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Beware of PowerCranks



 
 
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  #21  
Old June 3rd 07, 07:18 PM posted to rec.bicycles.racing,rec.bicycles.marketplace,rec.bicycles.tech
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Default Beware of PowerCranks

On Jun 3, 7:58 pm, "Phil Holman" piholmanc@yourservice wrote:
I just checked their website and found another study of trained cyclists
that showed a 15.6% increase in VO2max and an 11.6% icrease in max
power.

http://powercranks.com/assets/pdfs/C...dixon_2006.pdf


Luttrell and Potteiger found no difference in VO2Max.

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  #22  
Old June 3rd 07, 07:32 PM posted to rec.bicycles.racing,rec.bicycles.marketplace,rec.bicycles.tech
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Default Beware of PowerCranks

On Sun, 03 Jun 2007 10:22:45 -0000, wrote:

On Jun 3, 6:42 am, wrote:

Am I right in thinking that there was an implied assumption that no
placebo effect encouraged the PowerCrank group to train harder with
their new toy for weeks than the other group, which used the same old
equipment?


In the study, in-lab training time was equal between the PowerCranks
and control group (1 hr per day, 3 days per week, 6 weeks of
training). I guess you have to assume that the subjects weren't
spending their unobserved free time doing extra workouts in an effort
to screw with the results.


Dear Robert,

Good grief!

They spent three hours a week training in a lab? For six whole weeks?
A staggering eighteen hours of pedaling in 42 days?

Thanks for the details--now I'm wondering what happened during the
other 990 hours of that 42-day span, 98.2% of their time. (I'd spend
twice as long on my daily ride in the same period.)

And I'm still wondering what happened during those 18 hours spread out
over 42 days. If we assume that the PowerCrank group did indeed show a
small but definite physiological improvement, was it due to the extra
muscles being recruited, or was it due to their 18 hours of training
being more intense due to the placebo or new-toy effect that the other
group lacked?

I seem to recall a number of posts, from both sides, that claim that
it takes a while just to learn how to pedal comfortably with
PowerCranks. Does anyone know whether the test group trained on
PowerCranks until they felt comfortable and then spent 18 hours in the
actual comparison test? Or did they come into the test cold and learn
during the testing?

Cheers,

Carl Fogel
  #23  
Old June 3rd 07, 09:02 PM posted to rec.bicycles.racing,rec.bicycles.marketplace,rec.bicycles.tech
Phil Holman
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Posts: 478
Default Beware of PowerCranks


wrote in message
ups.com...
On Jun 3, 7:58 pm, "Phil Holman" piholmanc@yourservice wrote:
I just checked their website and found another study of trained
cyclists
that showed a 15.6% increase in VO2max and an 11.6% icrease in max
power.

http://powercranks.com/assets/pdfs/C...dixon_2006.pdf


Luttrell and Potteiger found no difference in VO2Max.


That group trained for 3 hours per week at 70% of VO2Max for 6 weeks
versus 8 hours per week (20% anaerobic) for 6 weeks. The second test was
considerably more extensive. There was also no control group for the
second test. What does it take to get an appropriate and properly
designed test?
Max sums it up well.......Dr. Testa was quick to indicate that a fully
controlled study is still needed, but that preliminary impressions from
several high caliber athlete's had been very positive. With riders like
Danielle Nardello and Stefano Garzelli liking the results and producing
more even power output from using them. He had also seen some 25 - 30
watt gains at LT (lactate threshold) in people using them for the first
time, but also said that other training stimulus were present. He calls
them a "very valuable tool" and something that forces everyone, pro's
and amateurs alike, to be more efficient by forcing you to carry the
weight of the up stroke leg and also maintain force through the entire
range of motion. "It's something that nothing else forces you to do and
it makes you do work that is without a doubt of benefit.""


