The pedaling technique thread

[Alex Simmons/RST]

Frank is talking out the south end of a north facing bull. The cranks are uncoupled. A counterweight on one crank therefore can have no impact to the other.

It's akin to two weights, one on the ground and another on a table top. Unconnected. Drop the weight from the table top and the weight on the floor does not move.

 

[FrankDay]

Re: Re:

You guys are really showing your ignorance of generally accepted engineering principles. If you are in school take this problem to a mechanical engineering prof. If not, good luck. I suspect you also have trouble understanding how airplanes fly or iron ships float (even though it is easy to understand why wooden ships float). Ask any well trained PowerCranker. Two legged pedaling with PowerCranks is a lot easier than single legged pedaling (what this study found) and no different that two legged pedaling on regular coupled cranks.

Frank, this is a yes/no question. Does the energy used in the downstroke of one leg reduce the energy used in the upstroke of the opposite leg when using uncoupled cranks.

It would if one crank was uncoupled and the other was a coupled counterweight or coupled crank. It doesn't if both are uncoupled. Your logical error here is in thinking that uncoupled cranks can help the other crank up whereas uncoupled cranks cannot. The problem with this approach is the energy that goes to push the other leg up robs from the energy that goes to drive the bicycle. Uncoupled cranks force forward driving pressure the complete circle so all the downward pressure goes to driving the bicycle.

Please edit your post to be coherent...

Also please just answer the question. If I can decipher you horribly inconsistent word use, I believe you said NO, uncoupled cranks can not transfer energy from one leg to the other. Thanks, we all knew that already. Glad you could agree.

It was coherent. You simply do not understand and, apparently, never have. It is possible for uncoupled cranks to transfer energy from one leg to another if only one crank is uncoupled and the transfer has to go from the uncoupled crank to the one coupled to the axle. In the case of PowerCranks, both cranks are uncoupled so it is not possible to transfer any energy. PowerCranks require that all the potential energy increase in each leg come from the muscles of that leg as there can be no assisting from the other leg. As long as that condition is met PowerCranks work just like regular cranks.

 

[JamesCun]

Frank, you said "Your logical error here is in thinking that uncoupled cranks can help the other crank up whereas uncoupled cranks cannot" this makes no sense. I don't think uncoupled cranks work that way, you do. Pay attention to the 'un'.

And who on earth is talking about a crank with one side coupled and the other uncoupled. Why bring up things that have no relevance to the discussion? I'm assuming it is just to avoid the obvious errors in your theories.

 

[FrankDay]

Re: Re:

...
They are unconnected, do yo need me to write that again? Unconnected. They cannot have an effect on each other because they are not in any way connected. Spin one pedal, does the other move? No. Hold one pedal in a fixed position and spin the other, if the counterweight argument would hold any water the pedal would not spin. They are not connected, I thought that was the whole point of them, that they are INDEPENDENT.

------------------
Ah ....., but they ARE connected when positive torque is applied to both crank arms at the same time.
And at that time the rotational speed of both crank arms is equal, even if the amount of positive torque is different (as long as there is positive torque on both cranks).

True, with PowerCranks the downstroke doesn't 'push UP' on the other crank, but it helps maintain the rotational speed of the BB spindle, so the 'pull UP' force on the upstroke only needs to maintain the rotational speed of the foot to match the spindle.

Jay Kosta
Endwell NY USA

Thanks for the correction but this has no bearing in this situation, as you note, as a counterweight is a negative force.

Well, it does have some bearing as it might account for the low efficiency seen, even with the counterweight. The counterweight forces the pushing muscles to work harder than they otherwise would for the same power. In normal pedaling cyclists normally unwieght about 90-95% of the weight of the leg on the upstroke. The counterweight allows for no unweighting on the contralateral side. So, it would seem this improves things a lot efficiencywise on the backstroke but worsens things efficiencywise on the downstroke such that the net is an improvement in efficiency but still less than one would expect of a normal cyclist, which is around 20%.

 

[CoachFergie]

Typical efficiency of cyclists is 18-23% (Coyle etal., 1992)

http://d3epuodzu3wuis.cloudfront.net/R060.pdf

 

[FrankDay]

Re:

Frank, you said "Your logical error here is in thinking that uncoupled cranks can help the other crank up whereas uncoupled cranks cannot" this makes no sense. I don't think uncoupled cranks work that way, you do. Pay attention to the 'un'.

Get rid of the first un.

And who on earth is talking about a crank with one side coupled and the other uncoupled. Why bring up things that have no relevance to the discussion? I'm assuming it is just to avoid the obvious errors in your theories.

