title: A new approach to detecting asymmetries in gait.
abstract: BACKGROUND
  Traditional parameters used to assess gait asymmetries, e.g., joint range of motion or symmetry indices, fail to provide insight regarding timing and magnitude of movement deviations among lower limb joints during the gait cycle. This study evaluated the efficacy of a new approach for quantifying aspects of gait asymmetry.
  
  
  METHODS
  Asymmetric gait was simulated by joint bracing. The dominant leg knee or ankle was constrained in ten healthy young adult males. Kinematic data were collected during three-minute trials for treadmill-walking conditions: unbraced, knee-braced, and ankle-braced. We created a regions of deviation analysis, which compared asymmetric walking (flexion/extension behavior) relative to normative (group-averaged unbraced) data. Symmetry/asymmetry between bilateral joint pairs was quantified and the behavior of specific joints relative to normative data was assessed using this analysis.
  
  
  RESULTS
  While traditional measures (e.g., maximum range of motion) grossly detected asymmetries due to bracing, these new analyses identified significant regions of asymmetry. Knee-bracing affected the knee during mid-swing, but also increased ankle asymmetry during both terminal stance and mid-swing and hip asymmetry during mid-stance and mid-swing. Ankle-bracing created asymmetries at the ankle (terminal stance and initial swing) and hip (terminal stance), but none at the knee.
  
  
  CONCLUSIONS
  Region of deviation analysis effectively identified the timing and magnitude of deviations throughout the gait cycle, and provided information about the impact of a joint-mobility perturbation on neighboring joints. This new methodology will be useful in clinical settings to identify, characterize, and monitor recovery from asymmetric behaviors associated with injuries or pathologies.
authors.affiliation: Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, MC-244, 1206 W. Green Street, Urbana, IL 61801, USA.
authors.forename: K Alex
authors.initials: KA
authors.lastname: Shorter
authors.forename: John D
authors.initials: JD
authors.lastname: Polk
authors.forename: Karl S
authors.initials: KS
authors.lastname: Rosengren
authors.forename: Elizabeth T
authors.initials: ET
authors.lastname: Hsiao-Wecksler
mesh_terms: D000328:Adult; D000842:Ankle / Q000502:physiology; D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena; D001915:Braces; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007717:Knee / Q000502:physiology; D007719:Knee Joint / Q000502:physiology; D007866:Leg / Q000502:physiology; D008297:Male; D010828:Physiology, Comparative / Q000379:methods*; D011187:Posture / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D016138:Walking / Q000502:physiology