Cervical spine injury under multi-axis vibration: effect of active muscles on vibration injury risk

Professional drivers are frequently exposed to multi-axis vibration environments. The effect of active control of neck muscles on injury risk of cervical spine in a sustained vibration environment remains unclear. This study aims to explore the effect of multi-axis vibration and muscles on driver's neck health. A head-neck finite element model with active muscles was developed. The injury of the cervical spine tissues was analyzed under different muscle activation levels and vibration conditions. The results showed that compared with the uniaxial vibration, the vibration amplitude of head increased by 70.65% (vertical) under the multi-axis vibration condition. This indicated that the vibration of the head-neck was more intense under the multi-axis vibration environment compared with the uniaxial vertical vibration. Compared with passive muscles, the active muscles (activation level was 0.05) could reduce the head vibration amplitude by 39.88% in the vertical direction, 12.59% in the fore-aft direction, respectively, and this vibration suppression was more pronounced in the fore-aft direction compared with the vertical direction. In the multi-axis vibration environment, neck muscles could suppress head movements induced by vibration, especially in the fore-aft direction, reducing the risk of disc injury. The level of muscle activation was positively correlated with the suppressive effect.