In order to evaluate bicycle pedaling skills, it is important to know how bicycle crank are rotate. Several previous studies, crank angle were measured on a road cycle via a potentiometer (Hull and Davis, 1981) or photo encoder (Chapman et al., 2006). Alternatively, it is possible to use a motion capture device to measure the rotation state of the crank (Trumbower and Faghri, 2004); however, this necessitates the use of a large-scale system in order to measure angles precisely. In this study, we propose a simple measurement system for the technical evaluation of bicycle pedaling for beginner or novice class cyclists. The system consists of small wireless sensor units, and can simultaneously record the rotational state of the bicycle crank. Method: A wireless multi-axis sensor unit (9-axis motion sensor: Logical Products) was used for data acquisition. This unit was fixed to the bicycle crank in order to obtain the rotational state of the bicycle crank`s acceleration and angular velocity data. Twenty-four male test subjects pedaled the road cycle which was attached to a bicycle trainer (Power Beam Pro: CycleOps) with a fixed rear-axis at 70, 100 rpm and preferred revolution. Wireless multi-axis sensor data was acquired for 25 seconds at a sampling rate of 1 kHz, and data recording was controlled by a soft-ware application (Logical Products). Results: In this study, several results have been obtained as follows: (1) Using wireless multi-axis acceleration and angular velocity sensors, the rotational state of the bicycle crank can be measured at a high accuracy and frequency. By averaging, the angular velocity for each crank angle is provided more precisely. (2) We propose an `Angular Velocity Irregularity Index (AVII)` that is averaged root-meansquare error of the crank angular velocity per revolution. AVII depends on power and the number of revolutions. Additionally, the AVII has a tendency to be lower for an expert cyclist, and to be higher for beginners. (3) However, there are several beginner or intermediate cyclists having a low AVII. This shows the possibility that the AVII can become an evaluation index of the pedaling skill from the viewpoint of pedaling efficiency. Acknowledgments: This study was subsidized by JKA through its promotion funds from KEIRIN RACE.
© Copyright 2012 17th Annual Congress of the European College of Sport Science (ECSS), Bruges, 4. -7. July 2012. Veröffentlicht von Vrije Universiteit Brussel. Alle Rechte vorbehalten.