在職場中,人工物料搬運(Manual Materials Handling, MMH)作業仍然普遍存在。從事搬運作業時,物件的重量分配(Load Distribution)經常不對稱,例如工廠成品及物件裝箱、一般民眾搬家打包或雜貨商店啤酒箱中啤酒隨機擺置等情形。過去研究重量不穩定或重量不均衡的文獻多以探討背部肌肉及腰椎受力情形為主,對於手部肌群施力情形之影響,其探討仍為少數。本研究主要目的在於探討當物件配重不對稱時以及不同抬舉時間下,其手部施力、相關肌肉EMG、及肢體運動之變化。 本研究主要在於利用三軸力荷重計(Load Cell)及EMG肌電訊號量測系統收集15位受測者於不同配重型態抬舉作業時,其手部施力及肌電訊號等資料,進行一系統分析。抬舉作業型態包括5種配重方式與3種抬舉時間(1s/lift、2s/lift、3s/lift),共15種作業型態。 研究顯示,在配重型態方面,當負重非位於物件中心時,上肢肌肉所顯示的施力情形均較負重位於物件中心時高,因此建議從事人工物料搬運時,盡量使負重重心位於物件之中心。從事人工物料搬運時,抬舉時間對於手部作用力及上肢肌肉之施力影響極大,當抬舉時間短時,手部作用力與上肢肌肉%MVC均最大,亦即進行快速的抬舉作業所造成的肌肉骨骼傷害風險會較高。
Manual materials handling (MMH) is one of the most common activities in industries.The load distribution of objects are often unbalanced in lifting tasks. Compared with the lifting tasks with unbalanced load, there are few studies on biomechanical behavior of upper limbs in the literature. The purpose of this study is to explore the biomechanical behavior of upper limbs for the lifting task with unbalanced load distribution and different lifting time. In this study, an experiment was conducted to collect the biomechanical behavior of upper limbs in the laboratory where two 3-component force transducers and EMG system were executed. Fifteen subjects were recruited and 15 task patterns, which were the combinations of 5 load distributions, 3 lifting periods (1s/lift, 2s/lift and 3s/lift), were designed and performed in the experiment. The experiment results showed that the muscular exertions of upper limbs were higher when the load contribution of objects lifted was not balanced. It’s recommended that the load contribution of objects should be balanced while lifting. The lifting periods had the significant effect on the biomechanical behavior of upper limbs. The hand exertion and the %MVC of tested muscles become larger when the lifting period was short, implying that the risk of musculoskeletal disorders would be higher when fast lifting was performed.