Background/aims Electrical stimulation (ES) is used in rehabilitation to enhance circulation and muscle activation, but its effects on vascular function and fatigue compared with voluntary (VOL) exercise remain unclear. This study examined acute and short-term neuromuscular and vascular responses to higher-frequency ES and force-matched VOL isometric knee extensions. Methods Eleven healthy adults (5 women; 23 ± 4 years) completed two interventions in a crossover design: 40 isometric ES contractions at a pain-tolerated threshold and 40 force-matched VOL contractions, separated by a 14-day washout. Outcomes included force, heart rate (HR), superficial femoral artery (SFA) blood flow, vascular conductance, oscillatory shear stress (OSS), muscle oxygenation via near-infrared spectroscopy, femoral-popliteal pulse wave velocity (fpPWV), and flow-mediated dilation (FMD), assessed before, during, and up to 48 h post-exercise. Results Force declined more rapidly during ES, with greater strength loss at 24 and 48 h (p = 0.01) and increased soreness at 1, 24, and 48 h (p ≤ 0.04). HR was higher during ES until approximately contraction 20 (p textless 0.05). Net SFA blood flow was consistently greater with ES (p textless 0.01), while VOL produced greater retrograde flow (p textless 0.01) and OSS (p = 0.02). Total hemoglobin was higher during ES at earlier contractions (p = 0.01). No significant changes were observed in FMD (p ≥ 0.06) or fpPWV (p = 0.59). Conclusions Higher-frequency ES increases blood flow and reduces OSS compared with force-matched VOL contractions, at the cost of greater fatigue and soreness. These findings suggest ES may offer circulatory benefits relevant to rehabilitation, though optimal parameters are needed to minimize neuromuscular strain.