Characterization and comparison by bioelectrical impedance analysis of dry electrodes for use on human quadriceps, in a connected garment

Muscle tissue exhibits strong anisotropy due to the orientation of its fibers, and its electrical properties vary during contraction. Consequently, local impedance measurements can be used to detect muscle activity. This approach is particularly relevant for rehabilitation monitoring and serious game applications, where real-time physiological feedback is required. The objective of this study is to characterize and compare a set of dry electrodes of different types (textile and silicone), first on a phantom simulating human quadriceps tissue, and subsequently on two human subjects. The goal is to identify a suitable electrode for integration into a real-time connected garment. For each electrode, bipolar and quadripolar measurements of resistance (R) and reactance (X) were performed, and impedance (Z) was calculated. The electrodes were initially characterized on a phantom and then tested on the quadriceps of two adult subjects (one male and one female). The results show that, although the impedance values obtained are consistent with those reported in the literature for quadriceps tissue, they differ significantly from those obtained with the reference electrode. Furthermore, a significant variability was observed in quadripolar measurements depending on the electrode type. Nevertheless, this study demonstrates that electrodes can be selected based on their electrical properties and integrated into a connected garment, with performance comparable to that of standard gel electrodes.