated to evaluate the null-hypothesis. The investigators in the Dixon study were not neophytes in the scientific world. They designed their study as they did to try to make it "more powerful" (more subjects) so they might uncover smaller changes. It turns out that the changes were so large they probably could have done a more conventional study but they did what they did. If you don't like it why don't you repeat the study but us a "conventional" control group and see what happens.

Ah, so you've spotted the flaw. So why can't you see that same problem with your interpretation of the Dixon study data?

Every study has flaws. No study is perfect. Dixon did what they did and got the results they got. The fact you don't like it does not change what they did or found nor does it change their statistical analysis of their results. Their data rejected the null hypothesis and their data supports the claim that training with PowerCranks increase power (something most of our users already know).

They measured training impact of the intervention but there was no control. If there was a control, then control data would have been shown.

There has to be a control or they could not calculate the p-values. The control design was adequate for the CSEP. You should address your complaints to them. Until they retract the study the results stand whether you like it or not.

Since you are convinced there is control data, then show us the data.

I didn't do the study, I don't have the data. All I have is the study results.

All that study says is that some guys trained and their VO2max went up. Woopdie do. Incredible insight gained there.

Yes, went up more than would have been expected in a statistically significant way. If improving VO2max means nothing to you then feel free to ignore.

What it does not, and cannot say is whether the use of your cranks had anything to do with it.

Sure it can because their study design had the PowerCranks as the only variable.

To do that requires a control using regular cranks, be it the same riders at another time performing the same training under same conditions with same starting baseline, or via the use of another control group.

They had a control or they could not have calculated the p-values. You simply do not understand the study design. Anyway, lots of "studies" don't have controls. Take a study on global warming. Where is the control planet? The fact you don't understand more nuanced study design does not, per se, invalidate them.

Without controlling for crank use, it tells us nothing about the impact of the cranks. Claiming any impact of use of your cranks is just as invalid as claiming the results were because all of their bikes were blue.

The study stands on its own merits. The study credited the improvements they saw to the PowerCranks use and rejected the null hypothesis. It is what it is. You are peeing into the wind to try to argue against the study. The only real way to invalidate it is to repeat it using the same or a better study design (but equivalent intervention). The ball is in your court.

 

[CoachFergie]

Is the above comment about 'PCs harming performance when regular cranks are used', that you mention quite often?

I don't recall Frank actually saying that .... , only that power when tested on PC is higher than when tested on regular cranks, BUT that the power on regular cranks IS an improvement over pre-PC training (which I agree can't be DIRECTLY attributed to the PC training, but 'is what it is').

He said Ironman athletes perform who use powercranks in training perform worse on normal cranks in competition. Seems pretty clear cut they are harming performance.

Besides you're putting a lot of faith in the comments of a guy who has been caught in a lie that many times and there is no published data supporting his claims. Hence I don't engage him directly anymore.

I do check to see this forum is not getting spammed and find it so amusing that he thinks one cannot determine p-values from a single group being tested before and after an intervention. All Dixon shows is that training works, I think we all knew that already

 

[CoachFergie]

Would also add that I was invited to give an oral presentation at WCSS in Leeds this year and my study didn't have a control group. I used magnitudes based inferences so didn't even give p-values. It's not that big a deal. The real test will be seeing if my study gets published. My research was well received, probably because no one has done a study like that before. I'm told that Lutrell was laughed off stage at ACSM and their study was not published in ACSM's key journal, Medicine and Science in Sports and Exercise, rather it got published in the lesser Journal of Strength and Conditioning Research. All researchers strive to get their work published, that is a big deal, so Dixon never being published is quite telling!

 

[FrankDay]

He said Ironman athletes perform who use powercranks in training perform worse on normal cranks in competition. Seems pretty clear cut they are harming performance.

I did??? Can you point me to that statement. If so, perhaps I had forgotten about Sam Gyde, who trains on PowerCranks (and races on regular cranks) and has won his age-group at the World Championships the last 3 years running and winning the first after starting training on PowerCranks to which he gives the a large amount of the credit for his big improvements.

What really gave me a boost this year is the use of powercranks. Since January I am doing all my bike training with powercranks and that made me a lot stronger in the run and I also gained some watts extra power on the bike.

Besides you're putting a lot of faith in the comments of a guy who has been caught in a lie that many times and there is no published data supporting his claims. Hence I don't engage him directly anymore.

