MUSCLE STRENGTH, TASK-PERFORMANCE AND LOW-BACK LOAD IN NURSES

Poor muscle strength, relative to the physical demands of specific job s, is considered a risk factor for low back gain. To gain an understan ding of the underlying mechanisms, this study questioned whether muscl e strength was related to task performance and low back load in nursin g tasks. Trunk extension, elbow flexion and knee extension strength we re therefore measured in 17 nurses. The independent effects of muscle strength on task duration, jerkiness of effort and L5-S1 torque were i nvestigated as the nurses performed several patient handling tasks. De spite a large variation in muscle strength within the subject populati on, no effect of strength on task duration, jerkiness or L5-S1 torques was observed. In conclusion, poor muscle strength was found not to be related to increased low back load. If 'weaker' nurses were to be at a higher risk, it would be due to a reduced capability to withstand th e mechanical load, rather than to an increased mechanical load.