Robert Chung wrote:
>
> "The Pomeranian" <
[email protected]> wrote
> > No. The "maximize my power" claim is based solely on some presumptions, some circumstantial
> > evidence, and other subjective (and repeated) experiences I try to be objective as possible
> > about. I see no reason why the max horsepower v. rpm curve (for a human) would have a broad and
> > flat distribution. (Most motors don't. Why would a bio-motor?) That is to say, I presume that
> > the max horsepower at 50 rpm, 80 rpm, and 110 rpm will not be identical.
> >
> > How much different is a valid question, but bike racing is about performance at the margin. Even
> > a margin of 1% is huge in something like a hill climb race. And I suspect the difference is a
> > good deal more than that.
>
> Well, I agree with your latter point but even if it isn't flat, what makes you think the max is
> where you think it is?
Where do you think I think it is? I don't think it is 50 rpm.
> Here's some data of power by cadence for a guy doing a 40K TT (collected from a Power Tap--hence,
> the holes in the cadence numbers at 94, 99, and 102rpm):
>
http://mywebpage.netscape.com/rechung/wattage/cadence/cadence-plot1.png
>
> Here's some data for a completely different guy doing hillclimb intervals using a Polar S710:
>
http://mywebpage.netscape.com/rechung/wattage/cadence/cadence-plot2.png
>
> What do you see?
On cadence-plot1.png I see that the rider chose to pedal primarily in the 88 to 108 rpm range. The
highest power samples were in the high 80 to 105 range. But that seems probable because that's were
most of the samples are. High single point samples might not be sustainable. The red line peaks
between 90 and 100, so that suggests that may be where peak "sustainable" power is. The red line is
somewhat flat, but the number of samples is much less for the lower and higher cadences. "Flatness"
does not say that the red line values are sustainable for these other cadences with lower sample
counts. The concentration of samples in the "middle" cadences suggests the red line (average for rpm
I assume) value is sustainable for the middle vlaues. Did the rider "naturally move away" from the
lower and higher cadences because of the incentive of greater speed (power) at the middle cadences?
Is that what the graph says?
So similar data runs for identical time periods should be made with the rider focusing more on both
higher and lower cadences rather than the middle cadences. The difficulty with that is the fact that
it is a different run at a different time. I don't know what the stability of the rider's power
capability is over long time periods (like 1+ weeks). I don't know what the stability of the rider's
psychological focus is over longer time peroids. (I don't know that separate runs can assume "all
other things equal.") Because of these uncertainties, I would demand multitudinous sample runs over
all the conditions over time. The uncertainties demand statistical significance (high number of
sample runs), if one really wants to be scientific about it. By nature, the sample runs can't be
done "blind" because the subject has to be instructed to focus on particular cadences and try "just
as hard" with each. The price for meaningful data is rising and I still have no bidders.
On cadence-plot2.png, again this different rider has chosen to put his/her cadence up around 95 rpm
for most samples. There (in the red line) appears to be higher power output at lower cadences, but
the sample numbers are low and again this may point to unsustainability, and probably does
considering the rather significant power output.
So what does it mean that the two different riders seemed to choose a cadence of about 95 rpm? Why
would they choose this cadence? Maybe they looked at their speedometers and found they could get a
tad more sustainable speed when focusing on these cadences. That would be a very basic negative
feedback system. I still don't know how flat the max horsepower v. rpm curve is for most humans, and
I still don't see a reason to assume it is flat.