Reliability of the Identification of Functional Ankle Instability (IdFAI) Scale Across Different Age Groups in Adults.

Background: Functional ankle instability (FAI) is the tendency of the foot to 'give way'. Identification of Functional Ankle Instability questionnaire (IdFAI) is a newly developed questionnaire to detect whether individuals meet the minimum criteria necessary for inclusion in an FAI population. However, the reliability of the questionnaire was studied only in a restricted age group.