The importance of crank length to the cyclist.

[FrankDay]

Mizone (sports drink) funded research of their product in comparison to Gatorade and Powerade. The researcher did the study and submitted the results back to them and because he found a difference in performance between the drinks the study was published. The only catch was having to publish it in another journal to MSSI as Gatorade sponsor that journal and the results of the performance test used were in favour of Mizone.

I'm sure the Ciggarette companies have sponsored some real doozy's over the years but whether they funded independent research is another question.

Many of those cigarette funded studies got published also. The fact is: if a company funds a study it is not independent. It doesn't matter how good the study is, there is the potential for bias.

 

[acoggan]

Many of those cigarette funded studies got published also. The fact is: if a company funds a study it is not independent. It doesn't matter how good the study is, there is the potential for bias.

You're as much of a hypocrite as Tim Noakes (which isn't the only trait you seem to share):

http://www.ncbi.nlm.nih.gov/pubmed/14666944

 

[Caruut]

Hiring someone to do research inserts the same bias into the research. Only truly independent research is independent and, supposedly, without bias. I have done my own research and my product claims are based upon that research (and subsequent customer reports). While my "research" may not pass the test of many here it gave me results that seem to have passed the test of time in the marketplace and it does seem to have been good enough to get a few pretty good riders to give them a try and, then, actually stick with them (BTW, this off season we got a phone call from Taylor Phinney saying "Cadel tells me I need to get on these" - no study necessary for him!). Subsequent "independent" papers that have shown a positive result for my product have been criticized not on the methods but on the sole fact that I provided cranks for them to do the study and they didn't disclose this fact in the paper.

So, tell me again why I should pay to have studies done on my product which will only result in the same old criticisms from the same noise sources, when I have many many World and Olympic champions using the product now?

You should pay to have independent studies done because people like me might believe you then. As it is, any hint of actually having to back up the science is met with childish retorts; "Well if it's good enough for Cadel, it's good enough for you", or "I dunno about scientific testing, but it's stood the test of time in the marketplace". You keep yabbering on about how someone should do the study - I don't know how you think this is going to happen. Scientific studies do not just "appear"., someone has to spend time and money getting them done. Unless you believe some kind benefactor will volunteer their money, a well-meaning scientist will volunteer their time, or a government will suddenly go "Good lord, it's just struck me that we have no idea what the optimum crank length is!", then i that study is going to get done, you're going to have to pay for it.

Or could it be that you already paid for it, and the study came back saying "no difference"?

 

[blutto]

You're as much of a hypocrite as Tim Noakes (which isn't the only trait you seem to share):

http://www.ncbi.nlm.nih.gov/pubmed/14666944

...would this be the same Tim Noakes of whom you speak so highly..

http://dirtypitches.co.za/blog/tag/tim-noakes/

Cheers

blutto

 

[FrankDay]

You're as much of a hypocrite as Tim Noakes (which isn't the only trait you seem to share):

http://www.ncbi.nlm.nih.gov/pubmed/14666944

HUH??? The fact that there is a potential for bias doesn't mean that there is bias. The study exists and the results are what they are. Am I supposed to ignore those results because I helped the researcher out by providing him a pair of cranks so he could do the study? Your comment here (calling me a hypocrite) is exactly why it isn't worth my paying someone to do a "complete" study lasting 6 months or so. You discount Luttrell simply because I provided some cranks to him so he could do his little study. What would you say if I financed the whole thing?

I have recently been approached by a researcher in Europe who wants to do a study on the running benefits of the PowerCranks. Which is better for the world? Should I be "pure" and not provide him with product, meaning the study is probably not done at all, or provide him with product (as I did with Luttrell and others, including Dixon (who also had positive results), and even some others who have published "negative" results), which helps the study get done but injects some potential bias (but, at least, the study gets done and people can evaluate it)?

 

[acoggan]

...would this be the same Tim Noakes of whom you speak so highly..

http://dirtypitches.co.za/blog/tag/tim-noakes/

Cheers

blutto

Ex Africa semper aliquid novi.

