The Acute Physiological Effects of Multiple Muscle Stimulation

Neuromuscular electrical stimulation (NMES) has been shown to provide health benefits similar to those of exercise. The aim of this study was to quantify the acute physiological effects of multiple muscle stimulation on the whole body and individual muscles. Nine healthy young adults were tested. NMES of eight muscle groups was performed with NMES stimulators. The vastus lateralis, biceps femoris, medial gastrocnemius, and tibialis anterior muscles of both legs were stimulated for ten minutes with twitch stimulations at the highest comfortable stimulation current. Whole-body metabolism was measured using a metabolic cart. A finger pulse oximeter and a tri-axial accelerometer were used to measure heart rate and muscle fatigue, respectively. Muscle metabolism (mVO₂) was measured using near-infrared spectroscopy (NIRS) during short periods of ischemia. Femoral artery blood flow was measured using Doppler ultrasound. Whole-body VO₂ and heart rate increased moderately by 36% and 22%, respectively, after 10 min of NMES. NMES increased mVO₂ by 12-fold higher than resting on average, with the gastrocnemius having the smallest increase and the vastus lateralis having the greatest increase. Peak diastolic blood flow velocity was significantly reduced by 50% after 10 min of NMES. Simultaneous lower-body NMES moderately improved whole-body metabolism, muscle metabolism, and blood flow, increasing our understanding of the beneficial effects of NMES.