Phil H


  #24  
Old June 3rd 07, 09:14 PM posted to rec.bicycles.racing,rec.bicycles.marketplace,rec.bicycles.tech
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Posts: 631
Default Beware of PowerCranks

On Jun 3, 10:02 pm, "Phil Holman" piholmanc@yourservice wrote:
There was also no control group for the second test. What does it
take to get an appropriate and properly designed test?


On the one hand, I'd say this is like Keystone Kops. On the other, I'd
have to admit that I've read some pretty bad manuscripts in my own
field, and I'm often surprised at how clueless supposedly smart people
can be about what constitutes a properly designed test.

  #25  
Old June 3rd 07, 09:16 PM posted to rec.bicycles.racing,rec.bicycles.marketplace,rec.bicycles.tech
Tim McNamara
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Posts: 6,945
Default Beware of PowerCranks

In article ,
"Phil Holman" piholmanc@yourservice wrote:

wrote in message
ups.com...
On Jun 3, 5:46 am, wrote:
On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman"


Frank Day. His last posts here were after a scientific study
showed a statistically significant 1.5% gross efficiency
improvement. The experts here still wouldn't buy it.


No offense, but that sounds like 200 watts rising to 203 watts.


Well, the difference was in gross efficiency, not in power. Frank
Day calls them PowerCranks, not EfficiencyCranks. Phil may know
whether there has been a published RCT that shows an increase in
power.


I just checked their website and found another study of trained
cyclists that showed a 15.6% increase in VO2max and an 11.6% icrease
in max power.


My understanding- which may not be correct- is that VO2 max is
biologically determined and that training does not significantly change
this.

PowerCranks have always been marketed a bit too much like the Second
Coming for my tastes.
  #26  
Old June 3rd 07, 09:45 PM posted to rec.bicycles.racing,rec.bicycles.marketplace,rec.bicycles.tech
Phil Holman
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Posts: 478
Default Beware of PowerCranks


"Tim McNamara" wrote in message
...
In article ,
"Phil Holman" piholmanc@yourservice wrote:

wrote in message
ups.com...
On Jun 3, 5:46 am, wrote:
On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman"

Frank Day. His last posts here were after a scientific study
showed a statistically significant 1.5% gross efficiency
improvement. The experts here still wouldn't buy it.

No offense, but that sounds like 200 watts rising to 203 watts.

Well, the difference was in gross efficiency, not in power. Frank
Day calls them PowerCranks, not EfficiencyCranks. Phil may know
whether there has been a published RCT that shows an increase in
power.


I just checked their website and found another study of trained
cyclists that showed a 15.6% increase in VO2max and an 11.6% icrease
in max power.


My understanding- which may not be correct- is that VO2 max is
biologically determined and that training does not significantly
change
this.


I'll assume you are talking about a theoretical ceiling and not the
difference in the same athlete being in shape and not in shape.
The theoretical ceiling is biologically determined but what biologically
constitutes that ceiling is still up for discussion.


PowerCranks have always been marketed a bit too much like the Second
Coming for my tastes.


I thought you of all people could separate the science from the emotion.

Phil H


  #27  
Old June 3rd 07, 10:04 PM posted to rec.bicycles.racing,rec.bicycles.marketplace,rec.bicycles.tech
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Posts: 7,934
Default Beware of PowerCranks

On Sun, 3 Jun 2007 13:45:35 -0700, "Phil Holman"
piholmanc@yourservice wrote:


"Tim McNamara" wrote in message
...
In article ,
"Phil Holman" piholmanc@yourservice wrote:

wrote in message
ups.com...
On Jun 3, 5:46 am, wrote:
On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman"

Frank Day. His last posts here were after a scientific study
showed a statistically significant 1.5% gross efficiency
improvement. The experts here still wouldn't buy it.

No offense, but that sounds like 200 watts rising to 203 watts.

Well, the difference was in gross efficiency, not in power. Frank
Day calls them PowerCranks, not EfficiencyCranks. Phil may know
whether there has been a published RCT that shows an increase in
power.


