title: Step adjustments among young and elderly when walking toward a raised surface.
abstract: BACKGROUND
  Falls among the elderly are often associated with walking on uneven ground. Obstacle negotiation requires both postural reaction strategies and anticipatory strategies which may be impaired with age. Anticipatory strategies are necessary in many daily living situations such as crossing the street and negotiating a kerb. The aim of this study was to evaluate whether elderly and young people use different step adjustment strategies during the approach to a raised surface.
  
  
  METHODS
  Eleven community-dwelling elderly adults and 14 young adults participated in the study. Characteristics in the gait pattern leading to the negotiation of a raised surface were examined by the use of an electronic gait mat in a laboratory setting.
  
  
  RESULTS
  Both groups changed their gait pattern to adjust the placement of the last step leading to negotiation of the obstacle. The young participants had a tendency to gradually increase their step velocity and step length while the elderly participants slowed their velocity and shortened their step length. Major step length adjustments began four steps prior to ascending the platform among the young participants, but one step later among the elderly.
  
  
  CONCLUSIONS
  Elderly people use more cautious anticipatory strategies. These strategies allow more time for postural adjustments, but they also result in a loss of forward momentum which may influence the negotiation of a raised surface negatively.
authors.affiliation: Center for Sensory-Motor Interaction (SMI), Aalborg University, Fredrik Bajersvej 7 D, 9220, Aalborg, Denmark. ul@hst.aau.dk
authors.forename: Uffe
authors.initials: U
authors.lastname: Laessoe
authors.forename: Michael
authors.initials: M
authors.lastname: Voigt
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D059031:Anticipation, Psychological / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology; D012917:Social Adjustment; D013997:Time Factors; D016138:Walking / Q000502:physiology*