Pedaling Cadences & Force Peaks
27 Nov 2003
Pedaling in “agility” permits supplying power with less force delivered to the pedals (cf. Article: “High Pedaling Cadences”).
For every power level developed there exists an ideal pedaling cadence that grows linearly with the increase of force (cf. Article: “High RPM: further observations”).
If, thanks to specific training regimens, one succeeds in pedaling at ideal cadences, one finds that high force peaks are not necessary, even for significant power levels.
Even Lance Armstrong, for example, when he pushes 500 Watts at 100 RPM, develops force peaks at each pedal stroke of less than 60 kg.
Force peaks become more important in acceleration and in spurts: at 900 Watts of power with 100 RPM, the force required for every pedal stroke surpass 100 kg. But at this power level the ideal rate is around 125 RPM, thus reducing the required force to about 80 kg.
The best cyclists in sprints reach power levels close to 1500 Watts, which at 100 RPM require force peaks of nearly 180 kg!
Obviously sprinters choose higher pedal rates, even if they are probably under the ideal (at least 130 RPM).
The 53x11 is probably too long even for most of the classic sprints over long flat straight-aways: at 73 km/h this ratio requires 120 RPM. The 53x12 would probably be a better choice, since it allows development of the same speed at 130 RPM.
f the speed of the sprint is hindered by the wind, curves or light inclines, the choice should indicate shorter rations: at 60 km/h, instead of a 53x13, which requires 116 RPM, it would be preferable to use a 53x14 that only requires 125 RPM, or even a 53x15 with 134 RPM.
The choice of a shorter ration is also advantageous each time that one has to re-launch the speed, as one does after a curve or when one is obliged to slow down in mid-sprint.