Article

Traditional measures of postural stability consider movement of the center of
pressure (COP) or the center of mass (COM) without regard to the boundary of
support (BOS). A potentially more appropriate measure is postural time-to-contact
(TtC) which defines the spatio-temporal proximity of the COM or COP to the BOS.
Given the increasing popularity of TtC measures, it is important to determine
their reliability. Therefore, the purpose of this study was to determine the
effects of the number of trials and trial duration on the reliability of postural
TtC measures. COP data were collected (100 Hz) in 16 young healthy participants
during 10 trials (60-s duration) of quiet standing with eyes open on two
occasions - seven days apart. Postural TtC of each trial was calculated using two
different methods. The intersession reliability of the TtC measures was assessed
by calculating between session intraclass correlation coefficients (ICC(2,1))
using different combinations of the number of trials (1-10) and trial duration
(10, 20, 30, 40, 50 and 60s). Both TtC methods were very reliable. Additionally,
both measures of TtC were more reliable than the standard deviation of the
anterior-posterior COP and slightly more reliable than path length. This
difference was most pronounced when fewer and shorter trials were used.
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Langue : ANGLAIS