The importance of crank length to the cyclist.

[coapman]

2. In keeping with the above, I have measured both my CdA and my sustainable power in a wide range of aero positions while using a wide range of crank lengths. What I have found is that if I go too low, my power drops more than my CdA, and shortening the cranks by up to 22 mm doesn't help.

After that testing of crank lengths, can you reveal what your height is and your ideal crank length, or is it a secret?

 

[acoggan]

Are you saying that just because life on earth evolved to efficiently do repetitive reciprocal antagonist muscle activation to efficiently walk, chew, wing flap, or run that cycling is "natural" because we get to invoke that spinal reflex?

Yes.

to go a step further, are you saying that because people learn to use, essentially, the same pattern in cycling that we do in walking or running, that this means this has to be the most efficient cycling pattern simply because it is related to the most efficient running or walking pattern? If so, do you have any studies that back up this contention? Really? Why on earth would a pattern (walking/running) that only allows actual propulsive force application for 0.2-0.5 of the time be optimal for an "invented" pattern that allows power application for 100% of the time?

Because our muscles have evolved to match the demands imposed by that motor pattern (or vice-versa).

 

[acoggan]

After that testing of crank lengths, can you reveal what your height is and your ideal crank length, or is it a secret?

1. 183 cm (but w/ short-ish legs for my heights, such that my b.b.-to-saddle distance is only 72.5 cm).

2. My sustainable power in the aero position was essentially constant across the range of crank lengths I tested (i.e., from 148 to 170 mm).

 

[FrankDay]

1. 183 cm (but w/ short-ish legs for my heights, such that my b.b.-to-saddle distance is only 72.5 cm).

2. My sustainable power in the aero position was essentially constant across the range of crank lengths I tested (i.e., from 148 to 170 mm).

The question I would have is what position changes did you make as you shortened the cranks? Did you try to lower your front end any when you went to the shorter cranks? Or, did you keep it the same? Or, did you raise it as you raised your saddle? And, what do you think would have happened if you had tried even shorter cranks, 135 for example?

Do you have some pictures of your position tested with these different crank lengths?

 

[FrankDay]

Because our muscles have evolved to match the demands imposed by that motor pattern (or vice-versa).

But the motor pattern of walking/running isn't the same as cycling might allow. Walking/running only involve weight bearing when the leg is extended and only involve applying motive force in the horizontal direction parallel to the earth with a slight component to raise the body CG to compensate for the "fall" when off the ground. It is particularly narrow minded in my opinion to think this coordination is the best a cyclist can do.

The great thing about biological systems they have evolved to be able to adapt to a wide variety of demands put upon them. To say a cyclist cannot adapt to a more extensive demand when attached to pedals and constrained to a circular motion because we evolved to the demands of running ignores the adaptive nature of the species. Prove your contention or accept that something more might actually be possible.

 

[Ripper]

This thread

So the majority of this thread (1,400+ posts) is related to a wingnut salesman for powercranks and some other dude asking random questions covered with science speak Wow

There are intermittent reality checks provided by Coach Fergie and Andrew Coggan.

 

[Martin318is]

Hey - I'd like to think that I made a contribution at times too...

 

[acoggan]

The question I would have is what position changes did you make as you shortened the cranks? Did you try to lower your front end any when you went to the shorter cranks? Or, did you keep it the same? Or, did you raise it as you raised your saddle? And, what do you think would have happened if you had tried even shorter cranks, 135 for example?

Do you have some pictures of your position tested with these different crank lengths?

I measured my sustainable (i.e., 20 min) power when using 148, 165, or 170 mm cranks at saddle-to-elbow pad distances of 10.5, 16.5, and 20.5 cm, as well as when sitting upright (i.e., hands in outboard position with 10.5 cm drop to elbow pads). Toss in a couple of 'run-in' efforts and a couple of repeats, and we're talking about over 15 full-out efforts.

After evaluating the above data in the context of numerous prior wind tunnel and field test experiments to determine the effect of elbow pad height on my CdA, below is the best position (i.e., highest power:CdA) for me under UCI rules - anything lower than this reduces my power more than my CdA:

 

[acoggan]

But the motor pattern of walking/running isn't the same as cycling might allow. Walking/running only involve weight bearing when the leg is extended and only involve applying motive force in the horizontal direction parallel to the earth with a slight component to raise the body CG to compensate for the "fall" when off the ground. It is particularly narrow minded in my opinion to think this coordination is the best a cyclist can do.

The great thing about biological systems they have evolved to be able to adapt to a wide variety of demands put upon them. To say a cyclist cannot adapt to a more extensive demand when attached to pedals and constrained to a circular motion because we evolved to the demands of running ignores the adaptive nature of the species. Prove your contention or accept that something more might actually be possible.

While one can certainly learn to pedal differently, the question is, why would you want to? Our muscles are already optimized (in terms of their size, attachments, and contractile speeds) for upright, bipedal locomotion; it therefore simply makes sense to take advantage of that fact, especially since there is absolutely zero evidence that anything else is better.

