Tour de France 2002
9th Stage: Lanester-Lorient, 55 km – time trial.
This will be the first important face-off between the riders who hope to win the 2003 Tour de France.
I‘m watching the TV, watching the pedaling rate of the most interesting competitors. I am timing the tempo of 10 complete pedal rotations, which I then divide by 600 to get the rotation/minute time.
The tempo for 10 rotations is 5.65 seconds, which corresponds to (600/5.65) 106 turns per minute.
It is a rather hilly time trial, and it is windy.
Usually the racers maintain an average rate of around 95-100 RPMs over a time trial of this length in similar conditions.
But there are exceptions. A real specialist like Gonchar produces average rates of 70-80 RPM, and Gonzalez de Galdeano and Botero pedal at 80-90 RPM.
All push very high gears.
Their time trial results are excellent, but how will they do on the climbs in the Pyrenees that will bring on huge fatigue and tax the riders’ powers of recovery? Joints and muscle fiber will have to face these stress factors and produce, at every turn of the pedal, pressures that can reach 100 kilos.
Armstrong is at the opposite extreme. Normally in a time trial like this he maintains rates of between 105 and 115 RPM, which seem to suit him best.
But today his pedaling cadences vary from 5.20 to 4.80 seconds, which correspond to 115 and 125 RPM respectively.
An average rate of 120 RPM is fine for a 4km pursuit on track, but certainly not for a time trial of a full hour.
At these rates, even Armstrong becomes less efficient: too much energy will be expended to move the mass of the lower limbs and deal with the internal friction in muscles and joints.
One can calculate that the use of pedaling cadence above 8-10% with respect to optimal rates, leads to a lessening of performance of about 1% - corresponding to 30-40 seconds in a one hour race.