Evidence please. What was the lie, where was it said (links please)? LOL

I do check to see this forum is not getting spammed and find it so amusing that he thinks one cannot determine p-values from a single group being tested before and after an intervention. All Dixon shows is that training works, I think we all knew that already

My friend, read Dixon again. He did his best to control for training effect. Let me ask you this question. How much would you expect the power of the average racer to increase after the end of their racing season as they move into the off season if they were to just continue their baseline training for the next 6 weeks? If you are going to suggest it would increase do you have a study to suggest this is so. I think most people think their power drops during the off season even though they continue to ride. That is the basis of the Dixon study design. If you have some real data to suggest that assumption is false show it to us all. Then answer the question as to why everyone doesn't stop intense training 6 weeks before their A race if they could expect a 14% increase in power over what they can expect continuing doing what they are doing.

Anyhow, again, as you know, Davis concluded, with a statistical probability of being wrong of about 1 in 100, that PowerCranks work to increase power and VO2max after about 48 hours of vigorous immersion PC training done over 6 weeks. It is what his independent study showed with a pretty clear statistical certainty.

 

[elapid]

My friend, P-values are calculated to evaluate the null-hypothesis. ... There has to be a control or they could not calculate the p-values.

etc, etc, etc

As far as scientific knowledge and study design are concerned, Frank, you are an epic fail.

 

[FrankDay]

etc, etc, etc

As far as scientific knowledge and study design are concerned, Frank, you are an epic fail.

If you say so. Please tell us how do you explain how Dixon calculated those p-values and why they were seemingly accepted by the CSEP? And, you might note, I didn't design the Dixon study. I am simply trying to explain, as I understand it, the rational behind their study design.

 

[elapid]

If you say so. Please tell us how do you explain how Dixon calculated those p-values and why they were seemingly accepted by the CSEP? And, you might note, I didn't design the Dixon study. I am simply trying to explain, as I understand it, the rational behind their study design.

You've been told on numerous occasions how the p-values were calculated. Before and after in the same group and not a control group.

There are lots of less than ideal studies being published. Sometimes they are published in lesser journals with low impact factors because these journals are less stringent in their requirements and are more willing to accept these lower level studies. The impact factors for Medicine and Science in Sports and Exercise and Journal of Strength and Conditioning Research are 4.48 and 1.80, respectively.

Regardless, numerous scientists and researchers have spoken out recently and all have criticized your "facts" and scientific design. Rather than steadfastly hold your position in the face of overwhelming criticism from well-respected people in the field, perhaps you can attempt to learn from those with more experience rather than be stubborn and argumentative.

 

[CoachFergie]

You've been told on numerous occasions how the p-values were calculated. Before and after in the same group and not a control group.

There are lots of less than ideal studies being published. Sometimes they are published in lesser journals with low impact factors because these journals are less stringent in their requirements and are more willing to accept these lower level studies. The impact factors for Medicine and Science in Sports and Exercise and Journal of Strength and Conditioning Research are 4.48 and 1.80, respectively.

Regardless, numerous scientists and researchers have spoken out recently and all have criticized your "facts" and scientific design. Rather than steadfastly hold your position in the face of overwhelming criticism from well-respected people in the field, perhaps you can attempt to learn from those with more experience rather than be stubborn and argumentative.

From my own experience I take it there is a considerable difference between being invited to give an oral presentation at a conference and getting published. My invitation to give a short oral presentation at WCSS was based from submission of an abstract. Would also expect that invitation does not equal endorsement of the study in any way.

Publication will require submission of the whole paper and then goes to peer review. Acceptance for a conference doesn't mean all that much. I suspect 90% of the poster and short oral presentations of research at any conference will never get published. This was the case for Dixon. Notable that neither Dixon or Luttrell have published anything since.

Franks P value comments just show how little he understands the scientific process.

 

[coapman]

I did??? Can you point me to that statement. If so, perhaps I had forgotten about Sam Gyde,

After a week of PC familiarization, can a masher continue to produce the same TT torque in his down stroke as he continues to train on PC's. If not, you have the proof that trying to apply additional torque during upstroke across the top and bottom will only result in an overall loss of power.

 

[JamesCun]

My friend, read Dixon again. He did his best to control for training effect. Let me ask you this question. How much would you expect the power of the average racer to increase after the end of their racing season as they move into the off season if they were to just continue their baseline training for the next 6 weeks? If you are going to suggest it would increase do you have a study to suggest this is so. I think most people think their power drops during the off season even though they continue to ride. That is the basis of the Dixon study design. If you have some real data to suggest that assumption is false show it to us all. Then answer the question as to why everyone doesn't stop intense training 6 weeks before their A race if they could expect a 14% increase in power over what they can expect continuing doing what they are doing.