Well, this would be the case if we were to do this test using powercranks on the good leg side. As long as the cranks were at 180º and he kept positive force around the entire circle (pretty easy for this guy I would expect) I would expect the exact same result whether the driving cranks was coupled to the axle or not. The only difference is when you add two uncoupled cranks into the mix the pushing leg is no longer required to do the extra work to get the weight up because that work is done by the muscles of the other leg but both legs still get the benefit of the potential energy put into the rising leg when gravity brings it down.

 

[CoachFergie]

Re: Re:

It is possible for uncoupled cranks to transfer energy from one leg to another if only one crank is uncoupled and the transfer has to go from the uncoupled crank to the one coupled to the axle.

Hilarious.

I think there is a university that would like their engineering degree back!

 

[JayKosta]

Re: Re:

...
It is possible for uncoupled cranks to transfer energy from one leg to another if only one crank is uncoupled and the transfer has to go from the uncoupled crank to the one coupled to the axle.
...

---------------------------------------------------------------
I think wording of the above is causing confusion ....
My guess is that it could be said more precisely as

"and the transfer has to go from the
CRANK THAT IS CAPABLE OF UNCOUPLING (BUT WHICH IS CURRENTLY COUPLED BECAUSE POSITIVE TORQUE IS APPLIED)
to the one coupled to the axle"

Jay Kosta
Endwell NY USA

 

[FrankDay]

Re: Re:

...
It is possible for uncoupled cranks to transfer energy from one leg to another if only one crank is uncoupled and the transfer has to go from the uncoupled crank to the one coupled to the axle.
...

---------------------------------------------------------------
I think wording of the above is causing confusion ....
My guess is that it could be said more precisely as

"and the transfer has to go from the
CRANK THAT IS CAPABLE OF UNCOUPLING (BUT WHICH IS CURRENTLY COUPLED BECAUSE POSITIVE TORQUE IS APPLIED)
to the one coupled to the axle"

Jay Kosta
Endwell NY USA

I thought that went without saying.

 

[sciguy]

Re:

After reading this

Frank Day
The problem is you guys are really up the creek without a paddle if someone replicates the study and gets the same or similar results. All your smartness will be shown for what it is, a bunch of bias.

It seemed like the right time to bring this beauty of a post back up to the surface for a bit of careful scrutiny.

I'll let Frank go first and give us his feelings about the studies then come back tomorrow and talk about his obvious bias in regards to them.

A new study to add to the Leirdahl study (link)

Results: Mean work rate was 279 W, mean FCC was 93.1 rpm, and mean GE was 21.7%. FE was 0.47 and 0.79 after correction for inertial forces; DC was 27.3% and 25.7%, respectively. DC size correlated better with GE (r = 0.75) than with the FE ratio (r = 0.50). Multiple regressions revealed that DC size was the only significant (P = 0.001) predictor for GE. Interestingly, DC size and FE ratio did not correlate with each other.

new study link here

The most notable results were as follows: gross efficiency (r = -0.72, P < 0.05 at 250 W) was inversely correlated with the ratio of minimum to peak torque, particularly at higher work rates. There was a highly significant inverse correlation between delta efficiency and average minimum torque at 200 W (r = -0.76, P < 0.01). Cycling experience was positively correlated with delta efficiency and gross efficiency, although experience and the ratio of minimum to peak torque were not related. These results show that variations in pedalling technique may account for a large proportion of the variation in efficiency in trained cyclists.

 

[FrankDay]

Re: Re:

After reading this

Frank Day
The problem is you guys are really up the creek without a paddle if someone replicates the study and gets the same or similar results. All your smartness will be shown for what it is, a bunch of bias.

It seemed like the right time to bring this beauty of a post back up to the surface for a bit of careful scrutiny.

I'll let Frank go first and give us his feelings about the studies then come back tomorrow and talk about his obvious bias in regards to them.

A new study to add to the Leirdahl study (link)

Results: Mean work rate was 279 W, mean FCC was 93.1 rpm, and mean GE was 21.7%. FE was 0.47 and 0.79 after correction for inertial forces; DC was 27.3% and 25.7%, respectively. DC size correlated better with GE (r = 0.75) than with the FE ratio (r = 0.50). Multiple regressions revealed that DC size was the only significant (P = 0.001) predictor for GE. Interestingly, DC size and FE ratio did not correlate with each other.

new study link here

The most notable results were as follows: gross efficiency (r = -0.72, P < 0.05 at 250 W) was inversely correlated with the ratio of minimum to peak torque, particularly at higher work rates. There was a highly significant inverse correlation between delta efficiency and average minimum torque at 200 W (r = -0.76, P < 0.01). Cycling experience was positively correlated with delta efficiency and gross efficiency, although experience and the ratio of minimum to peak torque were not related. These results show that variations in pedalling technique may account for a large proportion of the variation in efficiency in trained cyclists.

