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post #16 of 391

Re: Powercranks

jtrimble001@ameritech.net wrote:
> I'm a Ph.D. physiologist/biomechanical engineer

Then you should know that Google Groups can be your friend. http://tinyurl.com/28e2a

In one of those threads is a short exchange between Frank Day, the inventor of Powercranks, and Jim
Martin, who was present at the ACSM meetings when the abstract for the recently published article
was discussed.
post #17 of 391

Re: Powercranks

Hjalmar Duklæt wrote:
>>
> I'm not talking about weight. I'm talking about using more muscle groups to do the work. And I
> don't understand that doing so isn't benefitial. Why are xc skiers using their arms (using extra
> muscle groups) when skiing if it's the cardiovascular system that's the limiting factor? They
> could have thrown their poles into the forrest and saved some weight and only using their legs
> harder. I don't believe in this. Hjalmar (cyclist and skier from Norway)

You're concluding from this that using more muscle groups makes cycling faster. I conclude that
cycling isn't xc skiing.
post #18 of 391

Re: Powercranks

Hi, I just got an idea for a cheap power crank. get a crankset and instead of putting the pedals
opposite to each other, put them next to each other. so, when you pedal, instead of having one foot
pushing down helping the other come up, you'll be forced to lift with both legs making them used to
pulling up. You can accomplish this by taking one foot out of the pedal and pedaling with one foot.
However, pulling up with both feet at the same time really isolates the hamstrings. Shall I take
this idea to Las Vegas?

For those who don't think that pulling gives you an advantage, here is a scientific test. Get
yourself on a trainer and put a pedal at 12 o'clock. push down with your hand to six o clock and
stop, letting the wheel spin, and count the turns of the wheel. Now, put the pedal at six o
clock, and lift with hands to 12:00 and continue the full circle all the way down to 6:00 and
count the wheel turns. If you get the same number of turns, it makes no difference. If you get
more turns, it does.

BTW, I want to sell my power crank concept to Sheldon so he can try to sell on april 2nd.

Andres

jtrimble001@ameritech.net wrote in message news:<n99u10p9b4dljjdhta8gapq8hnm7ee9lfd@4ax.com>...
> WOW!!!!!!!!!!!!!!! I never thought such an innocent question would provoke such controversy!
> Clearly the group is quite divided on this subject! As for me, I'm an age-group triathlete who
> usually finishes in the top 20% or so of the pack. Strongest in the bike, worst on the run.
> Looking forward to doing some TT's in the spring.
>
> What intrigued me was the idea that the PowerCranks might wake up some muscles that may have not
> been used for a while (or ever!) Took a look on e-Bay and found some. So, I'll give them a try,
> keep a journal, and see if I can make some scientific sense out of all of this (I'm a Ph.D.
> physiologist/biomechanical engineer). If the experiment fails, look for the on e-Bay! Also, time
> to dig up those articles on the biomechanics and energetics of cycling! I'll be back again when I
> can pedal for about an hour or so at a decent cadence. BTW - There is NO WAY I'm going to ride
> these things on anything but the Computrainer!! Meanwhile, I'll be an avid reader of this NG and
> chime in now and then when I think I can make a contribution. Thanks for all the feedback.
>
> John
>
> On Tue, 03 Feb 2004 00:45:54 GMT, "Mike Jacoubowsky/Chain Reaction Bicycles"
> <MikeJ@ChainReaction.com> wrote:
>
> >> I hadn't though of it that way but now that you mention it, it is a great act of faith, a type
> >> of religion. As long as there is that faint thread of credibility there will be faithful
> >> followers, the fainter the thread the greater the faith. People love to believe in unbelievable
> >> things.
> >
> >Jobst: "Faith" and "belief systems" aren't such a terrible thing; people do tend to succeed at
> >that which they believe in. I have no doubt that my employee is now pedaling more smoothly,
> >and developing power more equally in both legs. He is probably even able to ride faster now
> >because of it.
> >
> >But... if he'd demonstrated the same amount of resolve at other types of training, he may have
> >accomplished similar or even better results. But there is obviously something that appeals to him
> >about the Powercranks, something that caused him to buy into the religion as it were. For him,
> >it's possible they might be the best thing to come along. For someone else, absolutely not.
> >Particularly for the poster who expected to get used to them in just a few rides!!!
> >
> >--Mike-- Chain Reaction Bicycles www.ChainReaction.com
> >
> ><jobst.brandt@stanfordalumni.org> wrote in message
> >news:0imTb.12157$XF6.236444@typhoon.sonic.net...
> >> Mike Jacoubowsky writes:
> >>
> >> >> Hi. I'm new the the group but thought this would be the right place to ask. Just got a set
> >> >> of Powercranks and put them on the bike I've been using on my Computrainer. Gee, I used to
> >> >> enjoy my Computrainer! Now I can only ride it for about 3 miles! Anyone else had experience
> >> >> with Powercranks? Does this get better or is this why I see them on e-bay so often?
>
> >> > One of our employees uses Powercranks; it's taken him months and months and months to get
> >> > proficient at them. This is apparently normal; they require a degree of dedication that goes
> >> > beyond simple logic... you've really got to believe in them in an almost religious manner.
> >>
> >> I hadn't though of it that way but now that you mention it, it is a great act of faith, a type
> >> of religion. As long as there is that faint thread of credibility there will be faithful
> >> followers, the fainter the thread the greater the faith. People love to believe in unbelievable
> >> things.
> >>
> >> Jobst Brandt jobst.brandt@stanfordalumni.org
post #19 of 391

