The Powercrank Thread

[FrankDay]

Frank,

The above statement has to be one of the silliest statements you've made this week. Let me get this straight, you're contending that the motion involved in the lifting of free weights is more constrained than the motion involved in pedaling a bicycle? I guess you've never spent any time lifting free weights or compared that effort/motion to lifting via a machine weights where the motion is constrained. You also seem to be under the impression that even though the pedals and cranks constrain a fixed cranker's leg motion the offer no feedback to the cyclist.............That a fixed cranker will just aimlessly keep pushing downward at the bottom of the stroke without having a clue that they're doing so.......not noticing the unweighting of the saddle that would occur if one did this. Give our feeble cyclist' brains some credit. They're amazing at processing these sorts of subtle cues and have been for millions of years.


Hugh

The motion of the foot is effectively more constrained when lifting weights, be they free or attached to a mechanism that forces a purely vertical motion than the motion of the foot when attached to a bicycle pedal because, when lifting weights, if the CG isn't kept directly over the fixed feet the lift will fail because balance will be lost.

No, I know that a bicyclist doesn't just push down without regard to the pedal position but saddle weight is always changing, that is hardly useful feedback to pedaling technique other than as a feedback of effort (which isn't much use compared to how hard one is breathing). In fact, because cyclists do stop pushing down and unweight some on the back stroke suggests that, in fact, technique is involved. When to start pushing, when to stop, and in what direction. If technique is involved then there has to be an optimum technique. Technique matters when trying to develop power on the bicycle yet some of you are unable to wrap you little heads around this concept holding to the proposition is that all one need do to generate more power is to "just push harder". While "pushing harder" might work to increase power I think one could hardly describe that as a description of a technique nor an optimum technique.

They're amazing at processing these sorts of subtle cues and have been for millions of years.

Ugh, the feedback that the cyclist gets on regular cranks are indeed subtle and the brain isn't very good at figuring them out. If it were one wouldn't have any trouble when they got on PowerCranks (the case for about 1 in 1,000). The feedback that PowerCranks provides isn't very subtle but more like being hit in the head with a brick such that even the least aware can figure out what they should be doing and what they are not. Perhaps that is why they are effective in eventually changing the pedaling technique of almost everyone. Just sayin'…

 

[FrankDay]

What have your tests shown when you look at muscle activation through the pedal stroke? Would be simple to strap on some electrodes and do some EMG readings on pre/post PC training.

Of course, once you determine if PC can make a lasting change to activation patterns, you would need to show that a different pattern is actually more efficient.

I haven't done that test but others have (see posts 8 and 10 in this thread. Of course, Leirdahl did show a different pattern (increasing the DC forces) to be more efficient.

What has yet to be done is watching how the pedaling pattern changes with time with continued PowerCranks training and if and when changes can be shown to correlate with either efficiency or power improvements and if additional training results in additional changes and improvements. If such a test were actually done we might actually begin to learn if one part of the stroke is more important than another.

 

[sciguy]

Of course, Leirdahl did show a different pattern (increasing the DC forces) to be more efficient.
/QUOTE]

but then in his follow up study didn't support the earlier study. Hmmmmmmm funny how you always fail to not mention that point.

 

[FrankDay]

Of course, Leirdahl did show a different pattern (increasing the DC forces) to be more efficient.

but then in his follow up study didn't support the earlier study. Hmmmmmmm funny how you always fail to not mention that point.

Wow, two studies came up with different results!!! How can we ever know which is more correct? I guess we could wait for the experiment to be repeated 2, 3, or more times to see those results. Or we could compare the studies to see if there might be a clue (Leirdahl mentioned some differences that might explain the difference in findings) I was unable to find the statistical analysis of this result in the second study to compare to the first (p<.0.001). Then, there is Burns and Luttrell that both found a change in efficiency with a presumed change in DC.

You guys seem to think a single negative study can prove your argument whereas no number of positive studies support my argument.

Can't we agree that the scientific support isn't perfect for any view on almost any topic and that it is normal, when involved in an argument, to emphasize those studies that support your side.

