Swing Phase Mechanics of Young and Elderly Men: Profiles, Variability & Compensatory Synergies

Abstract

The general purpose of this project was to gain further insight into the effect of ageing on swing phase biomechanics during walking. A particular emphasis was placed on the effect of ageing on the critical gait variables anterior-posterior heel contact velocity (A-P HCV) and minimum toe clearance (MTC). In addition, techniques were developed to i) obtain three-dimensional (3D) joint kinematics from an electromagnetic tracking system (ETS) and ii) quantify a compensatory synergy in a multiple degree-of-freedom (DOF) precision task, namely gait. Intra-trial, intra-day/inter-tester and inter-day/intratester repeatability of gait kinematics acquired using the ETS-based technique was equivalent or superior to that obtained using optoelectronic and video based systems. Compared with young participants, the elderly exhibited a greater A-P HCV and greater MTC variability. The postural configuration of the elderly at the time of MTC (timeMTC) was different to that of the young, while no marked differences in joint angle variability at timeMTC were identified. Both the young and elderly were found to exhibit compensatory synergies between kinematic DOFs that acted to minimise MTC variability. The overall strength of these synergies was similar for the young and elderly however the number of DOFs involved in the synergy was less for the elderly than the young. In conclusion, healthy elderly individuals exhibit changes in their walking pattern that may place them a greater risk of a slip and or trip-related fall than their younger counterparts.