Validity of the lower extremity functional movement screen in patients with chronic ankle instability

[Purpose] The purpose of this study was to provide evidence of construct validity for the lower extremity functional movement screen (LE-FMS) based on hypothesis testing in patients with chronic ankle instability (CAI). [Subjects] The subjects were 20 healthy subjects and 20 patients with CAI who had a history of ankle sprain with pain for more than 1 day. [Methods] All participants were measured using the Foot and Ankle Disability Index (FADI) and evaluated with the LE-FMS. The screen included the deep squat, the hurdle step (HS) and the in-line lunge (ILL). The symmetry ratios (RS) were accurately measured during the deep squat trial. [Results] Between the two groups, there were significant differences in scores on the LE-FMS, HS, ILL, RS, FADI, and FADI-sport. The FADI was strongly correlated with both LE-FMS score (r=0.807) and ILL score (r=0.896). There was a strong relationship (r=0.818) between LE-FMS score and FADI-sport. [Conclusion] These results suggest that the LE-FMS may be used to detect deficits related to CAI. Additionally, this instrument is reliable in detecting functional limitations in patients with CAI.