Anyhow, again, as you know, Davis concluded, with a statistical probability of being wrong of about 1 in 100, that PowerCranks work to increase power and VO2max after about 48 hours of vigorous immersion PC training done over 6 weeks. It is what his independent study showed with a pretty clear statistical certainty.

What was the training protocol for the Dixon study? I've only seen the abstract and I'm sure we aren't basing everything on that limited amount of info.

 

[CoachFergie]

What was the training protocol for the Dixon study? I've only seen the abstract and I'm sure we aren't basing everything on that limited amount of info.

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.

Illustrates the folly of just reading abstracts. No information about how they defined aerobic and anaerobic and what types of aerobic and anaerobic training were performed. It is claimed, albeit by a guy with a track record of lying, that this was performed at the end of a season and all subjects were in peak fitness. How was this determined. At the end of most seasons I see a lot of overtrained people. Not ones I coach as we use power meters to make sure they don't overtrain

But without a control group there is no way to determine what caused the changes in performance. Considering several other similar studies (Sperlich was a similar training load) have not found similar improvements I suspect there were some pretty big measurement errors which is probably why the study was never published.

 

[sciguy]

What was the training protocol for the Dixon study? I've only seen the abstract and I'm sure we aren't basing everything on that limited amount of info.

I've never been able to understand after why Frank hasn't been given access to the complete study. Since he was the one that gave or loaned the Powercranks to the folks for the project you'd think the least they would do as a thank you is to provide him with the fine details of the whole study. Even more troubling, it makes no sense to me that Frank never sought these details out. There is enough inconsistency between what Frank as told us and what the limited abstract data implies to make all of us very interested in the finer details.

So what's stopping you from getting Dixon to cough up the full study details Frank? It certainly wouldn't be rude for you to ask for them as you provided a good deal of assistance.


Hugh

 

[FrankDay]

You've been told on numerous occasions how the p-values were calculated. Before and after in the same group and not a control group.

Really? Must have missed it. Since the p-value

In statistical significance testing, the p-value is the probability of obtaining a test statistic result at least as extreme as the one that was actually observed, assuming that the null hypothesis is true.

is a test of the null hypothesis I really don't understand how one can do a p-value calculation without some expectation as to what would have happened without the intervention (that is all a control group is) but I will await your reply to educate me.

There are lots of less than ideal studies being published. Sometimes they are published in lesser journals with low impact factors because these journals are less stringent in their requirements and are more willing to accept these lower level studies. The impact factors for Medicine and Science in Sports and Exercise and Journal of Strength and Conditioning Research are 4.48 and 1.80, respectively.

Indeed, and some of them are those so-called studies that show that PowerCranks have no benefit that last 5 or 6 weeks and involve part-time use. I guess they are useful in the sense that they reinforce what we say that it takes 6 weeks of use before most users start to see benefit. Why someone would design such a study to test our claims though is beyond me.

Regardless, numerous scientists and researchers have spoken out recently and all have criticized your "facts" and scientific design. Rather than steadfastly hold your position in the face of overwhelming criticism from well-respected people in the field, perhaps you can attempt to learn from those with more experience rather than be stubborn and argumentative.

Really, got a name or two? And exactly which of my "scientific designs" have they criticized since I have really had no hand in designing any of the studies under discussion. I did recently have some input in helping one researcher design a running study to help overcome the weaknesses in a previous study that was done without any input from me. That study showed a positive benefit.

 

[FrankDay]

I've never been able to understand after why Frank hasn't been given access to the complete study. Since he was the one that gave or loaned the Powercranks to the folks for the project you'd think the least they would do as a thank you is to provide him with the fine details of the whole study. Even more troubling, it makes no sense to me that Frank never sought these details out. There is enough inconsistency between what Frank as told us and what the limited abstract data implies to make all of us very interested in the finer details.

Yes, one would think that but my contact (who had contacted me all excited that the study had been selected for oral presentation) just disappeared after the presentation. I wish I had the complete study but I don't. But, the abstract is available to us all.

So what's stopping you from getting Dixon to cough up the full study details Frank? It certainly wouldn't be rude for you to ask for them as you provided a good deal of assistance.


Hugh

Nothing is stopping me. I would love to get my hands on it. All my efforts have failed though. Maybe you can contact one of the authors and convince them to release the study to me or someone else.

