title: Effect of progressive horizontal resistive force on the comfortable walking speed of individuals post-stroke.
abstract: BACKGROUND
  Individuals post-stroke select slow comfortable walking speeds (CWS) and the major factors used to select their CWS is unknown.
  
  
  OBJECTIVE
  To determine the extent to which slow CWS post-stroke is achieved through matching a relative force output or targeting a particular walking speed.
  
  
  METHODS
  Ten neurologically nonimpaired individuals and fourteen chronic stroke survivors with hemiplegia were recruited. Participants were instructed to "walk at the speed that feels most comfortable" on a treadmill against 12 progressively increasing horizontal resistive force levels applied at the pelvis using a robotic system that allowed participant to self-select their walking speed. We compared slope coefficients of the simple linear regressions between the observed normalized force vs. normalized speed relationship in each group to a slope of -1.0 (i.e. ideal slope for a constant relative force output) and 0.0 (i.e. ideal slope for a constant relative speed). We also compared slope coefficients between groups.
  
  
  RESULTS
  The slope coefficients were significantly greater than -1.0 (p < 0.001 for both) and significantly less than 0 (p < 0.001 for both). However, compared with nonimpaired individuals, people post-stroke were less able to maintain their walking speed (p = 0.003).
  
  
  CONCLUSIONS
  The results of this study provide evidence for a complex interaction between the regulation of relative force output and intention to move at a particular speed in the selection of the CWS for individuals post-stroke. This would suggest that therapeutic interventions should not only focus on task specific lower-limb strengthening exercises (e.g. walking against resistance), but should also focus on increasing the range of speeds at which people can safely walk.
authors.affiliation: Department of Physical Therapy, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, Alabama, 35294, USA. cphurt@uab.edu.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Hurt
authors.affiliation: Centre of Rehabilitation, The Second Affiliated Hospital of Jiaxing University, Jiaxing, China. jingwang109@126.com.|Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany. jingwang109@126.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Physical Therapy and Human Movement Sciences, Northwestern University, Evanston, USA. capolugo@uab.edu.|Interdepartmental Neuroscience Program (NUIN), Northwestern University, Chicago, Illinois, USA. capolugo@uab.edu.
authors.forename: Carmen E
authors.initials: CE
authors.lastname: Capo-Lugo
authors.affiliation: Department of Physical Therapy, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, Alabama, 35294, USA. dbrownpt@uab.edu.|Department of Occupational Therapy, University of Alabama at Birmingham, Birmingham, USA. dbrownpt@uab.edu.
authors.forename: David A
authors.initials: DA
authors.lastname: Brown
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D005080:Exercise Test; D005081:Exercise Therapy; D005260:Female; D006429:Hemiplegia / Q000534:rehabilitation; D006801:Humans; D008297:Male; D008875:Middle Aged; D000071939:Stroke Rehabilitation; D016138:Walking / Q000502:physiology*