Analysis of Conducting Waves Using Multichannel Surface EMG Based on Arc-Shaped Electrode

Surface electromyogram (EMG) is recorded as the interference of action potentials, which are produced by some motor units of a muscle. If the composition of the interference wave can be analyzed, the detailed mechanism of muscle contraction may be elucidated. Therefore, we proposed a multichannel method, extracted all the conducting waves existing in the surface EMG, and examined the characteristics of each conducting wave. Consequently, it became possible to consider the detailed mechanism of muscle contraction. In the previous study, biceps brachii and triceps surae were used as test muscles, and it was found that the number of conducting waves obtained by triceps surae was smaller than that of biceps brachii. Therefore, in this study, we proposed and measured an arc-shaped electrode. We aimed to consider whether a conducting wave could be obtained even with electrodes having different electrode widths or influence on the conducting waveform, owing to the difference in shape between the ladder-type and arc-shaped electrodes. Accordingly, first, the maximal voluntary contraction of muscle was measured. Thereafter, the biceps brachii and triceps surae muscles were tested, and myoelectric potential data were acquired under load. The analysis was performed using the multichannel method. Based on the experimental results, it was found that the number of conducting waves increased using the arc-shaped electrode, regardless of the test muscle. Moreover, the conducting waves obtained from the ladder-type electrode were characteristic.