Voluntary neuromuscular activation is enhanced when paired with a mechanical stimulus to human plantar soles

The purpose of this investigation was to determine if the location and the timing relative to muscle activation onset, of a mechanical stimulus applied to the soles impacted the neuromuscular activation associated with a voluntary movement. The subjects completed a series of dorsiflexion or plantarflexion movements during which a stimulus was applied to either the heel or ball of the foot at one of three time periods relative to the initiation of the agonist muscle. Surface electromyography from the tibialis anterior and soleus was collected during the movements. The results show that if the stimulus was applied shortly before agonist muscle activation, regardless of stimulation site, the neuromuscular activity associated with the movement was greatly increased.