My response is pretty simple. The problem with this second study is they didn't control for anything. Cadence? could have been all over the map and cadence affects pedal forces and torque. Muscle physiology? Could have been all over the map and muscle physiology affects efficiency. It is an interesting findind and not necessarily what I would have expected but in order to understand cycling one needs to be able to explain their findings. There isn't enough data here to do so. Nothing here counters my thoughts. I agree with their last sentence. "Our results confirm that there is a multi-factorial relationship between cycling experience, muscle physiology, biomechanics, and whole-body efficiency on a bicycle. Further work is needed to determine which pedalling strategies are advantageous, or whether, in fact, manipulating pedalling technique holds any potential for improving performance at all."

Edit: I will make one more observation. From figure 3 the person with the lowest GE has an obvious problem with R/L balance. We don't have a clue what is going on with either of these cyclists technique because they are looking at the combined torque of the two legs. While the lower rider does have the highest DC torque there is obviously something else going on here that might be influencing overall efficiency. Not enough data to make any sense of any of this. But, I am sure you will try to make more of this than one should.

 

[CoachFergie]

Re: Re:

But, I am sure you will try to make more of this than one should.

Oh the irony!

 

[sciguy]

Re: Re:

After reading this

Frank Day
The problem is you guys are really up the creek without a paddle if someone replicates the study and gets the same or similar results. All your smartness will be shown for what it is, a bunch of bias.

It seemed like the right time to bring this beauty of a post back up to the surface for a bit of careful scrutiny.

I'll let Frank go first and give us his feelings about the studies then come back tomorrow and talk about his obvious bias in regards to them.

A new study to add to the Leirdahl study (link)

Results: Mean work rate was 279 W, mean FCC was 93.1 rpm, and mean GE was 21.7%. FE was 0.47 and 0.79 after correction for inertial forces; DC was 27.3% and 25.7%, respectively. DC size correlated better with GE (r = 0.75) than with the FE ratio (r = 0.50). Multiple regressions revealed that DC size was the only significant (P = 0.001) predictor for GE. Interestingly, DC size and FE ratio did not correlate with each other.

new study link here

The most notable results were as follows: gross efficiency (r = -0.72, P < 0.05 at 250 W) was inversely correlated with the ratio of minimum to peak torque, particularly at higher work rates. There was a highly significant inverse correlation between delta efficiency and average minimum torque at 200 W (r = -0.76, P < 0.01). Cycling experience was positively correlated with delta efficiency and gross efficiency, although experience and the ratio of minimum to peak torque were not related. These results show that variations in pedalling technique may account for a large proportion of the variation in efficiency in trained cyclists.

My response is pretty simple. The problem with this second study is they didn't control for anything. Cadence? could have been all over the map and cadence affects pedal forces and torque. Muscle physiology? Could have been all over the map and muscle physiology affects efficiency. It is an interesting findind and not necessarily what I would have expected but in order to understand cycling one needs to be able to explain their findings. There isn't enough data here to do so. Nothing here counters my thoughts. I agree with their last sentence. "Our results confirm that there is a multi-factorial relationship between cycling experience, muscle physiology, biomechanics, and whole-body efficiency on a bicycle. Further work is needed to determine which pedalling strategies are advantageous, or whether, in fact, manipulating pedalling technique holds any potential for improving performance at all."

Edit: I will make one more observation. From figure 3 the person with the lowest GE has an obvious problem with R/L balance. We don't have a clue what is going on with either of these cyclists technique because they are looking at the combined torque of the two legs. While the lower rider does have the highest DC torque there is obviously something else going on here that might be influencing overall efficiency. Not enough data to make any sense of any of this. But, I am sure you will try to make more of this than one should.

I find it especially disingenuous that you've failed to even mention the first of the two studies since it seems to be a favorite of yours.

From your web site:

From Frank's web site

COMMENT: A great study in experienced competitive cyclists to counter the "pedaling technique doesn't matter, just push harder" crowd. Leirdal and Ettema looked at a different metric, the "dead center" force, the minimal net force of the two cranks together usually seen when the cranks are perpendicular to the ground or at Top and/or Bottom "dead center". Using this metric they were able to correlate cycling efficiency to how small or large the force was here — with a chance of this study being wrong of less than 1 in 1,000. This is the first study that I know of that shows that a metric such as the CompuTrainer SpinScan has some real utility because SpinScan actually measures this DC torque. Of course, this also supports the PowerCranks as a training tool because the one thing we have been definitely been shown to improve is the torque across the top and bottom of the stroke (see below). PowerCrankers typically see an improvement in the "SpinScan" number of about 10 points.

Despite what the "just push harder" crowd says, pedaling technique matters. We disagree somewhat with their analysis of why this change occurs but the fact remains, it does occur."

