title: Impaired limb shortening following stroke: what's in a name?
abstract: BACKGROUND
  Difficulty advancing the paretic limb during the swing phase of gait is a prominent manifestation of walking dysfunction following stroke. This clinically observable sign, frequently referred to as 'foot drop', ostensibly results from dorsiflexor weakness.
  
  
  OBJECTIVE
  Here we investigated the extent to which hip, knee, and ankle motions contribute to impaired paretic limb advancement. We hypothesized that neither: 1) minimal toe clearance and maximal limb shortening during swing nor, 2) the pattern of multiple joint contributions to toe clearance and limb shortening would differ between post-stroke and non-disabled control groups.
  
  
  METHODS
  We studied 16 individuals post-stroke during overground walking at self-selected speed and nine non-disabled controls who walked at matched speeds using 3D motion analysis.
  
  
  RESULTS
  No differences were detected with respect to the ankle dorsiflexion contribution to toe clearance post-stroke. Rather, hip flexion had a greater relative influence, while the knee flexion influence on producing toe clearance was reduced.
  
  
  CONCLUSIONS
  Similarity in the ankle dorsiflexion, but differences in the hip and knee, contributions to toe clearance between groups argues strongly against dorsiflexion dysfunction as the fundamental impairment of limb advancement post-stroke. Marked reversal in the roles of hip and knee flexion indicates disruption of inter-joint coordination, which most likely results from impairment of the dynamic contribution to knee flexion by the gastrocnemius muscle in preparation for swing. These findings suggest the need to reconsider the notion of foot drop in persons post-stroke. Redirecting the focus of rehabilitation and restoration of hemiparetic walking dysfunction appropriately, towards contributory neuromechanical impairments, will improve outcomes and reduce disability.
authors.affiliation: Department of Physical Therapy, University of Florida, Gainesville, FL, United States of America; Rehabilitation Science Doctoral Program, University of Florida, Gainesville, FL, United States of America; Brain Rehabilitation Research & Development Center, Malcolm-Randall VA Medical Center, Gainesville, FL, United States of America.
authors.forename: Virginia L
authors.initials: VL
authors.lastname: Little
authors.affiliation: Department of Physical Therapy, University of Florida, Gainesville, FL, United States of America; Brain Rehabilitation Research & Development Center, Malcolm-Randall VA Medical Center, Gainesville, FL, United States of America.
authors.forename: Theresa E
authors.initials: TE
authors.lastname: McGuirk
authors.affiliation: Department of Physical Therapy, University of Florida, Gainesville, FL, United States of America; Rehabilitation Science Doctoral Program, University of Florida, Gainesville, FL, United States of America; Brain Rehabilitation Research & Development Center, Malcolm-Randall VA Medical Center, Gainesville, FL, United States of America; Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States of America.
authors.forename: Carolynn
authors.initials: C
authors.lastname: Patten
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D007596:Joints / Q000503:physiopathology; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000503:physiopathology*; D013997:Time Factors