Is it Truly Necessary for Bicycle Power Meters to Rapidly Sample Angular Velocity?

TL;DR

This paper investigates whether bicycle power meters need to sample angular velocity rapidly, concluding that average angular velocity is generally sufficient for accurate power measurement, with potential exceptions involving harmonics.

Contribution

It challenges the assumption that high-frequency angular velocity sampling is necessary, showing average values often suffice for accurate power calculation.

Findings

Average angular velocity is usually enough for accurate power estimation.

Rapid sampling may only be necessary in specific cases involving harmonics.

The study counters previous research emphasizing high-frequency sampling.

Abstract

Bicycle Power Meters have become ubiquitous in professional and amateur cycling. These devices claim high levels of accuracy, and this accuracy is indeed essential if they are to serve their purpose as reliable training aids and indicators of improvements in fitness. Power is generally obtained via the independent estimation of torque and angular velocity. Designs vary in the way in which they estimate angular velocity. Some power meters estimate angular velocity many times a second, whereas other power meters compute an average value for each pedal stroke. The aim of this paper is to investigate whether it is necessary to rapidly sample angular velocity in order to obtain accurate power values under conditions of dynamic equilibrium. Countering previous research on the topic, this paper finds that average angular velocity alone is usually sufficient for the purposes of computing power, although there may be certain exceptional circumstances where consideration of harmonics may appreciably improve fidelity.