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