 

[coapman]

You guys seem to think a single negative study can prove your argument whereas no number of positive studies support my argument.

Common sense is the decider. On return to standard cranks, how does the pedalling (ie. objectives) of the PC'er differ from that of the circular pedaller.

 

[elapid]

Wow, two studies came up with different results!!! How can we ever know which is more correct? I guess we could wait for the experiment to be repeated 2, 3, or more times to see those results. Or we could compare the studies to see if there might be a clue (Leirdahl mentioned some differences that might explain the difference in findings) I was unable to find the statistical analysis of this result in the second study to compare to the first (p<.0.001). Then, there is Burns and Luttrell that both found a change in efficiency with a presumed change in DC.

You guys seem to think a single negative study can prove your argument whereas no number of positive studies support my argument.

Can't we agree that the scientific support isn't perfect for any view on almost any topic and that it is normal, when involved in an argument, to emphasize those studies that support your side.

The number of studies for PCs (n = 2; Luttrell et al and Dixon et al) and against PCs (n = 8; Diaz et al, Otto et al, Bohm et al, Van Zant & Bouillon, Williams et al, Hanaki-Martin et al, Sperlich et al, Burns et al) are not as lopsided as you like to make out. Cherry picking studies to suit your purposes and not presenting a balanced view of the literature just exemplifies your weak position. Furthermore, when there are conflicting papers, and hence no consensus, then the problem is most likely not with the science but the subject (in this case PCs). This is further highlighted by the fact that there are far more studies against (8) rather than for (2) PCs. Lastly, these studies are looking for significant differences. These significant differences are likely to be far smaller than the claims you make when training with PCs: none get close to the 2-3mph and 40% increase in power that you claim.

 

[FrankDay]

The number of studies for PCs (n = 2; Luttrell et al and Dixon et al) and against PCs (n = 8; Diaz et al, Otto et al, Bohm et al, Van Zant & Bouillon, Williams et al, Hanaki-Martin et al, Sperlich et al, Burns et al) are not as lopsided as you like to make out. Cherry picking studies to suit your purposes and not presenting a balanced view of the literature just exemplifies your weak position. Furthermore, when there are conflicting papers, and hence no consensus, then the problem is most likely not with the science but the subject (in this case PCs). This is further highlighted by the fact that there are far more studies against (8) rather than for (2) PCs. Lastly, these studies are looking for significant differences. These significant differences are likely to be far smaller than the claims you make when training with PCs: none get close to the 2-3mph and 40% increase in power that you claim.

LOL, a large number of poorly designed studies against something is hardly convincing of anything. I was, quite frankly, surprised that Luttrell and Dixon showed positive results in view of the fact that they also only lasted 6 weeks and one involved part-time use. (Actually, I am not surprised that Dixon demonstrated a difference but am surprised at the magnitude in such a short period.) It would appear that 6 weeks is the bare minimum that a study must last, especially if involving part-time use, if one hopes to refute the null hypothesis (Luttrell, Burns, Fiolo). Your simply counting these numbers as meaning anything regarding this product simply substantiates how ignorant you are regarding how the product works. This is especially evident when it seems you seem to be making the argument that a study lasting 5-6 weeks using part-time use can possibly be used to demonstrate the improvement claimed after 6-9 months of immersion training (2-3 mph, 40% power increase on average) is bogus. But, you have zero interest in learning how it works so I suspect we will continue to have to put up with such silly arguments as seen above. sigh :-(

 

[CoachFergie]

The number of studies for PCs (n = 2; Luttrell et al and Dixon et al) and against PCs (n = 8; Diaz et al, Otto et al, Bohm et al, Van Zant & Bouillon, Williams et al, Hanaki-Martin et al, Sperlich et al, Burns et al) are not as lopsided as you like to make out. Cherry picking studies to suit your purposes and not presenting a balanced view of the literature just exemplifies your weak position. Furthermore, when there are conflicting papers, and hence no consensus, then the problem is most likely not with the science but the subject (in this case PCs). This is further highlighted by the fact that there are far more studies against (8) rather than for (2) PCs. Lastly, these studies are looking for significant differences. These significant differences are likely to be far smaller than the claims you make when training with PCs: none get close to the 2-3mph and 40% increase in power that you claim.