I just checked their website and found another study of trained
cyclists that showed a 15.6% increase in VO2max and an 11.6% icrease
in max power.


My understanding- which may not be correct- is that VO2 max is
biologically determined and that training does not significantly
change
this.


I'll assume you are talking about a theoretical ceiling and not the
difference in the same athlete being in shape and not in shape.
The theoretical ceiling is biologically determined but what biologically
constitutes that ceiling is still up for discussion.


PowerCranks have always been marketed a bit too much like the Second
Coming for my tastes.


I thought you of all people could separate the science from the emotion.

Phil H


Dear Phil,

I'm skeptical (as you've noticed), but I also suspect that my
skepticism gets in the way of understanding.

So here's a dumb question . . .

Is the claimed improvement for PowerCranks thought to be due to a
mostly physiological change, very roughly the equivalent of bigger
biceps letting you lift a larger weight?

Or is it due to a mostly mechanical change in technique, with the
rider's body left unchanged and the improvement due to the rider
learning to use the same muscles in a more efficient manner?

My assumption was that it's supposed to be a raw physiological
improvement, but maybe I've been missing the point and technique is
supposed to play a major role.

Cheers,

Carl Fogel
  #28  
Old June 3rd 07, 10:50 PM posted to rec.bicycles.racing,rec.bicycles.marketplace,rec.bicycles.tech
Phil Holman
external usenet poster
 
Posts: 478
Default Beware of PowerCranks


wrote in message
...
On Sun, 3 Jun 2007 13:45:35 -0700, "Phil Holman"
piholmanc@yourservice wrote:


"Tim McNamara" wrote in message
...
In article ,
"Phil Holman" piholmanc@yourservice wrote:

wrote in message
ups.com...
On Jun 3, 5:46 am, wrote:
On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman"

Frank Day. His last posts here were after a scientific study
showed a statistically significant 1.5% gross efficiency
improvement. The experts here still wouldn't buy it.

No offense, but that sounds like 200 watts rising to 203 watts.

Well, the difference was in gross efficiency, not in power. Frank
Day calls them PowerCranks, not EfficiencyCranks. Phil may know
whether there has been a published RCT that shows an increase in
power.


I just checked their website and found another study of trained
cyclists that showed a 15.6% increase in VO2max and an 11.6%
icrease
in max power.

My understanding- which may not be correct- is that VO2 max is
biologically determined and that training does not significantly
change
this.


I'll assume you are talking about a theoretical ceiling and not the
difference in the same athlete being in shape and not in shape.
The theoretical ceiling is biologically determined but what
biologically
constitutes that ceiling is still up for discussion.


PowerCranks have always been marketed a bit too much like the Second
Coming for my tastes.


I thought you of all people could separate the science from the
emotion.

Phil H


Dear Phil,

I'm skeptical (as you've noticed), but I also suspect that my
skepticism gets in the way of understanding.

So here's a dumb question . . .

Is the claimed improvement for PowerCranks thought to be due to a
mostly physiological change, very roughly the equivalent of bigger
biceps letting you lift a larger weight?

Or is it due to a mostly mechanical change in technique, with the
rider's body left unchanged and the improvement due to the rider
learning to use the same muscles in a more efficient manner?

My assumption was that it's supposed to be a raw physiological
improvement, but maybe I've been missing the point and technique is
supposed to play a major role.


Two things:
Elimination of pedaling inefficiencies
Increased aerobic capacity due to greater muscle utilization.

Both of these are subject to the same adaptation of pedaling technique
and in my case, required substantial training hours to realize the
adaptation. Mostly in the form of conditioning the hip flexors and
hamstrings to pull up.

Your previous mention of the placebo effect is interesting. It "may"
work for determining VO2Max or Maxpower where the subject was less than
motivated and pooped out early on the "before" test. However, I don't
see how a placebo effect can explain a change in gross efficiency.

