Phelan Denis, O'Sullivan Leonard
Jacobs Engineering, Ireland.
Ergonomics and Product Design Research Group, Enterprise Research Centre, University of Limerick, Castletroy, Limerick, Ireland.
Appl Ergon. 2014 Nov;45(6):1384-91. doi: 10.1016/j.apergo.2014.03.007. Epub 2014 Apr 24.
A high incidence of Musculoskeletal Disorders (MSDs) has been reported in the construction sector. The use of ladders in the workplace has long been identified as a significant risk that can lead to workplace accidents. However, it is unclear if platform types have an effect on the physical risk factors for MSDs in overhead work. The aim of this study is to perform a pilot study on the effects of hand activity on both shoulder muscle loading and task performance while working on ladders versus Mobile Elevated Working Platforms (MEWPs). It is hypothesised that work on ladders would result in greater muscle loading demands, increased levels of discomfort, and reduced performance due to the restrictions on postures that could be adopted. A field study (n = 19) of experienced electricians on a construction site found that workers spent approximately 28% of their working time on ladders versus 6% on MEWPs. However, the durations of individual tasks were higher on MEWPs (153 s) than on ladders (73 s). Additionally, maximum levels of perceived discomfort (on a VAS 0-100) were reported for the shoulders (27), neck (23), and lower regions of the body (22). A simulated study (n = 12) found that task performance and discomfort were not significantly different between platform types (ladder vs. MEWP) when completing either of three tasks: cabling, assembly and drilling. However, platform and task had significant effects (p < 0.05) on median electromyographic (EMG) activity of the anterior deltoid and upper trapezius. EMG amplitudes were higher for the deltoid than the upper trapezius. For the deltoid, the peak amplitudes were, on average, higher for ladder work over MEWP work for the hand intensive cabling (32 vs. 27% Maximal Voluntary Exertion (MVE)) and the assembly task (19 vs. 6% MVE). Conversely, for drilling, the peak EMG amplitudes were marginally lower for ladder compared to the MEWP (3.9 vs. 5.1% MVE). The general implication was that working on the MEWP involved lower shoulder muscle loading for cabling and assembly task. A difference due to platform type was not present for drilling work.
建筑行业中肌肉骨骼疾病（MSDs）的发病率较高。长期以来，工作场所使用梯子一直被视为可能导致工作场所事故的重大风险。然而，尚不清楚平台类型是否会对高空作业中MSDs的身体风险因素产生影响。本研究的目的是进行一项初步研究，以探讨在梯子和移动升降工作平台（MEWPs）上工作时，手部活动对肩部肌肉负荷和任务绩效的影响。研究假设，由于可采用的姿势受到限制，在梯子上工作会导致更大的肌肉负荷需求、更高的不适感以及更低的绩效。一项针对建筑工地上经验丰富的电工的现场研究（n = 19）发现，工人在梯子上花费的工作时间约为28%，而在MEWPs上为6%。然而，MEWPs上单个任务的持续时间（153秒）高于梯子上（73秒）。此外，肩部（27）、颈部（23）和身体下部区域（22）报告的最大感知不适水平（采用0 - 100视觉模拟评分法）。一项模拟研究（n = 12）发现，在完成布线、组装和钻孔这三项任务中的任何一项时，平台类型（梯子与MEWP）之间的任务绩效和不适感没有显著差异。然而，平台和任务对三角肌前部和斜方肌上部的肌电图（EMG）中位活动有显著影响（p < 0.05）。三角肌的EMG振幅高于斜方肌上部。对于三角肌，在手部密集的布线工作（32%对27%最大自主用力（MVE））和组装任务（19%对6% MVE）中，梯子工作的峰值振幅平均高于MEWP工作。相反，对于钻孔工作，梯子的EMG峰值振幅略低于MEWP（3.9%对5.1% MVE）。总体而言，在MEWP上工作时，布线和组装任务涉及的肩部肌肉负荷较低。钻孔工作不存在因平台类型导致的差异。
