The Powercrank Thread

[coapman]

Well, people are seeing the power improvements (sometimes inferred from speed improvements) now. The 2nd generation PM's should confirm our explanation as to how and why these improvements are occurring. Or, if we are wrong, give us an alternative explanation as to why these improvements are occurring.

What is your explanation as to how and why these improvements are occurring and maybe you could add, where exactly in the pedalling circle you believe they are occurring.

 

[FrankDay]

What is your explanation as to how and why these improvements are occurring

training and invoking of more muscles into the power production while also improving the efficiency of the pedaling stroke such that more power is generated from the muscles that are used compared to before.

and maybe you could add, where exactly in the pedalling circle you believe they are occurring.

essentially, the entire circle is involved. This goes way beyond simply teaching people to unweight. It is the only way to explain the very high power improvements that people frequently see.

 

[coapman]

training and invoking of more muscles into the power production while also improving the efficiency of the pedaling stroke such that more power is generated from the muscles that are used compared to before.essentially, the entire circle is involved. This goes way beyond simply teaching people to unweight. It is the only way to explain the very high power improvements that people frequently see.

What pedalling technique were you using before you began using PC's. can you still use that technique.

 

[FrankDay]

What pedalling technique were you using before you began using PC's. can you still use that technique.

I suppose my technique was like everyone elses, partial unweighting on the upstroke and ignoring the top and the bottom. Yes I can still use that technique when riding platform pedals and forced to do so.

 

[coapman]

I suppose my technique was like everyone elses, partial unweighting on the upstroke and ignoring the top and the bottom. Yes I can still use that technique when riding platform pedals and forced to do so.

Why do you have to be forced to do it, do you not have a brain in your head, give it the correct objectives and it will control your pedaling. All that's required to test PC's is for you to get a sinusoidal graph of your power application when riding at max power output for 10 seconds with the pre PC style and repeat the exercise with the PC style.
I can guarantee you will get the same result that Coyle got when comparing circular and mashing styles.

 

[FrankDay]

Why do you have to be forced to do it, do you not have a brain in your head, give it the correct objectives and it will control your pedaling. All that's required to test PC's is for you to get a sinusoidal graph of your power application when riding at max power output for 10 seconds with the pre PC style and repeat the exercise with the PC style.
I can guarantee you will get the same result that Coyle got when comparing circular and mashing styles.

Well, assuming I have retrained myself (as is my intention) to totally unweight on the upstroke and assuming I try not to spend any time "thinking" about pedaling technique if I were to totally unweight on platform pedals my foot would come off the pedal and it would be very difficult to do much until I got it back on. But, as soon as my system knows what it must do to ride this bike it can revert back to a less than total unweighting on the backstroke.

Anyhow, once I have the ability to measure these forces I intend to gather just this kind of information.

And, thanks for your guarantee. I will take it for what it is worth coming from someone with zero experience with the system. I will instead rely upon what I learn when I actually gather this data. If you are right you will be able to gloat. I suspect you are not. We will see.

 

[coapman]

How does smooth pedalling while using a pair of old style well worn cotter pins compare with smooth pedalling while using PC's.

 

[FrankDay]

How does smooth pedalling while using a pair of old style well worn cotter pins compare with smooth pedalling while using PC's.

What are you talking about? A crank set where there is some play? If so, there should be no difference. Allowing zero negative forces around the circle prevents any play from being noticed on both sets of cranks.

 

[coapman]

After a year's PC training, for how long can a cyclist continue with one legged pedalling while using only the right leg.

 

[FrankDay]

After a year's PC training, for how long can a cyclist continue with one legged pedalling while using only the right leg.

I don't know. How long can an amputee one-legged pedal after 1 year of training? They seem to be able to go for hours. Regarding PC trained riders I do know that we have had users out on a ride when one of their clutches broke and they one-legged it back home for 15-20 miles. People seem to be able to do whatever they have trained themselves to do.

 

[coapman]

I don't know. How long can an amputee one-legged pedal after 1 year of training? They seem to be able to go for hours. Regarding PC trained riders I do know that we have had users out on a ride when one of their clutches broke and they one-legged it back home for 15-20 miles. People seem to be able to do whatever they have trained themselves to do.

http://www.bing.com/videos/watch/vi...-reaches-for-personal-national-best/1d08vn0zw

You being the expert here, how does blood flow to this man's leg compare to that of a two legged PC'er ?

 

[FrankDay]

http://www.bing.com/videos/watch/vi...-reaches-for-personal-national-best/1d08vn0zw

You being the expert here, how does blood flow to this man's leg compare to that of a two legged PC'er ?

Blood flows the same way it does for a two legged cyclist - its flow is determined by the needs of the muscles, however hard he is working them. Looking at him it appears he is pulling up much harder on the back stroke than the typical PC'er (who normally doesn't do much more than simply unweight) so he is probably generating more wattage and needing more blood flow in that leg than the typical PC'er and way more wattage and way more blood flow than the typical two legged cyclist on fixed cranks.

