Immediate effects of a tibiofibular joint manipulation on lower extremity H-reflex measurements in individuals with chronic ankle instability.

Persistent muscle inhibition of the fibularis longus and soleus muscles and altered joint arthrokinematics may play a role in chronic ankle instability (CAI). Joint mobilization has been shown to improve ankle joint motion, but effects on surrounding musculature is unknown. The purpose of this study was to determine the change in fibularis longus and soleus activation following tibiofibular joint manipulation in individuals with CAI. Forty-three subjects were randomized to one of three groups (proximal tibiofibular manipulation, distal tibiofibular manipulation, or control). A two-way mixed model ANOVA was used to compare changes in the ratio of the maximum H-reflex and maximum M-wave measurements (H/M ratio) of the fibularis longus and soleus between groups over time (pre, post 0, 10, 20, 30 min). The distal tibiofibular joint manipulation group demonstrated a significant increase (P<.05) in soleus H/M ratio at all post-intervention time periods except 20 min post-intervention (P=.48). The proximal tibiofibular joint manipulation and control groups did not demonstrate a change in soleus H/M ratios. All groups demonstrated a decrease (P<.05) from baseline values in fibularis longus (10-30 min post-intervention) and soleus (30 min post-intervention) H/M ratios. Interventions directed at the distal tibiofibular joint acutely increase soleus muscle activation.