Data (was PowerCranks Study)

"Frank Day" wrote in message
om...
Why don't you just wait until you can read the study then criticize
what was finally published.

I only wrote what I did because, two lines above in this thread, you asked
me about the criticisms. (See: Was the criticism of the original study you
heard similar to the
criticisms heard about "cold fusion" (impossible) or related to the methods
and design of the study?)

Did you not want an answer till later?

Cheers,

Jim


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Frank Day wrote

Unfortunately for the debunkers, if the claims are substantiated by
the study, then one should not claim the study is bogus simply because
the researchers didn't propose a mechanism beforehand. Rather, the
question should be either: (for the non-believers) Can the study be
improved and is the study repeatable? or (for the believers) What is
the mechanism?

I'm interested in the mechanism but is improved efficiency only one of
several possible hypotheses. FWIW my pet theory was the utilization of
additional muscle mass in the pedaling action would increase max aerobic
output. Effectiveness over efficiency every time otherwise we'd all be
riding around at 60rpm. Doesn't the highest V02 max occur in sports that
utilize whole body musculature (e.g. X country skiing).

Phil Holman

(Frank Day) wrote in message . com...


Are they as good as Rotor Cranks. That really isn't the question,
becaause these two products do different things. The question is: Are
they as good as they claim? And, if not, how good are they? Or, are
they not worth anything?

Let me rephrase the question: which one will make you go faster, if
either?
What is curious is that one trains to overcome the "problem", the
other compensates for the "problem", much like Biopace. It is
conceivable power cranks force one to train properly, but


This study, I think, goes some towards answering those questions.


Not as presented, we don't know the statistical significance, which
means the apparent positive results could have been due to chance.

A problem I have, having had an inside view of this sort of testing,
is that if you pay me to do a study, I can get the results you want,
or something that seems to support them. This is why it takes many
studies before something becomes accepted. But does Museew really
email other pros telling them they have to use the crank??

Frank


(RK) wrote in message
Biopace still has its advocates. The question is: are they as good as
rotor Cranks? They are being used by some 2nd division pros, Spanish
triathletes, et al. They look to be an eccentric cam device intended
to eliminate the dead spot that Power Cranks emphasize for training.

http://www.rotorbike.com/eng/home.htm

RK wrote:

A problem I have, having had an inside view of this sort of testing,
is that if you pay me to do a study, I can get the results you want,
or something that seems to support them. This is why it takes many
studies before something becomes accepted. But does Museew really
email other pros telling them they have to use the crank??

No, he e-mails them reminders to visit their vet for treatment of their
tubes for wasp stings.

Jim,

I understood that to be the original criticism and that is what i
asked, but I took your answer to indicate there could not be any
acceptable hypothesis to study these cranks at anytime because there
was no scientific literature to suggest that they should work. If that
criticism was present then I suspect it would be present now. My
remarks, I guess, would mostly be applicable to the earlier criticism
of the earlier paper and I was premature in anticipating your
criticisms of this one.

My comments were also directed to the scientific research and
publishing process in general, in that, sometimes bias enters the
review process just as much as it enters the study process and efforts
should be made to remove bias in the scientific process wherever it
exists.

There can be lots of reasons not to publish a paper, mostly involving
bad design and/or data collection, but also involving inadequate
discussion of results or having little relevance to the target
audience. Those are valid and can be corrected by the author. If
studies are expected to be perfect, however, there would be no
published studies. Unfortunately, the author can do nothing to correct
bias on the part of the gate keeper.

Frank

"Jim Martin" wrote in message ...
"Frank Day" wrote in message
om...
Why don't you just wait until you can read the study then criticize
what was finally published.

I only wrote what I did because, two lines above in this thread, you asked
me about the criticisms. (See: Was the criticism of the original study you
heard similar to the
criticisms heard about "cold fusion" (impossible) or related to the methods
and design of the study?)

Did you not want an answer till later?

Cheers,

Jim


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Like I said Frank, using an "n" number of 12 is already such a significant fault of the study design, that all
you people touting its conclusions are just reinforcing your total lack of understanding of items like
standard deviation, statistics in general, and imprecision of measuring equipment.

