Currently, there are limited guidelines for the trial duration of quiet single-limb postural control tests. However, trial duration may influence the results of postural control assessments.
To examine the effect of trial duration on instrumented measures of postural control in healthy adults.
Patients or Other Participants:
Ten healthy adults (eight females, two males; age = 22.1 ± 1.5 years; 167.4 ± 9.3 cm; 67.4 ± 12.3 kg).
Static postural control was assessed using quiet single-limb stance on a force plate. With eyes open and closed, participants stood barefoot on one limb. Instructions were stand with hands on hips and remain as motionless as possible. A practice trial was performed before the collection of three 10 s trials on each limb for each visual condition. The data collected during each trial were analyzed as the initial 2.5 s, the initial 5 s, and 10 s.
Main outcome Measures:
The independent variables included vision, limb, and trial duration. The dependent variables included postural control examined using time-to-boundary (TTB) variables: mean of TTB minima (TTB-M) and the standard deviation of TTB minima (TTB-SD) in the anterior-posterior (AP) and medial-lateral (ML) directions.
No significant 3-way or 2-way interactions or limb main effects were identified. Main effects were identified for vision and trial duration in all TTB variables. Post hoc analysis revealed significant differences between all trial durations in all TTB variables.
Greater TTB values were exhibited during the 10 s trial durations compared with 5 s and 2.5 s, and 5 s trial durations compared with 2.5 s, indicating postural control improved with longer trial durations. This suggests differing aspects of postural control may be examined with different trial durations.
Cameron Powden is with the College of Health Sciences at Old Dominion University in Norfolk, VA.
Matthew Hoch is with the School of Physical Therapy and Athletic Training at Old Dominion University in Norfolk, VA.