RUI: Body Size, Limb Posture and Muscle Strain During Terrestrial Locomotion

在陆地运动中的身体大小、肢体活动和肌肉紧张。霍利奥克学院的GillisMount四足哺乳动物在大小上有很大的差异，通常在运动时采用不同的肢体姿势。小动物使用蜷缩的姿势，它们的四肢保持更弯曲，而大动物使用更直立的姿势，它们的四肢保持相对直。尽管我们了解这种肢体结构的缩放，但我们对这种姿势差异如何影响不同大小动物的同源肢体肌肉的动作知之甚少。 事实上，我们对四足哺乳动物肢体肌肉的体内行为几乎没有认识，因为没有一种动物的髋、膝和踝伸肌的动作能被很好地理解为任何步态。拟议的工作涉及研究模式的长度变化和激活的主要后肢肌肉的选定哺乳动物物种，在大小上有很大的差异。两个实验方法将被用来探讨如何身体大小和肢体姿势影响肢体肌肉功能在运动。首先，使用sonomicrometry和肌电图，应变和激活模式将被测量和比较四肢肌肉的大小范围超过三个数量级（小鼠水豚）的多个啮齿动物物种。数据将被用来测试的一般假设，同源肌肉功能不同的密切相关的动物，不同的大小和肢体姿势。在第二种方法中，肢体姿势，肌肉结构和肌肉应变和激活模式的特点将在几个哺乳动物物种的个体发育。 这种方法将解决在生长过程中发生的大小变化是否以类似于在各种哺乳动物物种中进化的大小差异的方式影响肢体肌肉。 总之，这些不同的方法将（1）提供关键的洞察整个哺乳动物后肢的肌肉如何在体内运动过程中运作，（2）将有助于澄清动物的大小在塑造个体发育和跨发育的肢体肌肉的行动的重要性。 拟议的工作还将产生更广泛的影响，为对生物科学感兴趣的有才华的年轻妇女提供研究机会。PI在一个单一性别的机构工作，每年有两名学生将在项目上合作，学习宝贵的研究技能，在国家会议上展示他们的工作成果，并共同撰写论文。

RUI: Body Size, Limb Posture and Muscle Strain During Terrestrial LocomotionGary B. GillisMount Holyoke CollegeQuadrupedal mammals that differ greatly in size generally adopt distinct limb postures during locomotion. Small animals use a crouched posture with their limbs held more flexed while large animals use a more upright posture with their limbs held relatively straight. Despite our understanding of this scaling of limb configuration, we know little about how such postural differences influence the actions of homologous limb muscles in animals of varying size. Indeed, we have little appreciation for the in vivo behavior of quadrupedal mammalian limb muscles more generally; for no animal are actions of a hip, knee and ankle extensor well understood for any gait. The proposed work involves studying patterns of length change and activation in major hindlimb muscles of select mammalian species that differ widely in size. Two experimental approaches will be used to explore how body size and limb posture affect limb muscle function during locomotion. First, using sonomicrometry and electromyography, strain and activation patterns will be measured and compared among limb muscles of multiple rodent species ranging in size over three orders of magnitude (mice to capybara). Data will be used to test the general hypothesis that homologous muscles function differently in closely related animals that differ in size and limb posture. In the second approach, limb posture, muscle architecture and patterns of muscle strain and activation will be characterized in several mammal species over ontogeny. This approach will address whether changes in size that occur during growth influence limb muscles in a manner similar to size differences that have evolved among various mammalian species. Together, these distinct approaches will (1) provide critical insight into how muscles throughout the mammalian hindlimb operate in vivo during locomotion and (2) will help clarify the importance of animal size in shaping the actions of individual limb muscles both through ontogeny and across phylogeny. The proposed work will also have the broader impact of fostering research opportunities for talented young women interested in the biological sciences. The PI works at a single-gender institution and two students each year will collaborate on the projects, learning valuable research skills, presenting results from their work at national meetings, and co-authoring papers.