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dc.contributor.advisorDingwell, Jonathan B.en
dc.contributor.committeeMemberBarr, Ronalden
dc.contributor.committeeMemberGrabiner, Marken
dc.contributor.committeeMemberMarkey, Miaen
dc.contributor.committeeMemberNeptune, Richarden
dc.creatorYoung, Patricia Maryen
dc.date.accessioned2011-06-01T21:24:38Zen
dc.date.accessioned2011-06-01T21:24:49Zen
dc.date.accessioned2017-05-11T22:22:05Z
dc.date.available2011-06-01T21:24:38Zen
dc.date.available2011-06-01T21:24:49Zen
dc.date.available2017-05-11T22:22:05Z
dc.date.issued2011-05en
dc.date.submittedMay 2011en
dc.identifier.urihttp://hdl.handle.net/2152/ETD-UT-2011-05-2738en
dc.descriptiontexten
dc.description.abstractFalling during walking leads to millions of emergency room visits every year for all age groups and is a significant medical concern. While gait training has shown some promise for fall prevention, we know relatively little about how humans maintain stability, how we can quantify it and how we can use this knowledge to increase the success of fall prevention training. In this dissertation, I studied how human stability responds to continuous, small magnitude perturbations and to voluntary changes in gait characteristics by examining movement variability and long-term and instantaneous dynamic stability. In the first set of experiments, participants were exposed to continuous, pseudo-random external perturbations of the visual field and support surface in a Computer Assisted Rehabilitation ENvironment (CAREN). Participants exhibited increased step widths, shorter step lengths and increased step variability, orbital and short-term local instability. Despite this, mean instantaneous lateral stability remained approximately constant. In the second set of experiments, participants voluntarily adopted changes in their step widths and step lengths. Wider steps were associated with increased step width variability, decreased nonlinear stability, decreased anterior-posterior margins of stability and increased instantaneous lateral stability. Shorter steps were associated with decreased short-term and orbital stability but did not affect mean instantaneous stability. When instantaneous stability was examined between steps, as opposed to as an average over many steps, results from both studies indicated a relationship between each step’s stability and the stability of the immediately preceding step. From these studies, we now know that unpredictable, continuous perturbations during human walking applied in a given direction can be used to elicit predictable responses in motion variability and stability in that same direction. We know that the type of stability examined can influence the conclusions drawn about an individual’s stability during perturbed walking. For example, an individual’s variability may indicate increased risk of falling while he or she simultaneously demonstrates increased orbital stability and instantaneous lateral stability. A challenge faced in this area of research will be to understand how quantitative measures of stability relate to how we perceive our stability.en
dc.format.mimetypeapplication/pdfen
dc.language.isoengen
dc.subjectDynamic stabilityen
dc.subjectWalkingen
dc.subjectPerturbationsen
dc.subjectStep widthen
dc.subjectStep lengthen
dc.subjectVoluntary gait changesen
dc.subjectGait in humansen
dc.subjectFall preventionen
dc.subjectFalls (Accidents)en
dc.titleDynamic stability of human walking during perturbations and voluntary gait changesen
dc.description.departmentBiomedical Engineeringen
dc.type.genrethesisen
dc.date.updated2011-06-01T21:24:49Zen


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