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Amy Hackney, Michael Cinelli; Avoiding Two Vertical Obstacles: An Age-Related Comparison. Journal of Vision 2012;12(9):184. doi: 10.1167/12.9.184.
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© ARVO (1962-2015); The Authors (2016-present)
When individuals must pass through an aperture, young adults (YA) initiate a shoulder rotation at smaller relative aperture widths1 (i.e. Critical Point) than older adults (OA)2,3. It is unknown whether individuals initiate changes to actions at similar relative aperture widths between obstacles in unconfined space as in a confined aperture-crossing. The current study aimed to determine the Critical width at which individuals change action strategies and if age-related differences exist when avoiding obstacles in unconfined space. Young (N=12) and older adults (N=12) were instructed to walk a 9m path toward a goal and avoid two poles placed 5m along the path on either side of the midline (0.6-1.8x shoulder width). Results showed that the Critical width of YA was 1.4x shoulder width while OA was 1.6. In confined and unconfined space the passability of apertures remains similar, however the action strategy differs. Rather than change shoulder position, a change in travel path occurs. When changes in travel path were made, YA deviated from straight walking further from the obstacles than OA (2.68m versus 1.78m, p<0.001). At the time-of-crossing, OA displayed a larger lateral clearance than YA (0.70m versus 0.31m, p<0.001). This suggest that OA require more time to process information and make appropriate action changes but their subsequent strategies are more cautious. Overall, this study confirms the persistence of age-related differences in action strategies and that Critical width governs the initiation of action changes in unconfined space. However, the strategy used is task-specific. 1.Warren&Whang (1987).Visual guidance of walking through apertures:Body-scaled information for affordances. J.Experimental Psychology,13:371-83. 2.Wilmut&Barnett (2010).Locomotor adjustments when navigating through apertures. Human Movement Science,29:289-98. 3.Hackney&Cinell (2011).Action strategies of older adults when walking through apertures.Gait and Posture,33:733-36.
Meeting abstract presented at VSS 2012
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