 

[acoggan]

HUH??? The fact that there is a potential for bias doesn't mean that there is bias. The study exists and the results are what they are. Am I supposed to ignore those results because I helped the researcher out by providing him a pair of cranks so he could do the study? Your comment here (calling me a hypocrite) is exactly why it isn't worth my paying someone to do a "complete" study lasting 6 months or so. You discount Luttrell simply because I provided some cranks to him so he could do his little study. What would you say if I financed the whole thing?

I have recently been approached by a researcher in Europe who wants to do a study on the running benefits of the PowerCranks. Which is better for the world? Should I be "pure" and not provide him with product, meaning the study is probably not done at all, or provide him with product (as I did with Luttrell and others, including Dixon (who also had positive results), and even some others who have published "negative" results), which helps the study get done but injects some potential bias (but, at least, the study gets done and people can evaluate it)?

1. I discount the study in question because of the poor experimental design (e.g., no control group) and the fact that the results cannot be replicated by others. That Potteiger failed to fulfill his ethical obligation to state any potential conflicts of interest reflects poorly on him, but has nothing to do w/ how much weight I give the study (although it could very well influence others who aren't aware that you supported the study).

2. As for what you should do, I think you should stop whinging about potential bias in research due to the source of support while simultaneously citing studies you helped fund because you like the results. Doing so makes you a hypocrite, just as Noakes' acceptance of support from sports drink/nutrition companies while complaining that others doing so have been "bought" makes him one.

 

[FrankDay]

You should pay to have independent studies done because people like me might believe you then. As it is, any hint of actually having to back up the science is met with childish retorts; "Well if it's good enough for Cadel, it's good enough for you", or "I dunno about scientific testing, but it's stood the test of time in the marketplace". You keep yabbering on about how someone should do the study - I don't know how you think this is going to happen. Scientific studies do not just "appear"., someone has to spend time and money getting them done. Unless you believe some kind benefactor will volunteer their money, a well-meaning scientist will volunteer their time, or a government will suddenly go "Good lord, it's just struck me that we have no idea what the optimum crank length is!", then i that study is going to get done, you're going to have to pay for it.

Or could it be that you already paid for it, and the study came back saying "no difference"?

Look, if you choose to ignore what has been done already showing that these things have real potential (Luttrell, Dixon, Fernández-Peña, Nuckles, and Leirdal) that is fine with me (and with your competition who are using them, I am sure). One more study, paid for by me, probably won't change your mind.

Other related studies are located here, if you are interested.

 

[FrankDay]

1. I discount the study in question because of the poor experimental design (e.g., no control group) and the fact that the results cannot be replicated by others. That Potteiger failed to fulfill his ethical obligation to state any potential conflicts of interest reflects poorly on him, but has nothing to do w/ how much weight I give the study (although it could very well influence others who aren't aware that you supported the study).

No control group???? From the abstract:

We examined the effects of 6 wk of training on cyclists using Powercranks (n=6) or normal cranks (n=6)

Sounds like a control group to me. Do you actually read the stuff you comment on?

And, no one has actually tried to replicate his results. Replicating the results requires actually replicating the study in every way. Luttrell's study group were much less capable than others who have "repeated" this study using more elite cyclists. And, others have used a smaller stress, (5 weeks vs 6, 10 hours vs 18) Therefore, it is quite possible that Luttrell's group responded, where others didn't, due to these differences. One must understand all these nuances to be able to fairly evaluate and compare these differing results.

And it is quite possible that Potteiger "failed to fulfill his ethical obligation to state any potential conflicts of interest" because he probably did not know of them. The cranks were sent to Luttrell.

2. As for what you should do, I think you should stop whinging about potential bias in research due to the source of support while simultaneously citing studies you helped fund because you like the results. Doing so makes you a hypocrite, just as Noakes' acceptance of support from sports drink/nutrition companies while complaining that others doing so have been "bought" makes him one.

