Center for Ergonomics, Industrial and Operations Engineering, University of Michigan, Ann Arbor, Michigan, USA.
J Occup Environ Hyg. 2010 May;7(5):261-71. doi: 10.1080/15459621003640502.
This study evaluated inter-worker variability in lower body posture and work activity during highly-structured assembly line work. Data were collected from 79 unique assembly line workstations in an engine manufacturing plant. Because the plant utilized work teams, 4-8 workers rotated through each workstation. At least 30 min of videotape was collected from at least three workers at each workstation. A computer-assisted work sampling procedure randomly selected 200 video "freeze-frames" for each worker. Lower body posture/movement (e.g., sit, stand, walk, etc.) was determined for each frame and used to estimate the percentage of time the worker spent in various postures and activities. Chi-square analyses were performed for each workstation to assess the significance of inter-worker differences. Due to variations in individual work methods, significant differences (p <.05) were found at 57 out of 79 workstations (72%). The greatest differences occurred when workers had the option to choose between standing and sitting (significant in 8 of 8 cases; in extreme examples, sit time ranged between 0-100% on one job, and 6.5-98% on another). Studying a single worker (or "proxy") can contribute to substantial error when estimating exposures in workplace studies of ergonomic stressors, since the proxy may not be representative of all workers who perform the job. Individual measurements are preferable, particularly for jobs where workers have substantial latitude to develop individualized work methods.
本研究评估了高度结构化装配线工作中工人之间下肢姿势和工作活动的变异性。数据来自一家发动机制造厂的 79 个独特的装配线工作站。由于工厂采用了工作团队，每个工作站有 4-8 名工人轮流工作。每个工作站至少从 3 名工人收集了至少 30 分钟的录像带。计算机辅助工作抽样程序随机为每个工人选择了 200 个视频“冻结帧”。为每个帧确定下肢姿势/运动（例如，坐、站、走等），并用于估计工人在各种姿势和活动中花费的时间百分比。对每个工作站进行卡方分析，以评估工人之间差异的显著性。由于个体工作方法的差异，在 79 个工作站中的 57 个（72%）工作站发现了显著差异（p <.05）。当工人可以选择站立和坐姿时，差异最大（8 个中的 8 个存在显著差异；在极端情况下，一个工作的坐姿时间范围在 0-100%之间，另一个工作的坐姿时间范围在 6.5-98%之间）。在研究人体工程学应激源的工作场所研究中，研究单个工人（或“代理”）可能会导致暴露估计出现大量误差，因为代理可能无法代表执行该工作的所有工人。个体测量更可取，特别是对于工人有很大的自由度来制定个性化工作方法的工作。
