OXYGEN AVAILABILITY AND MOTOR UNIT-ACTIVITY IN HUMANS
OXYGEN AVAILABILITY AND MOTOR UNIT-ACTIVITY IN HUMANS
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DOI：
10.1007/bf00843767
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发表时间：
1992-06-01
影响因子：
3
通讯作者：
SHINOHARA, M
中科院分区：
文献类型：
--
作者：
MORITANI, T;SHERMAN, WM;SHINOHARA, M
六名男子进行了研究，以确定血液供应，运动单位（MU）的活动和乳酸浓度之间的相互关系，在间歇性等长收缩的手握肌肉。受试者以最大随意收缩（MVC）的20%重复收缩2 s，然后休息2 s，持续4 min，在第1和第2 min之间给予无阻碍的血液循环或动脉闭塞。同时记录的肌内MU尖峰和表面肌电图（EMG）数据表明，平均MU尖峰幅度，放电频率和表面EMG功率谱的参数（平均功率频率和均方根振幅）在无阻碍循环的实验期间保持恒定，没有提供肌肉疲劳的电生理学迹象。然而，在动脉闭塞的收缩过程中，平均MU尖峰幅度和频率明显增加。表面肌电谱参数和静脉乳酸浓度也观察到类似的显着变化模式，而积分力-时间曲线保持不变。这些数据表明，活跃肌肉的代谢状态可能在运动期间MU募集和速率编码模式的调节中发挥了重要作用。
Six men were studied to determine the interrelationships among blood supply, motor unit (MU) activity and lactate concentrations during intermittent isometric contractions of the hand grip muscles. The subjects performed repeated contractions at 20% of maximal voluntary contraction (MVC) for 2 s followed by 2-s rest for 4 min with either unhindered blood circulation or arterial occlusion given between the 1st and 2nd min. The simultaneously recorded intramuscular MU spikes and surface electromyogram (EMG) data indicated that mean MU spike amplitude, firing frequency and the parameters of surface EMG power spectra (mean power frequency and root mean square amplitude) remained constant during the experiment with unhindered circulation, providing no electrophysiological signs of muscle fatigue. Significant increases in mean MU spike amplitude and frequency were, however, evident during the contractions with arterial occlusion. Similar patterns of significant changes in the surface EMG spectra parameters and venous lactate concentration were also observed, while the integrated force-time curves remained constant. These data would suggest that the metabolic state of the active muscles may have played an important role in the regulation of MU recruitment and rate coding patterns during exercise.