Recent advances in flexible noninvasive electrodes for surface electromyography acquisition

Surface electromyography (sEMG) is used to detect and analyze human muscle biopotential. Recently, flexible noninvasive electrodes (FNEs) have emerged to extract bioelectrical signals from individual bodies. For FNEs to be deployed as a central component of physiological signal acquisition, the quest for elevated signal-to-noise ratio and density is compelling owing to the small amplitude of sEMG. Herein, we review recent progress in FNEs for sEMG acquisition. We summarize the needed properties of FNEs, compare the differences between passive electrodes and active electrodes and exemplify applications of FNEs. We also conclude the current challenges and future opportunities in sEMG acquisition.