Re: Powercranks

Hjalmar Duklæt wrote:
> "Robert Chung" <invalid@nospam.com> wrote
>>
>> You're concluding from this that using more muscle groups makes cycling faster. I conclude that
>> cycling isn't xc skiing.
>>
> Yeah, in a way I do. Can somebody tell me why using more muscle groups isn't better? And also why
> do your muscles get tired/exhausted? Is it only because your cardiovascular system is not keeping
> up, or can the muscles get tired even if they get enough fuel? I know that I've been a better
> rider after starting to use the back stroke actively.

I think it's less the number of muscles than which muscles and how exactly they're being used. The
issue then becomes an empirical one, not a theoretical one. Alternating between walking on your
hands and your legs isn't likely to make you walk faster or allow you to walk farther, even though
you're using more muscle groups. Hooking up the muscles that move your eyebrows up-and-down isn't
likely to make you cycle faster or allow you to ride farther, even though you're using more muscle
groups. The question about Powercranks is, in a nutshell, can training the leg flexors help to
increase either power or reduce fatigue in use of the leg extensors? I don't know the answer, but
your xc skiing example is probably the wrong thing to do.
post #20 of 391

Re: Powercranks

In article <qVf*DW+bq@news.chiark.greenend.org.uk>,
David Damerell <damerell@chiark.greenend.org.uk> wrote:
> >race. After he recovered he got a trike where he is using his arms to peddle. I asked him if he
> >is only pushing the pedals with his arms or if he both pushes and pulls. What do you think the
> >answere was? And what do you think would be the best thing to do? And what is the difference
> >using your legs instead of your arms?
>
> The difference (as really ought to be blindingly obvious) is that it is enormously more difficult
> to develop the arm muscles to a point where they are not the limiting factor rather than the
> cardiovascular system, because they are inherently much smaller and not exercised by walking.

On occasions when I've not fancied doing anything with my legs --- such as 72 hours after my
vasectomy --- I've used those hand-crank things in the gym. I can't recall why, but I did them daily
for about three months last summer, and in fact I did get up to a point where I might just about
have been heart-rate limited rather than muscle strength limited. I did this by turning them quickly
against a light-ish resistance.

I've briefly ridden the hand-crank trike of a friend of my parents who's in a chair. His has the two
hand grips next to each other, rather than in the more obvious 180 degree relationship like the
pedals on a bike, because his break is quite high and opposed cranks require stomach muscles to
stabilise.

ian
post #21 of 391

Re: Powercranks

Hjalmar Duklæt wrote:
>>
> I just come to think of another exampel. There is a former rider here in town that got paralysed
> in his legs from a crash with a car during a road race. After he recovered he got a trike where
> he is using his arms to peddle. I asked him if he is only pushing the pedals with his arms or if
> he both pushes and pulls. What do you think the answere was? And what do you think would be the
> best thing to do? And what is the difference using your legs instead of your arms? Do you see
> the point?