Also to add that Lutrell did not find an improvement in performance in an IAT test and because Dixon is only an abstract, and clearly doesn't have a control group, says nothing about how the improvement in performance occurred.

 

[JayKosta]

Common sense is the decider. On return to standard cranks, how does the pedalling (ie. objectives) of the PC'er differ from that of the circular pedaller.

=======================================
Well ... my 'common sense' it that is depends on what really are the 'objectives' of the individual.

If the objective is to pedal with 'no negative torque' (and with maximum downstroke force) and the person has become adept using PCs so that the 'PC technique' feels natural and efficient, then I'd guess the technique on standard cranks would remain similar to the technique on PCs.

But if the person is not fully adept on PCs, and needs to force themself to concentrate on the PC technique, then I'd guess their technique would change from PC style to a typical 'circular' style with some amount of negative torque. Or even change to a 'masher' style if the person does not maintain the 'no negative torque' objective.

As you've mentioned, the 'objectives' of the rider (and the dedication to achieve them) is critical to the development of a pedaling style.

Jay Kosta
Endwell NY USA

 

[coapman]

=======================================
Well ... my 'common sense' it that is depends on what really are the 'objectives' of the individual.

If the objective is to pedal with 'no negative torque' (and with maximum downstroke force) and the person has become adept using PCs so that the 'PC technique' feels natural and efficient, then I'd guess the technique on standard cranks would remain similar to the technique on PCs.

You are forgetting about TDC/BDC where Frank claims all that 40% power increase takes place. It would have to be more than 40 there because of the reduction in down stroke force which Frank claims is part of the PC smoothing technique. There is no power increase, the most he can expect is the perfected circular technique which is not as effective as mashing.

 

[elapid]

LOL, a large number of poorly designed studies against something is hardly convincing of anything. I was, quite frankly, surprised that Luttrell and Dixon showed positive results in view of the fact that they also only lasted 6 weeks and one involved part-time use. (Actually, I am not surprised that Dixon demonstrated a difference but am surprised at the magnitude in such a short period.) It would appear that 6 weeks is the bare minimum that a study must last, especially if involving part-time use, if one hopes to refute the null hypothesis (Luttrell, Burns, Fiolo). Your simply counting these numbers as meaning anything regarding this product simply substantiates how ignorant you are regarding how the product works. This is especially evident when it seems you seem to be making the argument that a study lasting 5-6 weeks using part-time use can possibly be used to demonstrate the improvement claimed after 6-9 months of immersion training (2-3 mph, 40% power increase on average) is bogus. But, you have zero interest in learning how it works so I suspect we will continue to have to put up with such silly arguments as seen above. sigh :-(

I have an interest in learning. That's why I read the posts regarding where and when PCs are supposed to change pedalling technique without commenting because this is interesting to me and I am learning.

However, you have done nothing to prove that PCs work as claimed. Prove your claims and then I'll believe you. The weight of evidence is against you and you have done nothing other than duck and cover, try to deflect, show inconsistency after inconsistency, cherry pick anecdotes, and appeal for a leaps of faith. This is not furthering your cause and just makes you look silly. Prove your claims and I'll be the first in line to buy a pair of PCs.

 

[JayKosta]

You are forgetting about TDC/BDC where Frank claims all that 40% power increase takes place. It would have to be more than 40 there because of the reduction in down stroke force which Frank claims is part of the PC smoothing technique. There is no power increase, the most he can expect is the perfected circular technique which is not as effective as mashing.

=================================
No, I am stating MY views about what I think would happen.

And while I agree with Frank that during INITAL training on PCs that downward force would be reduced, I think that after the 'PC technique' is developed (after xx weeks) the user would start to apply more and more downward force as long as the PC technique could be maintained. After some longer interval of PC training I expect the user would be at or near their original level of downward force.

Jay Kosta
Endwell NY USA

 

[coapman]

=================================
No, I am stating MY views about what I think would happen.

