拉车作业之肌肉疲劳分析与预测

目的本研究的第一个目的是以肌力下降、耐受时间及主观评价来比较在不同负荷水平下拉车作业造成的肌肉疲劳水平;第二个目的是建立数学模型来量化拉车作业造成肌肉疲劳的程度;最终目的为提供拉车作业工作设计的提供依据,以降低劳动者肌肉骨骼伤害的风险。方法通过设计模拟手拉叉车实验,测量两种负荷下被试的实验前后拉力值、持续施力的耐受时间以及身体疲劳主观评价的数据,进行肌肉疲劳分析。结果实验数据显示拉车作业产生肌肉疲劳,性别和负荷对耐受时间、拉力下降速率产生显着影响;性别也显著影响被试对疲劳的主观评价,身体质量指数是影响耐受时间的显著因子。结论拉车作业中肌肉疲劳会导致拉力显著下降;性别是影响肌肉疲劳的重要因子,女性被试比男性被试更易疲劳;根据预测函数模型计算的男、女被试的疲劳速率k值分别为0.071、0.099。

Analyses and Predictions of Muscular Fatigue For Pulling Tasks

Objective The first purpose of this study was to compare the muscular fatigue levels between different workloads for pulling tasks via the analyses of muscular strength decrease, endurance time, and subjective ratings.The second purpose of this study was to establish mathematic models to quantify muscular strength for pulling tasks with the ultimate goal of providing basis for job design for pulling tasks so as to reduce the risk of musculoskeletal disorders.Methods A simulated pallet truck pulling task was designed to investigate the developing of muscular fatigue in performing a truck pulling task.The muscular strength of pulling before and after performing the pulling task, endurance time and the subjective ratings on muscular fatigue were analyzed.Results Pulling tasks resulted in muscular fatigue.Gender and workload significantly affected endurance time, and the decrease rate of the pulling strength.Gender affected the subjective ratings on muscular fatigue significantly.Body mass index was a significant factor on endurance time.Conclusion Pulling tasks resulted in the reduction of pulling strength due to muscular fatigue.Gender was an important factor affecting muscular fatigue.Males were more resistant to muscular fatigue than the females.The fatigue parameter k was 0.071 and 0.099 for male and female subjects, respectively.