本論文主要目的在探討使用單輪手推車時，負荷位置與施力方向對於肌肉活動反應、握力與自覺施力評量的影響，實驗研究共徵募9位受試者，每位受試者執行18種實驗組合包含2個施力方向（推、拉）以及9個負荷位置，應變數為左右兩邊的屈指淺肌、斜方肌與背直肌之肌肉活動反應（EMG）、雙手的握力以及自覺施力評量。研究結果顯示，前推握力及自覺施力評量分數小於後拉，此6條肌肉前推的最大肌肉活動反應皆比後拉高。當負荷離受試者越遠，則左右斜方肌與背直肌的EMG越小，而當負荷越接近受試者及在手部的同一側時，左右斜方肌與背直肌的EMG則會逐漸增加。同樣現象也出現在雙手的握力與自覺施力評量，負荷越靠近受試者身體的握力及自覺施力評量分數較負荷遠離受試者大，。根據研究結果，本研究建議當使用單輪手推車時，為了減輕肌肉負擔及施力，應將負荷安排放置在斗櫃的前方及輪胎軸線上。而本研究之發現可作為單輪手推車改善及人因再設計的方向。

The objective of the study was to explore the effects of load position and force direction on muscle activity, gripping force and rating of perceptual exertion(RPE) during wheelbarrow tasks. Nine participants were recruited to take part in the experiment. Each participant performed 18 trials consisting of 2 force directions (push and pull) and 9 load positions. The dependent variables were EMG of the bilateral flexor digitourm superficialis, trapezius and erector spinae, two hand’s gripping force and RPE. Results showed that the gripping force of pushing the wheelbarrow and the scores of RPE were less than that of pulling the wheelbarrow. The Peak EMG of six muscles in the pushing task were greater than those in the pulling task. EMG was lower for the bilateral trapezius and erector spinae when the load was positioned farther from the participant. EMG of the bilateral trapezius and erector spinae increased when the weight was near the participant and on the ipsilateral hand. A similar phenomenon was also found in the gripping force of the left hand/right hand and RPE. Participants exerted greater gripping force and RPE scales when the load was set near the body than when the load was set far away from the body. Based on the results, we suggest that loads be arranged in the anterior part of the bin in order to reduce muscle activity during the wheelbarrow task. This finding also provides some directions in the improvement and ergonomic redesign of the one-wheeled wheelbarrow.

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