Piezo-dynamometry of foot-to-floor interactions during locomotion

A compound instrument made of a six component strain gauged force platform and a pressure platform rigidly connected to it was developed aimed at analysing the foot-to-floor interaction during locomotion. Integrating these two instruments allowed the simultaneous estimation of resultant ground reaction components (vertical and shear resultant force components, free moment and location of the centre of pressure), pressure distribution throughout the foot-floor contact area, the trajectory of the centre of pressure superimposed to the contact area (foot print). All of these quantities were made available in each sampled instant of time during the execution of the locomotor act. In addition, the readings provided by the force plate allowed for a time dependent calibration of the pressure sensors. This permitted the authors to overcome the problems associated with the non-linear properties and hysteresis of the relevant sensing material.