And while I agree with Frank that during INITAL training on PCs that downward force would be reduced, I think that after the 'PC technique' is developed (after xx weeks) the user would start to apply more and more downward force as long as the PC technique could be maintained. After some longer interval of PC training I expect the user would be at or near their original level of downward force.

Jay Kosta
Endwell NY USA

Frank is wrong, maximal torque application needs total concentration, PC pedalling uses continuous split concentration around each pedalling circle same as the circular style and this results in a weaker down stroke. In my special technique total concentration can be given to each leg during its extended 180 deg. max force application stroke.

 

[CoachFergie]

Lots of claims, opinions and thinks being mentioned which is kinda stupid seeing all of this stuff is pretty well researched.

 

[FrankDay]

I have an interest in learning.

Fooled me. Good for you.

That's why I read the posts regarding where and when PCs are supposed to change pedalling technique without commenting because this is interesting to me and I am learning.

However, you have done nothing to prove that PCs work as claimed. Prove your claims and then I'll believe you. The weight of evidence is against you and you have done nothing other than duck and cover, try to deflect, show inconsistency after inconsistency, cherry pick anecdotes, and appeal for a leaps of faith. This is not furthering your cause and just makes you look silly. Prove your claims and I'll be the first in line to buy a pair of PCs.

This seems to me a cop out.

You being a self proclaimed expert on study design surely know how difficult it would be to design and complete a study to "prove" a change that requires a substantial commitment from the participant, would take more than 6 months to fairly evaluate, and require a large number of participants to guarantee reaching statistical significance - which is what you are asking me to do. If I were to do this you say you would be the "first in line" when, instead, it would be relatively easy for you to simply order a pair (I think it is clear you can afford them) and see what they do for you, proving to yourself their worth to you.

It just seems to me that you are simply not curious enough (and too lazy) to do that test for yourself so, instead, you try to bully me into doing what would be easy for you to do but almost impossible for me to do - even though even if we found they worked on average as we claim that is no guarantee they would work for you as we claim.

 

[sciguy]

The problem is that below 3 o'clock on the pedal stroke if one is using the quads the quads would drive the foot forward in relation to the knee when, the pedal is moving backwards. Contracting the quads past 3 o'clock is a complete waste of energy.

Frank,

So you're saying I don't need to extend my lower leg at all once my foot is at the 3 o'clock position? Sorry but that's just a bunch of hooely. The lower leg has to extend pretty much all the way to the 6 o'clock position and quads are very much involved in this extension. I'm not saying that the glutes and hamstrings don't also come to play in extending the upper leg as well in a really nicely coordinated symphony but the quads certainly play their part beyond 3 o'clock.

Yep, according to the con advocates cycling is the only sport in the world where technique doesn't matter to the major thing they do.

Frank,

Would you please quit making stuff up. This kind of statement reminds me of the old "do you still beat your wife?" sort of line of dialog. Of course technique is important for any sort of motion based activity. The con advocates simply believe that cyclists, like runners, develop very effective technique by cycling at the intensities they are likely to ride or race at without special need of some gimmick to reinforce the use of less effective muscle groups.

 

[elapid]

You being a self proclaimed expert on study design surely know how difficult it would be to design and complete a study to "prove" a change that requires a substantial commitment from the participant, would take more than 6 months to fairly evaluate, and require a large number of participants to guarantee reaching statistical significance - which is what you are asking me to do. If I were to do this you say you would be the "first in line" when, instead, it would be relatively easy for you to simply order a pair (I think it is clear you can afford them) and see what they do for you, proving to yourself their worth to you.

You seem to answer yourself:

This seems to me a cop out.

Frank, you can run, hide, and duck all you want, but all you are doing is making yourself look more foolish for refusing to prove that PCs work as claimed.

I am not going to be another one of your anecdotes. I am not going to take a leap of faith in someone I have absolutely no trust in based on the lies and bullying behaviour that you have repeatedly used on this and other threads, especially one asking for $1000 on an unproven product. You are not a charity. If you want my $1000, prove PCs work as claimed.

