Abstract: A “helmet-head-neck” musculoskeletal model is established to investigate the effect of helmet on soldier’head and neck muscular activities. The muscle activation is used as a comfort evaluation criterion and the muscle redundancy problem is solved by the “minimum-fatigue” criterion.The influences of the helmet weight, center of mass and tightening force of the lower jaw belt on the activities of muscle groups of head and neck are studied based on inverse dynamics. The results show that the weight andcentroid position of helmet have the effects on muscle activation in the sagittal plane. The neck muscle activation has little change when additional lateral bending moment is less than the corresponding threshold in the coronal plane. Enhancing the tightening force is advantageous to enhance the stability of helmet,which increases the activation of jaw muscles.The proposed musculoskeletal model can be used to calculate the change of muscle activation under different situations and conduct a quantitative analysis for helmet design.

Key words: ordnance science and technology, military helmet, musculoskeletal model, level of muscle activation, muscle activation, inverse dynamics