Determination of the Maximum Acceptable Weights of Lifting and Lowering Using the Direct Estimation Method

The maximum acceptable weights of lifting and lowering were determined using the direct estimation method. Five task frequencies (1, 2, 4, 6, and 8 handlings per minute) were studied. Both lifting and lowering were fixed at knuckle-shoulder height. A base load for each individual subject was first established using the psychophysical approach. The direct estimation method was then applied. The results revealed that task frequency exerted a significant role in the variation of the data. The type of tasks (lifting and lowering) also significantly affected the maximum acceptable capacity performing the tasks. The study shows that the direct estimation method is a faster and feasible way to determine the maximum acceptable weight that an individual can handle.