Effect of maximum acceptable vs. maximum capacity instructions for three lifting tasks

Psychophysical techniques for establishing lifting guidelines are used by industry and the military. The instructions used during industrial research refer to maximum acceptable lifts (MAL), while the military uses maximum capacity lifts (MCL). The purpose of this study was to determine male and female soldiers' load selections using two sets of instructions (MAL and MCL) and two lift heights (floor-knuckle and knuckle-shoulder) for three lifting tasks (one-repetition maximum, 1-hr and 8-hr repetitive lifting). Thirteen male and 13 female soldiers participated in this study. A repeated measures analysis of variance identified main effects. Newman-Keuls Comparison of Means were used to examine significant interactions. Results revealed no difference due to instructions. Men selected a greater load than women, and greater loads were selected for floor-knuckle versus knuckle-shoulder (p < 0.05). Although slight differences were seen between loads selected by industrial workers vs. soldiers, the research results appear comparable for repetitive lifting but not for single lifts.