title: Variability in inter-joint coordination during walking of elderly adults and its association with clinical balance measures.
abstract: BACKGROUND
  Walking requires coordination among multiple joints. Little is known about the association between the coordination ability and fall risks in elderly adults. This study investigated variability of inter-joint coordination in elderly adults and determined its correlation to clinical balance measures.
  
  
  METHODS
  Gait analyses of 15 non-fallers and 15 fallers were performed during walking. Continuous relative phase, derived from phase angles of two adjacent joints, was used to assess the inter-joint coordination. Variability of inter-joint coordination was calculated as the average standard deviation of all points on the ensemble continuous relative phase curve over a gait cycle, namely the deviation phase. Outcomes from three clinical balance tests, including Berg Balance Test, Dynamic Gait Index and Timed Up-and-Go, were examined.
  
  
  RESULTS
  No significant group differences were detected in hip-knee deviation phase values after accounting for differences in walking speeds. For the knee-ankle deviation phase, fallers demonstrated significantly greater values in the stance phase but smaller values in the swing phase. The hip-knee deviation phase values demonstrated a negative correlation with Dynamic Gait Index, and the knee-ankle deviation phase values had a negative correlation with Dynamic Gait Index and a positive correlation with Timed Up-and-Go time.
  
  
  CONCLUSIONS
  Excessive variability of the supporting limb and reduced variability of the swing limb in knee-ankle inter-joint coordination of fallers may contribute to their risk of imbalance or tripping during walking. Compared to Berg Balance Test and Timed Up-and-Go, Dynamic Gait Index scores might be more sensitive to reflect declines in inter-joint coordination during walking.
authors.affiliation: Motion Analysis Laboratory, Department of Human Physiology, University of Oregon, Eugene, OR 97403-1240, USA.
authors.forename: Shiu-Ling
authors.initials: SL
authors.lastname: Chiu
authors.forename: Li-Shan
authors.initials: LS
authors.lastname: Chou
mesh_terms: D000058:Accidental Falls; D000328:Adult; D000368:Aged / Q000502:physiology*; D000843:Ankle Joint / Q000502:physiology; D005260:Female; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007596:Joints / Q000502:physiology*; D007719:Knee Joint / Q000502:physiology; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D016138:Walking / Q000502:physiology