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

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.