Metabolic, ventilatory and cardiovascular responses to FES-cycling: A comparison to NMES and passive cycling

BACKGROUND: Cyclergometry with functional electrical stimulation (FES-cycling) is a feasible method for rehabilitation. The concept is to promote exercise induced by depolarization of the motoneuron and muscular contraction. OBJECTIVE: To measure acute physiological responses to FES-cycling. METHODS: Retrospective study of data from ten healthy volunteers who performed FES-cycling, passive cycling and neuromuscular electrical stimulation (NMES) alone. Metabolic, ventilatory and cardiovascular parameters were analyzed. RESULTS: Oxygen uptake enhanced 97 ± 15% during FES-cycling, with medium effect size compared to NMES and large effect size compared to passive cycling. Energy expenditure enhanced 102 ± 15% during FES-cycling, with medium effect size compared to NMES and large effect size compared to passive cycling. Minute ventilation enhanced 115 ± 26% during FES-cycling, with small effect size compared to NMES and medium effect size compared to passive cycling. Cardiac output enhanced 21 ± 4% during FES-cycling, with medium effect size compared to NMES and passive cycling. Arterial - mixed venous oxygen content difference enhanced 60 ± 8% during FES-cycling, with a medium effect size compared to NMES and large effect size compared to passive cycling. CONCLUSIONS: FES-cycling enhances metabolic, ventilatory and cardiovascular demands and the physiological responses are higher than NMES and passive cycling.