Effects on hemodynamic enhancement and discomfort of a new textile electrode integrated in a sock during calf neuromuscular electrical stimulation

PURPOSE: To compare fixed transverse textile electrodes (TTE) knitted into a sock versus motor point placed standard gel electrodes (MPE) on peak venous velocity (PVV) and discomfort, during calf neuromuscular electrical stimulation (calf-NMES). METHODS: Ten healthy participants received calf-NMES with increasing intensity until plantar flexion (measurement level I = ML I), and an additional mean 4 mA intensity (ML II), utilizing TTE and MPE. PVV was measured with Doppler ultrasound in the popliteal and femoral veins at baseline, ML I and II. Discomfort was assessed with a numerical rating scale (NRS, 0–10). Significance was set to p < 0.05. RESULTS: TTE and MPE both induced significant increases in PVV from baseline to ML I and significantly higher increases to ML II, in both the popliteal and femoral veins (all p < 0.001). The popliteal increases of PVV from baseline to both ML I and II were significantly higher with TTE versus MPE (p < 0.05). The femoral increases of PVV from baseline to both ML I and II were not significantly different between TTE and MPE. TTE versus MPE resulted at ML I in higher mA and NRS (p < 0.001), and at ML II in higher mA (p = 0.005) while NRS was not significantly different. CONCLUSION: TTE integrated in a sock produces intensity-dependent increases of popliteal and femoral hemodynamics comparable to MPE, but results in more discomfort at plantar flexion due to higher current required. TTE exhibits in the popliteal vein higher increases of PVV compared to MPE. TRIAL REGISTRATION: Trial_ID: ISRCTN49260430. Date: 11/01/2022. Retrospectively registered.