Electrically induced hemodynamic enhancement via sock-integrated electrodes is more comfortable and efficient at 1 hz as compared to 36 hz

Abstract

Abstract This study evaluated the hemodynamic effects, discomfort, and energy efficiency of low-intensity neuromuscular electrical stimulation (LI-NMES) of the calf delivered via sock-integrated transverse textile electrodes (TTE) at different frequencies and plateau times. Fifteen healthy participants underwent NMES stimulation through 3 × 3 cm TTE with ten combinations of frequency (1–36 Hz) and plateau times (0.5–7 s). NMES was increased until plantar flexion occurred, at which point ultrasound-measurements were made of popliteal peak venous velocity (PVV), time-averaged mean velocity (TAMV), average duration of blood flow pulse (ADBP) and ejection volume (EV). Discomfort (NRS, 0–10), current amplitude, and energy consumption were recorded. Median values were analyzed with significance set at p < 0.05. Both 1 Hz and 36 Hz C-LI-NMES significantly improved PVV and TAMV (p ≤ 0.008). EV increased significantly for plateau times of 1.5, 5.0, and 7.0 s (p < 0.05). Compared to 36 Hz, 1 Hz showed significantly lower discomfort (NRS: 0.4 vs. 1.6) and energy consumption (0.4 vs. 31.3 mJ, both p ≤ 0.01) but required higher current amplitude (33.2 vs. 23.3 mA, p < 0.01) to reach plantar flexion. The study concludes that both 1 Hz and 36 Hz frequency improve venous hemodynamics, but 1 Hz stimulation minimizes discomfort and energy use while maintaining effectiveness. Trial registration: Retrospectively registered with Clinical Trials, trial ID: NCT06082297.