Dynamic Postural Stability Characteristic in Functional Ankle Instability

Functional Ankle Instability (FAI) is defined as the subjective feeling of ankle instability or recur-rent, symptomatic ankle sprains due to proprio-ceptive 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 expe-rienced residual symptoms, such as pain, subjec-tive instability, and repetitive ankle sprain (4, 5).