 

[sciguy]

There's more anecdotal evidence regarding Powercranks over on Slowtwitch today. It's a great read for all those considering making the leap. The OP is an MD and has used Powercranks for almost 5 years.

http://forum.slowtwitch.com/cgi-bin/gforum.cgi?post=4991414#4991414

The following was one of several interesting bits.

Unfortunately, training on these cranks were so difficult that I lost my cardio fitness that year. I could not physically or mentally train at the previous volume. I could not stand up on the pedals well. I lost strength in my quads. I could not maintain a decent cadence for more than a few seconds.

So I'd have to think he didn't make the 40% typical improvement?

Hugh

 

[CoachFergie]

There's more anecdotal evidence regarding Powercranks over on Slowtwitch today. It's a great read for all those considering making the leap. The OP is an MD and has used Powercranks for almost 5 years.

http://forum.slowtwitch.com/cgi-bin/gforum.cgi?post=4991414#4991414

The following was one of several interesting bits.



So I'd have to think he didn't make the 40% typical improvement?

Hugh

Well when the Creator gives examples of uncoupled crank use harming performance when racing on coupled cranks that story is not very surprising.

Specificity people! Train how you intend to race!!!

 

[FrankDay]

So I'd have to think he didn't make the 40% typical improvement?

Hugh

Usually, in order to see substantial improvement I might expect the rider should have adapted. It is clear he didn't/hasn't. I suspect there are a few reasons for this (his observation: "I think my heavy legs and thighs made powercranks particularly difficult, especially in regard to keeping a high cadence."). He is probably correct (the heavier the thighs the harder unweighting will be) and this is probably magnified by his insistence on riding high cadence and, probably, by his cranks being too long ("I am buying a new set of entry level powercranks with several pedal positions and intend to experiment with shorter crank lengths to get in a better time trial position."). Going to shorter cranks should help him immensely get his PowerCranks endurance (and cadence) up as it is my guess is he is riding cranks that are way too long for him.

I also found this quote interesting: "You might loose your coordination with regular cranks." Ugh, I thought that was the entire purpose of the PowerCranks, to help the rider lose their current coordination and substitute a better one. I would be interested in learning more detail of his experience and why he made that comment. If he is using them to help his running but still hopes to ride his bicycle using the "mashing style" I suspect he won't see much cycling benefit. Train the way you race, race the way you train.

 

[coapman]

I also found this quote interesting: "You might loose your coordination with regular cranks." Ugh, I thought that was the entire purpose of the PowerCranks, to help the rider lose their current coordination and substitute a better one.

Can you explain why it is a better one.

 

[sciguy]

this is probably magnified by his insistence on riding high cadence

I could finally ride at a cadence of 80-90 for an extended period.

Just for the record, what cadence are you recommending Powercrankers use if 80 is too high?

Hugh

 

[FrankDay]

Just for the record, what cadence are you recommending Powercrankers use if 80 is too high?

Hugh

I am not recommending a specific cadence per se. And, best cadence also depends upon the desired outcome. If one wants to maximize power for a sprint then high cadence is a necessity, 120-140. But, for maximum sustainable power for endurance events, then the main thing to consider is not cadence but pedal speed. The longer the cranks the slower the optimum cadence, the shorter the cranks the higher the optimum cadence. Since we seemed to evolve to prefer around 90 as the optimum running "cadence" for endurance activities I believe that is the reason we tend to choose 90 as our preferred cycling cadence because that cadence feels natural even if we have chosen a crank length that makes that combination less effective than that cadence and a shorter crank length (because we have never compared the two). (Edit: That having been said, studies repeatedly show that optimum cadence for cyclists (being tested on "normal" cranks) is around 60.

For triathletes it does seem that they ought to find the crank length that optimizes their cycling at a cadence near their running cadence. For cyclists I am not sure this is that important.

In the present case we know nothing about how tall the rider is. All we know is he is an older ex-weight lifter and a relatively new cyclist (certainly not our typical customer) who seems to think that he needs to maximize his pushing component (to take advantage of his background) and had a lot of trouble developing any endurance with the cranks at the high cadences he seemed to be forcing. We are left trying to guess at explaining why this is the case. My experience with the product (and with experimenting with shorter cranks - both myself and the reports of many customers) dictates my analysis of this situation. Your non-experience forces you to simply grasp at straws to draw conclusions that fits your bias.

Edit2: in the ST thread Dev Paul made this observation:

If you talk to powercrank users, they'll tell you that riding along at 100-130W can feel stupidly hard and that's true because a larger portion of your effort is going to lift your legs over the top dead center and that is hardly providing any mechanical work to the road.

This is an important observation and something I have been thinking about for a long time. When you look at how people pedal on regular cranks when they are cruising they seem to reduce their effort everywhere, both pushing and pulling (reducing a little more on the pulling part, seeming to give those muscles more rest) but when they are riding hard they increase the effort on the back stroke more than they increase the effort on the downstroke, getting to essentially zero negative forces on the backstroke. But, PowerCranks do not allow this adjustment because the backstroke cannot go less than fully unweighted. This is good for training those muscles but, until those muscles are really well trained, makes cruising feel like near VO2max. This, I think, is a good argument to train on PowerCranks but to race on regular cranks, so cruising is cruising for all the muscles.

