Jensen B R, Schibye B, Søgaard K, Simonsen E B, Sjøgaard G
Department of Physiology, National Institute of Occupational Health, Copenhagen, Denmark.
Eur J Appl Physiol Occup Physiol. 1993;67(5):467-75. doi: 10.1007/BF00376465.
Physiological responses to physical work were assessed for 29 female industrial sewing-machine operators during an 8-h working day under ordinary working conditions. During sewing-machine work, the average (left and right) static load in the trapezius muscle was 9% of the maximal electromyogram (EMG) amplitude (% EMGmax), while the average mean load was 15% EMGmax, and the average peak load was 23% EMGmax. The static load level was unrelated to the muscle strength of the sewing-machine operators, which for the group as a whole was within the normal range. The load levels remained unchanged during the working day, while changes in the EMG mean power frequency and zero crossing frequency rate occurred, both indicating the development of muscle fatigue in left and right trapezius muscle during the working day. In line with this, the rating of perceived exertion in the shoulder and neck region increased during the working day. Dividing the group of sewing-machine operators into two groups, those with the highest frequency and those with the lowest frequency of shoulder/neck troubles showed that the former group had significantly lower muscle strength, despite the fact that no differences in the surface EMG during sewing were found between the two groups. It was concluded that industrial sewing-machine work involves a pattern of shoulder muscle activity which induces fatiguing processes in the shoulder and neck regions. Furthermore, since the static shoulder muscle load was independent of muscle strength, factors other than working posture may be of significance for the static shoulder muscle load.
在正常工作条件下，对29名女性工业缝纫机操作员在8小时工作日内的身体工作生理反应进行了评估。在缝纫机工作期间，斜方肌的平均（左右）静态负荷为最大肌电图（EMG）幅度的9%（%EMGmax），而平均负荷为15%EMGmax，平均峰值负荷为23%EMGmax。静态负荷水平与缝纫机操作员的肌肉力量无关，该组整体肌肉力量在正常范围内。工作日期间负荷水平保持不变，而EMG平均功率频率和过零频率发生率发生了变化，这两者均表明工作日期间左右斜方肌出现了肌肉疲劳。与此一致的是，工作日期间肩部和颈部区域的主观用力感觉评分增加。将缝纫机操作员组分为两组，即肩部/颈部问题频率最高的组和最低的组，结果显示，尽管两组在缝纫过程中的表面肌电图没有差异，但前一组的肌肉力量明显较低。得出的结论是，工业缝纫机工作涉及一种肩部肌肉活动模式，这种模式会在肩部和颈部区域引发疲劳过程。此外，由于肩部肌肉的静态负荷与肌肉力量无关，除工作姿势外的其他因素可能对肩部肌肉的静态负荷具有重要意义。
