A requirement for the body orientation change during the approach phase to the bend section in sprinting

Abstract

When a runner is approaching bend section, his trunk leans toward the inside of the track. The authors assumed that the ground reaction force moment around COG would contribute to inclination of runner’s trunk during the approach phase to bend section. The purpose of this research was to examine how much the ground reaction force moment around COG contributes to inclination of runner’s trunk during the approach phase to bend section. The authors conducted an experiment to obtain kinetic and kinematic parameters using 50 force platforms and the motion capture system during the approach phase to bend section (radius:38.2m). As a result, clockwise and anticlockwise ground reaction force moment of the antero-posterior axis around COG is balanced during the approach phase to bend section. Therefore, it is suggested that ground reaction force moment around COG is not a key factor for inclination of runner’s trunk during the approach phase to bend section. Furthermore, the authors assume that gyroscopic effect by arm motion during the flight phase is a key factor for inclination of runner’s trunk during the approach phase to bend section.