But wait, one of the many cool things about science is that scientists who go on to do additional research on a particular topic may find that their or others' earlier work was flawed. This was the case with Stig Leirdal and Gertjan Ettema who went on to do a follow up study soon after the one that Frank seems so enchanted with. As it turns out in the original study the athletes were allowed to freely choose what cadence they would pedal at during their efforts. In their follow up study where they looked at "The relationship between cadence, pedalling technique and gross efficiency in cycling" These were the same two authors who Frank is so keen on, doing research just a few weeks after the study he cites on his web site. The interesting thing is that in this study where they looked at cadence's affect on pedaling technique as well as gross efficiency. The results were rather enlightening to say the least. For example, when they just looked at cadence versus GE there was an obvious distinctive pattern.

There is also a very strong relationship between cadence and FE.

In this second study they also had athletes work at their freely chosen cadence as well as a cadence 10 rpm higher and 10 rpm lower.

In their first study this strong relationship between cadence and GE as well as cadence and DC were not considered.

The upshot of the whole second study was that it essentially negated the first study where they had failed to take into account the influence of cadence on GE. The relationship between pedaling technique was not a causal one just one that correlated due to cadence's affect on both DC size as well as GE. As the authors put it:

In conclusion, energy expenditure is strongly coupled to cadence, but force effectiveness, as a measure for pedalling technique, is not likely the cause of this relationship. Along with other studies (Kautz and Hull 1993; Ettema et al. 2009; Lorås et al. 2009), we are inclined to conclude that FE is mostly affected by inertial forces, and thus the value of this parameter as a measure for technique should be questioned. Contrary to Leirdal and Ettema (2010), we do not find a significant relationship between DC and GE. Thus, the present study provides no indication for the notion that technique affects energy consumption.

So Frank, why do you ignore this followup study by the same two authors? You fault others for bias while you cite the first study by Leirdal and Ettema on your web page as evidence of the importance or pedaling technique but ignore their second study that negates the conclusions drawn by the first. If a doctor treated someone based on a study that was later found to be without merit by it's very own authors I'd imagine that would be grounds for a malpractice investigation. With you it seems to be business as usual.

We'll come back to the Edwards study another day.

I await your school girlish lols and spin doctoring.

Hugh

 

[FrankDay]

Re: Re:

After reading this

Frank Day
The problem is you guys are really up the creek without a paddle if someone replicates the study and gets the same or similar results. All your smartness will be shown for what it is, a bunch of bias.

It seemed like the right time to bring this beauty of a post back up to the surface for a bit of careful scrutiny.

I'll let Frank go first and give us his feelings about the studies then come back tomorrow and talk about his obvious bias in regards to them.

A new study to add to the Leirdahl study (link)

Results: Mean work rate was 279 W, mean FCC was 93.1 rpm, and mean GE was 21.7%. FE was 0.47 and 0.79 after correction for inertial forces; DC was 27.3% and 25.7%, respectively. DC size correlated better with GE (r = 0.75) than with the FE ratio (r = 0.50). Multiple regressions revealed that DC size was the only significant (P = 0.001) predictor for GE. Interestingly, DC size and FE ratio did not correlate with each other.

new study link here

The most notable results were as follows: gross efficiency (r = -0.72, P < 0.05 at 250 W) was inversely correlated with the ratio of minimum to peak torque, particularly at higher work rates. There was a highly significant inverse correlation between delta efficiency and average minimum torque at 200 W (r = -0.76, P < 0.01). Cycling experience was positively correlated with delta efficiency and gross efficiency, although experience and the ratio of minimum to peak torque were not related. These results show that variations in pedalling technique may account for a large proportion of the variation in efficiency in trained cyclists.

My response is pretty simple. The problem with this second study is they didn't control for anything. Cadence? could have been all over the map and cadence affects pedal forces and torque. Muscle physiology? Could have been all over the map and muscle physiology affects efficiency. It is an interesting findind and not necessarily what I would have expected but in order to understand cycling one needs to be able to explain their findings. There isn't enough data here to do so. Nothing here counters my thoughts. I agree with their last sentence. "Our results confirm that there is a multi-factorial relationship between cycling experience, muscle physiology, biomechanics, and whole-body efficiency on a bicycle. Further work is needed to determine which pedalling strategies are advantageous, or whether, in fact, manipulating pedalling technique holds any potential for improving performance at all."

Edit: I will make one more observation. From figure 3 the person with the lowest GE has an obvious problem with R/L balance. We don't have a clue what is going on with either of these cyclists technique because they are looking at the combined torque of the two legs. While the lower rider does have the highest DC torque there is obviously something else going on here that might be influencing overall efficiency. Not enough data to make any sense of any of this. But, I am sure you will try to make more of this than one should.

I find it especially disingenuous that you've failed to even mention the first of the two studies since it seems to be a favorite of yours.

