This document is copyright 1995 by Tom Holub. It may be freely
redistributed as long as this notice is retained. It may not be sold.
Cycling is the most efficient form of transportation known (the
second most efficient is the flight of the California Condor). A
cyclist using proper gearing and cadence can ride continuously for
hours; top racing cyclists can average 25 MPH over hilly courses of 150
to 200 miles, and Race Across AMerica participants cross the country in
about 8 days (and that includes all rest stops and sleep). These
cyclists are in top physical condition, but it is proper use of the
bicycle that allows them to accomplish these feats.
Unfortunately, there are few places to find accurate information on
the physiology and science of bicycling. Club cyclists introduce new
club members to the collected wisdom of 100+ years of cycling
experience, but the vast majority of recreational cyclists never join a
club and therefore don”t have the benefit of this tutelage. They are
taught “how to ride” by their parents–that is, how to sit on a bike
seat and move the pedals–but they know little about how to use their
bicycle effectively. They ride with cadence too low and gearing too
high and get frustrated when they tire out quickly. Most people have
the impression that cycling is hard work, because this kind of cycling
*is* hard work and this kind of cycling is all they know. But proper
cycling can be sustained for hours by anyone in reasonable physical
condition.
The two most important concepts are those of gearing and cadence
(they are closely related). “Cadence” is a measure of pedal revolutions
per minute, and the purpose of gearing is to keep cadence within a
specified range. Just as a car”s gears are designed to keep the engine”s
RPM between 2000 and 5000 (or whatever), your bike”s gears are designed
to keep the engine”s RPM (that is, your cadence) between 70 and 100.
Above 100 RPM you are wasting energy turning the pedals too fast, and
below 70 RPM you will burn out your muscles and “bonk.” Low cadence is
also the biggest cause of muscle pulls on bikes; the added strain on
tendons and ligaments, especially in the knee, is significant.
Most untrained cyclists have cadence between 40 and 60 RPM for
reasons they probably don”t understand but which I find quite
interesting. The body has been evolutionarily optimized for three
different “modes”, loosely classifiable as walking, running, and
climbing. Walking is done at low cadence with low muscle force, running
at high cadence with high muscle force but low muscle “stroke” (that is,
a small range of motion), and climbing (that is, going uphill or
traversing other uneven surfaces) at low cadence with high muscle force
and high muscle stroke. The bicycle, by supporting the rider”s weight,
allows the body to operate in a fourth mode; at high cadence with low
muscle force and high muscle stroke. But this is unnatural to our
bodies; low muscle force is associated with a walking cadence of about
120 paces per minute, or 60 RPM, and in the absence of instructions to
the contrary this is the cadence our body assumes. It is not difficult
to train your body to operate at 80 RPM, but it does take an effort of
will; an effort most cyclists never even know to make.
The reason higher cadence is more effective has to do with the way
our muscles work. There are two different chemical reactions our
muscles can use to produce power: aerobic and anaerobic. Aerobic
reactions use glucose and oxygen from the bloodstream, and can be
continued for as long as there is glucose and oxygen in the bloodstream.
Anaerobic reactions use glycogen, which is stored in limited supply in
the muscles, do not use oxygen from the bloodstream (hence the name),
and produce lactic acid as a byproduct (lactic acid causes muscle
soreness; if your muscles are sore after athletic activity, your muscles
were probably operating anaerobically). The supply of glycogen in the
average fit person”s muscles is enough to last for about 10 minutes;
when it is gone, it is gone for the day. Once your glycogen stores are
gone, you are bonked; you will be able to continue riding flats at 10-12
MPH, but you will have no energy to handle headwinds or hills, and you
will not be having any fun. Therefore, a cyclist interested in riding
for more than 10 minutes should jealously guard his stored glycogen by
keeping his cadence high.
If you are accustomed to a lower cadence, pedaling at 80 RPM will
probably “feel” wrong. You will probably feel like you”re not doing as
much work– because you”re not! Your speed may drop somewhat but your
range will increase dramatically, as will your enjoyment of cycling.
You will finish your rides feeling tired but relaxed and free of pain
and ready to ride again tomorrow. Ride Bike!
I had actually planned to get into gearing here but this is rather
longer than I expected, so I”ll save that for the next post. But
seriously, try to apply this to your cycling; check your cadence on a
flat road (count your pedal revolutions for a minute), and if it”s below
70, shift down a gear or two and try to get used to the new cadence.
It”s not that hard, and it will pay off for the rest of your cycling
career.
I hope to see you Sunday.
-Tom
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