探討蹲/跪作業姿勢對於作業人員生理負荷與健康危害之影響

Physiological workload and health risk among workers in squatting/kneeling task

張又升(You-Sheng Chang)

指導教授 ： 林彥輝

中山醫學大學/健康管理學院/職業安全衛生學系碩士班/碩士(2016年)

摘要

造成肌肉骨骼傷害的主要原因，與工作姿勢不良和長期暴露在一些設計不良的工作環境、工具、流程等有相當關聯性。若讓肌肉、骨骼、及神經系統受到細微的傷害，長久下來可能累積成疾，且這些麻、痛、無力等症狀，不只引起個人不適、降低其工作能力，更會對於生活品質產生重大影響。 過去流行病學研究中，被討論過與膝關節骨關節炎有關的職業性動作很多，但目前只有負重、抬舉與蹲跪等作業在眾多研究間的結果較為一致。另外，以蹲跪姿勢進行作業在某些行業是經常可以看到的動作，如採收農作物、油漆粉刷、地板舖設、賣場揀貨、樓地板鋼筋綁紮以及水電設備組立等。 本研究旨在探討蹲/跪作業姿勢對於作業人員生理負荷與健康危害之影響，共招募10名受測者進行實驗，實驗自變項包括：工作型態、持續時間、蹲/跪姿勢；實驗依變項包括：身體部位主觀疲勞反應量表、肌肉電位變化 (下背、大腿、小腿)、下肢圍度與心搏率等，據以評估生理負荷及肌肉骨骼疲勞程度。 研究結果顯示，影響膝關節和腿部肌肉疲勞的原因是作業時間的長短，而不同的姿勢與作業種類並不會直接影響腿部肌肉疲勞。研究發現MVC%在作業開始後的五到十分鐘內，呈現大幅度的增加，而作業開始後十分鐘的MVC%變化幅度則開始減緩，推測可能在那個時間內肌肉的負荷值達到最大，之後再增加的MVC%則是超出肌肉負荷量，而造成痠痛的可能原因。心物法的實驗中，發現受測者對於自身的肌肉疲勞最大值多半都高估，以致未能得知自身的腿部肌肉在作業中能夠負荷的時間，而造成肌肉痠痛或是需要更長的休息時間來恢復疲勞。因此，制定一套作業中休息的規範，不僅可以減少作業人員的肌肉痠痛程度，也可以避免這些累積傷害所造成的職業性肌肉骨骼危害。

關鍵字

蹲/跪作業 ； 肌肉骨骼危害 ； 心物法

並列摘要

Working in awkward posture and prolonged working in some poorly designed work environment, tools, processes, are related to musculoskeletal injuries. It would be a severe health risks while the muscles, bones, and nervous system are damaged for a long time, and these numbness, pain, weakness and other physical symptoms, caused personal discomfort and reduce their ability to work and quality of life.
Epidemiological studies had been discussed with the knee osteoarthritis, which is consistant results in the loading, lifting and squatting tasks. Furthermore, the squatting posture is common in some industries, such as harvesting crops, painting, paving, store picking, steel banding and hydropower equipment.
This study was designed to investigate the effects of physiological workload and health risk among workers in squatting/kneeling task. A total of 10 subjects were recruited in this study. Experimental independent variables include: work patterns, duration, and squatting / kneeling posture. Experimental dependent variables include: subjective fatigue scale in body parts, Electromyography data (lower back, thighs, legs), leg circumference and heart rate, to assess the physiological load and musculoskeletal fatigue.
The experimental results show that the impacts of knee and leg fatigue is related to the length of working time, and the types of job or working postures do not affect directly the leg fatigue. It also found that %MVC increased significantly between five and ten minutes after the start time. Besides, the changes of %MVC increased slowly after ten minutes, possible reason is the working muscles reached maximal loading during the period, and external loading is overexertion which is beyond muscle capacity caused discomfort. On th other hand, maximum acceptable time of squatting/kneeling determined on the basis of a trial period overestimate the actual time in the psychophysical approach. The implication of this relationship indicated the subject endurance time is unknown, and it is necessary to take longer rest periods to recover their fatigue. Therefore, this study suggest to establish a work-rest scheme to reduce muscle pain, and avoiding occupational musculoskeletal disorders.

並列關鍵字

squatting/kneeling task ； musculoskeletal disorders ； psychophysical approach

參考文獻

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