From your web site:

From Frank's web site

COMMENT: A great study in experienced competitive cyclists to counter the "pedaling technique doesn't matter, just push harder" crowd. Leirdal and Ettema looked at a different metric, the "dead center" force, the minimal net force of the two cranks together usually seen when the cranks are perpendicular to the ground or at Top and/or Bottom "dead center". Using this metric they were able to correlate cycling efficiency to how small or large the force was here — with a chance of this study being wrong of less than 1 in 1,000. This is the first study that I know of that shows that a metric such as the CompuTrainer SpinScan has some real utility because SpinScan actually measures this DC torque. Of course, this also supports the PowerCranks as a training tool because the one thing we have been definitely been shown to improve is the torque across the top and bottom of the stroke (see below). PowerCrankers typically see an improvement in the "SpinScan" number of about 10 points.

Despite what the "just push harder" crowd says, pedaling technique matters. We disagree somewhat with their analysis of why this change occurs but the fact remains, it does occur."

But wait, one of the many cool things about science is that scientists who go on to do additional research on a particular topic may find that their or others' earlier work was flawed. This was the case with Stig Leirdal and Gertjan Ettema who went on to do a follow up study soon after the one that Frank seems so enchanted with. As it turns out in the original study the athletes were allowed to freely choose what cadence they would pedal at during their efforts. In their follow up study where they looked at "The relationship between cadence, pedalling technique and gross efficiency in cycling" These were the same two authors who Frank is so keen on, doing research just a few weeks after the study he cites on his web site. The interesting thing is that in this study where they looked at cadence's affect on pedaling technique as well as gross efficiency. The results were rather enlightening to say the least. For example, when they just looked at cadence versus GE there was an obvious distinctive pattern.

There is also a very strong relationship between cadence and FE.

In this second study they also had athletes work at their freely chosen cadence as well as a cadence 10 rpm higher and 10 rpm lower.

In their first study this strong relationship between cadence and GE as well as cadence and DC were not considered.

The upshot of the whole second study was that it essentially negated the first study where they had failed to take into account the influence of cadence on GE. The relationship between pedaling technique was not a causal one just one that correlated due to cadence's affect on both DC size as well as GE. As the authors put it:

In conclusion, energy expenditure is strongly coupled to cadence, but force effectiveness, as a measure for pedalling technique, is not likely the cause of this relationship. Along with other studies (Kautz and Hull 1993; Ettema et al. 2009; Lorås et al. 2009), we are inclined to conclude that FE is mostly affected by inertial forces, and thus the value of this parameter as a measure for technique should be questioned. Contrary to Leirdal and Ettema (2010), we do not find a significant relationship between DC and GE. Thus, the present study provides no indication for the notion that technique affects energy consumption.

So Frank, why do you ignore this followup study by the same two authors? You fault others for bias while you cite the first study by Leirdal and Ettema on your web page as evidence of the importance or pedaling technique but ignore their second study that negates the conclusions drawn by the first. If a doctor treated someone based on a study that was later found to be without merit by it's very own authors I'd imagine that would be grounds for a malpractice investigation. With you it seems to be business as usual.

We'll come back to the Edwards study another day.

I await your school girlish lols and spin doctoring.

Hugh

Usually when there is conflicting data in science what the good scientist wants is more data, not necessarily to choose sides. That was the position of the authors of the second paper which is why I agreed with them. I didn't comment on the first paper because I have already done so and the second paper doesn't necessarily invalidate their findings. You are the one trying to read too much into their data. I think it reasonable to try explain why Lutrell (and others) can see efficiency improvement from pedaling technique changes when most people fail to see such changes. On my web site I think it reasonable that what we do is to explain to people our current view, rather than try to confuse them and most of that was written awhile ago so may not reflect every new study. We are trying to convince them that the product does work after all and that there is a theoretical basis for it doing so (rather than wishful thinking). We actually discuss scientific studies (even the negative ones), not many products do that. Can you show me another training product (a power meter perhaps) that does that? Then, we back up our thoughts with a pretty good money back guarantee.

 

[JayKosta]

...
Go ride your bike, discover that pedalling doesn't require all this much thought. Perhaps when you have done it for 20 or so years and coached it you will realise that mashing is the way to go. Just like Ed Coyle and co showed us with research in 1991.

I'd like to get a better understanding of your understanding and execution of 'mashing'.

First of all, do you ever find a need to explain it to your clients, or do you ever notice that they aren't doing it as you'd like and make suggestions about how they could do better? (some examples are below)

Wtih mashing, is there any concern or notice of what is happening on the upstroke? Or are you satsified that 'what comes naturally' to the rider is fine?

Is all of the emphasis for power generation on the downstroke - e.g. push down as hard and fast as possible (given the demands of the event regarding cadence, pacing, etc.) alternately with each leg, and don't be concerned or devote any conscious effort on the upstroke.

