Data (was PowerCranks Study)

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

As an athlete (swimming) who has somewhat latched onto recreational
cycling, I'd like to know this: what about the effects of cross training
six other cyclists and measuring these changes? I'm sure 6 weeks of
swimming/free dive training would increase VO2 max, HR, VO, and many other
factors a SIGNIFICANT amount BETTER than powercranks.

-Mike (VO2 max currently ~55, max ~57, age 19)

--On Monday, October 6, 2003 10:51 PM +0000 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

"Phil Holman" wrote in message nk.net...
Here is a condensed preview of the numbers from the PC testing. ...

My immediate question is: Why did the control group have higher hear
rates and lower efficiencies (however that was calculated) than the PC
group at the beginning of the test? Even if the PC group showed
greater improvement, it would seem that the two groups were not evenly
matched to begin with. Individuals in the PC group may have responded
to whatever training program was implemented better than the control
group, with or without any equipment differences.

I would like to see some definitive results, the PC seem like an
interesting training tool (but too expensive for me).

-David

"David Mackintosh" wrote in message
m...
"Phil Holman" wrote in message
nk.net...
Here is a condensed preview of the numbers from the PC testing. ...

My immediate question is: Why did the control group have higher hear
rates and lower efficiencies (however that was calculated) than the PC
group at the beginning of the test? Even if the PC group showed
greater improvement, it would seem that the two groups were not evenly
matched to begin with. Individuals in the PC group may have responded
to whatever training program was implemented better than the control
group, with or without any equipment differences.

I would like to see some definitive results, the PC seem like an
interesting training tool (but too expensive for me).

I can email the entire research article if you like. I do not see any
significance in the differences between HR and GE in the pre-training
test. It would be impossible to predict any bias from dividing the 12
athletes into 2 groups assuming these were selected prior to the
determination of the pre-training data. Average scatter was around +/-
10 bmp for HR and +/- 2.0 for GE.

Phil Holman

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

What is gross efficiency? How is it measured?

From the individual test reports I've read about PC (admittedly anecdotal,
but then a test group of 6 is barely less so), it took 3 months of training
with them to see major improvements. 6 weeks seems a bit short.

trg wrote:
Phil Holman wrote:
Significant is the 2% increase in Gross Efficiency of the PC group.

What is gross efficiency? How is it measured?

From: http://www.bsn.com/Cycling/articles/cadence.html

"[...] exercise efficiency has several precise definitions that are
summarized in Gaesser and Brooks (1975). They defined and compared four
types of efficiency measures with the goal of identifying the one that
best represented human muscular efficiency.
"These efficiency measures were 1 ) gross efficiency, the ratio of the
work accomplished to energy expended, that is, the effectiveness of
converting chemical energy into mechanical work; 2) net efficiency, the
ratio of the work accomplished to the energy expended above that during
rest, that is, the cost of resting metabolism is subtracted from the
denominator in the computation; 3) work efficiency, the ratio of the work
accomplished to the energy expended above that during cycling with no
load, calculated by subtracting from the denominator the cost of moving
the legs plus the resting metabolism, and 4) delta efficiency - the ratio
of the change in the power output to the change in the energy expended at
each power output."

As long as you can eat more food while riding, efficiency isn't really the
most important limiter to performance. That's why I'm more interested in
whether anything else showed a significant difference.