 

[FrankDay]

While one can certainly learn to pedal differently, the question is, why would you want to? Our muscles are already optimized (in terms of their size, attachments, and contractile speeds) for upright, bipedal locomotion; it therefore simply makes sense to take advantage of that fact, especially since there is absolutely zero evidence that anything else is better.

Why would you want to? Did you really ask that question? So, let me get this straight. You don't think it would be worth the effort to optimize the muscles we have for the demands and possibilities of cycling because we come optimized for a "upright, bipedal locomotion" and because of this it makes sense to you to take advantage of what is there naturally, before we get on our first bike? By that logic, cyclists would be better served by spending all their training time running (better developing that natural bipedal locomotion musculature and coordination) and only hop on their bikes for racing. Specificity indeed. LOL.

 

[FrankDay]

I measured my sustainable (i.e., 20 min) power when using 148, 165, or 170 mm cranks at saddle-to-elbow pad distances of 10.5, 16.5, and 20.5 cm, as well as when sitting upright (i.e., hands in outboard position with 10.5 cm drop to elbow pads). Toss in a couple of 'run-in' efforts and a couple of repeats, and we're talking about over 15 full-out efforts.

After evaluating the above data in the context of numerous prior wind tunnel and field test experiments to determine the effect of elbow pad height on my CdA, below is the best position (i.e., highest power:CdA) for me under UCI rules - anything lower than this reduces my power more than my CdA:

That is cool. What drop and crank length does that position represent? What percentage of the people who are reading this thread do you think have a position that looks like that? In other words, why would you think that your experience translates well to the majority following this thread?

 

[TarmacExpert]

While one can certainly learn to pedal differently, the question is, why would you want to? Our muscles are already optimized (in terms of their size, attachments, and contractile speeds) for upright, bipedal locomotion; it therefore simply makes sense to take advantage of that fact, especially since there is absolutely zero evidence that anything else is better.

When trying to establish whether or not two things are different, my statistics text book from my Uni maths course describes the outcome of failing to find a difference as "the null hypothesis cannot be rejected". I.e. we cannot discount the possibility that the null hypothesis is true. This is far from the same thing as finding the null hypothesis to be true beyond reasonable doubt. Of course, it is possible to then state the hypotheses differently to instead test whether we can conclude beyond reasonable doubt that two things are the same - I don't think I can tell whether or not this was done from the information I've seen on the pedalling technique studies.

It seems to me that testing different pedalling techniques is inherently quite problematic. For example, there could be benefits to a different technique, even if efficiency and maximum power are unaffected. E.g. making use of more muscles would increase the total available muscle glycogen, which could affect time to exhaustion when that is a limiting factor. There may be other fatigue mechanisms where using more muscles has benefits even if efficiency is unchanged. There is also the issue of it potentially taking many months of training for someone to fully adapt to a different technique. Cross-sectional studies risk being confounded by better cyclists being better due to other factors that might outweigh technique differences. Sometimes when someone is really good at something, they can succeed while dismissing things that less talented people need to optimise to do well. E.g. you can often see slower swimmers with visibly better technique than faster swimmers, with the faster swimmers having a sufficiently superior physiology to get away with laughing at the idea that they need to work on their technique.

Perhaps there really is no impact, but I'm personally not yet convinced that the story won't change in the future with further research, just as it has for other areas in the past.

 

[coapman]

While one can certainly learn to pedal differently, the question is, why would you want to?

Because the use of muscles in pedaling and running is only similar when riding 'out of the saddle', with hips well over BB. Try running with your hips in that rearward position as when seated on the saddle. 'Out of the saddle ' pedaling is the most effective way to power the cranks, by changing technique you can reproduce this same effect while seated. All that's involved is knowing how to use the muscles of the lower leg instead of leaving them lying idle. Alex Simmons is living proof of this (idling) fact.

 

[FrankDay]

When trying to establish whether or not two things are different, my statistics text book from my Uni maths course describes the outcome of failing to find a difference as "the null hypothesis cannot be rejected". I.e. we cannot discount the possibility that the null hypothesis is true. This is far from the same thing as finding the null hypothesis to be true beyond reasonable doubt. Of course, it is possible to then state the hypotheses differently to instead test whether we can conclude beyond reasonable doubt that two things are the same - I don't think I can tell whether or not this was done from the information I've seen on the pedalling technique studies.

I am not aware of a single instance of this having been done

It seems to me that testing different pedalling techniques is inherently quite problematic. For example, there could be benefits to a different technique, even if efficiency and maximum power are unaffected. E.g. making use of more muscles would increase the total available muscle glycogen, which could affect time to exhaustion when that is a limiting factor. There may be other fatigue mechanisms where using more muscles has benefits even if efficiency is unchanged. There is also the issue of it potentially taking many months of training for someone to fully adapt to a different technique. Cross-sectional studies risk being confounded by better cyclists being better due to other factors that might outweigh technique differences. Sometimes when someone is really good at something, they can succeed while dismissing things that less talented people need to optimise to do well. E.g. you can often see slower swimmers with visibly better technique than faster swimmers, with the faster swimmers having a sufficiently superior physiology to get away with laughing at the idea that they need to work on their technique.

