Ontogeny of Heel-Strike in Hominoids

类人猿脚跟着地的个体发育

• 批准号: 1517561
• 负责人: Angel Zeininger
• 金额: $ 8.43万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1517561&HistoricalAwards=false
• 关键词: Ontogeny; Heel; Strike; Hominoids

This project will study a particular feature of walking and foot anatomy that may provide new insight about the evolution of bipedalism (walking upright) in humans. Humans and our closest living relatives, the African great apes, use a unique foot strike pattern in which they strike the ground with the heel first, before the rest of the foot (heel strike) when walking. Yet the factors influencing the evolution of a specialized foot posture and the first appearance of our unique (human) footfall patterns are still poorly understood. It is unknown to what degree heel strike is similar across humans and African apes, how it develops throughout an individual's lifetime, and how different patterns of heel strike are reflected in the anatomy of foot bones. This study tracks the development of foot posture in African apes and provides a unique opportunity to understand why African apes and humans heel strike, and to explore how fossil hominin foot bones might tell us about walking patterns during hominin evolution. This project will support an early career female scientist and provide numerous research opportunities for graduate and undergraduate students, with a specific focus on female and minority students. At the end of the project, all video and image data will be made available to other scientists and educators, and used to promote the research and education goals of public zoological facilities and sanctuaries. Information on heel strike can be applied not only to the fossil record but also to studies of foot development and injuries in humans.The objective of this project is to quantify patterns of heel strike functional morphology throughout ontogeny in African hominoids. The study will quantify the range of variation in pedal mechanics and anatomy among living primates who use a heel strike through an experimental, comparative, ontogenetic approach, and ask: (1) are the mechanics of heel strike the same in all contexts in which it occurs?, (2) how do body size, behavior, age, and hind limb dynamics influence heel strike mechanics?, and (3) can heel strike be detected in external and internal calcaneal anatomy? To test hypotheses regarding the effect of hind limb mechanics on heel strike, kinematic data are analyzed from non-invasive video recordings of infant and adult chimpanzees and gorillas walking. To investigate how foot inversion and associated ground reaction forces that load the calcaneus change during locomotor development, the center of pressure and ground reaction forces incurred by the foot are recorded with a pressure mat mounted on top of a force platform. These data are compared with previously collected video data of wild chimpanzees. Magnetic resonance imaging (MRI) and medical computed tomography (CT) are used to model how the African ape heel pad attenuates impact forces in the absence of a calcaneal lateral plantar process. These data are compared with microCT data of calcaneal trabecular architecture in captive and wild extant apes and humans and then applied to early fossil hominin calcanei (A. afarensis, and A. sediba). This integrative project is transformative because it investigates an entire functional chain: locomotor behavior and gait mechanics (kinematics, kinetics, and plantar pressure) throughout ontogeny, internal and external calcaneal structure in extant apes, and interpretation of fossil foot bone functional morphology. A comprehensive understanding of heel strike variation in living apes and its evolution in fossil hominins is an essential first step toward a broader understanding of the evolution of heel strike in hominoids.

该项目将研究步行和足部解剖学的一个特殊特征，这可能为人类两足行走（直立行走）的进化提供新的见解。人类和我们现存的近亲非洲类人猿都使用一种独特的足部着地模式，即行走时先用脚跟先着地，然后再用脚的其余部分（后跟着地）。然而，影响特殊足部姿势进化和我们独特的（人类）足部模式首次出现的因素仍然知之甚少。目前尚不清楚人类和非洲猿的足跟着地的相似程度、人一生中足跟着地的相似程度、足跟的不同模式如何反映在足骨的解剖结构中。这项研究追踪了非洲猿足部姿势的发展，并提供了一个独特的机会来了解非洲猿和人类脚后跟撞击的原因，并探索古人类脚骨化石如何告诉我们古人类进化过程中的行走模式。该项目将为早期职业女性科学家提供支持，并为研究生和本科生提供大量研究机会，特别关注女性和少数民族学生。项目结束时，所有视频和图像数据将提供给其他科学家和教育工作者，并用于促进公共动物设施和保护区的研究和教育目标。有关脚跟着地的信息不仅可以应用于化石记录，还可以应用于人类足部发育和损伤的研究。该项目的目的是量化非洲人科动物在整个个体发育过程中脚跟着地功能形态的模式。该研究将通过实验、比较和个体发生的方法，量化使用脚跟着地的活体灵长类动物的踏板力学和解剖学的变化范围，并提出以下问题：（1）足跟着地的机制在发生足跟着地的所有环境中都是相同的吗？（2）身体尺寸、行为、年龄和后肢动力学如何影响足跟着地力学？（3）脚后跟能否在跟骨的外部和内部检测到？ 解剖学？为了检验有关后肢力学对脚跟着地的影响的假设，对婴儿和成年黑猩猩和大猩猩行走的非侵入性视频记录的运动学数据进行了分析。为了研究足部内翻和加载跟骨的相关地面反作用力在运动发展过程中如何变化，用安装在力平台顶部的压力垫记录足部产生的压力中心和地面反作用力。这些数据与之前收集的野生黑猩猩的视频数据进行了比较。磁共振成像 (MRI) 和医学计算机断层扫描 (CT) 用于模拟非洲猿足跟垫在没有跟骨外侧跖突的情况下如何减弱冲击力。将这些数据与圈养和野生现存猿类和人类的跟骨小梁结构的 microCT 数据进行比较，然后应用于早期古人类跟骨化石（阿法种和源泉种）。这个综合项目具有变革性，因为它研究了整个功能链：整个个体发育的运动行为和步态力学（运动学、动力学和足底压力）、现存猿类的内部和外部跟骨结构，以及化石足骨功能形态的解释。全面了解现存猿类的足跟着地变化及其在化石人科动物中的进化，是更广泛地了解古人类足跟着地进化的重要第一步。