| Summary: | 碩士 === 華梵大學 === 工業工程與經營資訊學系碩士班 === 100 === Objective: This study used psychophysical approach to examine the effects of working height and holding time on the holding capacity when holding against a wall.
Background: The backache and the musculoskeletal injury resulted in manual material handling (MMH) had been considered to be one of the major sources that caused damage in the industry, but information regarding holding capacity of psychophysical approach is still in-sufficient.
Methodology: There were 30 participants recruited in this study (15 males and 15 females). The psychophysical method was used to investigate the effects of working height (elbow height, shoulder height and over head), holding time (30 seconds, 1 minute, 2 minutes and 3 minutes) and sex (males and females) on maximum acceptable holding weight (MAWH), heart rate (HR), and perceived exertion rating (RPE).
Result: (1) Sex had a significant on MAWH, HR and RPE, the females held 30% less MAWH than the males; and the HR and RPE of females were larger than those of males. (2) Working height had a significant effect on MAWH and HR; however, it had no significant effect on RPE. Working with overhead height can induce the largest MAWH (8.62 kg) and the smallest HR (90.34beats/min). (3)Holding time had a significant effect on MAWH and wrist-RPE; however, it had no significant effect on HR, the largest MAWH (9.35 kg) was 30 seconds and the largest RPE (14.48) was 3 minutes. (4)Sex*working height and sex* holding time had a significant interaction on MAWH. Sex* body parts, working height *body parts and holding time* body parts had a significant interaction on RPE. (5) A total of ten prediction models were developed for male and female respectively.
Conclusion: The combinations of 30 seconds of holding time and working with overhead resulted in the greatest holding capacity. A comparison of the models revealed that the model 6(anthropometric data after screening, R-Square=0.7961，PRESS＝243) and the model 5(anthropometric data, static and dynamic strength, R-Square=0.924，PRESS＝72) were the best for male and female, respectively.
Application: The holding tasks should be done as short as possible and holding against a wall with large muscle groups to improve job performance and reduce occupational injuries.
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