The importance of crank length to the cyclist.

[onetrack]

Martin (2001) found a significant drop in ability to produce power as crank length went from 145 to 120mm.

That's hard data rather than personal observations or input from someone who markets adjustable length cranks.

Send me a power meter, and I will gladly submit the numbers I am putting out at various crank lengths.

 

[blutto]

1. You're confusing learning effects with training effects.

2. You can find all of Jim's crank length studies by searching PubMed, and download at least those published in J Appl Physiol for free.

...nah...but you are definitely confusing a tongue-in-cheek statement with something that is not...wasn't the kidding aside comment an obvious enough clue...

...ok ok...all kidding aside...no really...thanks for the info on how to access the articles...

Cheers

blutto

 

[FrankDay]

Now you're just being purposely obtuse. Try doing a free weight squat, using a rack in the standard positon. Next try it with your back straight up and down.

It is not being obtuse. There has to be a physiological explanation as to why simply bending over causes the same legs to lose power. Then, once one understands what that reason is or reasons are for the power loss one can examine if something like shorter cranks addresses some of those issues. Isn't that sort of what this thread is intended to be all about?

 

[FrankDay]

Send me a power meter, and I will gladly submit the numbers I am putting out at various crank lengths.

Don't bother because if the numbers don't fit their bias they won't believe you anyhow and they will conclude it must be placebo since you are such an advocate for the change already.

 

[FrankDay]

the part in bold leaves me dumbfounded...

Brad Wiggans and Tommy Voeckler are nothing alike physically, nor are their bikes set up the same way. Brad and Fabian are closer physically and they still don't have the same position.

If we were to accept the idea that we are all pretty much the same then nobody would need to be positioned professionally, we could just buy offf the rack and go racing. If we were all the same then there would be a higher quantity of conclusive research published because of the removal of variation

Nothing alike physically? Really? How on earth do doctors ever learn of all these idiosyncracies to be able to operate if ever necessary.

Last I looked, while there are some variations, everyone's hip joint has pretty much the same range of motion and the same type of ball joint. the muscles use the same contractile mechanism and insert on the same bones in pretty much the same relative positions, etc. etc. So, while there is some size variations these are so minor that they do not interfere with the basic anatomy and physiology of how the body works. I am not aware of a single study where it has been concluded that cyclists need be sorted by size and shape before a study might apply to them. Perhaps it is true but I don't believe that work has been done. No study would ever have any relevance if we were all so different that we each had to be studied individually before any conclusions could be drawn.

So, I guess it is possible one might find an outlier who behaves completely differently (maybe Alex's scrunched up rider is an example) but most science is looking at the average person, which is pretty well defined.

 

[FrankDay]

1. Neither my wife nor I find a measurable loss of power in the aero position with normal cranks. We do train in that position a good bit.

2. Since those using Powercranks must rely on their hip flexors to raise the rear pedal the "scrunched" position puts the hip flexors are into a very poor bio-mechanical orientation to exert sufficient force to raise the pedal. The action of the quads on the other hand is unhindered by being scrunched.

To get the pedal over the top one must either rely on the hip flexors, or push it up using the other leg, or use some combination of these two ways. Most use the "some combination" approach. It may very well be that there may be a discernible difference in effect between PC'ers and mashers. I don't know. And, for you, your "losses" may be small because you are not very low (choosing to not go lower because you could sense a power loss coming) or you have the flexibility of a circus contortionist. I don't know.

Since, to my knowledge this work has never been done it seems like this would make for an "easy" masters thesis. It would be especially interesting if one also tried to correlate flexibility to the amount of power loss.

 

[blutto]

Now you're just being purposely obtuse. Try doing a free weight squat, using a rack in the standard positon. Next try it with your back straight up and down.

...might be better to use a leg press machine with a moveable back...tried that this morning in the gym I frequent...very interesting...there is definitely a discernable difference though beyond my abilities to understand why ( no real grounding in exercise physiology I'm afraid )...

...bottom line...seems much easier to move weight as hip angle opens up...not scientific perhaps but definitely repeatable and something anyone with access to a well equipped gym can try...

Cheers

blutto

 

[blutto]

. No study would ever have any relevance if we were all so different that we each had to be studied individually before any conclusions could be drawn.

So, I guess it is possible one might find an outlier who behaves completely differently (maybe Alex's scrunched up rider is an example) but most science is looking at the average person, which is pretty well defined.

...kinda funny but this post touches of some of the major gripes I have with a fundamentalist application of science...

