Association between corticospinal inhibition and active dorsiflexion range of motion in patients with chronic ankle instability

Decreased corticospinal excitability of the anterior tibialis muscle may contribute to the persistent deficits in dorsiflexion range of motion (DFRoM) associated with chronic ankle instability (CAI). The purpose of this study was to examine the association between corticospinal excitability and inhibition of the anterior tibialis muscle and active DFRoM in patients with CAI. Twenty-one participants (age = 22.7 ± 3.3 years, height = 168.43 ± 8.0 cm, weight = 70.6 ± 14.4 kg) were enrolled in this controlled laboratory study. Corticospinal excitability and inhibition were assessed using Transcranial Magnetic Stimulation. Eight stimuli were delivered at 120% of active motor threshold. Each peak-to-peak motor evoked potential (MEP) amplitude, and subsequent cortical silent period (CSP) was recorded for statistical analysis. Maximum active DFRoM was assessed using a bubble inclinometer with participants seated on the edge of a treatment table and the knee flexed to 90°. Separate Spearman Rho and Pearson product moment correlations were used to assess the relationship between measures of corticospinal excitability and inhibition and active DFRoM. A moderate negative correlation was found between CSP and DFR0M (P =.006, r = −.533). Corticospinal inhibition of the anterior tibialis may influence active DFRoM. Addressing centrally mediated alterations may be an important factor in restoring DFRoM in individuals with CAI.