Context: Chronic ankle instability (CAI) is a common problem associated with impaired postural stability. Whole-body vibration (WBV) has been developed to improve muscle function and reportedly improves postural stability. The aim of this study was to evaluate the effect of 12 sessions of WBV on postural control during standing postural task in participants with CAI.
Design: A controlled clinical trial study.
Methods: Sixteen participants with CAI and 16 healthy participants aged between 20 and 40 years included in this study. They received WBV (30-Hz frequency, 3 series of four 45-s exercises with a 45-s rest) for a total of 12 sessions, 2 session per week for 6 weeks. Postural control was assessed by center of pressure (COP) parameters, including mean and SD in the anterior-posterior and medial-lateral displacement during single-leg standing. Assessments were done before and immediately after the first session and after the 12th session of WBV, with opened and closed eyes associated with easy and difficult cognitive tasks.
Results: The results showed that the SD of COP displacement in the x-axis was significant in eyes opened and SD of COP displacement in the x- and y-axes were significant between groups in the eyes-opened, and eyes-closed conditions (P < .05). Analysis of variance indicated that the effect of WBV training was significant for the mean of COP displacement in the y-axis. Post hoc indicated that the effect of 12 sessions of WBV on the mean of COP displacement was significant in the CAI group (P < .05). However, the acute effect of WBV was not significant on the COP displacement in all axes (P > .05).
Conclusion: Higher postural sway associated with postural cognitive interactions might be considered in the rehabilitation of CAI. Twelve sessions of WBV might induce some improvement in postural control with the method of WBV used in this study.
Keywords: cognitive function; dual task; force plate; vibrating platform.