Strategies used by older adults to change travel direction.
BACKGROUND
A distinct body reorientation strategy during steering tasks has been reported in young adults. As challenges to whole-body stability in older adults occur when navigating complex environments, this study was designed to examine control strategies used by older adults to initiate a voluntary change in travel direction.


METHODS
Thirteen older adults, recruited from an independent living division of a local retirement residence, were instrumented with reflective markers and whole-body kinematic data were monitored using a video camera (30 Hz). Participants executed self-paced walking trials 3-m along a straight path and were instructed prior to the trial to continue either straight ahead or randomly turn 40 degrees left or right and continue walking for an additional 2-m. Timing of changes with respect to when the trunk crossed the turning point were calculated for deviations in head and trunk position and foot rotation in the medial-lateral plane.


RESULTS
Older adults reoriented themselves into the new travel direction in a top-down, segmental sequence, beginning with head reorientation followed by trunk reorientation, foot rotation and foot displacement into the new travel direction. These changes were initiated over two or more steps 69% of the time and over one step 31% of the time. A significant relationship between turning strategy used and balance confidence was observed; the frequency of using a turning strategy involving two or more steps to initiate a change in travel direction increased as balance confidence decreased.


CONCLUSIONS
Older adults made segmental changes to voluntarily reorient themselves in a new travel direction in a similar sequence to that observed in young adults. Older adults chose primarily to initiate these changes two or more steps prior to the turn; the selection of this strategy was related to balance confidence.
Fuller
Jason R
JR
Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ont., Canada NIG 2W1.
Adkin
Allan L
AL
Vallis
Lori Ann
LA
D000222:Adaptation, Physiological; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D008297:Male; D009949:Orientation / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D014741:Video Recording; D016138:Walking / Q000502:physiology*