Doctoral Dissertation Improvement Grant: Energetics and mechanics of quadrupedal walking and running in prosimians

长期以来，能量学一直是灵长类学家和古人类学家关注的一个重要问题，他们对现存和灭绝物种的运动性能感兴趣。例如，以单位距离或单位时间衡量的移动成本已被纳入各种资源获取、领土防御和迁移行为的模型中。对几种四足灵长类动物耗氧率的测量表明，与大多数动物一样，它们表现出一种模式，即速度越快，代谢成本越高，体重越重，代谢成本越低。这项研究旨在了解四足灵长类动物陆地运动的力学和代谢成本之间的联系，重点是他们的肢体肌肉如何产生力量和调节运动过程中的能量使用。四足灵长类动物在步态特征（肢体偏移角度）和肢体设计（肌肉质量分布和肌肉肌腱结构）方面与大多数其他四足哺乳动物不同。最近的研究表明，这两个变量将影响运动过程中招募的活动肌肉的体积，并且由于能量使用必须由骨骼肌活动设定，因此将影响运动的成本。这项研究将评估灵长类动物的肌肉-肌腱系统如何产生力，以及为了产生单位力消耗了多少代谢能量。为此，将进行两个单独的实验。代谢率在运动的水平上将测量两种原猴亚目动物，并与以前公布的数据比较，更cursorial陆地哺乳动物。然后，将从一种灵长类动物物种和一种类似大小的非灵长类四足哺乳动物物种中收集解剖学，视频和力板数据，以确定它们各自的活动肌肉体积，关节工作和功率生产在运动过程中的水平在一系列的速度。这项研究将是第一次尝试将灵长类动物运动和肢体形态的独特方面与它们的代谢成本联系起来。总之，这些实验将产生经验数据，测试代谢和力学之间的基本关系，这对于理解灵长类动物的能量使用和肌肉功能之间的关系具有重要意义。这项研究的结果将提供关键的洞察灵长类动物生物学，并提供生理基础，了解形态进化的运动能量成本的影响。这项研究的更广泛影响包括开发了一系列计算工具，用于整合生物力学研究的视频和测力板数据，这些数据将在网上提供给国际社会。这项工作也将为约翰霍普金斯大学的本科生创造研究机会。这些学生将被纳入代谢，运动学和力板数据收集和分析以及计算机编程方面，提供跨越生物和物理科学的跨学科经验。

Energetics has long been an important issue to primatologists and paleoanthropologists interested in the locomotor performance of extant and extinct species. The cost of locomotion, measured per unit distance or per unit time, for example, has been incorporated into various models of resource acquisition, territory defense and migratory behavior. Measurements of the rate of oxygen consumption in several quadrupedal primate species have shown that, like most animals, they exhibit a pattern of increasing metabolic costs with faster speeds and decreasing costs with larger body weight. This study seeks to understand the link between the mechanics and metabolic cost of terrestrial locomotion in quadrupedal primates by focusing on how their limb muscles generate force and modulate energy use during exercise. Quadrupedal primates differ from most other quadrupedal mammals in both their gait characteristics (limb excursion angles) and limb design (muscle mass distribution and muscle-tendon architecture). Recent studies indicate that both of these variables will impact the volume of active muscle that is recruited during locomotion and, because energy use must be set by skeletal muscle activity, will impact the cost of movement. This study will evaluate how the primate muscle-tendon system produces force and how much metabolic energy is consumed in order to generate a unit force. To do this, two separate experiments will be carried out. Metabolic rate during locomotion on the level will be measured for two species of prosimians and compared with previously published data for more cursorial terrestrial mammals. Then, anatomical, video and force-plate data will be collected from one primate species and one similarly sized nonprimate quadrupedal mammal species in order to determine their respective active muscle volumes, joint work and power production during exercise on the level across a range of speeds. This study will be the first to attempt to link the unique aspects of primate locomotion and limb morphology to their metabolic costs. Together, these experiments will generate empirical data testing a fundamental relationship between metabolics and mechanics that is significant for understanding the relationship between energy use and muscle function in primates. The results of this study will provide critical insight into primate biology and provide a physiological basis for understanding the effects of morphological evolution on the energetic cost of locomotion. The broader impacts of this study include the development of a series of computational tools for integrating video and force-plate data from biomechanical studies, which will be made available online to the international community. This work will also create research opportunities for undergraduates at Johns Hopkins University. These students will be included in aspects of metabolic, kinematic and force-plate data collection and analysis as well as computer programming, providing an interdisciplinary experience that spans the biological and physical sciences.