Watanabe H, Iwase S, Mano T
Department of Autonomic and Behavioral Neurosciences, Nagoya University, Japan.
Jpn J Physiol. 1995;45(1):123-35. doi: 10.2170/jjphysiol.45.123.
The aim of the present study was to determine whether static biceps brachii contraction by handcurling enhances the muscle sympathetic nerve activity (MSNA) in the resting muscle. In six healthy men (age: 19-23 years), we measured MSNA in the tibial nerve microneurographically, with heart rate, blood pressure, biceps electromyogram (EMG), and the intensity of local fatigue sensation in the working muscle. Subjects performed static biceps brachii contraction for 2 min (short exercise) at 30% of maximal voluntary contraction, and then they made fatiguing exercise to exhaustion (long exercise). During the short exercise, the heart rate and mean arterial blood pressure increased significantly (p < 0.05). In the last 30s of the short exercise, the MSNA burst rate and total MSNA increased significantly but integrated EMG did not increase. In long exercise, MSNA burst rate, total MSNA, mean arterial blood pressure, heart rate, EMG activity, and local fatigue sensation increased progressively with advancing exercising time. There was a significant correlation between integrated EMG and total MSNA (r = 0.64, n = 63, p < 0.001), and local fatigue sensation and total MSNA (r = 0.41, n = 63, p < 0.001) during the long exercise. Post-exercise recovery of the MSNA response to static handcurling was more prompt in short exercise than that in long exercise. We conclude that MSNA is enhanced during submaximal static handcurling, and the magnitude of enhancement correlates with EMG activity and subjective fatigue sensation in the biceps brachii, which might be attributed to the stimulation of metaboreceptors in the working muscle.
本研究的目的是确定通过手持哑铃进行静态肱二头肌收缩是否会增强静息肌肉中的肌肉交感神经活动（MSNA）。在6名健康男性（年龄：19 - 23岁）中，我们通过微神经电图测量了胫神经中的MSNA，并记录了心率、血压、肱二头肌肌电图（EMG）以及工作肌肉中的局部疲劳感强度。受试者以最大自主收缩的30%进行2分钟的静态肱二头肌收缩（短时间运动），然后进行疲劳性运动直至 exhaustion（长时间运动）。在短时间运动期间，心率和平均动脉血压显著升高（p < 0.05）。在短时间运动的最后30秒，MSNA爆发率和总MSNA显著增加，但积分EMG未增加。在长时间运动中，MSNA爆发率、总MSNA、平均动脉血压、心率、EMG活动和局部疲劳感随运动时间的推进而逐渐增加。在长时间运动期间，积分EMG与总MSNA之间存在显著相关性（r = 0.64，n = 63，p < 0.001），局部疲劳感与总MSNA之间也存在显著相关性（r = 0.41，n = 63，p < 0.001）。短时间运动后MSNA对静态手持哑铃运动的反应恢复比长时间运动更迅速。我们得出结论，在次最大强度的静态手持哑铃运动期间MSNA增强，增强的幅度与肱二头肌中的EMG活动和主观疲劳感相关，这可能归因于工作肌肉中代谢感受器的刺激。
