Study of the relationship between muscle thickness and the conducting waves of multichannel surface electromyography

Abstract

The contraction of skeletal muscle is regulated by the number of motor units (MUs) and muscle fibre types. The analysis of MU recruitment is feasible for elucidating the mechanisms of muscular contraction and diagnosing muscular diseases. Therefore, various studies using multichannel surface electromyography (EMG) have been conducted. In our previous study, we proposed a method to search for all conducting waves appearing in multichannel surface EMG quantitatively by calculating the similarity of waveforms. By examining conducting waves, it may be possible to estimate MU recruitment. However, the certainty of such results depends solely on considerations of anatomical and physiological knowledge. One quantitative evaluation of muscle thickness is its measurement using ultrasound imaging. In this study, we investigated the feasibility of conducting wave analysis by examining the relationship between conducting waves and muscle thickness which can be an indicator of muscle hypertrophy or wasting. Multichannel surface EMG and muscle thickness measurements were conducted and on the biceps brachii muscles of 20 subjects and the results were analysed. We found that the mean amplitude and velocity of the conducting waves were proportional to bicep thickness, indicating that conducting wave analysis corresponds to muscle thickness as a quantitative index.