Abstract:
This thesis investigated attention focus and balance control in eighteen healthy
young adults and eighteen healthy older adults. All participants performed sixteen
consecutive trials of a balance task which involved standing for 30-s on an unstable
platform that could rotate only in the roll direction. There were no attention focus
instructions provided on any of the sixteen trials. Following the completion of the initial
and final attempt in the series, participants reported "where" their attention had been
focused when performing the task. The results showed differences in balance between
young and older adults and improvements in balance with practice in both young and
older adults. However, there were no differences in attention focus strategies between
young and older adults. Both age groups directed attention to multiple sources during the
balance task. An equal focus on internal (i.e., feet, trunk, and other body parts) and
external (i.e., the platform) sources with little focus on events not related to the task
dominated on the first attempt of the balance task. Focus on internal sources was
maintained and focus on events not related to the task increased at the expense of focus
on external sources on the final attempt of the balance task. Following the series of
sixteen trials to establish "natural" attention focus, participants performed three randomly
presented trials, each with specific attention focus instructions (i.e., think about
minimizing movements of the feet, the trunk, or the platform). The results showed that,
in contrast to the literature, instructions to focus on an internal source, the trunk, actually
augmented control of the task as reflected in reduced trunk sway whereas instructions to
focus on an internal source, the feet, or an external source, the platform, did not benefit
performance on the task. Thus, the distance fi-om the interaction point of the body with the external source is critical and may not depend on whether the source is internal or
external. Thus, a global attention focus instruction may not be beneficial and the nature of
the task should be considered when adopting attention focus instructions for young and
older adults.