...a couple of points...first, understand that the average person mentioned in the second line in the quoted section does not exist except perhaps as an invented prop to allow science to operate( see statement 1 above as how important average is to science )...and second, could one, or should one, consider a winner, especially a dominant winner, to be an outlier...and if it that is in fact the case one could make the argument that science, because it, by definition focuses on the average, never really deals with the special conditions that define the winner ( the outlier ) ( and for that matter each and everyone of us individuals...because, like, nobody is really average are they? )...

... and one last thing...in this week's newspaper was an article on the absolute failure of the science of economics over the last decade...one the lines that stood was the following....economists mistook impressive-looking mathematics, and the science it engenders, for truth...cycling sciences and its disciples do the same ...and the truth for us, my friends, is on the road, not in the journals ( which are usually playing catch-up to the outliers...whether in excercise physiology or any other science..neither Newton nor Einstein were average but CoachWhatEver certainly is...in fact its his calling card...)...

Cheers

blutto

 

[FrankDay]

...kinda funny but this post touches of some of the major gripes I have with a fundamentalist application of science...

...a couple of points...first, the average person mentioned in the second line in the quoted section does not exist except perhaps as a prop to allow science to operate...and second, could one, or should one, consider a winner, especially a dominant winner, to be an outlier...and if it that is in fact the case one could make the argument that science, because it, by definition focuses on the average, never really deals with the special conditions that define the winner ( the outlier ) ( and for that matter each and everyone of us individuals...because, like, nobody is really average are they? )...

Cheers

blutto

Interesting thoughts here as to how one might apply science. I think we can all agree that science is generally a good thing but it certainly has its limitations. For instance, in physics one cannot look at any one uranium atom and be able to predict when it will decay but it can look at the entire population and predict how the group will decay and be able to determine an accurate half-life. I think this issue becomes especially troublesome in this area of exercise physiology, where there are so many variables and so much training time is involved. What really is important in setting people apart?

And, what to do with outliers who are winners? The Usain Bolt's of the world. Is he a freak or simply a random confluence of small advantages leading to a large advantage or something else? Before Bolt I believe it was considered a disadvantage for a sprinter to be tall. Maybe it is but he makes up for it with other physiologic advantages or maybe it isn't. How does one know?

 

[blutto]

How does one know?[/QUOTE

...indeed...one can, as one does in historical studies ( my field ) work thru the material using experience and an understanding of methodology and past work in the area as a guide...or one can drive down the highway using only the rearview mirror for direction ( the analogy for science fundamentalism at its worst )...

...stumble forward a la historical studies and learn from your mistakes may be the best avenue available to us...and/or discussions like this to perhaps limit the number of mistakes...though I guess also bring a thick skin to weather the lumps when we are wrong which we will all at some point be...

Cheers

blutto

 

[FrankDay]

...stumble forward a la historical studies and learn from your mistakes may be the best avenue available to us...and/or discussions like this to perhaps limit the number of mistakes...though I guess also bring a thick skin to weather the lumps when we are wrong which we will all at some point be...

It is hard to advance the field (any field) if one's major concern is to avoid making mistakes or ever being found to be wrong.

I recently heard an interview with a co author with Stephen Hawking about their new book. They were discussing a point and this author was confused about what Stephen was saying so went back and showed him something he had written earlier. Stephen came back to him "well, I was wrong."

 

[CoachFergie]

Casting doubts over science does nothing to address the absence of evidence for running a short crank. No significantly greater power, no significantly improved efficiency and based on riders positions from World Time Trial Champs no apparent limit to attaining a horizontal torso and aerodynamic position while delivering sustained power.

 

[blutto]

Casting doubts over science does nothing to address the absence of evidence for running a short crank. No significantly greater power, no significantly improved efficiency and based on riders positions from World Time Trial Champs no apparent limit to attaining a horizontal torso and aerodynamic position while delivering sustained power.

...actually its casting doubts over your use of science...science is a wonderful tool but it was not handed down to someone on a mountain in a stone tablet format....

Cheers

blutto

 

[Parera]

...actually its casting doubts over your use of science...science is a wonderful tool but it was not handed down to someone on a mountain in a stone tablet format....

Cheers

blutto

Huh? I prefer being able to scrutinize someone's methods and data as opposed to just accepting some words written down in a book as the best authority on a topic; skepticism is healthy in an adult mind. In fact, this little quip is beyond insipid; you're literally criticizing the thing that makes science the best invention ever.