 

[FrankDay]

After a week of PC familiarization, can a masher continue to produce the same TT torque in his down stroke as he continues to train on PC's.

Yes, but they don't because if they do the cadence comes up so fast that they can't keep up on the back stroke so they tend to back off on the pushing during the transition.

If not, you have the proof that trying to apply additional torque during upstroke across the top and bottom will only result in an overall loss of power.

Sorry, no proof here.

 

[FrankDay]

What was the training protocol for the Dixon study? I've only seen the abstract and I'm sure we aren't basing everything on that limited amount of info.

I think there is enough detail in the abstract to answer your question.

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.

If you wanted to design a study to reproduce that description I am sure you would have no trouble.

 

[CoachFergie]

I've never been able to understand after why Frank hasn't been given access to the complete study. Since he was the one that gave or loaned the Powercranks to the folks for the project you'd think the least they would do as a thank you is to provide him with the fine details of the whole study. Even more troubling, it makes no sense to me that Frank never sought these details out. There is enough inconsistency between what Frank as told us and what the limited abstract data implies to make all of us very interested in the finer details.

So what's stopping you from getting Dixon to cough up the full study details Frank? It certainly wouldn't be rude for you to ask for them as you provided a good deal of assistance.


Hugh

You would think that Frank would have got the study from Dr Stephen Cheung who was an author of the study. Who is actively reviewing cycling products and performing exercise physiology research.

 

[JamesCun]

I think there is enough detail in the abstract to answer your question.If you wanted to design a study to reproduce that description I am sure you would have no trouble.

You can't really be serious here. That abstract says nothing about the study design. What is aerobic/anaerobic training? What was the training load before the study, what was the history and fitness level prior to the study, etc etc.

A change of 15% vo2 in a 6week period is huge. My first assumption would be measurement flaws or poor initial fitness of the subjects. Maybe they did the study after a huge training block and everyone was depressed. 6 weeks of recovery/training brought them back to normal levels.

The fact that you can't get access to the data is very telling. What legitimate researcher disappears and refuses to pass on data??

 

[Oldman]

You can't really be serious here. That abstract says nothing about the study design. What is aerobic/anaerobic training? What was the training load before the study, what was the history and fitness level prior to the study, etc etc.

A change of 15% vo2 in a 6week period is huge. My first assumption would be measurement flaws or poor initial fitness of the subjects. Maybe they did the study after a huge training block and everyone was depressed. 6 weeks of recovery/training brought them back to normal levels.

The fact that you can't get access to the data is very telling. What legitimate researcher disappears and refuses to pass on data??

...you've just entered the Mobius zone.

 

[coapman]

Yes, but they don't because if they do the cadence comes up so fast that they can't keep up on the back stroke so they tend to back off on the pushing during the transition.Sorry, no proof here.

The proof is in your answer. The fact is, even if you could train these weakest muscles to generate crank torque, to apply this extra torque at a cadence of 90, your brain/muscles will have to make twelve 90 deg direction changes per second in the forces being applied. As you said above, this is an impossible task and results in a weaker down stroke. The same applies when a rider tries to use the perfected circular pedalling style. In addition you can't combine a maximal force with a minimal force in the same leg as a PC user is trying to do without losing power in your maximal force. My special technique combines maximal force with maximal force in each leg's half of the pedalling circle (11-5 o'c)

 

[CoachFergie]

The proof is in your answer. The fact is, even if you could train these weakest muscles to generate crank torque, to apply this extra torque at a cadence of 90, your brain/muscles will have to make twelve 90 deg direction changes per second in the forces being applied. As you said above, this is an impossible task and results in a weaker down stroke. The same applies when a rider tries to use the perfected circular pedalling style. In addition you can't combine a maximal force with a minimal force in the same leg as a PC user is trying to do without losing power in your maximal force. My special technique combines maximal force with maximal force in each leg's half of the pedalling circle (11-5 o'c)

Wow, then any power meter would easily be able to detect a rider pedalling normally and a rider using your method. I mean studies by Lim showed that a power meter could detect the difference between tyres inflated to 60psi and 120psi. It's so cool having these tools so readily available to disprove Frank's and your bogus claims.

 

[Alex Simmons/RST]

You would think that Frank would have got the study from Dr Stephen Cheung who was an author of the study. Who is actively reviewing cycling products and performing exercise physiology research.

The data matches Joaquin's. 'nuff said.