Forty-five patients with chronic ankle instability (CAI) with a history of ≥1 ankle sprain sustained within the previous 12 months and experiencing inflammatory symptoms were randomized to undergo whole body vibration (WBV) therapy combined with shoes that have an unstable surface (n=15), WBV alone (n=15), or a control consisting of 10 sessions of physical therapy (n=15). The WBV therapy was conducted for 4 weeks consisting of 12 sessions, 3 sessions/week supervised by an experienced physical therapist. The primary outcome of interest is dynamic balance evaluated using the modified Star Excursion Balance Test (SEBT; anterior, posterolateral, and posteromedial). Secondary outcomes of interest included function using the single-leg hop for distance test (Hop-Test), muscle strength (i.e., peak torque of the concentric evertor, eccentric evertor, concentric invertor, eccentric invertor) and joint position (i.e., active 5 degrees, active 15 degrees, passive 5 degrees, and passive 15 degrees). All outcomes were measured a 4 weeks post-intervention except for mSEBT and Hop-Test, which were were additionally evaluated at 2 weeks follow-up. Results revealed no statistical significant difference across all 3 groups for peak torque (i.e., concentric evertor, eccentric evertor, concentric invertor, and eccentric invertor) and for joint position sense error (i.e., active 5 degrees, active 15 degrees, passive 5 degrees, and passive 15 degrees) (p>0.05 for all). For the posteromedial modified SEBT, no statistical significant difference was observed across the WBV group, WBV combined with unstable-surface shoe group, and control groups (p=0.81). In addition, a statistically significant improvement in SEBT scores was observed in the WBV and WBV plus unstable-surface shoe group when comparing scores after 4 weeks post-intervention and 2 weeks follow-up compared to baseline (p<0.05 for all) for the anterior and posterolateral modified SEBT outcome. Yet, a time effect was not observed in the control group for both the anterior and posterolateral modified SEBT. Moreover, for the Hop-test, a statistical significant time effect was observed in the WBV plus unstable-surface shoe group at 4 weeks post-intervention and 2 weeks follow-up compared to baseline values (p=0.004) but this was not observed for the WBV and control groups (p>0.05).