Aims: To evaluate the inßuence of wobble board training on complaints and on the control of ankle motion in functionally unstable ankles during a sudden inversion in the standing position. Methods: 25 patients were randomly allocated to a training group (13 persons, 15 ankles), or to a control group (12 persons, 15 ankles). Patients were only included if they suffered invalidating disabilities following at least two ankle inversion trau-mañs followed by at least 6 weeks of rehabilitation. They were randomly allocated to a wobble board training group (6 weeks), or to a no intervention control group. Accelerometric and electromyographic analysis of functional control during a sudden ankle inversion of 50û in the standing position and a validated functional impairments index were used to assess efþcacy. Results: Trained patients with Òmedium latencyÒ reßexes (n= 5) showed signiþcantly earlier decelerations with the ankle displaying in a signiþcantly smaller inversion displacement (p< 0.05, power=0.96). Trained patients with Òshort latencyÒ reßexes (n= 10) showed no signiþcant change in inversion control. All trained patients showed signiþ cantly less impairments compared to the control group. Conclusions: These results support the treatment strategy that wobble board training should be included in the rehabilitation of functional ankle instability.