The Effect of a Single Session of Functional Electrical Muscle Stimulation During Walking in Patients with...

Background: Functional electrical stimulation (FES) is widely used in post-stroke rehabilitation to restore motor activity and improve walking. However, the immediate effects of a single FES session on gait biomechanics and muscle activity remain insufficiently studied. This pilot study aimed to evaluate the direct neuromotor effects of a single multichannel FES session during walking in patients with post-stroke hemiparesis. Methods: Eight patients with hemiparesis in the early or late recovery period after ischemic stroke underwent gait biomechanics and electromyography (EMG) assessment before and immediately after a single 30 min FES session. FES was applied to the tibialis anterior, gastrocnemius, quadriceps femoris, and hamstring muscles of the paretic limb during walking, synchronized with gait phases. Spatial-temporal, kinematic, and EMG parameters were recorded using an inertial system. Pre- and post-intervention data were compared using paired tests (a paired t-test or the Wilcoxon signed rank test, p < 0.05), while the standardized effect sizes (Cohen's d) were calculated for all pre-post comparisons. Results: A significant decrease was observed in the single support phase of the paretic limb after FES (p < 0.05). Knee joint movement amplitude increased significantly in the nonparetic limb. Surface EMG amplitudes decreased in the tibialis anterior of the nonparetic limb and in the hamstring and gastrocnemius of the paretic limb (p < 0.05). No significant changes were detected in overall gait speed, rhythm, or phases of muscle activity peaks. Conclusions: A single session of multichannel FES induces neuromotor changes reflected by redistribution of muscle activity and compensatory adjustments in gait biomechanics without immediate improvement in global kinematic parameters. The direct biomechanical changes in the gait function can be interpreted as evidence of the onset of fatigue. The procedure demonstrated good tolerability and safety, confirming its feasibility for early post-stroke rehabilitation.