Inertial stresses of national and international motorcycle circuit racing riders

Abstract

The forces on the human body associated with motorcycle racing are currently unpublished, and this study aimed at quantifying the negative and positive accelerations that circuit racers experience during real competitions via direct measurements in different classes of racing. Kinematical measurements of braking actions and corner exits during competitive laps were identified via GPS signal in 23 riders competing in 13 different circuits and categories (i.e. European Junior Cup 2016, national and world level 600 cc SuperSport). Fully equipped body mass of riders was measured and individual inertial forces were calculated. Riders in an entry-level class championship experienced 87 ± 11 brakes per race, while national and world SS600 class championships were found to have on average 144 ± 14 and 171 ± 28 brakes per race, respectively. For each braking action, the calculated inertial mean force acting on the rider centre of gravity was from 476 to 513 N on average, and peak forces doubling these values. Moreover, the mean inertial forces generated while accelerating to exit the corners were from 300 to 384 N on average, with the WSS class recording 33% larger accelerations compared to the entry category EJC. The findings of this study: suggest that international level riders experience positive and negative inertial loads considerable in volume, frequency and intensity; provide novel information enhancing the knowledge on the performance model for motorcycle circuit racing; and, offer a profile useful for the design of training programmes aiming at preparing riders for competition.