Use of verbal protocol analysis in the investigation of a manual handling task

Abstract

Concurrent verbal protocols were used to collect reports of subjects' thoughts during the completion of a manual handling task, and to investigate whether the content of these thoughts was influenced by changes in the weights and positions of the loads which were handled. A taxonomy was constructed to help in the analysis of the potential effects of weight of the load and of load position on the numbers of reports of a range of dependent variables such as posture, load, elements of the task and outcome. An association was found between load position and numbers of references to posture when handling loads of 8kg weight. This suggested that postural awareness might be heightened when more extreme postures were adopted during the handling of loads above a weight threshold. However, the references were often ambiguous, raising concerns about the subjects' depth of awareness of the postures they were adopting.