National Institute for Occupational Safety and Health, Cincinnati, OH 45226, USA.
Ergonomics. 2009 May;52(5):569-83. doi: 10.1080/00140130802449682.
This study examined the internal validity of observational-based ergonomic job analysis methods for assessing upper limb force exertion and repetitive motion. Six manual tasks were performed by multiple 'workers' while direct measurements were made to quantify force exertion and kinematics of the upper limb. Observational-based analyses of force and upper limb motion/repetition were conducted by 29 professional ergonomists. These analysts overestimated the magnitude of individual force exertions - temporal aspects of force exertion (duty cycle) were estimated more accurately. Estimates of the relative severity of repetitive motions among the jobs were accurate. Absolute counts of repetitive motions were less accurate. Modest correlations (r(2) = 0.28 to r(2) = 0.50) were observed between ratings of hand activity level and measured joint velocities. Ergonomic job analyses relying on systematic observation should be applied and interpreted with consideration given to the capabilities and limitations of analysts in estimating the physical risk factors. These findings are relevant to a better understanding of the internal validity of ergonomic job analysis methods based on systematic observation.
本研究考察了基于观察的人体工程学工作分析方法在评估上肢力和重复运动方面的内部有效性。 由多名“工人”进行了六项手动任务，同时进行了直接测量以量化上肢的力和运动学。 29 名专业人体工程学家对力和上肢运动/重复进行了基于观察的分析。 这些分析人员高估了个体力的大小 - 力的时间方面（工作周期）的估计更为准确。 对工作中重复性运动的相对严重程度的估计是准确的。 重复性运动的绝对次数不太准确。 在手部活动水平评分与测量关节速度之间观察到适度的相关性（r(2) = 0.28 至 r(2) = 0.50）。 应该应用并解释基于系统观察的人体工程学工作分析，同时考虑到分析人员在估计物理风险因素方面的能力和局限性。 这些发现对于更好地理解基于系统观察的人体工程学工作分析方法的内部有效性具有重要意义。
