A New Assessment Method of Muscle Contraction: Video Myography

The assessment of muscle activity and contraction is significant in biomechanical research and clinical applications. Such information is commonly measured and characterized by electromyography, ultrasound imaging, and laser Doppler. In this paper, we propose a new method of Video Myography (VMG) that can be used to obtain muscle contraction information. The proposed VMG produces two results to measure muscle contraction: the Video Myogram (VMM) is used to obtain the strength of muscle contraction, and the Muscle Activity Vector-Field (MAV-F) is used to describe the two-dimensional displacement field of muscle contraction. Conventional muscle contraction measurement methods obtain a one-dimensional vibration signal of the muscle, where the contraction of muscle fibers induces a two-dimensional or even three-dimensional displacement field in the tissue, which cannot be properly quantified by these methods because they only provide a single scalar quantity. However, the Muscle Activity Vector (MAV) in the MAV-F quantifies the intensity and direction of the muscle contraction. To verify the validity of VMG, we compared the muscle activation and the signal amplitude of the VMM signal and the standard surface Electromyography (sEMG) measured by the skin electrodes. sEMG and VMM signals are simultaneously acquired and processed. The experimental results on nine participants show the validity of the VMG method.