不对称搬举劳动负荷及有关因素的表面肌电分析

Evaluation of work load and related factors during asymmetric lifting with surface electromyography

目的应用表面肌电描记术(SEMG)分析、评价不对称搬举的劳动负荷及有关因素。方法13名男性志愿者以2种速度、4种躯干旋转角度,分别搬举重6和13 kg的箱子,搬举箱子从地面至指节高度,共执行16项搬举任务。在搬举作业中测量T10和L3部位两侧竖脊肌的肌电信号。结果搬举13 kg重量时竖脊肌肌电平均幅度(43．30%MVE)明显比搬举6 kg重量时(37．70%MVE)高,差异有统计学意义(P＜0．01)。快速搬举时的肌电平均幅度(41．80%MVE)明显比慢速搬举(39．19%MVE)时高,差异亦有统计学意义(P＜0．05)。随躯干旋转角度的增加,竖脊肌肌电幅度呈升高的趋势,但差异无统计学意义(P＞0．05)。在T10部位右侧竖脊肌肌电幅度高于左侧(分别为50．31%MVE、25．88%MVE),而在L3部位则是左侧竖脊肌肌电幅度高于右侧(分别为45．60%MVE、40．22%MVE),差异均有统计学意义(P＜0．01)。多元逐步回归分析结果显示,搬举重量对竖脊肌肌电平均幅度贡献最大,其次是搬举速度。结论不对称搬举作业的工效学危险因素主要是搬举重量和速度。在不对称搬举时,左右两侧的竖脊肌肌电活性不同。

Objective To evaluate the work load and related factors for asymmetric lifting tasks using surface electromyogaphy（EMG）. Methods Thirteen male volunteers lifted loads of 6 and 13 kg at two speeds, in varying angles of trunk rotation, from floor to knuckle height, performing 16 lifting tasks. During lifting, surface electremyography signals from the erector spinae, bilaterally at level of T10 and L3, was continually recorded. The work load and related factors for asymmetric lifting tasks were evaluated by comparing the average amplitude of EMG signals. Results The EMG average amplitude when lifting the load of 13 kg（43.30%MVE） was significantly greater than that when lifting the load of 6 kg（37.70% MVE） （ P 〈 0.01） .The EMG average amplitude when lifting at the higher speed（41.80% MVE） was significantly greater than that at the lower speed （39.19% MVE） （ P 〈 0.05）. The EMG average amplitude was increased with the increase of the trunk rotation angle without significant difference （ P 〉 0.05）. At T10, the EMG average amplitude was greater on the right side than that on the left side （50.31%MVE and 25.88%MVE respectively） while at L3,it was on the contrary （45.60%MVE on the left and 40.22% MVE on the right respectively）（ P 〈 0.01 ）. Multiple stepwise regression analysis showed that the load of lifting was the factor contributing most to the EMG average amplitude followed by the lifting speed. Conclusion The risk factors related to work load for asymmetric lifting tasks are mainly the load and the speed of lifting. The EMG activity between the fight and left side of erector spiuae is different during such lifting.