ABSTRACT
OBJECTIVE: The main objective of the present study was to investigate the electromyographic (EMG) activity of gluteus medius (Gmed) and gluteus maximus (Gmax) muscles during functional exercises in subjects with chronic ankle instability (CAI) vs healthy controls. METHODS: Seventeen subjects (age, 24.4 ± 2.03 years) with CAI and 17 healthy controls (age, 24.6 ± 2.57 years) were recruited for the present study. For all participants, after testing maximum voluntary isometric contraction of the Gmed and Gmax muscle, EMG activity of these muscles was recorded during functional exercises, such as the Y Balance Test and the single-leg squat with and without Swiss ball. RESULTS: EMG activity of Gmed and Gmax was found to be significantly (P < .05) reduced during all functional exercises in subjects with CAI when compared with healthy controls. No significant differences (P > .05) were observed in the EMG activity of both muscles across different functional exercises. CONCLUSION: Our findings indicate that EMG activity of hip muscles is significantly reduced in CAI subjects, which might give an indication regarding the inclusion of hip muscle strengthening (Gmax and Gmed) in the rehabilitation of CAI. Moreover, Gmed and Gmax muscle activity did not vary during the different functional exercises within each group, which might indicate that activation pattern of these muscles are not sensitive to the type of functional task.