ABSTRACT
Previous research has relied on two main criteria to assess musculoskeletal injury risk exposure: those based on epidemiological investigations and those based on analysis of the potential biomechanical overload of the lumbar disks. Data from epidemiological studies point unequivocally to the existence of a relationship between the type and number of maneuvers involved in manual movement of patients and the occurrence of certain acute and chronic disorders of the lumbar spine (Bordini et al., 1999; Colombini et al, 1999a, 1999b). Biomechanical studies briefly refer to measurements of lumbar loads during lifting or handling movements with noncooperative patients. Gagnon (1986) calculated 641 kg as the maximum load acting on the lumbar disks when lifting a patient weighing 75 kg from sitting to standing position. Garg et al. (1991) calculated 448 kg as the average load on disk L5/S1 when moving a patient from bed to wheelchair. In a recent study, Ulin and Chaffin (1997) calculated a disk load of 1020 kg when moving a noncooperative patient weighing 95 kg.
