The Effects of Hand-held Load Carriage Techniques on Lower Extremity Continuous Relative Phase Variability

INTRODUCTION Despite the frequency of hand-held load carriage in many industrial settings, most research to date has focused primarily on packs as the means of load carriage. The Mover’s Assistive Device (MAD), developed in 2008 at Queen’s University in conjunction with local moving companies, is an on-body ergonomic aid designed to reduce musculoskeletal effort during hand-held load carriage. The MAD has been found to reduce muscular activity, as well as reduce users’ perceived exertion during loaded walking [1]. Interjoint coordination (quantified as the continuous relative phase (CRP) angle) variability has been used as an indicator of a person’s ability to respond to and recover from perturbations in unfavourable conditions during normal gait [2]. The purpose of this study was to quantify differences in CRP variability during load carriage when: 1) carrying a load anteriorly and posteriorly; and 2) wearing and not wearing the MAD.