The high incident rate of musculoskeletal back problems in nursing work has long been recognized, and in many studies patient handling has been identified as a contributory factor. This paper seeks to question the application of the 'ergonomic model' for risk assessment of manual handling operations (MHO) as advocated in the MHO regulations. It describes an exploratory study, which uses a participatory approach and the qualitative analysis method of grounded theory to determine the factors perceived as important by the nurses for patient-handling tasks. The development of a model of these factors is discussed, together with the main outcome of questioning the practical benefits of dividing the generic task of patient handling into subtasks, eg bathing, for MHO risk assessment.