Powercranks - Page 10

Re: Powercranks

Benjamin Lewis <bclewis@cs.sfu.ca> wrote in message news:<yy7od68rtqqp.fsf@css.css.sfu.ca>...
> Frank Day wrote:
>
> > "Andy Coggan" <acoggan@earthlink.net> wrote in message
> >>
> >> You don't think that using PCs made them think more about how they pedaled?
> >
> > No, not after the first few days.
>
> The users' accounts we've seen speak of difficulties using these cranks for much more than a few
> days. See, for example, http://www.byrn.org/gtips/gpc.htm
>
> It sounds to me like these users are still thinking more about how they are pedaling months after
> first trying these cranks.

While that is possible, it is not "normal". For instance, it is not really possible to be riding in
traffic and concentrating on your pedaling, at least safely. Most people are capable of riding these
things in traffic in only a couple of days. So, while they are occasionally reminded that they have
failed to pedal properly, these people do not have to "think" about their pedaling in order to do
it. I guess it depends upon what you mean by "think" about it.

Re: Powercranks

Frank Day wrote:

> Benjamin Lewis <bclewis@cs.sfu.ca> wrote in message news:<yy7od68rtqqp.fsf@css.css.sfu.ca>...
>> Frank Day wrote:
>>
>>> "Andy Coggan" <acoggan@earthlink.net> wrote in message
>>>>
>>>> You don't think that using PCs made them think more about how they pedaled?
>>>
>>> No, not after the first few days.
>>
>> The users' accounts we've seen speak of difficulties using these cranks for much more than a few
>> days. See, for example, http://www.byrn.org/gtips/gpc.htm
>>
>> It sounds to me like these users are still thinking more about how they are pedaling months after
>> first trying these cranks.
>
> While that is possible, it is not "normal". For instance, it is not really possible to be riding
> in traffic and concentrating on your pedaling, at least safely. Most people are capable of riding
> these things in traffic in only a couple of days. So, while they are occasionally reminded that
> they have failed to pedal properly, these people do not have to "think" about their pedaling in
> order to do it. I guess it depends upon what you mean by "think" about it.

I mean "awareness increased enough to affect experimental results."

--
Benjamin Lewis

"Love is a snowmobile racing across the tundra and then suddenly it flips over, pinning you
underneath. At night, the ice weasels come." --Matt Groening

Re: Powercranks

andbrad2002@yahoo.co.uk (Andrew Bradley) wrote in message news:<53029f74.0402070637.69bec66@posting.google.com>...
> fday@powercranks.com (Frank Day) wrote in message
> news:<69319bd2.0402061210.210e368e@posting.google.com>...
> > > >Simple mechanics says that perpendicular forces are more efficient at doing the work.
> > >
> > > I should be fascinated to read an explanation of what you mean by this. Start by explaining
> > > what you mean by "efficient" here.
> >
> > As opposed to mechanical systems biological systems expend energy if they are applying a
> > muscular force whether that force is doing any work or not. For this analysis assume all the
> > forces are applied as a result of muscular contraction. If one applies 100 lbs on the pedal but
> > at an angle of 45 degrees to the direction of movement of the pedal the resulting force that
> > drives the bicycle is only about 70 lbs-f but the muscular force expended by the rider is 100
> > lbs-f. If the rider could direct the force in the direction of movement then the rider need only
> > apply 70 lbs force to see the same effect, which is more efficient from an energy in/energy out
> > perspective than if the rider was exerting 100 lbs force to see the same result.
>
> You seem to be banking on efficiency being highly sensitive to "effectiveness" of pedal force (ie
> how tangential it is) - unlike mechanical systems.

I am really not banking on anything. I believe the improvements are real (too many users report such
improvements in the real world and these results are consistent with those improvements and were
"statistically significant"). It is simply a hypothesis that this change could account for some of
the improvement. Whether is is actually happening or not I don't know. I just say it is possible,
even though I think, when it is acutally studies, it will be found to be occuring to some extent.
>
> But the modelling above doesn't even establish a relationship between the two since an alternative
> is for your rider to gear down to produce his 70 lbs instead of "pedalling perpendicular". Same
> force, same contraction range, same time, same power, same efficiency... (many complexities
> neglected)

I don't understand. If the muscular force is better directed then less muscular force achieves the
same result. Why is this confusing?

>
> I've had this argument with myself before and predict your next move will be to say that higher
> cadence is less efficient. The counter is to ask why it would be within the confines of the model
> described... and we end up well away from simple mechanics (yet still miles away from real world
> complexity) attempting to prove or refute benefits that are orders of magnitude below your
> prefered claim range.

