Article

Although it is well established that postural threat modifies postural control,
little is known regarding the underlying mechanism(s) responsible for these
changes. It is possible that changes in postural control under conditions of
elevated postural threat result from a shift to a more conscious control of
posture. The purpose of this study was to determine the influence of elevated
postural threat on conscious control of posture and to determine the relationship
between conscious control and postural control measures. Forty-eight healthy
young adults stood on a force plate at two different surface heights: ground
level (LOW) and 3.2-m above ground level (HIGH). Centre of pressure measures
calculated in the anterior-posterior (AP) direction were mean position (AP-MP),
root mean square (AP-RMS) and mean power frequency (AP-MPF). A modified
state-specific version of the Movement Specific Reinvestment Scale was used to
measure conscious motor processing (CMP) and movement self-consciousness (MSC).
Balance confidence, fear of falling, perceived stability, and perceived and
actual anxiety indicators were also collected. A significant effect of postural
threat was found for movement reinvestment as participants reported more
conscious control and a greater concern about their posture at the HIGH height.
Significant correlations between CMP and MSC with AP-MP were observed as
participants who consciously controlled and were more concerned for their posture
leaned further away from the platform edge. It is possible that changes in
movement reinvestment can influence specific aspects of posture (leaning) but
other aspects may be immune to these changes (amplitude and frequency).

Langue : ANGLAIS