Marras W S, Lavender S A, Leurgans S E, Rajulu S L, Allread W G, Fathallah F A, Ferguson S A
Department of Industrial and Systems Engineering, Ohio State University, Columbus.
Spine (Phila Pa 1976). 1993 Apr;18(5):617-28. doi: 10.1097/00007632-199304000-00015.
Current ergonomic techniques for controlling the risk of occupationally-related low back disorder consist of static assessments of spinal loading during lifting activities. This may be problematic because several biomechanical models and epidemiologic studies suggest that the dynamic characteristics of a lift increase spine loading and the risk of occupational low back disorder. It has been difficult to include this motion information in workplace assessments because the speed at which trunk motion becomes dangerous has not been determined. An in vivo study was performed to assess the contribution of three-dimensional dynamic trunk motions to the risk of low back disorder during occupational lifting in industry. More than 400 repetitive industrial lifting jobs were studied in 48 varied industries. Existing medical and injury records in these industries were examined so that specific jobs historically categorized as either high-risk or low-risk for reported occupationally-related low back disorder could be identified. A triaxial electrogoniometer was worn by workers and documented the three-dimensional angular position, velocity, and acceleration characteristics of the lumbar spine while workers lifted in these high-risk or low-risk jobs. Workplace and individual characteristics were also documented for each of the repetitive lifting tasks. A multiple logistic regression model was developed, based on biomechanical plausibility, and indicated that a combination of five trunk motion and workplace factors distinguished between high and low risk of occupationally-related low back disorder risk well (odds ratio: 10.7). These factors included 1) lifting frequency, 2) load moment, 3) trunk lateral velocity, 4) trunk twisting velocity, and 5) the trunk sagittal angle. This analysis implies that by suitably varying these five factors observed during the lift collectively, the odds of high-risk group membership may decrease by almost 11 times. The predictive power of this model was found to be more than three times greater than that of current lifting guidelines. This study, though not proving causality, indicates an association between the biomechanical factors and low back disorder risk. This model could be used as a quantitative, objective measure to design the workplace so that the risk of occupationally-related low back disorder is minimized.
当前用于控制职业性下背痛风险的人体工程学技术包括对搬运活动期间脊柱负荷的静态评估。这可能存在问题，因为一些生物力学模型和流行病学研究表明，搬运的动态特征会增加脊柱负荷以及职业性下背痛的风险。由于尚未确定躯干运动变得危险的速度，因此很难将此运动信息纳入工作场所评估中。进行了一项体内研究，以评估三维动态躯干运动对工业中职业搬运期间下背痛风险的影响。在48个不同行业中研究了400多个重复性工业搬运工作。检查了这些行业中现有的医疗和伤害记录，以便能够识别出历史上被归类为与职业性下背痛报告相关的高风险或低风险的特定工作。工人佩戴三轴电子测角仪，并记录工人在这些高风险或低风险工作中搬运时腰椎的三维角位置、速度和加速度特征。还记录了每个重复性搬运任务的工作场所和个人特征。基于生物力学合理性开发了一个多元逻辑回归模型，该模型表明五个躯干运动和工作场所因素的组合能够很好地区分职业性下背痛风险的高与低（优势比：10.7）。这些因素包括：1）搬运频率，2）负荷力矩，3）躯干横向速度，4）躯干扭转速度，5）躯干矢状角。该分析表明，通过共同适当地改变搬运过程中观察到的这五个因素，高风险组的可能性可能会降低近11倍。发现该模型的预测能力比当前的搬运指南大三倍以上。这项研究虽然没有证明因果关系，但表明了生物力学因素与下背痛风险之间的关联。该模型可作为一种定量、客观的措施来设计工作场所，从而将职业性下背痛的风险降至最低。
