The Mechanical Loads on the Low Back during Different Patient Handling Tasks

High prevalence rate of low back disorders (LBD) is found among nursing personnel. To get a more detailed knowledge concerning the risk factor in the health care sector, the working postures and the mechanical load of the low back were measured during nine commonly used patient handling tasks. Further the variation in the load between the different tasks was compared with the variation between subjects when they perform the same tasks. The study includes 10 female nurses with no special education or course in patient handling technique and a male stroke patient. The load during the different tasks were quantified from the net moment at L4/L5 joint calculated by use of a 3D biomechanical dynamic multi-segment model, the measured muscle activity (EMG) in erector spinae muscles and the kinematics of the low back. Significant differences in the mean values for all the dependent variable both between tasks and between subjects were found. The highest moment was found during the two tasks typically involving a lifting procedure of the whole bodyweight of the patient. High moment was however also found during tasks where the patient is “only” being repositioned in the bed. The position data measured for the low back are more difficult to interpret since no recommendations for limits are available in the literature. A high intersubject variation is found for all the outcome variables for a given task. This emphasizes the importance of an exposure assessment including individual measures. Otherwise, the risk for misclassification may be high and a detailed task description less effective for recommending prevention strategy.