And as far as your gripe about the science of economics, I really don't know what to say. If you've ever spent any time around actual scientists at a university they usually refer to their colleagues in the social sciences (including economics) as practitioners of "soft science." This is largely because social scientists have *******ized the entire scientific method and haphazardly applied it their respective discipline. A social science theory, be it psychological or economic, is totally a different animal from what those lovely people in biology, physics, and chemistry develop.

but hey...it's just easier to throw out dumb assertions...because it doesn't really answer questions...and use ellipsis when they aren't called for...since basic grammar is too difficult...or whatever...

 

[acoggan]

If you've ever spent any time around actual scientists at a university they usually refer to their colleagues in the social sciences (including economics) as practitioners of "soft science."

A.k.a. "scl scntsts".

 

[FrankDay]

Huh? I prefer being able to scrutinize someone's methods and data as opposed to just accepting some words written down in a book as the best authority on a topic; skepticism is healthy in an adult mind. In fact, this little quip is beyond insipid; you're literally criticizing the thing that makes science the best invention ever.

Huh? I think you will find, if you read his comment carefully, he was criticizing how Coachfergie uses and interprets science, not, so much, science itself.

 

[onetrack]

...might be better to use a leg press machine with a moveable back...tried that this morning in the gym I frequent...very interesting...there is definitely a discernable difference though beyond my abilities to understand why ( no real grounding in exercise physiology I'm afraid )...

...bottom line...seems much easier to move weight as hip angle opens up...not scientific perhaps but definitely repeatable and something anyone with access to a well equipped gym can try...

Cheers

blutto

By "moveable back" do you mean backrest angle or distance to the pad you are pushing off of?

As a joint reaches full extension, the muscle acting on that joint gains influence. To illustrate this, see how much weight you can leg press starting with your knees near your chest, then again starting the lift with only 15 cm till full extension. you will be able to lift much more weight in the second position. the second position opens up both knee and hip angles allowing the muscles more influence over their respective joints. Assuming you weren't already doing this.

This is part of why short cranks work so well. They maintain the forceful range of motion while skipping the wasteful ranges of motion.

now, looking at the back end of the pedal stroke (which independent cranks train nicely). Muscles that flex (close) your knee and hip joints only allow so much range, and as they reach their limits, they loose influence over the joint. So, getting your pedal "over the top" is usually accomplished by your other leg forcing it over. This saps energy as your feet are in a tug-o-war of sorts over which direction to turn the pedals. Now, what if there were a way to get rid of the part of the pedal stroke that your flexors can't pull very well (if at all), and go straight to the part of the pedal stroke where your extensors can contribute the most force. oh wait! there is!

for those who are worried about losing leverage with short cranks, consider this. With arch mount cleats on 145mm cranks, in the 3 o' clock position, the ball of my foot is in the exact same place relative to the center of the bb as yours are with the cleat on the ball of your foot with 175mm cranks. I have about the same amount of toe overlap despite shortening the cranks nearly 3 cm. Also, I don't have to use my calves to stabilize my foot, cleat position does that for me. I prefer to save my oxygen for the muscles that actually more me forward.

 

[Oldman]

By "moveable back" do you mean backrest angle or distance to the pad you are pushing off of?

As a joint reaches full extension, the muscle acting on that joint gains influence. To illustrate this, see how much weight you can leg press starting with your knees near your chest, then again starting the lift with only 15 cm till full extension. you will be able to lift much more weight in the second position. the second position opens up both knee and hip angles allowing the muscles more influence over their respective joints. Assuming you weren't already doing this.

This is part of why short cranks work so well. They maintain the forceful range of motion while skipping the wasteful ranges of motion.

now, looking at the back end of the pedal stroke (which independent cranks train nicely). Muscles that flex (close) your knee and hip joints only allow so much range, and as they reach their limits, they loose influence over the joint. So, getting your pedal "over the top" is usually accomplished by your other leg forcing it over. This saps energy as your feet are in a tug-o-war of sorts over which direction to turn the pedals. Now, what if there were a way to get rid of the part of the pedal stroke that your flexors can't pull very well (if at all), and go straight to the part of the pedal stroke where your extensors can contribute the most force. oh wait! there is!

for those who are worried about losing leverage with short cranks, consider this. With arch mount cleats on 145mm cranks, in the 3 o' clock position, the ball of my foot is in the exact same place relative to the center of the bb as yours are with the cleat on the ball of your foot with 175mm cranks. I have about the same amount of toe overlap despite shortening the cranks nearly 3 cm. Also, I don't have to use my calves to stabilize my foot, cleat position does that for me. I prefer to save my oxygen for the muscles that actually more me forward.

