There are actually no sufficient data for lifting technique assessment.A laboratory study was undertaken to determine the effect of 3 regular lifting techniques on erector muscle activation,cardiovascular strain and s...There are actually no sufficient data for lifting technique assessment.A laboratory study was undertaken to determine the effect of 3 regular lifting techniques on erector muscle activation,cardiovascular strain and subjective response.Thirty student volunteers participated in the study,and were required to lift a weight with different techniques.Stoop-,squat-,semi-squat-lifting resulted in 3,2 and 1 time of the highest percentage of the maximum voluntary electrical activation(MVE%) respectively.In the same order,the lowest median frequency(MF) existed 1,1 and 2 times.Muscle fatigue was 4 times in squat,36 in semi-squat and 43 in stoop lifting.Heart rate was the highest in squat and lowest in stoop respectively,with a middle level in semi-squat lifting.It may be recommended to adopt mainly the semi-squat technique for daily lifting works.For heavy lifting,it should use the squat technique.Stoop lifting may also be used alternatively but for light things.展开更多
文摘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。
基金supported in part by a grant from the Chinese Ministry of Science and Technology (No. 2006BAI06B08)
文摘There are actually no sufficient data for lifting technique assessment.A laboratory study was undertaken to determine the effect of 3 regular lifting techniques on erector muscle activation,cardiovascular strain and subjective response.Thirty student volunteers participated in the study,and were required to lift a weight with different techniques.Stoop-,squat-,semi-squat-lifting resulted in 3,2 and 1 time of the highest percentage of the maximum voluntary electrical activation(MVE%) respectively.In the same order,the lowest median frequency(MF) existed 1,1 and 2 times.Muscle fatigue was 4 times in squat,36 in semi-squat and 43 in stoop lifting.Heart rate was the highest in squat and lowest in stoop respectively,with a middle level in semi-squat lifting.It may be recommended to adopt mainly the semi-squat technique for daily lifting works.For heavy lifting,it should use the squat technique.Stoop lifting may also be used alternatively but for light things.
