摘要
目的应用表面肌电技术(sEMG)测定分析重复性操作时上肢肌肉的疲劳状态并探讨指标的适宜性。方法8名男性大学生志愿受试者在实验室(以平均40个/min的速度)连续地抓取、移动和放置零件(5 g),每完成80个零件为1个时间段(约2 min),共4组(约8 min)。同时遥测记录肱桡肌、肱二头肌、三角肌、斜方肌的表面肌电信号,采用时域、频域及肌电术振幅频谱联合分析方法(the joint analysis of EMG spectrum and amplitude,JASA)的指标进行分析。结果4块肌肉肌电的最大自主收缩百分比(the percent of maximal voluntary electrical activation,MVE%)随重复性操作时间延长均呈上升趋势(P>0.05)。中位频率(mean frequency,MF)和平均功率频率(mean power frequency,MPF)降低,即所谓频谱左移,只是在最后一两个时段不再下降,反而升高。所测肌肉肌电频率的斜率在第1时段均为负值,在其余3时段则出现时而为负值、时而又为正值的变动,MF和MPF及其斜率的变化趋势一致。JASA分析表明,上肢肌肉在动态作业过程中呈疲劳、恢复和负荷增加的变动。结论在本例重复性操作中,肌肉呈疲劳、恢复、负荷增加或再次疲劳的变化。累及的肌肉主要是斜方肌、三角肌和肱桡肌,肱二头肌次之。肌电指标(如MVE%,MF,MPF及其斜率)在操作过程中的变化可以反映动态劳动的肌肉疲劳,JASA分析证实了这一点。
Objective To determine the muscle fatigue of upper limbs during repetitive performances by sEMG and estimate the suitability of some EMG parameters. Methods 8 student volunteers in seat position were requested to grasp a part weighted 5 g from one plate to another with right hand. The frequency of movement was 40 times/min for 8 minutes to simulate a repetitive work in the laboratory. The EMG signal was recorded simultaneously from brachioradialis, biceps, deltoid and trapezius then analyzed with amplitude, spectrum or combined indices called the joint analysis of EMG spectrum and amplitude（JASA）. Results As increase of the performance time, the amplitude in MVE% of the 4 muscles showed an increase tendency, although it was not significant （P〉0.05）. EMG spectrum analysis showed the mean frequency （MF） and the mean power frequency （MPF） decreased along with the performance that means the left shift of frequency. However, the frequency didn＇t decrease hut increase during the last 2 time periods. The slope of MF from all the muscle was negative at the first time period and sometimes negative or positive during the other time intervals. The MPF and its slope showed the same changes. According to JASA method, the muscles existed changes in fatigue, recovery, and load increase. Conclusions The muscles showed such function changes as fatigue, recovery, load increase or re-fatigue during the period of repetitive work. Mainly involved were muscles of trapezium, deltoid and brachioradialis but biceps was relatively less. The EMG parameters such as MVE%, MF and MPF, and especially their changes during the performance were still able in indicating muscle fatigue during repetitive work, which was demonstrated further by the JASA method.
出处
《工业卫生与职业病》
CAS
CSCD
北大核心
2007年第1期5-8,共4页
Industrial Health and Occupational Diseases
