Gait modulation for the reactive recovery of balance

Abstract

Falls have a high impact worldwide with respect to health care and employer costs. In the last years there were advances in understanding mechanisms for balance recovery during walking but little is known about motor patterns during gait when experiencing slips. The aim of this study was to investigate gait pattern modulation during slips while walking. Eight healthy subjects walked along a walkway with a moveable force platform embedded in the center. Subjects stepped with the right foot on the platform which elicited perturbations at heel strike. Surface electromyography was collected from lower limbs, trunk and neck muscles, from which motor modules and activation coefficients were extracted by non-negative matrix factorization. Comparisons were made between normal, unperturbed gait and perturbed trials. Five modules were sufficient to account for more than 80% of the variation for both the normal and perturbed walking. Moreover, a robust inter-subject similarity for normal and perturbed walking (r=0.81±0.1 and r=0.79±0.1 respectively), as well as high similarity (r>0.75) between modules of normal and perturbed walking were found for four out of five modules. The second module for perturbed walking had lower similarity in comparison to modules of normal gait (r~0.70), which may represent the reactive responses from the perturbation during early stance phase.. It can be concluded that the recovery of balance during walking may not require higher complexity from CNS, which recruited mostly similar modules to perform the task. © 2011 Springer-Verlag.