CYCLIST'S PEDALLING PARAMETERS USING KINEMATIC AND DYNAMIC MEASUREMENTS AND DISCRIMINATIVE VARIABLE ANALYSIS METHOD

Abstract

INTRODUCTION: This work deals with the pedalling study of the cyclist in a seated position. The aim of this paper is two fold. Firstly a new kinematic and dynamic sensor is described to measure the absolute angle of the pedal and the applied forces in the sagittal plane. Secondly, the discriminative variable analysis method is presented and the experimental results are discussed. In this approach, the data have been obtained on three cyclists’ experience classes (3 cyclists per class). METHODS: The 360 degrees resistive sensor indicates the relative angle b of the pedal through a tooth belt. The crank angle a is measured with 8 photoelectric cells triggered by a marker fixed on the crank (cf. figure). In a previous work [Ref.], this variable was recorded with a camera which reveals to be of difficult use. Strain gauges attached to the pedals give the horizontal and tangential forces. This apparatus is fixed on a laboratory bicycle. Each cyclist pedals during 5 minutes with a constant velocity (1,5 r/s) and a constant power (150 W). Many variables (24) have been considered characterizing the measured data such as the amplitudes of the angular movements a and b, the variation of b with respect to a and Fourier components of the applied forces. RESULTS AND DISCUSSION: With this new sensor the applied power can be visua-lized in real time. Evaluating inter- and intra-variances taking the three cyclists classes into account, it can be shown that among the 24 variables considered, the two principal ones are the absolute pedal angle and the applied vertical force. Other classes could be presented as well. Thanks to the proposed method, pertinent variables enable to identify the pedalling parameters. CONCLUSION: Using this new kinematic and dynamic sensor and the above reported analysis, a significant analysis of the pedalling activity is feasible. Further work under progress will extend this procedure to a larger number of cyclists. Applications are pursued in sports with an amateur team to improve training techniques. REFERENCE: Deslandes J. et al. (1996). Etude expérimentale du pédalage à l'aide de la force appliquée sur la pédale et de son orientation. Arch. Phys. Bioch, 104, 614.