This was posted today on USENET by Jobst Brandt, author of The Bicycle Wheel, and a well known (if cantankerous) and respected authority on the physics of biking.
Here it is. Just another idea to stir the pot a bit.
Yes. In days of yore, the cadence people were "ankling" folks who
attributed great improvement in cycling speed, efficiency and
enjoyment if one were to articulate the ankles suitably while
pedaling. Ultimately, the whole idea was discredited by researchers
who photographed the best professional bicyclists, who were often
mentioned as having special talents in this respect. The outcome was
that ankling is peculiar to individual people like walking styles,
ones by which one can recognize people at a distance. It had nothing
to do with the claimed advantages, especially since some of the best
racers did not use much ankle motion.
The same goes for the Spin-Coach folks who encourage uncomfortably
high cadences for people who would be better served by choosing the
gear in which they feel most comfortable.
Ruining knees is the bugaboo that hides behind the admonition to keep
cadence high. This ignores that when climbing hills, leg force
(therefore, load on the knees), is far higher than on the flats in
almost any gear. Adults who have not bicycled in many years may have
atrophied knees that don't take kindly to articulation under load,
seldom having bent the knee more than required when walking stairs.
Pedaling a bicycle involves bending the knees under load, twice as
much as for stairs. This can hurt, but has little to do with cadence.
I've heard the horror stories of not keeping cadence high. No one has
offered and proof or reason for doing so other than citing that racers
use high cadence in racing... but they are also traveling about 30mph.
Palo Alto CA