From: BRANDT_JOBST/HP1900_01@HPLOMG.HPL.HP.COM
Newsgroups: rec.bicycles
Subject: Re: pedaling efficency
Date: 9 Apr 92 22:24:20 GMT

Frank Williams writes:

> one, I remain unconvinced.  My personal experience is that, regardless of
> cadence, when I catch myself simply stomping down, I can always speed up
> by pedaling "round".  When I go out with the fast guys and am humbled into
> sucking wheel, the only way to survive is to pedal "round".  Am I doing
> what I think I'm doing?  Maybe not.  Am I doing what Lemond writes he thinks
> he does?  I think so.  I've been wrong in worse company.  Still, the more we
> know about the physiological parameters in question, the better we can
> coach riders to attain their full potential.

Frank suggests that engaging more muscles to convert the aerobic capacity
of heart and lungs to useful energy.  I believe that the human body is,
in this respect, no different than all other "machines" in that each motor
has its own overhead and that 100 one HP engines, for instance, burn more
fuel than one 1 HP engine for the same output.  There are, no doubt, limits
to this parallel but we are talking here of more then 90% of the work being
done by the downstroke and whether including other muscles to augment this
main muscle group improves energy conversion.  I believe it does not and
I readily believe researchers who have not found any substantial work done
by other muscles at peak output.

This all gets back to an earlier thread that suggested that, ideally, one
spin up hills at the same cadence used in the flats.  This contention
arises from a misconception that, were there not massive evidence to the
contrary, I might believe.  The reasons for slower cadence when climbing
were detailed at great length.  Because there is less kinetic energy and
slower ground speed against a constant retarding force, the power stroke
must be longer.  It gets longer by pushing over the top and all the way
down to the bottom and even some backward pull.  Depending on the rider,
this encompasses at least 180 degrees.  To recover from this long stroke,
a longer rest period is needed and this can only be achieved by a slower
cadence.  A shorter power stroke would cause cyclic speed variation with
related acceleration losses.

Therefore, if one were to round pedal in the flats as riders must on
steeper long grades, the cadence would drop to that used on such hills.
In a TT, power is delivered at a fairly high cadence and it is limited
to a main thrust between 1:30 and 4:00 o'clock.  The rest of the stroke
is mostly follow through with relatively little power.  To experiment
with the validity of the pulsed output let me suggest a method that
makes this strikingly clear.  While cruising on the flats at 20+ mph,
count mentally 1-2-3-1-2-3-1-2-3 pedaling only once every third pedal
stroke so that you alternate between the legs.  I think you will notice
that you can maintain practically the same speed with no additional
effort with a strong pulse interspersed with a long recovery time.
It is not smooth and it is not natural but it demonstrates recovery
and an obviously short power pulse that is certainly less than 1/3 of
the time.

I think that from recovery time and the concept of hill climbing cadence
the effects of "round" pedaling can be put into perspective.  I propose
that round pedaling destroys the recovery cycle and wastes power in the
overhead of engaging more muscles when they are not required.  In climbing
these muscles must be engaged to conserve constant velocity for these
losses are greater than muscular losses.  The racer chooses the most
efficient mode naturally.

jobst_brandt@hplabs.hp.com
Newsgroups: rec.bicycles