Data (was PowerCranks Study)

I will withhold comment about the study until I can read the whole thing.
For one thing, the report below does not provide confidence intervals or
level of significance; 2% could be accidental. As for Racer X's comments
on one aspect: both groups would have been training for those 6 weeks, not
just the experimental group; otherwise, his comment would be accurate (I am
making the assumption both were training as normal). 6 in each group is a
small number; one of the common issues with exercise studies.

Potteiger is a well-respected researcher with many peer review papers to his
name. Do a PubMed search if you want. His credentials are just fine.

It will probably not appear in NATURE, more likely (if it gets published) it
will be in Medicine and Science in Sport and Exercise or maybe Journal of
Biomechanics.


"RACER X" wrote in message
...
HOLE MAN,

Why would a person who wants to find out whether or not POWER CRANKS are
better than regular cranks introduce the highly variable noise that this
study does?

I could just as easily conclude from this data set that the reason why it
showed a 2% increase in "gross effiency" is because the subjects tested
simply had an additional 6 weeks worth of training under their belt. In
no
way, shape, or form, could one conclude that the extra 2% gain was due
solely to the use of Power Cranks. In fact, the subjects claimed 2% gain
could have just as easily have come from a 3-4% increase in fitness output
coupled to a decrease of 1-2% (caused by the Power Cranks), thereby
resulting in a 2% net gain.

Also, no reputable scientist claims confidance in a study with an "n"
number of only 6 subjects.

In addition, the University of Kansas and Miami University are both party
schools and any "scientific study" out of these overglorified frat houses
probably aren't going to be appearing in Nature anytime soon.

It was a nice infomercial though. One question: do Power Cranks come with
a ****ing bucket of OxyClean?

Take care,

Racer X



Phil Holman wrote:

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

"Sam" wrote in message
nk.net...
I will withhold comment about the study until I can read the whole
thing.
For one thing, the report below does not provide confidence intervals
or
level of significance; 2% could be accidental. As for Racer X's
comments
on one aspect: both groups would have been training for those 6
weeks, not
just the experimental group; otherwise, his comment would be accurate
(I am
making the assumption both were training as normal). 6 in each group
is a
small number; one of the common issues with exercise studies.

Potteiger is a well-respected researcher with many peer review papers
to his
name. Do a PubMed search if you want. His credentials are just fine.

It will probably not appear in NATURE, more likely (if it gets
published) it
will be in Medicine and Science in Sport and Exercise or maybe Journal
of
Biomechanics.

I can email the entire article if you want. It's not a very good pdf
file but readable.

Phil Holman

Phil Holman wrote:

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

1. Anything about delta efficiency?
2. Any other significant differences between groups?

Sam I am Green Eggs and Ham,

This study also wasn't double-blind, and there is no real way that one can
actually measure something as small as a 2% increase in "efficiency" with any
reasonable degree of confidance that couldn't just as easily be ascribed to
standard deviation or imprecision of the measuring equipment.

As for making it into a journal, so did hundreds of studies that supposedly
"proved" post-menopausal women benfitted from hormone replacement therapy. Now
they are saying it's actually bad for them and all the science that went into
it was never really good to begin with.

This study reaks of junk science in many ways. The low n number itself of 12
was reason enough to not even conduct the study. The fact that he did it with
12 cyclists and is then trying to pawn off the results as being statistically
significant is already bad news for his reputation.

You are mistaken when you say the low number is merely a problem. It is a
fatal problem.

How much do you want to bet that these Power Cranks do as well as Biopace when
all is said and done?

Racer X

Sam wrote:

I will withhold comment about the study until I can read the whole thing.
For one thing, the report below does not provide confidence intervals or
level of significance; 2% could be accidental. As for Racer X's comments
on one aspect: both groups would have been training for those 6 weeks, not
just the experimental group; otherwise, his comment would be accurate (I am
making the assumption both were training as normal). 6 in each group is a
small number; one of the common issues with exercise studies.

Potteiger is a well-respected researcher with many peer review papers to his
name. Do a PubMed search if you want. His credentials are just fine.

It will probably not appear in NATURE, more likely (if it gets published) it
will be in Medicine and Science in Sport and Exercise or maybe Journal of
Biomechanics.

"RACER X" wrote in message
...
HOLE MAN,

Why would a person who wants to find out whether or not POWER CRANKS are
better than regular cranks introduce the highly variable noise that this
study does?

I could just as easily conclude from this data set that the reason why it
showed a 2% increase in "gross effiency" is because the subjects tested
simply had an additional 6 weeks worth of training under their belt. In
no
way, shape, or form, could one conclude that the extra 2% gain was due
solely to the use of Power Cranks. In fact, the subjects claimed 2% gain
could have just as easily have come from a 3-4% increase in fitness output
coupled to a decrease of 1-2% (caused by the Power Cranks), thereby
resulting in a 2% net gain.

Also, no reputable scientist claims confidance in a study with an "n"
number of only 6 subjects.

In addition, the University of Kansas and Miami University are both party
schools and any "scientific study" out of these overglorified frat houses
probably aren't going to be appearing in Nature anytime soon.

It was a nice infomercial though. One question: do Power Cranks come with
a ****ing bucket of OxyClean?

Take care,

Racer X



Phil Holman wrote:

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

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.



"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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"Robert Chung" wrote in message ...
Phil Holman wrote:

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

1. Anything about delta efficiency?
2. Any other significant differences between groups?

If you send me your real email I'll send you a copy. Per Jim Martin's
comment, this has not been published yet and according to the source
of the data, this was scheduled to happen in November. According to
Jim, it might be a challenge.

Phil Holman

RACER X wrote in message ...

You are mistaken when you say the low number is merely a problem. It is a
fatal problem.

How much do you want to bet that these Power Cranks do as well as Biopace when
all is said and done?

Racer X



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

Power Cranks are training aids designed to improve pedal stroke
with conventional circular cranks. They have little in common
with BioPace, which was designed to accomodate poor pedal strokes.

The moral of this study is it's a good idea to work on pedal
stroke. One legged pedalling, low-cadence climbing, downhill spinning --
there are many approaches. This is just one.

Dan


RK wrote:
RACER X wrote in message ...


You are mistaken when you say the low number is merely a problem. It is a
fatal problem.

How much do you want to bet that these Power Cranks do as well as Biopace when
all is said and done?

Racer X




Biopace still has its advocates.

"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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Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.522 / Virus Database: 320 - Release Date: 9/29/2003

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.