Doctoral Dissertation Research: Form and function of the hip joint and pelvis in relationship to walking biomechanics and implications for the evolution of bipedalism

用两条腿走路--也被称为两足行走--是人类血统的一个标志。目前尚不清楚人类最早的祖先的两足行走类型是否以及如何与现代人的不同。这项博士论文研究使用3D运动分析来研究双腿行走时，腿部骨骼外观的变化与生物力学表现之间的关系。除了直接观察之外，这个项目还通过实验测试了人的骨骼解剖对两足动物性能的影响。这一变革性的方法旨在为未来研究人类运动行为的多样性提供一个经过验证的方法学框架。该项目的预期成果包括人类学家、临床和功能解剖学家、物理治疗师和其他临床医生感兴趣和使用的大型数据集，以及可供人类学家、形态学家和临床医生使用的用于测量骨骼特征的新的开源工具。该项目支持一位来自STEM代表性不足群体的早期职业科学家的工作，并为本科生提供生物人类学、解剖学、放射学、3D运动分析等方面的培训机会。虽然南方古猿和早期人被广泛认为是习惯性的两足动物，但不同原始人物种的两足动物形式以及类似人类的两足步态出现的时间仍然是争论的主题。骨盆形态和下肢骨骼的扭转在不同的原始人类分类群中存在差异，由于这种差异与现代人两足行走的生物力学差异有关，因此有一个独特的机会来测试南方古猿和早期人类与后来的原始人类之间假想的步态差异。这项博士论文研究结合了超低剂量立位双平面X线片和活体人体样本的3D运动分析，以量化骨盆和下肢骨骼扭转的变化，并确定骨骼扭转对活体运动能力的影响。这项研究将一种新的3D测量活体受试者骨骼形态的方法与既定的运动分析方法相结合，以探索功能形态和人类进化的基本问题。这些发现可以更好地表征骨骼变异的功能意义及其对理解人类运动行为多样性的影响，并提供一个镜头来解释运动在人类进化中的作用，这被认为是人属进化的关键。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Walking on two legs – also known as bipedalism – is a hallmark of the human lineage. It remains unclear whether and how the types of bipedalism in humans’ earliest ancestors differed from that in modern humans. This doctoral dissertation research uses 3D motion analysis to investigate how variation in the appearance of the lower limb skeleton is related to biomechanical performance while walking on two legs. In addition to direct observation, this project also experimentally tests the effects of hominin skeletal anatomy on bipedal performance. This transformational approach aims to produce a validated methodological framework for future research into the diversity of locomotor behavior in hominins. The project's anticipated outcomes include a large dataset of interest and use to anthropologists, clinical and functional anatomists, physical therapists, and other clinicians, and a new, open-source tool for measuring skeletal features that can be used by anthropologists, morphologists, and clinicians. This project supports the work of an early career scientist from a group underrepresented in STEM and provides training opportunities for undergraduates in biological anthropology, anatomy, radiology, 3D motion analysis, and more.While Australopithecus and early Homo are widely agreed to have been habitual bipeds, the form of bipedality in different hominin species and the timing of emergence of a human-like striding bipedal gait remain a subject of debate. Pelvic morphology and torsion in the lower limb bones vary among hominin taxa, and because this variation is associated with variation in the biomechanics of bipedalism in living humans, there is a unique opportunity to test hypothesized gait differences in Australopithecus and early Homo compared to later hominins. This doctoral dissertation research uses a combination of ultra-low dose standing biplanar radiographs and 3D motion analysis in a sample of living humans to quantify variation in pelvic and lower limb skeletal torsion and determine the effects of skeletal torsion across the lower limb on locomotor performance in vivo. This study integrates a novel method for measuring skeletal morphology of living subjects in 3D with established approaches to motion analysis to explore fundamental questions in functional morphology and human evolution. These findings can better characterize the functional significance of skeletal variation and its implications for understanding the diversity of locomotor behavior in hominins, as well as provide a lens through which to interpret the role of locomotion in hominin evolution, which are argued to be critical to the evolution of the genus Homo.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.