The point is that one's arms aren't one's legs. A second point is that the leg flexors aren't the
leg extensors.
post #22 of 391

Re: Powercranks

"Phil Holman" <philjud@earthlink.not> wrote in message news:<7OITb.9831$F23.5169@newsread2.news.pas.earthlink.net>...
> "Carl Fogel" <carlfogel@comcast.net> wrote in message
> news:8bbde8fc.0402022245.69e29011@posting.google.com...
> > "Phil Holman" <philjud@earthlink.not> wrote in message
> news:<rJBTb.9296$F23.7727@newsread2.news.pas.earthlink.net>...
> > > <jobst.brandt@stanfordalumni.org> wrote in message
> > > news:NdmTb.12155$XF6.236433@typhoon.sonic.net...
> > > > Bill who? writes:
> > > >
> > > > >> Hi. I'm new the the group but thought this would be the right
> place
> > > > >> to ask. Just got a set of Powercranks and put them on the bike I've been using on my
> > > > >> Computrainer. Gee, I used to enjoy my Computrainer! Now I can only ride it for about 3
> > > > >> miles!
> Anyone
> > > > >> else had experience with Powercranks? Does this get better or
> is
> > > > >> this why I see them on e-bay so often?
>
> > > > > Here is some interesting feedback:
> > > >
> > > > http://www.pezcyclingnews.com/?pg=fullstory&id=1882
> > > >
> > > > > The author, Josh Horowitz, should be comming upon his one month update shortly.
> > > >
> > > > That makes painful reading for me, having ridden Power Cranks on a demo just long enough to
> > > > understand what the concept is. No doubt
> it
> > > > is exhausting and it builds new muscles to do a task that ordinary cranks make unnecessary.
> > > > The easiest way to return the
> foot/pedal/leg
> > > > from the bottom of the stroke to the next power stroke is to let
> it
> > > > ride. That is, unless you don;t have two reasonably equal legs
> that
> > > > are balanced when you sit on the bicycle without a chain.
> > > >
> > > > If you see two riders, one with weight lifter muscles and a slim,
> no
> > > > fat rider with big lungs, I believe that most riders will
> recognize
> > > > the bikie as the slender guy. That's because only for sprints are
> big
> > > > extra muscles useful. The limit of most fit bicyclists is not
> muscles
> > > > but cardiovascular. More muscles and using otherwise unused
> muscles
> > > > in propulsion is someone's dream of a speed secret.
> > > >
> > > > This goes in the same bucket as round pedaling and ankling.
> > > >
> > > > This sounds so much like patent medicine with no supporting
> evidence:
> > >
> > > Save your debunking for Easter bunnies, Keebler elves and thinner
> thighs
> > > in 30 days.
> > >
> > > http://tinyurl.com/2nthp
> > >
> > > There is plenty of empirical observation plus it is now supported by some scientific testing
> > > which at the very least would require the
> most
> > > cynical pundit to re-evaluate their position. With your demonstrated bias and misconceptions
> > > of physiological function I wouldn't even consider you worthy of that category.
> > >
> > > Phil Holman
> >
> > Dear Phil,
> >
> > I remember seeing that web page before, but was disappointed to find that it's just the
> > abstract.
> >
> > Unless I missed something, the actual article requires either a $105 subscription or else twenty
> > bucks for a single article.
> >
> > Can you suggest any similar links that aren't quite so expensive?
> >
> > Or offer a quick interpretation for the layman of what the somewhat dense abstract is saying?
>
> A rough interpretation is "hand over your money and don't be such a tight wad" :-)
>
> Basically there was a gross efficiency improvement of around 2.6%. A normal efficiency of say
> 22.5% means that of the total energy expended, only 22.5% of it actually ends up propelling the
> rider. An increase of
> 2.6% means that now 26.1% is propelling the rider.

Duh, make that 25.1%. I've been burning the midnight oil again and paying the price.

Phil Holman
post #23 of 391

Re: Powercranks

It is unlikely that the PowerCranks "work" as a result of either the Hawthorne effect or placebo
because the first experience of every user is a substantial worsening of performance. Only after
several weeks or months effort do the benefits become evident, although the typical new user can see
the potential for benefit almost immediately.