Well, higher cadence is less efficient (at least above an optimum cadence). The reasons though have
nothing to do with this argument. It has to do that the energy required to just make the pedals go
around (no power to the wheel), at least by my calculations, varies with the square of the cadence.
That means the power loss to the wheel varies with the cube of the cadence.

>
> Coyle et all (them again) measured "effectiveness" in their study as the ratio of tangential pedal
> force to total force. The poorer riders scored better on effectiveness but interestingly the
> downstrokes were more effective than the upstrokes (cut out the upstroke?)

Such a study proves nothing to me because it can't take into account the overall capability of each
rider. A better study would be to take the same people and change the way they pedal, then analyze
which is best. In effect, that is what this study did except the changes in pedal dynamic wasn't
measured, only inferred.

>
> It is an interesting question as to why they measured "effectiveness" in the first place (maybe AC
> can help as he was in the study). They didn't claim a link to efficiency.

Good question.

>
> They didn't factor out leg mass effects in their calculations BTW, did you in your 35-40% figure?

What 35-40% figure.

Frank

Re: Powercranks

Frank Day wrote:
> I think your analogy of the race car is wrong. You are presuming these athletes are getting
> "higher gas mileage" at full throttle. They are not. These people were getting higher gas mileage
> at 69% full throttle. That is, their HR at this power dropped 15 (which turns out to be a 10%
> drop, amazing how these things work out isn't it?). To asume this doesn't represent a capability
> to achieve an increased power (probably 10% I would predict) presumes that their VO2 max HR and
> racing HR drops a similar amount. Such a presumption is a stretch and not based upon any previous
> experience I know of.

I'm very definitely *not* presuming that they were getting higher gas mileage at full throttle --
but even if I were, the point remains that their a prior hypothesis was that PowerCranks would
improve efficiency, and that they did not test any hypothesis about improved power.

Re: Powercranks

"Robert Chung" <invalid@nospam.com> wrote in message news:<40253211$0$28602$626a14ce@news.free.fr>...
> Frank Day wrote:
> > I think your analogy of the race car is wrong. You are presuming these athletes are getting
> > "higher gas mileage" at full throttle. They are not. These people were getting higher gas
> > mileage at 69% full throttle. That is, their HR at this power dropped 15 (which turns out to be
> > a 10% drop, amazing how these things work out isn't it?). To asume this doesn't represent a
> > capability to achieve an increased power (probably 10% I would predict) presumes that their VO2
> > max HR and racing HR drops a similar amount. Such a presumption is a stretch and not based upon
> > any previous experience I know of.
>
> I'm very definitely *not* presuming that they were getting higher gas mileage at full throttle --
> but even if I were, the point remains that their a prior hypothesis was that PowerCranks would
> improve efficiency, and that they did not test any hypothesis about improved power.

That is true. However, it is not unreasonable to infer same from the results. If I can now get the
same power to the wheel as I could 6 weeks ago at a HR 15 beat lower than I required 6 weeks ago
then it is natural to presume that I could probably achieve higher power now than I could 6 weeks
ago. Albeit, I admit, the presumption is not proved.

Re: Powercranks

Tim McNamara <timmcn@bitstream.net> wrote in message news:<m2r7x669v6.fsf@Stella-Blue.local>...
> fday@powercranks.com (Frank Day) writes:
>
> > jobst.brandt@stanfordalumni.org wrote in message
> > news:<IQYUb.13151$XF6.251667@typhoon.sonic.net>...
> >> Frank Day writes:
> >>
> >> >>> Simple mechanics says that perpendicular forces are more efficient at doing the work.
>
> >> >> I should be fascinated to read an explanation of what you mean by this. Start by explaining
> >> >> what you mean by "efficient" here.
>
> >> > As opposed to mechanical systems biological systems expend energy if they are applying a
> >> > muscular force whether that force is doing any work or not. For this analysis assume all the
> >> > forces are applied as a result of muscular contraction. If one applies 100 lbs on the pedal
> >> > but at an angle of 45 degrees to the direction of movement of the pedal the resulting force
> >> > that drives the bicycle is only about 70 lbs-f but the muscular force expended by the rider
> >> > is 100 lbs-f.
> >>
> >> I can't imagine that you are unaware of the falseness of this line of response. Force is not
> >> work and work is not power and you mix all three of them in spin doctor from Washington way.
> >> There is probably a great career awaiting you in some governments.
> >
> > Where in the above statement do I mention work? I am concerned about energy cost.
>
> Stop shifting around. State your point and back it up. If you can't back it up, admit it. Don't
> play semantic games, it's a waste of time.

