Effect of a semirigid ankle brace on the in vivo kinematics and muscle activity of patients with functional ankle instability during simulated ankle sprain

Ankle braces can effectively decrease the incidence of recurrent ankle sprain; however, whether the brace can decrease the severity of sprain and its related mechanism during sprain remain unknown. Twenty-two patients with functional ankle instability (FAI) (12 males and 10 females) and 16 healthy subjects (8 males and 8 females) were enrolled in this study. All of the subjects walked on a custom-built tilting platform that offered a 30° inversion (IV) to mimic the IV of ankle sprain. We collected the kinematic and surface electromyography data of patients with FAI with or without ankle brace and normal controls 6 times. The FAI without brace group showed significantly higher maximum IV angles and average IV velocities than the control group (P