 

[coapman]

Edit2: in the ST thread Dev Paul made this observation:This is an important observation and something I have been thinking about for a long time.

If the PC technique is the most difficult way of taking the pedal over TDC, how can you claim it is here at TDC that most of that 40% PC power increase occurs.

 

[JayKosta]

If the PC technique is the most difficult way of taking the pedal over TDC, how can you claim it is here at TDC that most of that 40% PC power increase occurs.

-
What was actually said is -
" ... because a larger portion of your effort is going to lift your legs over the top dead center and that is hardly providing any mechanical work to the road"

This occurs with PCs because the pedal does not 'push' the foot at any time, and the untrained PC-rider must use muscles that are not accustomed to doing that motion. So the rider views this new use of muscles as being 'extra work'. But it is simply maintaining pedal speed and NOT allowing the foot to exert any negative-torque on the pedal until the foot is in good position for applying power (via any techinque, spinning, mashing, etc).

With the 'coapman' technique, how much power is being used (and not contributing to rear wheel power) to 'push' the foot from the end of the 'power segment' to the beginning of the next 'power segment'?

Do you think there is an advantage to having the foot 'pushed' back into position rather than the rider moving it into position by muslce use?
I think this is the crux of the question about whether PCs can help train someone to produce more power.

Jay Kosta
Endwell NY USA

 

[FrankDay]

-
What was actually said is -
" ... because a larger portion of your effort is going to lift your legs over the top dead center and that is hardly providing any mechanical work to the road"

This occurs with PCs because the pedal does not 'push' the foot at any time, and the untrained PC-rider must use muscles that are not accustomed to doing that motion. So the rider views this new use of muscles as being 'extra work'. But it is simply maintaining pedal speed and NOT allowing the foot to exert any negative-torque on the pedal until the foot is in good position for applying power (via any techinque, spinning, mashing, etc).

With the 'coapman' technique, how much power is being used (and not contributing to rear wheel power) to 'push' the foot from the end of the 'power segment' to the beginning of the next 'power segment'?

Do you think there is an advantage to having the foot 'pushed' back into position rather than the rider moving it into position by muslce use?
I think this is the crux of the question about whether PCs can help train someone to produce more power.

Jay Kosta
Endwell NY USA

Thank you. Someone out there actually seems to be getting it. Yes, the new user sees what the PC's require as "extra work" when, in fact, it is is the same amount of work just being done with different muscles. It is the new muscles that see this "extra work" so they "complain", at least until they have been trained to do the work required.

And, to answer Coapman's question. The reason the biggest gains in power are seen over the top is because that is, in most people, the weakest part of most peoples stroke so that is the area where the biggest gains can be made relatively "easily."

 

[coapman]

Thank you. Someone out there actually seems to be getting it. Yes, the new user sees what the PC's require as "extra work" when, in fact, it is is the same amount of work just being done with different muscles. It is the new muscles that see this "extra work" so they "complain", at least until they have been trained to do the work required.

And, to answer Coapman's question. The reason the biggest gains in power are seen over the top is because that is, in most people, the weakest part of most peoples stroke so that is the area where the biggest gains can be made relatively "easily."

How do the muscles used in pulling up differ from those used in applying that forward torque at TDC?

 

[coapman]

-
What was actually said is -
" ... because a larger portion of your effort is going to lift your legs over the top dead center and that is hardly providing any mechanical work to the road"



With the 'coapman' technique, how much power is being used (and not contributing to rear wheel power) to 'push' the foot from the end of the 'power segment' to the beginning of the next 'power segment'?

Do you think there is an advantage to having the foot 'pushed' back into position rather than the rider moving it into position by muslce use?
I think this is the crux of the question about whether PCs can help train someone to produce more power.

Jay Kosta
Endwell NY USA

Minimal energy is used in my back stroke because all that's involved is drawing back the pedal/lower leg around 5 o'c as knee is bending and unweighting around 7 o'c where upward acceleration of leg weight begins, from 9 o'c muscles are already being prepared for maximal forward force application at 11 without reducing down stroke power as is the case with the PC and circular styles. This is because total concentration is always focussed on the 180 deg. power strokes. Letting the momentum of the downward leg drive the rising pedal up and over TDC would be the sensible way to do it

 

[FrankDay]

How do the muscles used in pulling up differ from those used in applying that forward torque at TDC?

How do the muscles used in lifting your knee to your chest differ from those used to kick a soccer ball? The combination of muscles used to achieve any particular directional force vary depending upon the orientation and direction. Plus, this is constantly changing around the pedaling circle as the orientation and direction constantly changes.

 

[coapman]

How do the muscles used in lifting your knee to your chest differ from those used to kick a soccer ball? The combination of muscles used to achieve any particular directional force vary depending upon the orientation and direction. Plus, this is constantly changing around the pedaling circle as the orientation and direction constantly changes.

Not very different, in that both sets are only capable of generating almost minimal torque and applying even less when a fast moving target is involved. Is it worth training these muscles over a year for such a poor return, not forgetting that because of the extra effort involved, you will probably lose more power in your down stroke than what these newly trained muscles can produce?