Do you ever suggest that a rider somehow 'prepare' his foot for the downstroke - e.g.
angle of foot,
where relative to TDC that the rider begins the downstroke effort,
that the rider should try to get his foot in position for the downstroke 'quicker' or 'faster'?

Jay Kosta
Endwell NY USA

 

[CoachFergie]

I coach riders to achieve the goals they come to me with. A pretty simple goal setting process of establishing the demands of the goal, the current state of the athlete and deciding on a plan of attack to get from A to B.

Based on the current literature and considerable experience having worked with hundreds of cyclists over the last 24 years I have never had to teach a rider how to pedal. I spend most of my time working on fitting the bike to the rider, teaching them to use their gears, riding safely in a bunch and tactics to race well.

 

[sciguy]

Re: Re:

After reading this

Frank Day
The problem is you guys are really up the creek without a paddle if someone replicates the study and gets the same or similar results. All your smartness will be shown for what it is, a bunch of bias.

It seemed like the right time to bring this beauty of a post back up to the surface for a bit of careful scrutiny.

I'll let Frank go first and give us his feelings about the studies then come back tomorrow and talk about his obvious bias in regards to them.


new study link here

The most notable results were as follows: gross efficiency (r = -0.72, P < 0.05 at 250 W) was inversely correlated with the ratio of minimum to peak torque, particularly at higher work rates. There was a highly significant inverse correlation between delta efficiency and average minimum torque at 200 W (r = -0.76, P < 0.01). Cycling experience was positively correlated with delta efficiency and gross efficiency, although experience and the ratio of minimum to peak torque were not related. These results show that variations in pedalling technique may account for a large proportion of the variation in efficiency in trained cyclists.

My response is pretty simple. The problem with this second study is they didn't control for anything. Cadence? could have been all over the map and cadence affects pedal forces and torque. Muscle physiology? Could have been all over the map and muscle physiology affects efficiency. It is an interesting findind and not necessarily what I would have expected but in order to understand cycling one needs to be able to explain their findings. There isn't enough data here to do so. Nothing here counters my thoughts. I agree with their last sentence. "Our results confirm that there is a multi-factorial relationship between cycling experience, muscle physiology, biomechanics, and whole-body efficiency on a bicycle. Further work is needed to determine which pedalling strategies are advantageous, or whether, in fact, manipulating pedalling technique holds any potential for improving performance at all."

Edit: I will make one more observation. From figure 3 the person with the lowest GE has an obvious problem with R/L balance. We don't have a clue what is going on with either of these cyclists technique because they are looking at the combined torque of the two legs. While the lower rider does have the highest DC torque there is obviously something else going on here that might be influencing overall efficiency. Not enough data to make any sense of any of this. But, I am sure you will try to make more of this than one should.

I find it especially disingenuous that you've failed to even mention the first of the two studies since it seems to be a favorite of yours.

From your web site:

From Frank's web site

COMMENT: A great study in experienced competitive cyclists to counter the "pedaling technique doesn't matter, just push harder" crowd. Leirdal and Ettema looked at a different metric, the "dead center" force, the minimal net force of the two cranks together usually seen when the cranks are perpendicular to the ground or at Top and/or Bottom "dead center". Using this metric they were able to correlate cycling efficiency to how small or large the force was here — with a chance of this study being wrong of less than 1 in 1,000. This is the first study that I know of that shows that a metric such as the CompuTrainer SpinScan has some real utility because SpinScan actually measures this DC torque. Of course, this also supports the PowerCranks as a training tool because the one thing we have been definitely been shown to improve is the torque across the top and bottom of the stroke (see below). PowerCrankers typically see an improvement in the "SpinScan" number of about 10 points.

Despite what the "just push harder" crowd says, pedaling technique matters. We disagree somewhat with their analysis of why this change occurs but the fact remains, it does occur."

But wait, one of the many cool things about science is that scientists who go on to do additional research on a particular topic may find that their or others' earlier work was flawed. This was the case with Stig Leirdal and Gertjan Ettema who went on to do a follow up study soon after the one that Frank seems so enchanted with. As it turns out in the original study the athletes were allowed to freely choose what cadence they would pedal at during their efforts. In their follow up study where they looked at "The relationship between cadence, pedalling technique and gross efficiency in cycling" These were the same two authors who Frank is so keen on, doing research just a few weeks after the study he cites on his web site. The interesting thing is that in this study where they looked at cadence's affect on pedaling technique as well as gross efficiency. The results were rather enlightening to say the least. For example, when they just looked at cadence versus GE there was an obvious distinctive pattern.

There is also a very strong relationship between cadence and FE.

In this second study they also had athletes work at their freely chosen cadence as well as a cadence 10 rpm higher and 10 rpm lower.

In their first study this strong relationship between cadence and GE as well as cadence and DC were not considered.

