A Study of Physical Work Capacity for Mannual Materials Handling Tasks

인력물자취급의 생리적 작업능력에 관한 연구

The objective of this study was to make comparison of the physical work capacities(PWCs) for three different types of tasks. For this purpose, an ergometer exercise, a treadmill exercise, and lifting activities with four different frequencies (2, 5, 8, 11 lifts/min) for the lifting range from floor to 76cm were considered. Oxygen consumption rates and heart rates were measured during the exercises and lifting activities. The PWC values for ergometer exercise test was 2562.71 ml-O$_{2}$/min and the one for treadmill exercise was 2874.89 ml-0$_{2}$/min. The value of lifting PWC increased from 1774.07ml-0$_{2}$/min to 2296.76 ml-0$_{2}$/min as the lifting frequency increased from 2 to 11 lifts/min. The ratio of the lifting PWCs to the ergometer PWCs increased from 69.36% to 89.77% as the lifting frequency increased. To the treadmill PWCs, the ratio increased from 62.21% to 85.24% as the lifting frequency increased. From this result, it is appears that the PWCs based on the lifting tasks rather than PWCs by ergometer or treadmill exercise should be considered to determine the physiological criterion for safe weights for lifting tasks. Therefore, the physiological criteria of the NIOSH Guideline should be reexamined.