Maximum weights of asymmetrical loads acceptable to industrial workers for symmetrical manual lifting

This paper presents 'maximum acceptable weight of lift' design databases for lifting asymmetrical loads by industrial male and female workers. These databases were developed by first collecting experimental data on experienced and inexperienced workers under identical conditions (Study A) and then applying the trends developed, as a result of data comparison, to the data collected on inexperienced workers in a separate independent study (Study B) dealing with lifting asymmetrical loads. Several different task variables are accounted for in the data. These include the following: lifting height (floor to knuckle, knuckle to shoulder, and shoulder to reach); frequency of lift (2, 4, and 6 lifts/min; box-size (30.48, 45.72, and 60.96 cm long in the sagittal plane); and load asymmetry (indicated by the offset of the center of gravity in the frontal plane: 0, 12.7, and 25.4 cm from the mid-sagittal plane; the 0 cm center of gravity (c.g.) offset indicates symmetrical load).