The upshot of the whole second study was that it essentially negated the first study where they had failed to take into account the influence of cadence on GE. The relationship between pedaling technique was not a causal one just one that correlated due to cadence's affect on both DC size as well as GE. As the authors put it:

In conclusion, energy expenditure is strongly coupled to cadence, but force effectiveness, as a measure for pedalling technique, is not likely the cause of this relationship. Along with other studies (Kautz and Hull 1993; Ettema et al. 2009; Lorås et al. 2009), we are inclined to conclude that FE is mostly affected by inertial forces, and thus the value of this parameter as a measure for technique should be questioned. Contrary to Leirdal and Ettema (2010), we do not find a significant relationship between DC and GE. Thus, the present study provides no indication for the notion that technique affects energy consumption.

So Frank, why do you ignore this followup study by the same two authors? You fault others for bias while you cite the first study by Leirdal and Ettema on your web page as evidence of the importance or pedaling technique but ignore their second study that negates the conclusions drawn by the first. If a doctor treated someone based on a study that was later found to be without merit by it's very own authors I'd imagine that would be grounds for a malpractice investigation. With you it seems to be business as usual.

We'll come back to the Edwards study another day.

I await your school girlish lols and spin doctoring.

Hugh

Usually when there is conflicting data in science what the good scientist wants is more data, not necessarily to choose sides. That was the position of the authors of the second paper which is why I agreed with them. I didn't comment on the first paper because I have already done so and the second paper doesn't necessarily invalidate their findings. You are the one trying to read too much into their data. I think it reasonable to try explain why Lutrell (and others) can see efficiency improvement from pedaling technique changes when most people fail to see such changes. On my web site I think it reasonable that what we do is to explain to people our current view, rather than try to confuse them and most of that was written awhile ago so may not reflect every new study. We are trying to convince them that the product does work after all and that there is a theoretical basis for it doing so (rather than wishful thinking). We actually discuss scientific studies (even the negative ones), not many products do that. Can you show me another training product (a power meter perhaps) that does that? Then, we back up our thoughts with a pretty good money back guarantee.[/quote]

Frank,

Did you actually read my post. It's regarding Leirdal's initial study versus his follow up study which negates the first. I wasn't talking about the Edwards study yet. Why don't you link to the follow up study where they come to the realization that they were incorrect in the first study. They came to the conclusion that it was variation in cadence that cased the varying GE not differences in DC size yet yo trumpet the first flawed study and ignore the followup. Bias much???

 

[JayKosta]

Re:

...
Based on the current literature and considerable experience having worked with hundreds of cyclists over the last 24 years I have never had to teach a rider how to pedal. I spend most of my time working on fitting the bike to the rider, teaching them to use their gears, riding safely in a bunch and tactics to race well.

-------
Thanks,
Jay Kosta
Endwell NY USA

 

[FrankDay]

Re: Re:

Frank,

Did you actually read my post. It's regarding Leirdal's initial study versus his follow up study which negates the first. I wasn't talking about the Edwards study yet. Why don't you link to the follow up study where they come to the realization that they were incorrect in the first study. They came to the conclusion that it was variation in cadence that cased the varying GE not differences in DC size yet yo trumpet the first flawed study and ignore the followup. Bias much???

You know, that if you want me to figure out exactly what you want me to respond to it might be better if you asked direct questions instead of posting links to entire studies then hoping I would discern your intent. Anyhow, I am not aware of anything that specifically invalidates Leirdahls initial study findings. He did, as I remember, reach a p<0.001 in that first study which suggests a pretty strong relationship. However, since then there are conflicting studies meaning additional data is necessary to resolve the issue. But, as a general principle I believe that pedaling technique matters from both a power production and efficiency standpoint. To assert otherwise simply goes against all engineering principles. What I can't tell you is exactly which technique is optimum. I have ideas but I don't know. So, if you have a specific question you would like me to address then ask it.

 

[CoachFergie]

Re: Re:

Anyhow, I am not aware of anything that specifically invalidates Leirdahls initial study findings.

Apart from the follow up study where they said the results were counter to the the first.

 

[FrankDay]

Re: Re:

Anyhow, I am not aware of anything that specifically invalidates Leirdahls initial study findings.

Apart from the follow up study where they said the results were counter to the the first.

Counter results do not specifically invalidate the other counter results. If the authors had posted a retraction saying they subsequently found a researcher manipulated the data or some such thing, that would be a specific invalidation. In liew of something like that all we have are conflicting results which happens in science all the time. The solution is more and better studies.

 

[backdoor]

Re:

[quote="CoachFergie"

Based on the current literature and considerable experience having worked with hundreds of cyclists over the last 24 years I have never had to teach a rider how to pedal. [/quote]


Has any research been done on the "unweighting" technique ?