I've done the best I can. Sorry
>
> >> > If the rider could direct the force in the direction of movement then the rider need only
> >> > apply 70 lbs force to see the same effect, which is more efficient from an energy in/energy
> >> > out perspective than if the rider was exerting 100 lbs force to see the same result.
> >>
> >> Your arguments remind me of the "snap-over cranks" hucksters designed for automobile engines
> >> under the same argument of highest piston pressure pushing on no lever length because the crank
> >> is at TDC. Ignored was that the gas is expanded and all the work goes into the crank until the
> >> valves open.
> >
> > Exactly, the difference being the automobile engine is not a mechanical system.
>
> Come again?
Oops. Biological system.
>
> > At the Naval Academy (when I was there) there was a little hazing thing called shoving out that
> > entailed assuming a sitting position without the aid of a chair. No "work" was involved in the
> > scientific sense. However, it was plenty of work in the biologic human sense. Try it, see how
> > long you can do it. You should have no trouble going for several minutes since your quads are in
> > pretty good shape.
>
> Which proves nothing whatsoever in relation to the claims of these cranks, which are not an
> isometric exercise.

try it, it does prove that one doesn't have to be at VO2 max to put the muscles into anaerobic
metabolism and that muscles can do a lot of"work" in the biological sense without doing any "work"
in the physical sense.
>
> >> > That is what I mean.
> >>
> >> Pushing down on pedals beginning at TDC and ceasing to push at BDC induces pedal force x
> >> distance work into the chain at a rate that can be measured in ft-lbs/sec or power. Stop your
> >> nonsense speak.
> >
> > Exactly which distance work are you referring to, the distance between TDC and BDC or the
> > circumferential distance? Exactly what force direction are you referring too, a constant
> > downward force or a changing direction force? Nonsense speak, I don't think so.
>
> Ya know, Frank, between Andrew and Jobst you've got access to a lot of knowledge and experience
> about exercise physiology and engineering. Instead of being so defensive, you could benefit.
> Remember that no one has to disprove the claims of these cranks; the claims made about these
> cranks have to be proven.

Huh? Thanks for the advice. No one has to do anything or believe anything I presume. It is not even
my job to prove them because if I tried it would clearly be coming from a biased investigator, a
reason to discount the investigation. They are what they are. You can choose to believe it, or me,
or AC, or any of those who have used them and reported benefit or those who have used them and not
reported benefit (if you can find any).

>
> Contrary to what would seem like common sense, "circular" pedaling is not more energy-cost-
> efficient than "normal" pedaling. In fact, it's probably less efficient. If you want to understand
> efficient use of energy in cyclists, don't study racers as they are not efficient from an energy-
> cost standpoint. Study randonneurs who are doing 400 to 600 km in a day or two.

Thanks for that analysis of the pedaling stroke. Very helpful. I have been put in my place and will
no longer think that the pedaling stroke can be improved. Obviously even AC has been wasting his
time trying to study it when all he had to do is ask you.

Frank

Re: Powercranks

Benjamin Lewis <bclewis@cs.sfu.ca> wrote in message news:<yy7oznbusp1r.fsf@css.css.sfu.ca>...

> I mean "awareness increased enough to affect experimental results."

Holy cow, the whole concept of the Powercranks is to make the rider "aware" of how they pedal a
bicycle and then change it. Now, people are saying that the results are invalid because they might
have actually done that. Or, is there another objection I don't understand.

So, we need to have our "awareness effect" group to see if it is just being made aware of pedaling
style that does it or is it the manner in which they are being made aware. Are PC's a requirement or
can it be done without them? Everyone can step right up and place your bets. We know where AC stands
on this question and we know where I stand on it. Any others willing to be embarrassed 2 or 3 years
from now when the question should be definitively answered, I hope.

Now that you are aware that pedaling style is important why don't you think about it and report back
in 6 weeks and see if your HR has dropped 15 beats on your submaximal rides at about the same speed
or power. If it has then everyone can do it and the PC's can quietly go the way of Biopace because
they are clearly unnecessary.

Re: Powercranks

Frank Day wrote:

> Benjamin Lewis <bclewis@cs.sfu.ca> wrote in message news:<yy7oznbusp1r.fsf@css.css.sfu.ca>...
>
>> I mean "awareness increased enough to affect experimental results."
>
> Holy cow, the whole concept of the Powercranks is to make the rider "aware" of how they pedal a
> bicycle and then change it. Now, people are saying that the results are invalid because they might
> have actually done that. Or, is there another objection I don't understand.

