Interindividual variation of physical load in a work task
Interindividual variation of physical load in a work task
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DOI：
10.5271/sjweh.384
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发表时间：
1999-02-01
影响因子：
6.3
通讯作者：
Skerfving, S
中科院分区：
文献类型：
--
作者：
Balogh, I;Hansson, GÅ;Skerfving, S
目的本研究分析了从事相同工作任务的被试在体力劳动负荷方面的差异。方法记录49例女性在高重复性工业作业时的双侧斜方肌、冈下肌肌电图及腕关节运动。通过访谈和体格检查来确定12个潜在的解释因素，即年龄、人体测量、肌肉力量、工作压力和肌肉骨骼疾病。结果在肌电图中，第10百分位数的平均值分别为斜方肌和冈下肌最大自主电活动（%MVE）的2.2%和2.8%。然而，个体间差异非常大[变异系数（CV）分别为0.75和0.62]。大多数差异无法解释；只有高度、力量和2块肌肉的协同激活有显著影响（R-adj(2) 0.20-0.52）。对于相对自愿电活动（RVE）归一化的值，变异仍然很大，尽管较小（CV小于或等于0.63）。手腕运动的中位速度为29度/秒，个体间差异很小（CV小于等于0.24）。六个因素对解释方差有贡献（R-adj(2) 0.12-0.55）。结论在相同的工作任务下，腕部运动的个体间差异较小。相比之下，与使用MVE相比，RVE归一化后的肌电图变化较大，尽管较小，但减少了强度的影响。由于这些变化，需要几种肌电图来描述特定工作任务中肌肉负荷的暴露，当研究工人患肌痛的风险时，个人肌电图更可取。
Objectives This study analyzed the variation in physical work load among subjects performing an identical work task.Methods Electromyographs from the trapezius and infraspinatus muscles and wrist movements were recorded bilaterally from 49 women during a highly repetitive industrial work task. An interview and a physical examination were used to define 12 potential explanatory factors, namely, age, anthropometric measures, muscle strength, work stress, and musculoskeletal disorders.Results For the electromyographs, the means of the 10th percentiles were 2.2% and 2.8% of the maximal voluntary electrical activity (%MVE) for the trapezius and infraspinatus muscles, respectively. However, the interindividual variations were very large [coefficients of variation (CV) 0.75 and 0.62, respectively]. Most of the variance could not be explained; only height, strength, and coactivation of the 2 muscles contributed significantly (R-adj(2) 0.20-0.52). The variation was still large, though smaller (CV less than or equal to 0.63), for values normalized to relative voluntary electrical activity (RVE). For the wrist movements, the median velocity was 29 degrees per second, and the interindividual variations were small (CV less than or equal to 0.24). Six factors contributed to the explained variance (R-adj(2) 0.12-0.55).Conclusions The interindividual variation is small for wrist movements when the same work tasks are performed. In contrast, the electromyographic variation is large, even though less after RVE normalization, which reduces the influence of strength, than when MVE is used. Because of these variations, several electromyographs are needed to characterize the exposure of a specific work task in terms of muscular load, and individual electromyographs are preferable when the worker's risk of myalgia is being studied.