Functional Ankle instability (FAI) is defined as the subjective feeling of ankle instability or recurrent, symptomatic ankle sprains due to proprioceptive and neuromuscular deficits (1). Ankle sprains have the highest incidence rate, with 32% to 47% of these people having history with symptoms including sensations of giving way, subsequent sprains, and instability (2, 3). After initial injury, a high proportion of patients experienced residual symptoms, such as pain, subjective instability, and repetitive ankle sprain (4, 5). . . .