Frank (inventor of PowerCranks for those who don't know me)

carlfogel@comcast.net (Carl Fogel) wrote in message news:
> Dear Tim,
>
> I agree that the two are technically different effects, but I think that their similarities
> combine quite nicely.
>
> As in the true Hawthorne effect, the subject seems to be motivated by being observed in our
> typical stirring tales of bicycle improvement, in which--sweet Jesus!--the subject is also the
> observer.
>
> (There is no Hawthorne effect when the subject is observed secretly--you can watch me for weeks
> through a telescope without motivating me to pedal any faster.)
>
> As in a true placebo effect, the subject also has pre-existing expectations that whatever
> contraption is being tested will help him, which it often does, suggesting that expectations have
> consequences when it's important how hard we try.
>
> (There is no placebo effect, for example, when people are told that a daily sugar tablet will make
> them grow taller--neither effort nor psychology has any known effect on growth rate.)
>
> Whatever the combined effects should be called, it's remarkable how often a cleaned chain,
> new tires, a different gear ratio, and a host of other tricks produce improved times--for a
> week or so.
>
> After that, we tend to drift back into slower times because we've forgotten how fast that new
> piece of equipment was going to make us and are no longer "observing" ourselves closely enough
> during the ride to motivate ourselves.
>
> (Real mechanical advantages don't dwindle.)
>
> I recently produced a marked improvement in my daily times just by noting what my watch said at
> seven check-points on my daily loop. I suspect that seven new goals motivated me to pay attention
> and pedal.
>
> When I stopped worrying about reaching each checkpoint, I relaxed--and my overall time dropped
> noticeably.
>
> Carl Fogel
post #24 of 391

Re: Powercranks

"Hjalmar Duklæt" <hjalmar.duklat@telenor.com> wrote
> >
> Yeah, in a way I do. Can somebody tell me why using more muscle groups isn't better? And also why
> do your muscles get tired/exhausted? Is it only because your cardiovascular system is not keeping
> up, or can the muscles get tired even if they get enough fuel? I know that I've been a better
> rider after starting to use the back stroke actively.

How's that? Your "back stroke" muscles only have about 10% of the power of your "fore stroke"
muscles, so 100% use would make you 3% faster. That's if you weren't already cardio-vascularly
limited, and didn't suffer from any overhead or inefficiencies in recruiting the extra muscles. I
think your gains are in your imagination.
post #25 of 391

Re: Powercranks

"Robert Chung" <invalid@nospam.com> wrote in message news:<401f5bc5$0$25453$626a54ce@news.free.fr>...
> jtrimble001@ameritech.net wrote:
> > I'm a Ph.D. physiologist/biomechanical engineer
>
> Then you should know that Google Groups can be your friend. http://tinyurl.com/28e2a
>
> In one of those threads is a short exchange between Frank Day, the inventor of Powercranks, and
> Jim Martin, who was present at the ACSM meetings when the abstract for the recently published
> article was discussed.

Actually I think Jim was at a presentation of an earlier work done by Luttrell several years ago. I
think the more recent research addresses some of the concerns raised at that meeting. I might be
wrong on this but I believe it to be the case. The people to address these questions to though are
really the authors of the study. If you were to read the study it is pretty clean and
straightforward.

Frank
post #26 of 391

Re: Powercranks

"Bill" <bill@example.invalid> wrote in message news:<c_hTb.157985$6y6.3084156@bgtnsc05-news.ops.worldnet.att.net>...
>
> Here is some interesting feedback: http://www.pezcyclingnews.com/?pg=fullstory&id=1882 The author,
> Josh Horowitz, should be comming upon his one month update shortly. Bill

I received some third hand reports yesterday that Josh had some interesting race results last
weekend that should have some relevance to this discussion. Many, but I especially, am looking
forward to his next report. (Some may not look forward to it as it might go against their bias).

Frank
post #27 of 391

Re: Powercranks

Phil Holman writes:

>>>> This goes in the same bucket as round pedaling and ankling.

>>>> This sounds so much like patent medicine with no supporting evidence:

>>> Save your debunking for Easter bunnies, Keebler elves and thinner thighs in 30 days.

>>> http://tinyurl.com/2nthp

>>> There is plenty of empirical observation plus it is now supported by some scientific testing
>>> which at the very least would require the most cynical pundit to re-evaluate their position.
>>> With your demonstrated bias and misconceptions of physiological function I wouldn't even
>>> consider you worthy of that category.

>> The article is full of qualified claims that can mean almost anything. Let's see how the same
>> high level racers perform on TT's before and after this regimen. For instance, how did they do
>> on the Mt Evans Hill Climb or on a flat one rather than "better gross efficiency on a
>> submaximal ride".

> Of course something like that is harder to control experimentally and in my own case I've seen my
> performance improvements discounted so why would anyone else's be different and why the need for
> high level racers?

