Methods for assessing the physical demands of manual lifting: a review and case study from warehousing

Assessment of the physical demands of potentially hazardous manual material handling (MMH) activities is fundamental to the prevention of disabilities from occupationally related low back pain, a problem costing the nation billions of dollars annually. Although there is a variety of ergonomic assessment methods available for assessing MMH activities, there is a lack of practical information to assist users in choosing the most appropriate assessment methods of a particular job. This article reviews currently available assessment methods and presents case study results of a physically demanding repetitive manual lifting job in two grocery warehouses. The case study will provide a framework for a comparison of the methods and a discussion of relevant application issues designed to assist users in selecting appropriate methods for assessing MMH jobs. Based on the results of the study, it is concluded that all of the ergonomic methods were in agreement that the job of grocery selector has a high level of risk for low back pain. Differences between the methods were noted, however, that should be considered when choosing a specific method for a specific application.