Preparation of dynamic posture and occurrence of low back pain.

Improper posture is considered as one of the causes for low back pain. This study focused attention on low back pain that occurs when people adopt a dynamic posture. Low back pain in attendants was investigated as a typical example of low back pain in a dynamic posture. When multi-dimensional quantification III was applied to the results of the investigation, low back pain was found to occur in six postural patterns: bending knee posture, the posture of lifting and holding a light object, the posture of tilting the trunk, working posture to push a cart, the posture of turning or lifting a cart, and the posture of stretching. This survey found that low back pain frequently occurred when an unexpected load was imposed on the lumbar region and experiments were conducted to simulate the unexpected loading of this region. The experimental results showed that lumbar muscular activity was not fast enough to cope with the load and resulted in an increased swaying of the trunk. This swaying was considered to induce a load on the lumbar region. It is concluded that low back pain can be prevented if an appropriate preparatory set is taken.