Hey, I even like and discuss results, and put them on my web page, that seemingly show no benefit (Burns), because these show that if you don't use them enough don't expect any benefit. I supported Burns. Just because a "study" is negative does not make it well-conceived or without bias either. One has to be able to discuss everything. Of course, part of your problem is you actually refuse to even try these things, having pre-judged them to be useless, so your understanding of what would constitute a good study design to test the benefits of PowerCranks is based upon personal bias and ignorance.

 

[Semper Fidelis]

What size cranks should I use when I go vegan?

This is the best question I have seen in a while. I think you will prob need to use 175's but that is just a guess. What about wheel sizes?

 

[coapman]

HUH??? The fact that there is a potential for bias doesn't mean that there is bias. The study exists and the results are what they are. Am I supposed to ignore those results because I helped the researcher out by providing him a pair of cranks so he could do the study? Your comment here (calling me a hypocrite) is exactly why it isn't worth my paying someone to do a "complete" study lasting 6 months or so. You discount Luttrell simply because I provided some cranks to him so he could do his little study. What would you say if I financed the whole thing?

If you got two or three PC riders who are equally proficient on both standard and PC type cranks and asked them to do a seated sprint to max power output on each set of cranks. What results would you expect to get and how would their pedaling graphs (standard v PC) compare at max power output.

 

[FrankDay]

If you got two or three PC riders who are equally proficient on both standard and PC type cranks and asked them to do a seated sprint to max power output on each set of cranks. What results would you expect to get and how would their pedaling graphs (standard v PC) compare at max power output.

If they were equally proficient they would pedal both cranks in the same fashion. Therefore I would expect the results to be the same. The problem comes when they are not equally proficient, which is the usual case because this is very difficult to achieve.

Edit: The entire purpose of the PowerCranks is to change the way the rider unconsciously pedals the bike. If they are successful in this task then it shouldn't matter what cranks are on the bike as the rider should pedal the same. How long this takes can be quite variable and depends a lot on how many years of pedaling in a different fashion must be undone.

 

[veganrob]

This is the best question I have seen in a while. I think you will prob need to use 175's but that is just a guess. What about wheel sizes?

Yeah, that is what I use 175's. I am 6'1 and have a saddle height of 80 cm.

hope that helps.

Oh, and 700 on my road and TT , got both 26 and 29 mtn bikes




Cheers

Rob

 

[FrankDay]

Another report: "After you and I talked last week I changed from the 150 to the 130 length. After a bit it felt ok and as with the 150's I found climbing easier then with my 172.5's. I also found standing climbing with the 130's to be very easy and not nearly as brutal to my heart rate as is climbing on 172.5 PC's."

 

[Ripper]

Edit: The entire purpose of the PowerCranks is to ... give you a placebo effect and make you think you are a better cyclist

Fixed that for you

 

[Alex Simmons/RST]

Popped in and noticed this was still running....

http://www.youtube.com/watch?feature=player_detailpage&v=lGV5i_l65PA

Like the original, you note that despite being away for a long time there is no actual change in the story.

 

[CoachFergie]

So many things to experiment with in the performance equation and after 1000+ posts no valid or reliable data suggesting we should test crank length. Well done Frank.

 

[FrankDay]

So many things to experiment with in the performance equation and after 1000+ posts no valid or reliable data suggesting we should test crank length. Well done Frank.

And, not a single shred of anything suggesting we shouldn't. Seems, that is exactly the type of topic that needs more discussion such that it might, hopefully, lead to those studies that might address this question. Isn't that the point? Thanks for participating.

 

[CoachFergie]

And, not a single shred of anything suggesting we shouldn't. Seems, that is exactly the type of topic that needs more discussion such that it might, hopefully, lead to those studies that might address this question. Isn't that the point? Thanks for participating.

So experimenting for experimentations sake.

As a coach looking for performance improvement (cause who would pay my exorbitant fees if I didn't improve performance) I base my experimentation off research that shows a real improvement like training, diet, recovery, pacing, planning of training, goal setting, tactics, race day preparation and yes equipment selection.

A maximum 4watt improvement for the tallest and shortest of riders using 170mm cranks is no where close to experimenting when riders performing 2 weeks of short interval training see a 100% improvement in time to failure on the bike. I know where I will invest my time experimenting.

