Sternocleidomastoid muscle activity in keeping the head stable while slalom driving

Sternocleidomastoid (SCM) muscle activity to keep the head stable in slalom driving is analyzed by surface electromyography (sEMG). Using sEMG signals of SCM muscles, this study evaluates a passenger´s sensitivity to different vehicle dynamic characteristics, especially in terms of lateral and roll vabrations. In actual slalom driving, it is found that the sEMG signal is more active when the amplitude of the relative acceleration of the car body is higher. In a further experiment, a universal driving simulator is used to simulate the actual slalom driving for two kinds of slalom driving. Meanwhicle, 1-10 Hz white noise is input into the lateral and roll directions of the vehicle motion for the two types of slalom driving. The result shows that root-mean-square values of the sEMG signal of the SCM muscle in slalom driving with added lateral and roll vibrations are significantly higher than those in the normal slalom driving. Importantly, the study indicates that the amplitude of the sEMG is sensitive to lateral and roall vibrations of the vehicle, which may result in passenger discomfort.