Isotonic and isoelectric endurance tests for the upper trapezius muscle
Isotonic and isoelectric endurance tests for the upper trapezius muscle
复制标题
上斜方肌的等张和等电耐力测试
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
J. R. M. Ojok
中科院分区：
文献类型：
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作者：
G. Hägg;J. R. M. Ojok
作为评价上斜方肌肌力的传统耐力肌电(EMG)测试(等张测试，IT)的替代方法，我们研究了等电测试(IE)。9名受试者进行了这两项耐力测试。测试是在肩胛骨平面上水平伸直手臂的情况下进行的。在IE中，将肌电幅度反馈给受试者，并指示受试者保持恒定的肌电活动，使其与手臂无支撑时的水平相等。在实验过程中获得了局部疲劳的主观评分。根据平均功率频率(MPF)技术，对两个测试的肌电记录进行均方根值分析。所有受试者均可承受最大15min的IE，而IT组的中位耐力为11.9min。与IE相比，IT组感知疲劳的平均主观评分增加更多。来自IT的平均归一化MPF曲线增加，而来自IE的平均归一化MPF曲线不受影响。强积金在6分钟和8分钟的结果有显著差异。值得注意的是，尽管累积的生物力学负荷较高，但IT组的MPF较高。从这些研究得出的结论是，在低收缩水平下，将MPF降低解释为局部肌肉疲劳增加的指标是值得怀疑的。提示在职业病研究中，IE是一种更适合于上斜方肌低阈值运动单位功能评价的方法。
Abstract As an alternative to a conventional endurance electromyogram (EMG) test for assessment of muscle capacity in the upper trapezius muscle (isotonic test, IT), an isoelectric test (IE) has been investigated. Nine subjects performed the two endurance tests. The tests were performed with a straight horizontal arm in the plane of the scapula. In IE, EMG amplitude was fed back to the subject and the subject was instructed to maintain a constant EMG activity equal to the level with the arm unsupported. Subjective ratings of local fatigue were obtained during the experiments. The EMG recordings from both tests were analysed for the root mean square value as well as according to the mean power frequency (MPF) technique. All the subjects endured maximal 15 min IE while in IT the median endurance was 11.9 min. Average subjective ratings of perceived fatigue increased more in IT compared to IE. The average normalised MPF curve from IT increased while that from IE was unaffected. There was a significant difference between the MPF results at 6 and 8 min. It is noteworthy that the MPF was higher in IT in spite of a higher accumulated biomechanical load. It was concluded from these studies that the interpretation of decreased MPF as an indicator of increased local muscle fatigue is doubtful at low contraction levels. It is suggested that an IE is a more appropriate method for the functional evaluation of low threshold motor units of the upper trapezius muscle in research into occupational disorders.