Awareness could have an effect even if pedaling "style" doesn't change. I believe if you're thinking
more about what you are doing, you tend to work harder, even if you're pedaling in the same style.

--
Benjamin Lewis

"Love is a snowmobile racing across the tundra and then suddenly it flips over, pinning you
underneath. At night, the ice weasels come." --Matt Groening

Re: Powercranks

"Tim McNamara" <timmcn@bitstream.net> wrote in message
news:m2y8re2sxx.fsf@Stella-Blue.local...
> fday@powercranks.com (Frank Day) writes:
>
> > Thanks for that analysis of the pedaling stroke. Very helpful. I have been put in my place and
> > will no longer think that the pedaling stroke can be improved. Obviously even AC has been
> > wasting his time trying to study it when all he had to do is ask you.
>
> Ah, *there's* that sulky teenager we all know and love. Geez, Frank, a little less bombast and in-your-
> faceness towards people who've been riding and studying the physiology and engineering of
> bicycling for a long time would go a long way. But no, you've invented something new that will
> revolutionize cycling as we know it and prove us Luddites all wrong. You're biased and
> overinvested, trying to prove that the idea works rather than trying to find out if it works.

Proving anyone wrong is not the motivation here. Understanding the training effect is. There is
enough contradictory scientific evidence to reasonably pursue this form of training aid. Note that
the OP is a Ph.D. physiologist/biomechanical engineer.

>
> Let us know what you've gotten some well-structured and properly controlled studies completed, and
> tell us the results. I expect that in, say, 18 months, we'll never hear another word about this
> just as has been the case with hundreds of other revolutionary inventions. And if I'm wrong, then
> that will fine too. I'll wait for the real science.

I note you mention the hundreds that have failed but nothing about those that were successful. So
far only two effects have been addressed, improved efficiency and increased V02 due to the
utilization of additional muscle mass. The second requiring lengthy adaptation without necessarily
increasing cardiac output. The third I'm proposing is the use of a larger muscle mass than normal in
cycling allowing a greater cardiovascular training effect which would result in performance
improvement. This thread has been lively and informative and I hope it will set the scene for an
improved test next time.

Phil Holman

Re: Powercranks

Tim McNamara <timmcn@bitstream.net> wrote in message news:<m2y8re2sxx.fsf@Stella-Blue.local>...

> Let us know what you've gotten some well-structured and properly controlled studies completed, and
> tell us the results. I expect that in, say, 18 months, we'll never hear another word about this
> just as has been the case with hundreds of other revolutionary inventions. And if I'm wrong, then
> that will fine too. I'll wait for the real science.

I'm sorry you seem to think the "study" that has come up here as my responsibility. Of course,
coming up with that "well-structured and properly controlled" study may be difficult since AC or
yourself have not told me or anyone else how such a study should be structured and controlled,
despite my requests. Perhaps you think me and others too dense to understand so you don't bother.
So, we will just have to wait until the lesser scientists out there stumble across EXACTLY how to do
this, assuming any of them have any interest to do so since the likelyhood of finding anything
positive seems so dismal. That will probably increase the amount of time we will have to wait, even
to disprove the Luttrell study findings, assuming it is ever done up to your high standards (unless,
of course, if it disproves Luttrell, when the structure isn't important since that result is so
obvious). Oh, and while you're at it, why don't you inform Bettini, Musseuw, Garzelli, Evans,
Leipheimer, Hincapie, (and a few others) ... that they are wasting their time. Oh, and I just today
heard of a new one, a German, who is trying them out. Since I don't speak German he probably can't
be fooled by my rhetoric and outlandish claims so he will probably drop them quickly. Can't even
imagine why he would even want to try them, it is so obvious they can't do what we say.

The really cool thing about these groups are the comments are here for posterity. Be sure to remind
me in a few years if I should "still" be embarrassed by some (or all) of what I have said here. I'll
still be around.

Re: Powercranks

Terry Morse <tmorse@spamcop.net> wrote in message news:<tmorse-6911E3.08174908022004@news.covad.net>...
> Frank Day wrote:
>
> > Be sure to remind me in a few years if I should "still" be embarrassed by some (or all) of what
> > I have said here.
>
> I hope you're still embarassed by the whiny, arrogant tone of your posts here.