The study is not difficult to design. The length of the study is only a concern for you. You look weaker and more foolish every time you cop out and refuse to prove your claims.

 

[FrankDay]

Frank,

So you're saying I don't need to extend my lower leg at all once my foot is at the 3 o'clock position? Sorry but that's just a bunch of hooely. The lower leg has to extend pretty much all the way to the 6 o'clock position and quads are very much involved in this extension. I'm not saying that the glutes and hamstrings don't also come to play in extending the upper leg as well in a really nicely coordinated symphony but the quads certainly play their part beyond 3 o'clock.

Yes, the knee has to extend as the pedal goes from 3 to 6 o'clock but you are wrong in that it doesn't have to do so actively (unless you are out of the saddle). When the saddle is supporting the body weight the knee will extend just fine using gravity as the force to do so and the foot will apply propulsive force to the pedal just fine only using the glutes as the propelling muscles. It is an easy analysis to see that using the quads there is a waste of energy and will, probably, even work against you. Yes, everyone does use the quads because they are used to using them like they are running, walking. But, cycling is not running or walking and a more efficient muscle use is possible. The question then becomes, how to train it? Hey, I have an idea how that migh happen.

Frank,

Would you please quit making stuff up. This kind of statement reminds me of the old "do you still beat your wife?" sort of line of dialog. Of course technique is important for any sort of motion based activity. The con advocates simply believe that cyclists, like runners, develop very effective technique by cycling at the intensities they are likely to ride or race at without special need of some gimmick to reinforce the use of less effective muscle groups.

Would you stop thinking about this stuff like a luddite and demonstrate you live by your screen name, sciguy. It is a simple analysis. You think you need to use your quads all the way to 6 o'clock and a simple analysis easily demonstrates this is a dumb strategy for maximizing power.

 

[FrankDay]

Of course technique is important for any sort of motion based activity.

Now that we agree that technique is important let's see if we can agree as to what the optimal technique might be to optimize efficiency and power.

So, what is your optimal technique? What do you base this on? Do you have any evidence to support your view?

 

[sciguy]

Would you stop thinking about this stuff like a luddite and demonstrate you live by your screen name, sciguy.

Says the guy constantly whinging about others bullying him

It is a simple analysis. You think you need to use your quads all the way to 6 o'clock and a simple analysis easily demonstrates this is a dumb strategy for maximizing power.

So let's hear your simple analysis. It's interesting that on one hand you want cyclists to use every possible muscle to propel the cranks around, even those that are poorly suited due to fiber composition, size and attachment geometry but now you would rather just let gravity passively extend the lower leg? Sounds like a waste of good efficient muscle group to me. Oh, I forgot, if we use the quads effectively the cranks will go to fast for our hip flexors to keep up. My bad

Want me to hand you another shovel so you can keep on digging?

Hugh

 

[FrankDay]

Says the guy constantly whinging about others bullying him

Actually, I don't care if the bullies try to bully me. As you might have noted, it doesn't work on me.

It is a simple analysis. You think you need to use your quads all the way to 6 o'clock and a simple analysis easily demonstrates this is a dumb strategy for maximizing power.

So lets hear your simple analysis. It's interesting that on one hand you want cyclists to use every possible muscle to propel the cranks around, even those that are poorly suited due to fiber composition, size and attachment geometry but now you would rather just let gravity passively extend the lower leg? Sounds like a waste of good efficient muscle group to me. Oh, I forgot, if we use the quads effectively the cranks will go to fast for our hip flexors to keep up. My bad

Want me to hand you another shovel so you can keep on digging?

Hugh

All one need do is look at the action of each muscle at each position of the pedal stroke. At 3 o'clock the quads would move the foot forward but the pedal is moving down. Contracting the quads here costs energy but cannot do any useful work, a loss of efficiency. At 6 o'clock, the quads would move the foot forward but the pedal is moving the exact opposite, backwards. Contracting the quads here means the quads would be doing negative work resulting in both a loss of efficiency and a loss of power. Everywhere in between these two positions a similar issue exists but somewhere between these two extremes.

