Relationships between self-reported ankle function and modulation of Hoffmann reflex in patients with chronic ankle instability

•Patients with chronic ankle instability (CAI) reported ankle dysfunction.•Patients' ankle disability scores correlated with modulation of Hoffman reflex measures.•The lower perceived levels of ankle function, the less amount of modulation.•The results may provide insights into a mechanism of CAI-related ankle disability.

ObjectiveTo examine relationships between self-reported ankle function and Hoffmann (H) reflex modulation during changes in body positions in patients with chronic ankle instability (CAI).DesignObservational.SettingLaboratory.ParticipantsThirty-one young adults with CAI (19 males, 12 females) participated.Main outcome measuresThere were two subscales of Foot and Ankle Ability Measure (FAAM) to quantify self-reported ankle function during activities of daily living (ADL) and sports activities. Maximum H-reflexes (H-max) and motor waves (M-max) from soleus and fibularis longus were recorded while participants lied prone and stood in bipedal and unipedal stances. For each muscle, percent change scores in Hmax:Mmax ratios were calculated between each pair of positions: prone-to-bipedal, bipedal-to-unipedal, and prone-to-unipedal, and used as a measure of H-reflex modulation. Pearson correlation coefficients were calculated between FAAM and H-reflex modulation measures.ResultsThere were significant correlations between: (1) FAAM-ADL and soleus prone-to-unipedal modulation (r = 0.384, p = 0.04), (2) FAAM-Sport and soleus prone-to-unipedal modulation (r = 0.505, p = 0.005), (3) FAAM-Sport and fibular bipedal-to-unipedal modulation (r = 0.377, p = 0.05), and (4) FAAM-Sport and fibular prone-to-unipedal modulation (r = 0.396, p = 0.04).ConclusionsCAI patients presented moderate, positive relationships between self-reported ankle function and H-reflex modulation during changes in body positions.