akmal's bike park

akmal's bike park

Thursday, 25 September 2008

Power and Cadence

(excerpt from The Elegant Solution - Toyota's Formula for Mastering Innovation, Matthew E. May)

Run The Numbers
: Lance Armstrong

Following his bout with testicular cancer, Lance Armstrong found that his physiology had changed. he was lighter, with a diminished musculature. The way his body most efficiently produced power had changed. He needed a new way to ride the bike in order to compete at the elite level.

He examined the power equation:
Power = Force x Velocity
  • Force = the force applied to pedals
  • Velocity = leg speed, or pedal cadence
He did the math, looking at the variables.
If it takes 200 watts to move a bike at 20 mph, what were the possibilities? What were the differences of pedalling 70 rpm, versus 100 rpm?
Lower cadence requires higher force applied to each pedal stroke, which means more work for the leg muscles, and quicker fatigue.
Lower force to the pedals required higher cadence, which meant more work for his heart and aerobic system.

Given his stronger aerobic engine, he switched to spinning lower gears at a much higher cadence. It ran counter to widely accepted practice of driving big gears while seated. But it worked. No one could touch him in grueling mountain climbs of the Alps and Pyrenees.

Personal note:
Cadence was the the first thing I learnt about from a friend, Zaidi. He noticed I was using big rings while testing his hardtail (a very lightweight hardtail), and taught me about cadence and power.
It's with cadence that you could sustain long rides as with XC.

Well, I'm applying, and still learning.

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