CAREER: Understanding the Stabilizing Role of Muscle-Tendon Units in vivo

这个CAREER项目结合了研究、培训和教育活动，重点是提高对站立和行走时肌肉和肌腱功能的了解。众所周知，下半身的肌肉产生力量，而附着在肌肉上的肌腱将这些力量传递给骨骼，使动物能够站立和行走。然而，目前大多数关于肌肉和肌腱的知识来自于研究这些组织在体外功能时的实验。肌肉和肌腱是如何在体内作为一个综合系统发挥作用的，特别是它们如何在运动时满足保持平衡的需求，这一点还没有得到很好的理解。这个项目将测量肌肉和肌腱的机械行为，当身体对一个旨在挑战保持平衡能力的推动作出反应时。整合在研究部分的是培训两名来自代表性不足群体的学生攻读STEM博士学位。这些学生将获得该领域的知识，获得进行科学实验的第一手经验，并发展成为下一代跨学科科学家的领导者。这个CAREER项目将通过翻译关于肌肉和肌腱在运动过程中如何功能的新知识来影响社会，(1)为生物启发的假肢提供设计原则，(2)通过艺术（MECA）非营利组织为多元文化教育和咨询的学生提供教学单元和研讨会，该组织为休斯敦历史悠久的第六区K-12年级的学生（约4,000名服务不足的青少年）提供服务。这个CAREER项目的重点是了解肌肉肌腱单元在控制运动和稳定性方面的作用，使用活的、自由运动的动物，并将研究、教育、培训和推广相结合。运动稳定可以通过几个相互作用的机制来实现：肌肉的力调节特性，变刚度肌腱弹簧的能量调节能力，以及激动剂-拮抗剂肌肉-肌腱单元的共同行为。该项目的主要研究目标和成果是使用基于工作-能量的框架：(1)确定在原位主动延长期间调节能量吸收快速流动的肌肉-肌腱单元特性。(2)确定允许踝关节激动剂-拮抗剂肌肉-肌腱单元控制体内站立时引起的不稳定扰动的反应的特性。(3)确定允许踝关节激动剂-拮抗剂肌肉-肌腱单元控制体内行走时引起的不稳定扰动的反应的特性。实验方法包括使用定制的高性能线性致动器，以在站立和行走期间对身体产生意想不到的扰动。植入肌肉肌腱组织的定制传感器和力平台测量用于了解从控制踝关节功能的肌肉肌腱单元到全身力学等多个尺度上对扰动的响应。此外，该项目还将实施一项教育推广计划，推进STEM夏令营课程，为来自弱势群体的k -12年级学生提供服务。要开发的动手活动将集中在关键的生物力学概念，整合数学，物理和物理模型。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This CAREER project combines research, training, and educational activities that focus on advancing knowledge of how muscles and tendons function during standing and walking. It is well understood that muscles in the lower body produce forces and that tendons, which attach to muscles, transmit those forces to the skeleton, allowing animals to stand and walk. However, most current knowledge about muscle and tendon comes from experiments that study these tissues when functioning outside of the body. What is not well understood is how muscle and tendon function as an integrated system within the body and, in particular, how they function to meet the demands of maintaining balance while moving. This project will measure the mechanical behavior of muscle and tendon when the body responds to a push intended to challenge the ability to maintain balance. Integrated within the research component is training for two students from underrepresented groups pursuing a PhD in STEM. These students will gain knowledge in the field, develop first-hand experience in carrying out scientific experiments, and develop as leaders in the next generation of interdisciplinary scientists. This CAREER project will impact society by translating new knowledge about how muscle and tendon function during movement by (1) contributing design principles for biologically inspired prosthetics and (2) developing teaching units and workshops offered to students at the Multicultural Education and Counseling through the Arts (MECA) non-profit organization, which serves K-12 grade students (~4,000 underserved youth) in Houston’s historic 6th Ward.This CAREER project focuses on understanding the role of muscle-tendon units to control movement and stability using a live, freely moving animal, and integrates research, education, training, and outreach. Movement stabilization can be accomplished by several interacting mechanisms: a muscle’s force-modulating properties, the energy-modulating capacity of variable-stiffness tendon springs, and the co-behavior of agonist-antagonist muscle-tendon units. The project’s primary research objectives and outcomes are to use a work-energy based framework to: (1) Determine the muscle-tendon unit properties that modulate the rapid flow of energy absorption during active lengthening in situ. (2) Determine the properties that allow ankle joint agonist-antagonist muscle-tendon units to govern the response of destabilizing perturbations elicited during standing in vivo. (3) Determine the properties that allow ankle joint agonist-antagonist muscle-tendon units to govern the response of destabilizing perturbations elicited during walking in vivo. The experimental approach involves the use of a custom-built, high performance linear actuator to elicit unexpected perturbations to the body during standing and walking. Custom sensors implanted into muscle-tendon tissue and force platform measurements are used to understand the response to perturbations at multiple scales, from muscle-tendon units that control ankle joint function to whole body mechanics. In addition, the project will implement an educational outreach plan that will advance a summer STEM camp curriculum that serves K-12th graders from underrepresented groups. The hands-on activities to be developed will focus on key biomechanical concepts that integrate math, physics, and physical models.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.