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Psychophysically Determined Asymmetrical Lifting Capacity of Chinese Males over an 8h Work Shift

國人男性八小時工作時間之心物法非對稱抬舉能力

摘要


本實驗性研究旨在調查非對稱抬舉對於心物法所決定的最大可承受抬舉能力(MAWL)、心搏率(HR)以及施力知覺評量(RPE)的效應。有八位男性大學生以自由式的抬舉方式,在一次最大、每分鐘1次和4次下,以矢狀面和三種不同的非對稱角度(30°、60°和90°),從地面抬舉一個箱子到76 cm高的棧板上。結果發現:(1)非對稱的最大可承受抬舉重量顯著低於對稱式的矢狀面抬舉。最大可承受抬舉重量隨著非對稱角度的增加而下降。然而心搏率和施力知覺評量則保持不變;(2)抬舉頻率對於最大可承受抬舉重量的下降百分比並無顯著效應,以矢狀面的對稱式抬舉爲基準,受試者從矢狀面到扭轉30°、60°和90°的MAWL其修正係數分別下降6、11和16%。此一數值比NIOSH 1991方程式的數值還低;(3)心搏率和RPE隨著抬舉頻率的增加而增加,但MAWL則隨之下降。從一次最大到每分鐘1次和4次的MAWL值分別下降40%和49%左右。心搏率則由每分鐘一次(94.3跳/分)到每分鐘四次(112.5跳/分)上升約19%,受試者主觀認爲壓力最大者爲下背。

並列摘要


A laboratory study was conducted to investigate the effects of asymmetrical lifting on the psychophysically determined maximum acceptable lift weight (MAWL) and resulting heart rates and ratings of perceived exertion (RPE). Eight Chinese male college students lifted a box in the sagittal plane and at three different angles of asymmetry (30°, 60° and 90°) from the floor to a 76 cm high shelf at a rate of one-time maximum, 1 and 4 lifts/min using a free-style lifting technique. The results showed that: (1) The maximum acceptable weights were significantly lower for asymmetrical lifting than for symmetrical lifting in the sagittal plane. The maximum acceptable lift weight decreased with an increase in the angle of asymmetry, however, the heart rate and ratings of perceived exertion remained unchanged; (2) The lifting frequency had no significant effect on the percentage decrease in maximum acceptable lift weight during asymmetric lifting, using the symmetric lifting in the sagittal plane as the base line. Correction factors of 6, 11, and 16% for maximum acceptable lift weights at 30°, 60° and 90° in asymmetrical lifting, respectively, are recommended. The values are lower than those of the asymmetry multiplier of the 1991 NIOSH equation. (3) Both heart rate and RPE increased with an increase in lifting frequency though maximum acceptable lift weights decreased. The maximum acceptable weights decreased markedly by nearly 40% and 49% from one-time maximum to one lifts/min and four lifts/min, respectively. The heart rates increased by nearly 19% from one lifts/min (94.3 beats/min) to four lifts/min (112.5 beats/min). The most stressed body part was the lower back.

參考文獻


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