Avoidance Choice Strategies During Walking In Older And Young People

In the course of the aging, some declines remarkably impair the walking. Sensorimotor functions are necessary to face everyday situations such as obstacle avoidance with maximum accuracy and without errors. In order to perform locomotor demands such as when an unexpected object crosses the pathway, people need to have these functions optimally to perform a fast reaction response in order to avoid tripping and falling. Situations that involve obstacle avoidance are frequently performed, mainly in time constraints situations. The aim of this study was to compare the strategies adopted by older (OG) and young (YG) people on obstacle avoidance. Fifteen young (24.67+3.63 years) and fifteen older adults (72.27+6.47 years) were tested. Sensorimotor functions were assessed according to the short-form of Physiological Profile Assessment (PPA), in five aspects: contrast sensitivity, hand reaction time, postural sway, proprioception and lower limb muscular strength. The total score of PPA provides a falls risk measure. Participants walked 6m at their self-selected speed on a pathway covered by the GAITRite® system. A home-made system was developed to simulate an unexpected obstacle on the pathway. Participants were free to choose any obstacle avoidance strategy. Three attempts for each condition (with and without target) were fully randomized. Three control walking trials performed before the test were used in the comparison analysis. Gait parameters, avoidance behavior and avoidance choice strategies were assessed. Statistical procedures were performed using SPSS 18.0 for Windows®. After confirm normal data distribution groups, demographic data, PPA variables were compared using Student t-test. An ANOVA two-way with repeated measures (group X condition) was used to compare gait parameters and avoidance behavior for each avoidance choice strategy. A chisquare test was used to compare the avoidance choice strategies independent of group. For all tests a p<0.05 was considered statistically significant. Sensorimotor function scores for YG and OG participants are statistically different for: Contrast sensitivity (p=0.0001), postural sway area (p=0.0001), lower limb muscular strength (p=0.0001) and PPA total score (p=0.001). Two distinct avoidance choice strategies were observed: frontal step (FS) and lateral step (LS). Both groups performed similar avoidance choice strategies (X²=0.32). To perform FS strategy, YG and OG had the same behavior and gait patterns. But to perform LS, OG had a more conservative avoidance behavior. Seems that this older behavior can be related to sensorimotor functions impairment.

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