title: Combined effects of age and gender on gait symmetry and regularity assessed by autocorrelation of trunk acceleration.
abstract: BACKGROUND
  The gait of a healthy person is believed to be more regular and symmetrical than those of an individual with a disease. Thus, symmetry and regularity are important indicators of human gait.
  
  
  METHODS
  The effects of age and gender on gait symmetry and regularity were investigated in 87 Japanese participants by measuring trunk accelerometry during a 7-m walk. The younger group included 26 female and 21 male students, and the elderly group included 24 females and 16 males. Average age for each group was 20 and 70 years, respectively. Gait symmetry and regularity were evaluated on the basis of autocorrelation functions of trunk accelerations of vertical and anteroposterior axes.
  
  
  RESULTS
  The relationship between age and gait symmetry and regularity was statistically significant for both vertical and anteroposterior axes. Elderly participants showed lower symmetry and regularity in their gait than young participants. A significant gender effect was observed for the symmetry index of both axes but not for the regularity index. Male participants showed lower gait symmetry than females. An interaction effect between age and gender was significant in the symmetry index of anteroposterior acceleration. Gender effect was appeared more clearly in elderly than young participants.
  
  
  CONCLUSIONS
  Elderly participants showed a more asymmetrical and irregular gait than young participants. In addition to age, a significant gender effect was observed on gait symmetry. However, the effect size of gender was smaller than that of age, and it was not significant for gait regularity. The gait indices obtained by autocorrelation of trunk acceleration can be considered useful to evaluate aging effect on gait.
authors.affiliation: Department of Nursing, Ishikawa Prefectural Nursing University, 1-1 Gakuendai, Kahoku, Ishikawa 929-1212, Japan. kobayasi@ishikawa-nu.ac.jp.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Wataru
authors.initials: W
authors.lastname: Kakihana
authors.forename: Tasuku
authors.initials: T
authors.lastname: Kimura
mesh_terms: D000054:Acceleration; D061725:Accelerometry; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D060726:Torso; D055815:Young Adult