Arm sway holds sway: Locomotor-like modulation of leg reflexes when arms swing in alternation

Highlights • A special neural coupling occurs between arms and legs when arms move in locomotor-like alternation. • Soleus H-reflex was inhibited and showed a bell-shape modulation during alternated arm swing. • This modulation was independent of the Soleus EMG background activity or M-wave. • This likely depends on neural circuits (CPG’s) to move limbs in rhythmic alternation. • Locomotor-like trunk rotation also inhibited soleus H-reflex in the legs.