Abstract
BACKGROUND: Chronic ankle instability (CAI) is a common condition following an ankle sprain. This study investigated the effects of whole body vibration (WBV) and shoe with an unstable surface training on balance, functional performance, strength, joint position sense in people with CAI. METHOD: Thirty- four peoples with unilateral CAI were randomly assigned to three groups: WBV group, WBV with shoe with an unstable surface (WBV-S), and no treatment control group (CON). The WBV group received 4 weeks progressive WBV training and the WBV-S group received progressive WBV training with shoe with an unstable surface. Modified star excursion balance test (mSEBT)reach distance, Hop-Test, muscle strength, and joint position sense were measured at baseline and after the 4 weeks; Moreover, the mSEBT and Hop-Test were reassessed again 2 weeks post intervention. RESULTS: The result showed a significant group-by-time interaction for anterior and posterolateral directions of mSEBT. The reach distance of these directions at post-intervention and follow-up increased significantly compare to pre-intervention in the WBV and WBV-S groups but not significantly change in the CON group. The Hop test in the WBV-S group was significantly more at post-intervention and follow-up compared to pre-intervention. However, no significant changes were observed in WBV and CON groups. No significant changes were observed for mSEBT posteromedial direction, muscles strength, and joint position sense errors. CONCLUSION: The 4 weeks WBV and WBV-S interventions could improve balance in peoples with CAI. Improvement in Hop test was only observed in the WBV-S group suggesting the added value of combining WBV and shoe with an unstable surface as an effective therapy compared to WBV training alone. The use of WBV and WBV-S were not associated with significant changes in strength and joint position sense variables over a four-week period. TRIAL REGISTRATION: This work registered in the Iranian Registry of Clinical Trials ( IRCT20151118025105N4 ).