Abstract
The purpose of this thesis is attempting to devise a static task adjustment rating point to KIM LHC checklist to improve accuracy in assessing static-related operations, the methodology is to conduct an experiment according to WISHA screening tool for devising an adjustment rating scale for the time rating of KIM LHC checklists. KIM checklist is one of newly developed checklists under EU-OSHA’s sponsorship. The KIM checklist consists of 3 versions：KIM LHC, KIM PP, KIM MHO. KIM LHC was designed for whole body tasks, including lifting、holding and carrying, KIM PP for pushing and pulling tasks, KIM MHO for manual hand operation tasks, such as product assembly, food processing. KIM LHC is especially easy-to-use and almost fit-all, risk score is the product of time rating and the summation of three other ratings. WISHA screening tool is an ergonomics guideline proposed by Washington State as a musculoskeletal hazard standard. It is considered as a major reference for assessing the goodness of checklists. Although KIM LHC is very promising, it does not explicitly take into account the difference in fatigue between dynamic and static operations. In theory, dynamic task is interposed with work and rest durations, during rest durations, the O2 deficit occurring during work periods can be replenished, and metabolite wasted can be expelled. Therefore, fatigue can be lessened. On the other hand, for static tasks, O2 deficit is continuing increased and waste is accumulated, and fatigue and exhaustion are the inevitable outcome. In reality, it is generally agreed that static tasks is far more fatiguing than dynamic tasks. Therefore, it is wondered that a supplement adjustment rating for the time rating scale of KIM LHC can be devised. The experiment is to compare the difference in KIM LHC risk score and subjective fatigue perception on 4 static experimental conditions against the dynamic control condition. The control condition is based on the caution zone of WISHA screening tool. These 4 dynamic static experimental conditions vary in various work-rest periods, such as 5-2.5, 10-5, 20-10, 40-20 min. To be sensitive, an awkward working posture of holding 0.5 kg weight over the shoulders was devised. Ten young men were recruited as subjects. Based on experimental results, the difference between risk scores and subjective fatigue perception are compared, the discrepancy serves as the adjustment for the time rating scale of KIM LHC. According to this supplement, the risk scores of 5 old cases were re-assessed. The results show that the new supplement is able to fine-tune the risk score to match our subjective fatigue perception.