The real problem is testing whether one pedaling technique is better than another comes from the need to ensure that subjects are trained in a certain pedaling technique before testing. One needs to test subjects currently using a particular technique then adequately train them to use another technique and test again. Then, it would be optimum, to have them return to the previous technique if there was a difference to ensure the difference was not due to the training. Until my product it has been essentially impossible to reliably change any pedaling technique in a time-frame acceptable to the typical university study. Even with PowerCranks, we don't believe that 6 weeks is enough time to reliably change most riders technique. Even if it were, it seems to me that any study looking at this needs to also measure pedal forces to demonstrate that pedaling technique is indeed different when doing the measurements.

Perhaps there really is no impact, but I'm personally not yet convinced that the story won't change in the future with further research, just as it has for other areas in the past.

The problem is, as I see it, is the research in this area is simply atrocious. Yet, it is jumped upon by those with substantial biases as proving those biases.

 

[acoggan]

That is cool. What drop and crank length does that position represent?

10.5 cm drop, 170 mm cranks.

What percentage of the people who are reading this thread do you think have a position that looks like that? In other words, why would you think that your experience translates well to the majority following this thread?

I don't know, and I don't care. I was merely answering your question.

 

[acoggan]

The problem is, as I see it, is the research in this area is simply atrocious. Yet, it is jumped upon by those with substantial biases as proving those biases.

Pot, meet kettle.

 

[FrankDay]

I don't know, and I don't care. I was merely answering your question.

Well, you are here pontificating on a thread that many are following. If you are telling us that everything you say is based upon your own experience I think that now that we have a picture of "your experience" that most of the people reading this thread can assume that anything you say on the topic doesn't apply to them.

 

[FrankDay]

The problem is, as I see it, is the research in this area is simply atrocious. Yet, it is jumped upon by those with substantial biases as proving those biases.

Pot, meet kettle.

Huh? It would be inappropriate for me to do any "real" research on this subject since I would have a vested interest in the outcome which, of course, would bias any results. If you disagree and contend that at least some research in this area is not atrocious I would like for you to please put forward a study that you think is really great along these lines. And, why you are at it you can tell everyone why it is so wonderful.

 

[CoachFergie]

The problem is, as I see it, is the research in this area is simply atrocious. Yet, it is jumped upon by those with substantial biases as proving those biases.

The depth and quality of research in this area is considerable and the only person questioning in such a casual manner (without presenting real data to the contrary) is you.

I just came back from NZ Club Championships and 330 riders in the time trial (my riders won 4 Gold and 1 Bronze, nothing scientific about it, just bragging) and majority including numerous Masters riders age 50+ with excellent positions.

Some of us have more in our "aero position toolkit" than changing crank length. When you only see one solution to every problem in cycling it's easy to see the basis of faulty logic.

 

[Caruut]

Huh? It would be inappropriate for me to do any "real" research on this subject since I would have a vested interest in the outcome which, of course, would bias any results. If you disagree and contend that at least some research in this area is not atrocious I would like for you to please put forward a study that you think is really great along these lines. And, why you are at it you can tell everyone why it is so wonderful.

Or you could possibly hire someone to do so? Companies conduct scientific tests on their own products all the time. Who do you think is gonna pay for a study into the effects of crank length? Only those who have an interest in finding out. If you truly believed in your miraclecranks, then you'd have paid for a study by now. It seems clear to me that you do not.

 

[Boeing]

What size cranks should I use when I go vegan?

 

[FrankDay]

Or you could possibly hire someone to do so? Companies conduct scientific tests on their own products all the time. Who do you think is gonna pay for a study into the effects of crank length? Only those who have an interest in finding out. If you truly believed in your miraclecranks, then you'd have paid for a study by now. It seems clear to me that you do not.

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?

 

[CoachFergie]

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?

Numerous companies pay for independent research. Ludicrous thing in this example is that the research has been performed and independent cranks or manipulating crank lengths has no significant effect on performance.

Naming World and Olympic Champions is totally meaningless. Many riders use nasal strips and there has been no conclusive evidence of their benefit either. What about all the people who use IC's and have not improved or the World and Olympic Champion's who don't ride IC's or **** around with crank length. What explains their performance?

 

[FrankDay]

Numerous companies pay for independent research.

If a company pays for it then, by definition, it is not independent. Trust those studies paid for by the cigarette companies on smoking, did you?

 

[CoachFergie]

If a company pays for it then, by definition, it is not independent. Trust those studies paid for by the cigarette companies on smoking, did you?

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.