All your other discussions are moot because you'll NEVER convince any real scientist that using 12 subjects
can generate meaningful statistics of any kind.

Like I said, it's a fatal flaw and any further discussions of this study that attempt to gloss over the "n"
number problem cannot pass the laugh test.

Racer "Johnny Cochran" X



Frank Day wrote:

I think this is different than the original study they did, which i
saw many years ago, which never got published (maybe now I know why).
You, of course, are welcome to bash it again, if you see fit, after
it is published. Of course, now you will have to put your thoughts in
writing, affix a name to the criticism, and let your criticism undergo
editorial scrutiny and be forever embarrased if your criticism is
based solely on bias.

Was the criticism of the original study you heard similar to the
criticisms heard about "cold fusion" (impossible) or related to the
methods and design of the study?

Frank
"Jim Martin" wrote in message ...
Interesting that they finally got this study published. What journal
accepted it? When they presented the abstract at ACSM people lined up at the
mic to bash the study. The moderator finally had to cut it off.

Frank 24 Hours,

How does the study address the fatal flaw of using an "n" number of 12 subjects (6 in each group)?

Answer: it doesn't.

All your other debates about this study are moot because the n number problem is catastrophic to any of its
ostensible data and conclusions. And any scientist who would even attempt to pawn off conclusions on a study
that uses only 12 subjects is clearly trespassing into the realm of junk science.

I don't give a **** what journal needs to fill its pages, a study with an n number of 12 is better viewed as a
comedy act than an experiment.

I suggest you speak to some real researchers and statisticians about this fact and see what they say.

If you flip a coin 12 times, do you really think the statistics you can get on 1 trial are going to be
ANYWHERE near as accurate as if you flipped that coin 200 times?

Thanks,

Racer X



Frank Day wrote:

Why don't you just wait until you can read the study then criticize
what was finally published. I think you will find most of the concerns
you addressed adequately covered, except for, of course, the bias that
there really can't be any improvement over current pedaling technique
("because almost no one produces substantial negative power during the
flexion phase at pedaling rates under 100 rpm") so any demonstrated
improvement must come from measurement error and I don't believe they
reproduced the technical manuals for the equipment they used
regarding specific calibration procedures beyond commenting on
calibration protocol. Although I am sure the authors could provide
that to you if that criticism remains after you read the article.

Frank

"Jim Martin" wrote in message ...
If I recall correctly there were a three major concerns.

1) The study was not hypothesis driven. That is to say, the authors had no
reason, based on existing scientific literature, to hypothesize that
training with the power cranks would change efficiency. Cyclists may wish to
think that pedaling biomechanics will be improved and that the change in
biomechanics will improve efficiency. That is wishful thinking. No one has
ever reported a link between pedaling technique and efficiency. Indeed,
there is little to improve because almost no one produces substantial
negative power during the flexion phase at pedaling rates of under 100rpm.

2) If they had tried to express a hypothesis it could only be centered on a
notion that pulling up is inherently more metabolically efficient than
pushing down: that muscle that flex the leg are more efficient than those
that extend the leg. No one has ever reported such a difference and there is
no reason to hypothesize one.

3) The procedures for calibrating the metabolic system were not well
explained.

In my opinion the most reasonable explanation for their findings is that
something happened to their metabolic system between pre and post testing.

Cheers,

Jim


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I can offer an objective critique of the study. I'm not going to tell you
Power Cranks don't work. All I'm going to tell you is that this study
likely can't prove they do.

So I'm not the satanic, reckless debunker you people have me pegged for.
I'm just trying to follow the Scientific Method.

Racer X



Phil Holman wrote:

"Jim Martin" wrote in message
...
Interesting that they finally got this study published. What journal
accepted it? When they presented the abstract at ACSM people lined up
at the
mic to bash the study. The moderator finally had to cut it off.

Any of them named Racer X by chance. It hasn't been published yet so my
original post was a fyi and this one is a sneak preview of the data.
Anyone interested in a full copy of the article can email me (Racer X
included).

