Controlling Maximal Voluntary Contraction of the Upper Limb Muscles by Facial Electrical Stimulation.

In this paper, we propose to use facial electrical stimulation to control maximal voluntary contraction (MVC) of the upper limbs. The method is based on a body mechanism in which the contraction of the masseter muscles enhances MVC of the limb muscles. Facial electrical stimulation is applied to the masseter muscles and the lips. The former is to enhance the MVC by causing involuntary contraction of the masseter muscles, and the latter is to suppress the MVC by interfering with voluntary contraction of the masseter muscles. In a user study, we used electromyography sensors on the upper limbs to evaluate the effects of the facial electrical stimulation on the MVC of the upper limbs. The experimental results show that the MVC was controlled by the facial electrical stimulation. We assume that the proposed method is useful for sports athletes because the MVC is linked to sports performance.