 

[FrankDay]

I know where I will invest my time experimenting.

If only we all could be as smart as you. For those of us who are not we have to resort to discussions such as this.

 

[CoachFergie]

Perhaps you want to start a thread on the importance of coaching as my riders spend more money per year on me than a power meter

 

[42x16ss]

If only we all could be as smart as you. For those of us who are not we have to resort to discussions such as this.

Umm, I'm not sure that you have to be some kind of genius to recognise that perfecting training, diet, recovery, peaking etc will yield far greater and more lasting results than some gear upgrades.

Get a good coaching program, some kind of effort measuring device (even just a HRM W/Cadence), eat well and get plenty of rest.

 

[CoachFergie]

Umm, I'm not sure that you have to be some kind of genius to recognise that perfecting training, diet, recovery, peaking etc will yield far greater and more lasting results than some gear upgrades.

Get a good coaching program, some kind of effort measuring device (even just a HRM W/Cadence), eat well and get plenty of rest.

I may be 2 standard deviations above the mean but MENSA won't be knocking on my door any time soon.

Dr Will Hopkins suggested that a 0.8-1% improvement was the minimal performance improvement worth pursuing so 0.5% for a selected few doesn't cut the mustard.

The only person arguing for the importance of crank length has a strong commercial bias.

 

[Boeing]

I may be 2 standard deviations above the mean but MENSA won't be knocking on my door any time soon.

Dr Will Hopkins suggested that a 0.8-1% improvement was the minimal performance improvement worth pursuing so 0.5% for a selected few doesn't cut the mustard.

The only person arguing for the importance of crank length has a strong commercial bias.

it’s fine to share things about yourself. there are plenty of forums for it. in fact you can start a thread fyi. you can talk about yourself here as long as you loop the conversation back to the person who initiated the topic with out malicious intent to destroy them and prop yourself. . The best rule to follow is simply not to jump in too early with something about yourself all the damn time; the earlier you interject, the more likely you are to be making a play to get the attention on yourself. Instead, let the person tell most of their story or problem first, and then share your own experience.

internet conversational narcissists such as yourself always seek to turn the attention of others to back themselves . many posters here might disagree with frank but they believe the intent of this conversation was more cooperative instead of competitive.

he might indeed sell a product. at least he is neither consciously it subconsciously selling himself every sentence.

memo to mods kill this thread and frank lives on. kill this thread and coach has no place to go

 

[TarmacExpert]

A maximum 4watt improvement for the tallest and shortest of riders using 170mm cranks is no where close to experimenting when riders performing 2 weeks of short interval training see a 100% improvement in time to failure on the bike. I know where I will invest my time experimenting.

Earlier in this thread I mentioned that I had changed from 165mm cranks to 175mm after seeing Frank's wind tunnel data. I lowered my saddle by 1cm, so my thighs were coming 2cm higher at the top of the pedal stroke relative to full extension, which ought to be more aero, as it will get more of them behind my arms as well as making the thighs more horizontal. I have made some other changes since my last field test, so am not claiming that this is evidence of the effect of that specific change, but I did some field testing after the change and recorded my lowest ever field test CdA.

I then did my first 10 mile TT since the change last weekend, and improved my power PB by 3W, and my time PB by 25 seconds, with 20:08, a fairly respectable time.

So, I'm not unhappy with my experiment so far, and intend to try 180mm cranks when Rotor makes them available for the 3D models.

As for the benefits of interval training, I've been reaping those benefits for many months, but still managed to do power PBs for my interval sessions after the switch to 175mm cranks. Again, not saying this is necessarily cause and effect, but if Rotor sold a version of their 3D crank that allowed it to be adjusted in 5mm increments over a wide range, I'd personally feel it was worth experimenting with (at the same time as training in the best way I know how to). I think the limiter for me will actually be ground clearance, 175mm is already getting pretty close to the ground, and I think anything longer than 180mm would be unworkable with the low BB of my TT bike, indeed even 180mm might cause problems.