Thanks

Phil Holman




"Phil Holman" wrote in message
k.net...
Here is a condensed preview of the numbers from the PC testing. The
study was conducted by Mark D. Luttrell, Dept of Health, Sport and
Exercise Science, University of Kansas and Jeffrey A. Pottteiger,
Dept
of Physical Education, Health and Sports Studies, Miami University.

The effects of 6 weeks of training with PCs was examined for 6
cyclists
(+6 with regular cranks) to determine changes in V02 max, AT, HR,
V0,
and RER during a 1 hour submaximal ride (~69% V02 max).

Here are the numbers for Heartrate (HR) and Gross Efficiency (GE)
before
and after training.

Time (minutes)

PC Group 15 30 45 60

HR Pre 154 155 156 157

Post 141 140 141 141



GE (%)Pre 21.5 21.3 21.6 21.5

Post 23.1 23.0 23.6 23.9



Control Group

HR Pre 166 165 166 163

Post 159 159 159 160



GE (%) Pre 21.3 20.8 20.8 21.2

Post 21.8 21.5 21.3 21.0

Significant is the 2% increase in Gross Efficiency of the PC group.

Phil Holman




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Frank,

Your third paragraph below fails to mention that a study that uses 12 subjects cannot generate any
credible/reliable/accurate statistics. Yur standard deviation is HUGE, and far beyond acceptable for someonce
concluding a 2% "gain." The standard deviation is much larger than 2%.

Consequently, this study never should have even been done with an n number of 12.

There's no way around this fault. And I'm gonna have to ask you people to desist from engaging in further
superfluous debate on this study that treats the fatal n number flaw as if it can be painted over like some
rust on an El Camino.

All this talk about other possible flaws of the study that do not menton the n number of 12 is basically an
insult to anybody with a degree in science.

I won't patronize it.

Racer X



Frank Day wrote:

Jim,

I understood that to be the original criticism and that is what i
asked, but I took your answer to indicate there could not be any
acceptable hypothesis to study these cranks at anytime because there
was no scientific literature to suggest that they should work. If that
criticism was present then I suspect it would be present now. My
remarks, I guess, would mostly be applicable to the earlier criticism
of the earlier paper and I was premature in anticipating your
criticisms of this one.

My comments were also directed to the scientific research and
publishing process in general, in that, sometimes bias enters the
review process just as much as it enters the study process and efforts
should be made to remove bias in the scientific process wherever it
exists.

There can be lots of reasons not to publish a paper, mostly involving
bad design and/or data collection, but also involving inadequate
discussion of results or having little relevance to the target
audience. Those are valid and can be corrected by the author. If
studies are expected to be perfect, however, there would be no
published studies. Unfortunately, the author can do nothing to correct
bias on the part of the gate keeper.

Frank

"Jim Martin" wrote in message ...
"Frank Day" wrote in message
om...
Why don't you just wait until you can read the study then criticize
what was finally published.

I only wrote what I did because, two lines above in this thread, you asked
me about the criticisms. (See: Was the criticism of the original study you
heard similar to the
criticisms heard about "cold fusion" (impossible) or related to the methods
and design of the study?)

Did you not want an answer till later?

Cheers,

Jim


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It seems to me, from a scientific point of view (and from the point of
view of the non-believers) that the first thing that needs to be
proven is this question: Is there any worth to these things over what
can be done without them.

Once that is accepted then several questions arise such as how much
potential benefit is there, what is the optimum way to achieve that
benefit and what is the mechanism or mechanisms of the benefit.

Frank

"Phil Holman" wrote in message link.net...
I'm interested in the mechanism but is improved efficiency only one of
several possible hypotheses. FWIW my pet theory was the utilization of
additional muscle mass in the pedaling action would increase max aerobic
output. Effectiveness over efficiency every time otherwise we'd all be
riding around at 60rpm. Doesn't the highest V02 max occur in sports that
utilize whole body musculature (e.g. X country skiing).

Phil Holman