Exposure to unpredictable trips and slips while walking can improve balance recovery responses with minimum predictive gait alterations

Abstract

18INTRODUCTION: This study aimed to determine if repeated exposure to unpredictable trips 19 and slips while walking can improve balance recovery responses when predictive gait 20 alterations (e.g. slowing down) are minimised. 21 METHODS: Ten young adults walked on a 10-m walkway that induced slips and trips in fixed 22 and random locations. Participants were exposed to a total of 12 slips, 12 trips and 6 non-23 perturbed walks in three conditions: 1) right leg fixed location, 2) left leg fixed location and 3) 24 random leg and location. Kinematics during non-perturbed walks and previous and recovery 25 steps were analysed. 26 RESULTS: Throughout the three conditions, participants walked with similar gait speed, step 27 length and cadence(p>0.05). Participants' extrapolated centre of mass (XCoM) was anteriorly 28 shifted immediately before slips at the fixed location (p<0.01), but this predictive gait alteration 29 did not transfer to random perturbation locations. Improved balance recovery from trips in the 30 random location was indicated by increased margin of stability and step length during recovery 31 steps (p<0.05). Changes in balance recovery from slips in the random location was shown by 32 reduced backward XCoM displacement and reduced slip speed during recovery steps (p<0.05). 33 CONCLUSIONS: Even in the absence of most predictive gait alterations, balance recovery 34 responses to trips and slips were improved through exposure to repeated unpredictable 35 perturbations. A common predictive gait alteration to lean forward immediately before a slip 36 was not useful when the perturbation location was unpredictable. Training balance recovery 37 with unpredictable perturbations may be beneficial to fall avoidance in everyday life. 38 39