IS AVERAGE SPEED CONTROL SENSITIVE ENOUGH TO ENSURE NONACCELERATED RUNNING IN THE ANALYSIS OF RUNNING MECHANICS?

Abstract

The purpose of this study was to investigate whether average speed control by means of photocells is sufficient to guarantee the absence of center of mass velocity changes (CoMVC) and possible effects of such changes on running mechanics. A standard 3D inverse dynamics model was used to calculate kinematics and kinetics of 19 subjects running at 3,5m/s over a 25m track. CoMVC were controlled by calculating the ratio of propulsive to braking impulse (RPBI) of the GRF. Higher braking forces were achieved by increased negative work of the knee extensors while greater propulsive forces were mainly the effect of increased positive work of the plantar flexors. Differences in impact force were related to CoMVC. Implementation of RPBI control is recommended especially when sagittal plane mechanics and impact forces are to be investigated.