Your statement clearly indicates why the short cranks only reinforce and inefficient pedal stroke. Good riders have a round stroke with little gap in the power and if they have a "gap" they: a)have a too-low saddle position b)are too tired to push the gear they are riding c)haven't trained long enough to develop a proper pedal stroke. BMXers rarely worry about this competing in a race where they seldom sit on the saddle, use short cranks and ride for 1 minute. If your'e planning to ride a long race or a stage event you need to have as much flexibility of muscle groups and positions to use as possible.
You don't ride with one leg at a time, stamping the pedal down for long.

 

[blutto]

By "moveable back" do you mean backrest angle or distance to the pad you are pushing off of?

...the former...

Cheers

blutto

 

[blutto]

A.k.a. "scl scntsts".

...as opposed to a physicist I ride with who once called the excercise physiologist Ph D. who is also part of our ride group a glorified gym monkey...so what is your point...

Cheers

blutto

...and history, by the way, has been called the queen mother of all the sciences...but so what...

 

[Alex Simmons/RST]

Good riders have a round stroke with little gap in the power

The science that has been conducted on pedal forces shows this not to be the case.

Or perhaps I misunderstand what you mean by "round stroke" or what you mean needs better definition.

BMXers rarely worry about this competing in a race where they seldom sit on the saddle, use short cranks and ride for 1 minute.

Just checking (as I'm not sure whether you are saying BMX do or do not run short cranks).

In BMX (professional) it is far more common for cranks used to be longer than a typical roadie uses. 180mm or longer.

 

[FrankDay]

Your statement clearly indicates why the short cranks only reinforce and inefficient pedal stroke. Good riders have a round stroke with little gap in the power and if they have a "gap" they: a)have a too-low saddle position b)are too tired to push the gear they are riding c)haven't trained long enough to develop a proper pedal stroke. BMXers rarely worry about this competing in a race where they seldom sit on the saddle, use short cranks and ride for 1 minute. If your'e planning to ride a long race or a stage event you need to have as much flexibility of muscle groups and positions to use as possible.
You don't ride with one leg at a time, stamping the pedal down for long.

Really! And your evidence for this statement?

 

[Martin318is]

Nothing alike physically? Really? How on earth do doctors ever learn of all these idiosyncracies to be able to operate if ever necessary.

How about you try again without the point scoring? Are you telling us that - in the context of your statement that all riders are pretty much alike - that the heights, inseams, relative femur lengths, hip flexion, relative torso lengths, tibial lengths, muscle compositions, etc, etc of Bradley Wiggans and Thomas Voeckler are "pretty much alike"?

If that were true then there would be one bike frame size with one set of frame angles, a fixed stem/bar combo with no adjustment, non adjustable saddles, etc

We don't - and that is the basis for my comment earlier that even if research shows something has benefit for the 'average' cyclist, you still need to check it out for yourself if it changes your position. its not the same as buying a set of Zipps (and even with deep section rims, what works for the average rider could still put a lightweight climber into a tree due to wind effects)

 

[blutto]

Huh? I prefer being able to scrutinize someone's methods and data as opposed to just accepting some words written down in a book as the best authority on a topic; skepticism is healthy in an adult mind. In fact, this little quip is beyond insipid; you're literally criticizing the thing that makes science the best invention ever.

And as far as your gripe about the science of economics, I really don't know what to say. If you've ever spent any time around actual scientists at a university they usually refer to their colleagues in the social sciences (including economics) as practitioners of "soft science." This is largely because social scientists have *******ized the entire scientific method and haphazardly applied it their respective discipline. A social science theory, be it psychological or economic, is totally a different animal from what those lovely people in biology, physics, and chemistry develop.

but hey...it's just easier to throw out dumb assertions...because it doesn't really answer questions...and use ellipsis when they aren't called for...since basic grammar is too difficult...or whatever...

...some would argue that language ( of which science is but a subset , granted a very valuable subset, but a subset none the less ) is like the most muchmore bestest invention ever...

...oh and by the way that gripe was not mine but from a Nobel Laureate in Economics....hope that meets your high standards...

Cheers

blutto

 

[onetrack]

Your statement clearly indicates why the short cranks only reinforce and inefficient pedal stroke.

actually, my entire post clearly indicates why short cranks only work well for those who already have a very good pedal stroke.