Laboratory of Neuromuscular Biomechanics, Faculty of Liberal Arts and Sciences and School of International Liberal Studies, Chukyo University, Nagoya, Japan.
MTG Co., Ltd., Nagoya, Japan.
Physiol Rep. 2021 Feb;9(3):e14758. doi: 10.14814/phy2.14758.
The combined application of voluntary exercises and neuromuscular electrical stimulation (NMES) has been developed as a new type of exercise that can recruit motor units contributing to both aerobic and anaerobic energy metabolisms. We aimed to investigate the effect of voluntary exercise intensity on metabolic responses on the combination of voluntary exercise and NMES. In 13 volunteers, oxygen consumption and the blood lactate concentration were measured during (1) voluntary pedaling exercise at four different intensities: 50%, 75%, 100%, and 125% of the ventilatory threshold (VT) (VOL), (2) these voluntary exercises with superimposed NMES applied to the gluteus and thigh muscles (VOL+NMES), and (3) NMES only (NMES). Oxygen consumption and the blood lactate concentration in VOL+NMES were significantly greater than VOL at each exercise intensity (p < 0.05). Differences in oxygen consumption between VOL+NMES and VOL decreased with exercise intensity, and that at 125% VT was significantly lower than the net gain in oxygen consumption following NMES (p < 0.05). Differences in the blood lactate concentration between VOL+NMES and VOL increased with exercise intensity, and that at 50% VT was significantly lower than the net gain in the blood lactate concentration following NMES (p < 0.05). Our results suggest that voluntary exercise intensity has a critical impact on metabolic responses during the combined application of voluntary exercises and NMES. Superimposing NMES onto voluntary exercises at high exercise intensities may induce overlapping recruitment of motor units, leading to a markedly reduced benefit of additional metabolic responses on its superimposition.
自愿运动与神经肌肉电刺激（NMES）的联合应用已发展成为一种新的运动方式，可以募集参与有氧和无氧能量代谢的运动单位。我们旨在研究自愿运动强度对组合运动和 NMES 的代谢反应的影响。在 13 名志愿者中，在以下三种情况下测量了耗氧量和血乳酸浓度：（1）在四个不同强度（通气阈（VT）的 50%、75%、100%和 125%）下进行自愿踩踏运动（VOL），（2）在这些自愿运动上叠加应用于臀肌和大腿肌肉的 NMES（VOL+NMES），以及（3）仅 NMES（NMES）。在每个运动强度下，VOL+NMES 的耗氧量和血乳酸浓度均明显大于 VOL（p<0.05）。VOL+NMES 和 VOL 之间的耗氧量差异随运动强度的增加而减小，在 125%VT 时显著低于 NMES 后耗氧量的净增加（p<0.05）。VOL+NMES 和 VOL 之间的血乳酸浓度差异随运动强度的增加而增加，在 50%VT 时显著低于 NMES 后血乳酸浓度的净增加（p<0.05）。我们的结果表明，自愿运动强度对自愿运动与 NMES 联合应用时的代谢反应有重要影响。在高运动强度下将 NMES 叠加在自愿运动上可能会导致运动单位的重叠募集，从而显著降低 NMES 叠加的额外代谢反应的益处。
