ANKLE ORTHOSES EFFECT ON SINGLE-LIMB STANDING BALANCE IN ATHLETES WITH FUNCTIONAL ANKLE INSTABILITY

Objective:To test whether a rigid or a flexible ankle orthosis affects postural sway in single-limb stance as quantified by stabilometry. De sign: Crossover trial. Setting: University laboratory. Participants: T wenty-two athletes with functional ankle instability (consecutive samp le of patients with recurrent ankle sprains but without mechanical ins tability) and 22 healthy athletes (control group of volunteers matched to age, height, weight, physical activity). Interventions: Stabilomet ry in single-limb stance on a force platform. Participants were tested on each leg with and without a rigid or a flexible ankle orthosis. Th e order of test conditions was randomized. Main Outcome Measures: Sway velocities, sway pattern, and sway area as calculated from center of pressure movements.. The two groups were compared by Mann-Whitney test , and the different orthoses within each group were compared by Wilcox on test, paired samples (type I error 5%, Bonferroni adjustment). Resu lts: In athletes with functional ankle instability, both a rigid and a flexible ankle orthosis significantly reduced mediolateral sway veloc ity. A flexible ankle orthosis also changed sway pattern significantly , by reducing the percentage of linear movements of less than 5 degree s per .01 sec. Conclusions: In athletes with functional ankle instabil ity, ankle orthoses reduce mediolateral sway velocity, possibly becaus e of improved mediolateral proprioception. (C) 1998 by the American Co ngress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.