Department of Integrated Systems Engineering, The Ohio State University, Columbus, OH, USA.
Ergonomics. 2012;55(9):1104-14. doi: 10.1080/00140139.2012.692819. Epub 2012 Jun 7.
The objective of this study was to investigate potential associations between an individual's psychophysical maximum acceptable force (MAF) during pushing tasks and biomechanical tissue loads within the lumbar spine. Ten subjects (eight males, two females) pushed a cart with an unknown weight at one push every two minute for a distance of 3.9 m. Two independent variables were investigated, cart control and handle orientation while evaluating their association with the MAF. Dependent variables of hand force and tissue loads for each MAF determination and preceding push trial were assessed using a validated, electromyography-assisted biomechanical model that calculated spinal load distribution throughout the lumbar spine. Results showed no association between spinal loads and the MAF. Only hand forces were associated with the MAF. Therefore, MAFs may be dependent upon tactile sensations from the hands, not the loads on the spine and thus may be unrelated to risk of low back injury. Practitioner Summary: Pushing tasks have become common in manual materials handling (MMH) and these tasks impose different tissue loads compared to lifting tasks. Industry has commonly used the psychophysical tables for job assent and decision of MMH tasks. However, due to the biomechanical complexity of pushing tasks, psychophysics may be misinterpreting risk.
本研究旨在探讨个体在推物任务中的心理物理最大可接受力（MAF）与腰椎内生物力学组织负荷之间的潜在关联。10 名受试者（8 名男性，2 名女性）每隔两分钟推一次手推车，每次推 3.9 米。在评估推车控制和手柄方向对 MAF 的影响时，研究了两个独立变量。使用经过验证的肌电图辅助生物力学模型评估了每个 MAF 确定和前一次推试验的手力和组织负荷的依赖变量，该模型计算了整个腰椎的脊柱负荷分布。结果表明，脊柱负荷与 MAF 之间没有关联。只有手力与 MAF 有关。因此，MAF 可能取决于手部的触觉，而不是脊柱上的负荷，因此与腰部受伤的风险可能无关。从业者总结：推物任务在手动物料搬运（MMH）中变得很常见，与举物任务相比，这些任务会施加不同的组织负荷。行业通常使用心理物理学表格来评估工作和决定 MMH 任务。然而，由于推物任务的生物力学复杂性，心理物理学可能会误解风险。