A similar analysis can be done for each muscle of the leg to determine where it would be best to be contracting and where it would be best to be relaxed. Then, it seems to me, that optimum technique would be to put all this together into one coordinated pedaling pattern. Of course, the real issue is how to train such a pattern. It is probably not possible to attain perfection here but one should strive, it would seem, to get as close as possible.

So, in general, by my analysis

1. the quads are best utilized at the top quarter of the stroke when the pedal is moving forward.
2. the glutes are best utilized when the pedal is moving down and backwards. (2-6)
3. the hamstrings are best utilized when the pedal is moving back and up, the bottom quarter or so
4. the HF's are best utilized when the pedal is moving upwards. (8-11)

Any contraction outside of these optimum times is either a waste of energy or working against the cyclist as regards power production.

Now, let's hear your simple analysis as to what you think optimum technique should be, since you agree that there is one.

 

[FrankDay]

It's interesting that on one hand you want cyclists to use every possible muscle to propel the cranks around, even those that are poorly suited due to fiber composition, size and attachment geometry but now you would rather just let gravity passively extend the lower leg? Sounds like a waste of good efficient muscle group to me.

Since no one has responded to my last post let me state this in another way.

There are two major joints between the hip and the pedal, the hip joint and the knee joint. For our purposes each of these joints can move in one of two directions, they can extend or flex. So, I ask each of you to do this. Put your bike on a trainer and put the pedal at a position you would like to examine around the circle. Then unclip and contract the individual muscles to move these two joints in the two different directions (four movements in total) and compare the direction the foot moves to the direction the pedal is moving and ask yourself this question: would this be helpful or hurtful to my desire to generate power or to use my muscles efficiently?

Just because a muscle is big and strong is no reason to be using it if it is working against the desired goal. So, is letting the knee passively extend when the pedal is at 3 or 4 or 5 or 6 o'clock a "waste of good efficient muscle group" or not. You be the judge. Using the quad muscle there would be somewhat like using the hip flexors instead of the qlutes at 3 o'clock. A complete waste of effort and doing nothing more than robbing the rider of power.

This little experiment can be done at each point around the entire circle and you can see what is beneficial and what is not at each point of the circle. Keep in mind that muscle contractions and relaxations must start somewhat before optimum because of normal physiological delays between starting contraction and reaching full force. I look forward to someone explaining to me why there is an advantage to forcibly contracting the quads beyond 3 o'clock on the pedaling circle.

Oh, and for Coapman, it is not possible to think about this stuff when doing it for several reasons including, physiological delay between initiating a muscle action and it happening and the fact that the two legs are doing two different things at the same time. If one wants to really improve this stuff one needs to change the unconscious coordination.

 

[elapid]

There are two major joints between the hip and the pedal, the hip joint and the knee joint.

There are THREE major joints - hip, knee and ankle. Focusing too narrowly often results in missing the big picture.

 

[FrankDay]

There are THREE major joints - hip, knee and ankle. Focusing too narrowly often results in missing the big picture.

Adding the ankle doesn't change the direction of any force coming from the knee or hip. For most people all the ankle muscles do is try to fix the joint so the larger muscles of the leg can do their work efficiently. Anyhow, if you want to also add the ankle to the equation then go for it. You can flex and extend the ankle at any of these positions also to see if the calf or TA muscles are helping or hurting if used at any point. I look forward to hearing your analysis.

 

[coapman]

Oh, and for Coapman, it is not possible to think about this stuff when doing it for several reasons including, physiological delay between initiating a muscle action and it happening and the fact that the two legs are doing two different things at the same time. If one wants to really improve this stuff one needs to change the unconscious coordination.

If you do not have time to think or concentrate on each power application, your muscles will be only going through the motions around each of the pedalling circles. In slow motion the technique may appear ideal but at a cadence of 90 things are very different. The optimum technique is the one that uses the most powerful muscles for the longest possible time and makes maximal use of the ankle, lower leg and arm muscles, resulting in additional maximal torque at 12 and 1 o'c.