Predicting the Maximum Acceptable Weight of Lift for an Asymmetrical Combination Task

This paper presents prediction models based on a study of a combination lift and lower manual handling task that was designed to simulate the loading of grocery bags into a car trunk. Twelve male subjects performed an externally-paced task of lifting plastic grocery bags (with handles) loaded with weights from 15 cm above the floor and over a wooden sill. There were two different sill heights of 70 cm and 90 cm, and for each of these heights there were two frequencies of 3 and 6 lifts per cycle. A unique lifting sequence and a modified version of the psychophysical methodology was used to determine the maximum acceptable weight of lift (MAWOL). Prediction models were determined for MAWOL based upon task, physiological and anthropometric variables as well as a combinations of these. The results indicated that MAWOL could be predicted fairly well.