The increased incidence of injury demonstrated in epidemiological data for the elderly population, and females compared to males, has not been fully understood in the context of the biomechanical response to impact. A contributing factor to these differences in injury risk could be the variation in geometry between young and aged persons and between males and females. In this study, a new methodology, coupling a CAD and a repositioning software, was developed to reposture an existing Finite element neck while retaining a high level of mesh quality. A 5th percentile female aged neck model (F05_75YO) and a 50th percentile male aged neck model (M50_75YO) were developed from existing young (F05_26YO and M50_26YO) neck models (Global Human Body Models Consortium v5.1). The aged neck models included an increased cervical lordosis and an increase in the facet joint angles, as reported in the literature. The young and the aged models were simulated in frontal (2, 8, and 15 g) and rear (3, 7, and 10 g) impacts. The responses were compared using head and relative facet joint kinematics, and nominal intervertebral disc shear strain. In general, the aged models predicted higher tissue deformations, although the head kinematics were similar for all models. In the frontal impact, only the M50_75YO model predicted hard tissue failure, attributed to the combined effect of the more anteriorly located head with age, when compared to the M50_26YO, and greater neck length relative to the female models. In the rear impacts, the F05_75YO model predicted higher relative facet joint shear compared to the F05_26YO, and higher relative facet joint rotation and nominal intervertebral disc strain compared to the M50_75YO. When comparing the male models, the relative facet joint kinematics predicted by the M50_26YO and M50_75YO were similar. The contrast in response between the male and female models in the rear impacts was attributed to the higher lordosis and facet angle in females compared to males. Epidemiological data reported that females were more likely to sustain Whiplash Associated Disorders in rear impacts compared to males, and that injury risk increases with age, in agreement with the findings in the present study. This study demonstrated that, although the increased lordosis and facet angle did not affect the head kinematics, changes at the tissue level were considerable (e.g., 26% higher relative facet shear in the female neck compared to the male, for rear impact) and relatable to the epidemiology. Future work will investigate tissue damage and failure through the incorporation of aged material properties and muscle activation.

在对撞击的生物力学反应的背景下，老年人口的流行病学数据以及女性与男性相比，损伤发生率的增加尚未得到充分理解。造成这些伤害风险差异的一个因素可能是年轻人和老年人之间以及男性和女性之间几何形状的差异。在这项研究中，开发了一种结合 CAD 和重新定位软件的新方法来重新定位现有的有限元颈部，同时保持高水平的网格质量。从现有的年轻人（F05 _26YO和M50 _26YO）开发了一个5%的女性老年颈部模型（F05 _75YO）和一个50%的男性老年颈部模型（M50 _75YO）) 颈部模型（全球人体模型联盟 v5.1）。正如文献报道的那样，老年颈部模型包括颈椎前凸增加和小关节角度增加。在正面（2、8 和 15 克）和背面（3、7 和 10 克）冲击下模拟了年轻和老年模型。使用头部和相对小关节运动学以及标称椎间盘剪切应变来比较响应。一般来说，虽然所有模型的头部运动学相似，但老化模型预测的组织变形更高。在正面碰撞中，与 M50 _{26YO 相比}，只有 M50 _75YO模型预测了硬组织失效，这归因于更_靠前的头部随年龄增长的综合效应，以及相对于女性模特更大的颈部长度。在后部碰撞中，与 F05 _26YO相比，F05 _75YO模型预测了更高的相对小关节剪切_力，与 M50 _75YO相比，更高的相对小关节旋转和标称椎间盘应变。在比较男性模型时，M50 _26YO和 M50 _75YO预测的相对小面关节运动学相似。男性和女性模型在后部碰撞中的反应差异归因于女性与男性相比更高的前凸和小平面角度。流行病学数据报告说，与男性相比，女性在后部撞击中更有可能患上鞭打相关疾病，并且受伤风险随着年龄的增长而增加，这与本研究的结果一致。这项研究表明，虽然增加的前凸和小关节角度不会影响头部运动学，但组织水平的变化是相当大的（例如，女性颈部的相对小关节剪切力比男性高 26%，对于后方撞击）并且相关到流行病学。未来的工作将通过结合老化的材料特性和肌肉激活来研究组织损伤和衰竭。