头盔质量和质心对军机飞行员颈部肌力的影响

目的研究头盔质量和质心偏移对军机飞行员颈部肌肉活动特性的影响。方法基于AnyBody软件平台建立头颈部肌骨模型,包含C0、C1-7、T1和136组头颈部肌肉。采用集中载荷模拟头盔作用,对不同头盔质量、质心位置和加速度载荷下的7个主要肌群的肌力进行了仿真计算。结果当头盔质心与头部质心重合时,支配后伸的头半棘肌、肩胛提肌、头夹肌和颈夹肌处于收缩发力状态。当头盔质量增大,这些肌群肌力也随之线性增加,并且加速度载荷对肌力增大程度起放大作用。头盔质心后移,会降低后伸肌群的肌力,增大前屈肌群受力。头盔质心左右偏移引起的附加侧弯力矩则会激活支配侧弯功能的肌群的活动。结论头盔质量和质心位置对颈部肌群活动特性有明显影响,本文建立的头颈部肌骨模型可以计算不同状态下肌力的变化,头盔设计和使用过程可采用该技术进行定量分析。

Effect of helmet mass and mass center on neck muscle strength in military pilots

Objective To investigate the effect from helmet mass and deviation of mass center on neck muscle activity in military pilots. Methods Based on AnyBody software platform, a musculoskeletal model of head neck complex was established including C0, C1-C7, T1 and 136 muscles. Concentrated loads were applied to simulate the role of helmet. Strength from seven main muscle groups under different helmet mass, mass center and +Gz acceleration loads were simulated and calculated.Results When mass center of the helmet and the head coincided with each other, the muscle groups (such as semispinalis, levator scapulae, splenius capitis and cervicis) which took charge of extension were activated. Muscle strength increased with helmet mass linearly and +Gz acceleration loads would make this increase multiplied. Flexion muscle began to work when mass center of the helmet moved backward, so did the lateral bending muscles when mass center of helmet moved in the right-and-left direction. Conclusions Helmet mass and its center have an obvious influence on neck muscle activity in military pilots. The musculoskeletal model established in this paper can be used to calculate the change in muscle strength under different situations and conduct a quantitative analysis for helmet design and validation.