We investigated the effects of contralateral movement on the soleus H-reflex during bilateral movement of the ankles. The soleus H-reflex was evoked during unilateral or in-phase or antiphase bilateral ankle movement in healthy humans. The soleus H-reflex amplitude during antiphase movement was not significantly different from that during in-phase movement. The H-reflex amplitude during inphase movement was not significantly different from that during unilateral movement of the tested ankle. The H-reflex amplitude in the maximal plantar flexion phase of the tested ankle during antiphase movement was significantly smaller than that in the corresponding phase during unilateral movement. The amount of the decrease was 21%. The effect of contralateral movement is prominent during antiphase movement of the ankles.
The authors are with the School of Comprehensive Rehabilitation, Osaka Prefecture University, Osaka, Japan.