Trunk muscle fatigue and associated EMG changes during a dynamic iso-inertial test
Trunk muscle fatigue and associated EMG changes during a dynamic iso-inertial test
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动态等惯性测试期间躯干肌肉疲劳和相关肌电图变化
DOI：
10.1007/s004210050215
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
E. Schneider
中科院分区：
文献类型：
--
作者：
M. Morlock;V. Bonin;G. Müller;E. Schneider
本研究旨在探讨在动态等惯性测试中躯干肌疲劳与肌电信号变化之间的关系。11名受试者进行动态躯干屈曲/伸展运动对40%的最大随意收缩（MVC）扭矩，直到耗尽在三轴躯干测力计。通过分析肌电信号的幅值和频谱密度（使用过零率和中值频率）的变化，研究了肌电信号的时域和频域参数。根据运动速度和偏离所需运动平面的偏差，对运动进行了运动学分析。屈伸运动速度从试验开始到结束呈下降趋势。运动偏离矢状面到额状面和横向平面随着测试持续时间的增加而增加，肌电图振幅也是如此。在最大肌肉活动期间，中位频率下降，过零率也下降。躯干屈肌的振幅增加和中位频率降低比躯干伸肌更明显。在良好控制的动态收缩过程中，中位频率、过零率和振幅参数似乎是肌肉疲劳的敏感标识符。虽然运动学数据没有产生任何关于疲劳机制的信息，但EMG参数的变化表明，测试的持续时间受到躯干屈肌疲劳的限制。
This study was designed to investigate the relationship between trunk muscle fatigue and associated changes in the electromyographic (EMG) signals during a dynamic iso-inertial test. Eleven subjects performed dynamic trunk flexion/extension movements against 40% maximum voluntary contraction (MVC) torque until exhaustion in a tri-axial trunk dynamometer. EMG parameters in the time and frequency domain were studied by analysing changes of the signal amplitudes and the spectral density (using the zero-crossing-rate and the median frequency). The kinematics of the movement were analysed according to the movement velocities and the deviations from the required movement plane. The flexion and extension velocities decreased from the beginning to the end of the test. Movement deviations from the sagittal plane into the frontal and transverse plane increased with increasing test duration, as did the EMG amplitude. The median frequency during periods with maximum muscle activity decreased, as did the zero-crossing-rate. The increase in amplitude and decrease in median frequency were more pronounced in the trunk flexors than in the trunk extensors. The parameters of median frequency, zero-crossing-rate and amplitude seem to be sensitive identifiers of muscle fatigue during well-controlled dynamic contractions. While the kinematic data did not yield any information on the mechanisms of the fatigue, changes in the EMG parameters demonstrated that the duration of the test was limited by the fatigue of the trunk flexors.