Analysis of lumbar spine injury with different back inclinations under whole-body vibration: A finite element study based on whole human body models

Whole-body vibration was found to be a cause of low back pain. Different back inclinations might change the forces on the lumbar spine, resulting in different responses to the vibration. The aim of this study was to investigate the effects of back inclinations on the lumbar spine from the perspective of analysing the internal loads and deformations on the intervertebral discs. Whole human body finite element models at 90°, 95°, 100°, 105°, 110° and 115° inclinations were used to provide a whole-body condition when predicting the behaviour of the lumbar spine. Von Mises stress on the annulus fibrosus, intradiscal pressure, and intervertebral disc height were extracted. The Risk Factors were calculated to evaluate the spinal injury risk under long-term vibration conditions. The results showed that the internal loads and deformations on the intervertebral disc decreased and then increased with the increase of the inclination, and the responses were lower at the 95° and 100° inclinations. The Risk Factors at different inclinations at the 3 Hz load were 0.61, 0.49, 0.53, 0.58, 0.58, and 0.69, respectively, at the 7 Hz load were 0.97, 0.66, 0.71, 0.86, 0.87, and 0.97, respectively, which also showed that injury risk was at a lower level at 95° and 100° inclinations. This study found a relationship between injury risk and back inclination. Occupational drivers are advised to choose a back inclination between 95° and 100° to reduce the possible adverse effects of whole-body vibration during the working condition.