I suspect my tone will only be seen as whiny and arrogant in retrospect (at least by the bulk here
on this listserve) if my posts are shown to be substantially wrong. If they are proven to be
substantially right I am sure they will still be seen as whiny and arrongant by yourself and some
others. Nothing I can do about your perceptions.

Thanks for posting your opinion though rather than fuming in silence.

Re: Powercranks

fday@powercranks.com (Frank Day) wrote in message news:<69319bd2.0402081730.12376ee6@posting.google.com>...
> Terry Morse <tmorse@spamcop.net> wrote in message news:<tmorse-
> 6911E3.08174908022004@news.covad.net>...
> > Frank Day wrote:
> >
> > > Be sure to remind me in a few years if I should "still" be embarrassed by some (or all) of
> > > what I have said here.
> >
> > I hope you're still embarassed by the whiny, arrogant tone of your posts here.
>
> I suspect my tone will only be seen as whiny and arrogant in retrospect (at least by the bulk here
> on this listserve) if my posts are shown to be substantially wrong. If they are proven to be
> substantially right I am sure they will still be seen as whiny and arrongant by yourself and some
> others. Nothing I can do about your perceptions.
>
> Thanks for posting your opinion though rather than fuming in silence.

Personally I would hope others than just Frank are embarressed by this thread--whoever turns out to
be correct.

I for one am a bit embarressed by some of the things I've said when I've posted here years ago. One
does get emotional and caught up in the arguments.

Thanks to all for this thread. It has been really interesting. I've been really currious about
these cranks. When I first heard about them--before I read the claims about using the hip
flexors, I thought they would be really interesting to try just because of how they would effect
my pedal stroke.

I just wish they were not so expensive. Then I would give them a try.

Because so many pros are using them, it seems likely to me that they probably have some merit.
Hopefully someday soon it will be clear if that merit has anything to do with the arguments
presented here.

Re: Powercranks

Greg Lewis wrote:
>
> Because so many pros are using them, it seems likely to me that they probably have some merit.

Abstracting away from PowerCranks for a moment and generalizing to any piece of equipment or
training behavior, I would say that the fact that a pro does something or uses something in a
particular way is nearly useless as a basis of proof for anything.

http://i24.ebayimg.com/01/i/01/3e/28/94_1.JPG

Re: Powercranks

In reply to Andrew Bradley, "Frank Day" <fday@powercranks.com> wrote in
message news:69319bd2.0402071057.21b1879f@posting.google.com...

> A better study would be to take the same people and change the way they pedal, then analyze which
> is best.

You mean like this?:

http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract

> > It is an interesting question as to why they measured "effectiveness" in the first place (maybe
> > AC can help as he was in the study). They didn't claim a link to efficiency.
>
> Good question.

First, I was neither a subject in nor a coauthor of Ed's 1991 study, as it was performed after I'd
finished my doctorate. Second, the reason that they made all the force pedal measurements is because
they hypothesized - as many have - that the pattern of force application would have something to do
with cycling efficiency. This hypothesis, however, was *not* supported by the data, so very little
attention was paid to the concept when the data were discussed.

> > They didn't factor out leg mass effects in their calculations

That would help differentiate between muscular and inertial forces, but since leg mass didn't differ
dramatically between the higher performing/higher efficiency and lower performing/lower efficiency
groups, doing so wouldn't alter the overall conclusions.

Andy Coggan

Re: Powercranks

Benjamin Lewis <bclewis@cs.sfu.ca> wrote in message news:<yy7osmhms9ga.fsf@css.css.sfu.ca>...
> > Holy cow, the whole concept of the Powercranks is to make the rider "aware" of how they pedal a
> > bicycle and then change it. Now, people are saying that the results are invalid because they
> > might have actually done that. Or, is there another objection I don't understand.
>
> Awareness could have an effect even if pedaling "style" doesn't change. I believe if you're
> thinking more about what you are doing, you tend to work harder, even if you're pedaling in the
> same style.

Even though one may think they are riding "harder" if they are thinking about it it is not clear
they do. One cannot go beyond the physical capabilites of their muscles simply because they want
to or are "thinking about it". If one is "thinking" about something and improves it could just as
well come about because they have improved technique when they are thinking about it rather than
"riding harder".

The study we have been talking about, it seems to me, controls for this somewhat by keeping the
cadence and power constant (power hardness level) in the testing and then looks at what the "effort"
is in the form of HR and VO2 uptake (effort hardness level). Another way of doing this would be to
to keep the HR (effort hardness) the same and measure changes in power and VO2 uptake.

Frank