Effectiveness of external orthotic support on passive soft tissue resistance of the chronically unstable ankle.

Functional ankle instability, orthoses, and passive resistive torque tolerated have not been researched. The purpose of the study was to evaluate the passive resistance torque exerted by a flexible and semirigid orthosis for individuals with chronic instability. Twenty-two subjects were evaluated on the passive ankle resistance unit during unbraced, flexible, and semirigid brace conditions. Data from the final three trials for each condition were analyzed using a multiple analysis of variance with repeated measures for resistive torque and inversion range of motion. The semirigid and flexible braces tolerated significantly greater torque forces and less inversion range than the unbraced condition (P < 0.000). External orthotic support, in particular that of a semirigid orthosis, may be beneficial toward reducing injury or be an effective prophylactic for the healthy population.