Phil H


  #29  
Old June 3rd 07, 11:29 PM posted to rec.bicycles.racing,rec.bicycles.marketplace,rec.bicycles.tech
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Posts: 7,934
Default Beware of PowerCranks

On Sun, 3 Jun 2007 14:50:21 -0700, "Phil Holman"
piholmanc@yourservice wrote:


wrote in message
.. .
On Sun, 3 Jun 2007 13:45:35 -0700, "Phil Holman"
piholmanc@yourservice wrote:


"Tim McNamara" wrote in message
...
In article ,
"Phil Holman" piholmanc@yourservice wrote:

wrote in message
ups.com...
On Jun 3, 5:46 am, wrote:
On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman"

Frank Day. His last posts here were after a scientific study
showed a statistically significant 1.5% gross efficiency
improvement. The experts here still wouldn't buy it.

No offense, but that sounds like 200 watts rising to 203 watts.

Well, the difference was in gross efficiency, not in power. Frank
Day calls them PowerCranks, not EfficiencyCranks. Phil may know
whether there has been a published RCT that shows an increase in
power.


I just checked their website and found another study of trained
cyclists that showed a 15.6% increase in VO2max and an 11.6%
icrease
in max power.

My understanding- which may not be correct- is that VO2 max is
biologically determined and that training does not significantly
change
this.

I'll assume you are talking about a theoretical ceiling and not the
difference in the same athlete being in shape and not in shape.
The theoretical ceiling is biologically determined but what
biologically
constitutes that ceiling is still up for discussion.


PowerCranks have always been marketed a bit too much like the Second
Coming for my tastes.

I thought you of all people could separate the science from the
emotion.

Phil H


Dear Phil,

I'm skeptical (as you've noticed), but I also suspect that my
skepticism gets in the way of understanding.

So here's a dumb question . . .

Is the claimed improvement for PowerCranks thought to be due to a
mostly physiological change, very roughly the equivalent of bigger
biceps letting you lift a larger weight?

Or is it due to a mostly mechanical change in technique, with the
rider's body left unchanged and the improvement due to the rider
learning to use the same muscles in a more efficient manner?

My assumption was that it's supposed to be a raw physiological
improvement, but maybe I've been missing the point and technique is
supposed to play a major role.


Two things:
Elimination of pedaling inefficiencies
Increased aerobic capacity due to greater muscle utilization.

Both of these are subject to the same adaptation of pedaling technique
and in my case, required substantial training hours to realize the
adaptation. Mostly in the form of conditioning the hip flexors and
hamstrings to pull up.

Your previous mention of the placebo effect is interesting. It "may"
work for determining VO2Max or Maxpower where the subject was less than
motivated and pooped out early on the "before" test. However, I don't
see how a placebo effect can explain a change in gross efficiency.

Phil H


Dear Phil,

Assume that the small claimed improvement in gross efficiency is
indeed real (or any other measurements).

This real (not placebo) improvement could be the result of equal
efforts in training, with one training method recruiting new muscles.
The improvement would depend on the specific training method--no
PowerCrank, no improvement.

But the real improvement might also be the result of a placebo/new-toy
effect causing one group to train harder during the same number of
hours, not the recruitment of new muscles. The improvement would
depend not on the specific training method, but on getting the
subjects in one group to concentrate and train harder--PowerCrank,
electric shocks, Playboy models with whips, anything would work.

Either way, tests will show physiological improvement.

My question is whether the improvement is due to something making the
riders concentrate more on their training sessions (psychological
improvement leading to more intense physical training and thus to
improvement) or due to something that's purely physical (no extra
concentration during training).

As a rough analogy, I know that I can improve my daily ride times just
by finding something that makes me pay more attention. Put a pretty
girl in front of me, and I'll concentrate on keeping her in sight.
Given a six-week supply of pretty girls to try to catch, I'll probably
be in better shape than my twin brother, who rode the same route, even
though neither of us had PowerCranks--I'd just be training harder.

I gather that Tim expects some physiological limits to be unaffected
by training--that is, the only way for me to match Lance on some
measurements such as VO2 would be for me to pick different parents.

