Doctoral Dissertation Improvement: Hominid Forefoot Kinematics, Kinetics, and Bone Architecture

点击翻译按钮获取中文摘要

Habitual bipedalism - walking exclusively on two legs - is a form of gait practiced by humans to the exclusion of all other living primates, even their closest relatives, the African and Asian great apes. Traditionally, debates over the gait of the earliest human ancestors (hominins) have centered on the interpretation of lower limb structure. The methods used to date have proved to be inconclusive, especially regarding the functional implications of the structure of the forefoot. This problem is further compounded by a lack of data on how the forefoot function during gait in living humans and great apes (hominids), and how differences in function relate to foot structure.The proposed dissertation research will quantify the three-dimensional trabecular (spongy) bone structure at the 1st-3rd metatarsophalangeal joints (MTPJ) and measure MTPJ angles (kinematics) and respective plantar pressures (kinetics) in living hominids in order to test hypotheses about the locomotor regimes of fossil hominins. Trabecular bone is highly responsive to mechanical demand during life and therefore offers a new approach to test hypotheses that have long remained unresolved about joint function in fossils. Forefoot kinematics and kinetics will be documented for chimpanzees (Pan troglodytes), bonobos (Pan paniscus), and humans at key points during the gait cycle. This study will determine whether trabecular bone structure can differentiate species by joint postures and loading regimes. This approach will then be used to assess whether early hominins possessed a modern human-like toe-off mechanism. The overarching goals of this research are to help resolve current debates about early hominin locomotor regimes and provide a better understanding of the evolution of hominin and modern human bipedalism.The proposed research has several broad impacts. First, the results of this project will be relevant to all vertebrate morphologists studying form and function relationships. This project will also encourage interdisciplinary research by allowing a female doctoral student to be trained in techniques of physical anthropology and biomechanics under the guidance of both American and Belgian scientists.