Only with well trained riders is an improvement in performance a valid indication that the method
works. At less than that, just training would improve performance and having expensive training aids
such as these cranks induces the rider to train.

> A high level of performance isn't a requirement, in fact with all uncertainty of enhanced
> performance supplements, I would think a mid-pack rider out of the amateur ranks would be a better
> candidate for such an experiment. I say this from a scientific viewpoint and not from someone who
> has a marketing interest.

Against what criterion would that improvement be measured?

>> This like many gimmicks of the past will fade into obscurity after all the hyperbole.

> Possibly, although this won't have anything to do with whether they work or not. There is no free
> lunch with the cranks and the fact that they are such hard work may maintain their use by the more
> stalwart athlete.

I don't understand what you mean by that.

Jobst Brandt jobst.brandt@stanfordalumni.org
post #28 of 391

Re: Powercranks

Hjalmar Dukl?t writes:

>>>> If you see two riders, one with weight lifter muscles and a slim, no fat rider with big lungs,
>>>> I believe that most riders will recognize the bikie as the slender guy. That's because only for
>>>> sprints are big extra muscles useful. The limit of most fit bicyclists is not muscles but
>>>> cardiovascular. More muscles and using otherwise unused muscles in propulsion is someone's
>>>> dream of a speed secret.

>>> Well, this is probably true for maximum effort but I would believe that using extra muscle
>>> groups to do the work would be beneficial when it comes to endurance and submaximal efforts. It
>>> would take longer before the muscles were exhausted. During a 5 hours road race I guess this is
>>> what counts, not your cardiovascular maximum limit.Or am I completely wrong here?

>> For long events, the limits are very much cardiovascular. Weight is weight, whether it's fat,
>> muscle or bike, and it takes more work to haul weight uphill. In any sort of race with any
>> significant climbing, the lighter rider is at an advantage and it doesn't matter if it's fat or
>> muscle.

> I'm not talking about weight. I'm talking about using more muscle groups to do the work. And I
> don't understand that doing so isn't beneficial. Why are xc skiers using their arms (using extra
> muscle groups) when skiing if it's the cardiovascular system that's the limiting factor? They
> could have thrown their poles into the forest and saved some weight and only using their legs
> harder. I don't believe in this.

The example you give are for different functions that are complementary in the sport. Pedaling is a
singular effort and it is best done with the principal muscles that humans develop naturally. As I
said, adding hand cranks to a bicycle do not improve propulsion.

There is another exercise that makes the effect more apparent and that is to ride at a high constant
rate on the level while mentally counting cadence 1-2-3-1-2-3... on each down stroke while
monitoring speed on a speedometer. Changing the regimen to push down only on the count of "1"
reduces power strokes to 1/3 as many, yet speed at the same effort will remain constant. There is no
benefit to this method other than to show that the effort is cardiovascular and not round pedaling
or PowerCranks.

Jobst Brandt jobst.brandt@stanfordalumni.org
post #29 of 391

Re: Powercranks

Frank Day wrote:
> "Robert Chung" <invalid@nospam.com> wrote
>> Then you should know that Google Groups can be your friend. http://tinyurl.com/28e2a
>>
>> In one of those threads is a short exchange between Frank Day, the inventor of Powercranks, and
>> Jim Martin, who was present at the ACSM meetings when the abstract for the recently published
>> article was discussed.
>
> I think the more recent research addresses some of the concerns raised at that meeting.

Excellent. So, since you read the paper, can you summarize what their initial hypothesis was and its
relationship to efficiency?
post #30 of 391

Re: Powercranks

jobst.brandt@stanfordalumni.org wrote in message news:
> same effort will remain constant. There is no benefit to this method other than to show that the
> effort is cardiovascular and not round pedaling or PowerCranks.
>
> Jobst Brandt jobst.brandt@stanfordalumni.org

IMHO limitations in effort are "never" cardiovascular but "always" local. Rowers and XC skiers have
higher VO2 max capabilities than runners and cyclists because they use more muscle mass in their
sports. The cardiovasuclar system is perfectly capable of responding to almost any repeated stress
to improve capability. Unfortunately, this adaptation is slow and takes substantial time.

The limitations in performance come when anaerobic efforts ensue and this is always local, otherwise
we would all be stopping our efforts with chest pain, not exhaustion.
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