And it's worth pointing out for anyone reading that most of the low
hanging fruit in the training regimen orchard has already been picked.

On the one hand, this means that we're unlikely to see anything except
small and hard-to-prove improvements, so things like PowerCranks are
going to be tough to demonstrat--very small increases are hard to
separate from random variation and confounding factors.

On the other hand, it also means that larger and larger claims for
improvements are going to be harder and harder to believe. Increases
of 11% and 15% should either sweep the bicycle racing world like
wildfire, or else turn out to be bad science.

Unfortunately, the scientific record is littered with the corpses of
small, exciting studies that turned out work only when they were small
or conducted by particular researchers. Despite our natural
suspicions, no dishonesty is required to arrive at grossly mistaken
results:

http://skepdic.com/blondlot.html

The N-ray scientists were working with something far more cut and
dried than physiology and athletic training, where the opportunities
for deluding ourselves and failing to notice confounding factors are
legion.

But it would be fun to find out that my skepticism is mistaken.

Cheers,

Carl Fogel
  #30  
Old June 3rd 07, 11:31 PM posted to rec.bicycles.racing,rec.bicycles.marketplace,rec.bicycles.tech
Tim McNamara
external usenet poster
 
Posts: 6,945
Default Beware of PowerCranks

In article ,
"Phil Holman" piholmanc@yourservice wrote:

"Tim McNamara" wrote in message
...
In article , "Phil
Holman" piholmanc@yourservice wrote:

wrote in message
ups.com...
On Jun 3, 5:46 am, wrote:
On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman"

Frank Day. His last posts here were after a scientific study
showed a statistically significant 1.5% gross efficiency
improvement. The experts here still wouldn't buy it.

No offense, but that sounds like 200 watts rising to 203 watts.

Well, the difference was in gross efficiency, not in power.
Frank Day calls them PowerCranks, not EfficiencyCranks. Phil may
know whether there has been a published RCT that shows an
increase in power.


I just checked their website and found another study of trained
cyclists that showed a 15.6% increase in VO2max and an 11.6%
icrease in max power.


My understanding- which may not be correct- is that VO2 max is
biologically determined and that training does not significantly
change this.


I'll assume you are talking about a theoretical ceiling and not the
difference in the same athlete being in shape and not in shape. The
theoretical ceiling is biologically determined but what biologically
constitutes that ceiling is still up for discussion.


As I understand it (it's been a while since I had any reason to look
into this stuff and maybe new data has come to light in the interim), if
your VO max is 60 ml/kg/min then that is basically it. You can't "train
up" your VO2 by 15.6% at least from the data I had looked at a few years
back.

Miguel Indurain's published VO2 max was 88 ml/kg/min which is very much
at the high end. Lemond's was reported to be over 90 ml/kg/min. A
training technique that would net guys think this a 15.6% increase would
make them invincible. Nobody could touch them in an event like the Tour
de France. You can't get even those kinds of gains by doping.

There are things you can train up by quite a bit, such as your sustained
power output at lactate threshold, Wingate test, etc. Those things are
important and can make a big difference in race results.

PowerCranks have always been marketed a bit too much like the
Second Coming for my tastes.


I thought you of all people could separate the science from the
emotion.


Hype annoys me, what can I say. When the hype seems mighty unrealistic,
I get suspicious of there being a dose of snake oil in the mix. IMHO
people who are extremely competitive have a tendency to be a bit
gullible when it comes to things that promise improved performance.

Of interest to me would be whether whatever benefits are gained from
PowerCranks are durable. When people go back to regular cranks for
racing, do the maintain the neuromuscular pattern that a PowerCrank is
supposed to develop? Or do they go back to normal riding quickly? Do
they have to "brush up" with the PowerCranks periodically? My hunch is
that the muscle recruitment pattern is quickly unlearned and the rider
goes back to a normal pedal stroke within a week or so after returning
to using normal cranks.
 




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