 

[sciguy]

Re: Re:

Anyhow, I am not aware of anything that specifically invalidates Leirdahls initial study findings.

Apart from the follow up study where they said the results were counter to the the first.

Counter results do not specifically invalidate the other counter results. If the authors had posted a retraction saying they subsequently found a researcher manipulated the data or some such thing, that would be a specific invalidation. In liew of something like that all we have are conflicting results which happens in science all the time. The solution is more and better studies.

The simple fact is that the same two authors conducted a second more involved and evolved experiment that lead them to the realization that they had "missed" the huge roll of cadence in influencing both GE as well as DC size. Since they came up with a contradictory result compared to their first experiment, I'm sure that they thought long and hard before they declared:

In conclusion, energy expenditure is strongly coupled to cadence, but force effectiveness, as a measure for pedalling technique, is not likely the cause of this relationship. Along with other studies (Kautz and Hull 1993; Ettema et al. 2009; Lorås et al. 2009), we are inclined to conclude that FE is mostly affected by inertial forces, and thus the value of this parameter as a measure for technique should be questioned. Contrary to Leirdal and Ettema (2010), we do not find a significant relationship between DC and GE. Thus, the present study provides no indication for the notion that technique affects energy consumption.

The fact that you have chosen to only cite Leirdal's earlier, less involved study that seems to agree with your premise regarding pedaling techniques shows your obvious bias if not dishonesty in this matter.

Hugh

 

[FrankDay]

Re: Re:

Anyhow, I am not aware of anything that specifically invalidates Leirdahls initial study findings.

Apart from the follow up study where they said the results were counter to the the first.

Counter results do not specifically invalidate the other counter results. If the authors had posted a retraction saying they subsequently found a researcher manipulated the data or some such thing, that would be a specific invalidation. In liew of something like that all we have are conflicting results which happens in science all the time. The solution is more and better studies.

The simple fact is that the same two authors conducted a second more involved and evolved experiment that lead them to the realization that they had "missed" the huge roll of cadence in influencing both GE as well as DC size. Since they came up with a contradictory result compared to their first experiment, I'm sure that they thought long and hard before they declared:

In conclusion, energy expenditure is strongly coupled to cadence, but force effectiveness, as a measure for pedalling technique, is not likely the cause of this relationship. Along with other studies (Kautz and Hull 1993; Ettema et al. 2009; Lorås et al. 2009), we are inclined to conclude that FE is mostly affected by inertial forces, and thus the value of this parameter as a measure for technique should be questioned. Contrary to Leirdal and Ettema (2010), we do not find a significant relationship between DC and GE. Thus, the present study provides no indication for the notion that technique affects energy consumption.

The fact that you have chosen to only cite Leirdal's earlier, less involved study that seems to agree with your premise regarding pedaling techniques shows your obvious bias if not dishonesty in this matter.

Hugh

Of course I have a bias that technique influences efficiency. This is obvious from the OP in this thread. But, more importantly, engineering principles demand such a view. Your assertion that it doesn't is so naive in this regards as to be laughable. But, if you don't understand this nothing I am going to say is going to change your mind. The only real question to an engineer is exactly what are all the elements involved in this "influencing" and how to optimize them. The fact that the same researchers came up with two conflicting results is no more compelling that one is right and the other wrong than if it were two different researchers. The statement "Thus, the present study provides no indication for the notion that technique affects energy consumption" is not evidence that technique doesn't affect energy consumption but only indicates that this study didn't find it. Perhaps their cohort were different the second time around such that the DC differences were so small in this group that differences couldn't be detected. All this represents is conflicting data. Technique has to affect energy efficiency, there is no other rational option.

 

[JamesCun]

Re: Re:

Of course I have a bias that technique influences efficiency. This is obvious from the OP in this thread. But, more importantly, engineering principles demand such a view. Your assertion that it doesn't is so naive in this regards as to be laughable. But, if you don't understand this nothing I am going to say is going to change your mind. The only real question to an engineer is exactly what are all the elements involved in this "influencing" and how to optimize them. The fact that the same researchers came up with two conflicting results is no more compelling that one is right and the other wrong than if it were two different researchers. The statement "Thus, the present study provides no indication for the notion that technique affects energy consumption" is not evidence that technique doesn't affect energy consumption but only indicates that this study didn't find it. Perhaps their cohort were different the second time around such that the DC differences were so small in this group that differences couldn't be detected. All this represents is conflicting data. Technique has to affect energy efficiency, there is no other rational option.

You seem to be missing the point here. People aren't saying that technique doesn't matter, they are suggesting that the 'natural' technique that people use has been demonstrated to be just as efficient (or more efficient) as modified techniques. Your bias is displayed when you promote one study that supports your view, while at the same time downplaying another study, by the same authors, that doesn't support your view.