BRC-BIO: Trade-offs in locomotor performance: comparing hoppers and jumpers in variable environments

生物在环境或栖息地中生存的方式会受到个体生理和环境物理特性的影响。更具体地说，生物与之相互作用的基质会在运动过程中产生各种挑战，从而影响其表现。运动的适应需要生物体的神经系统、解剖学和肌肉生理学之间的动态相互作用，它们共同驱动全身运动。然而，一种动物使用的生理策略可能并不理想地适合不同的栖息地或基质类型。这项研究旨在了解特定的运动方式，更具体地说，跳跃和跳跃如何限制生物体对环境瞬时变化的反应。青蛙和蟾蜍提供了一个独特的模型来理解运动策略的变化。该项目将研究肌肉募集的全身运动和神经系统控制，以响应基底刚度的变化。此外，该项目将研究肌腱组织的力学和组织，以更好地了解肌腱刚度在特殊运动形式中的作用。肌肉和肌腱生理上的这种独特适应可以告知栖息地环境变化对运动的影响，以及处理环境干扰的工程系统的设计参数。这项研究的广泛影响将增加研究机会和对在STEM领域历史上代表性不足的本科生的指导，并使基于教育研讨会的培训和资源的发展能够增加整个家庭机构获得STEM研究机会的机会。纵观历史，新运动模式的出现对动物适应新栖息地的能力起着至关重要的作用。例如，微栖息地之间的行为转变可能会导致动物运动策略的更微妙的变化。在某些情况下，运动系统可能足够灵活，以适应环境物理特性的变化。提出的工作旨在了解运动的特殊方式如何具有独特的约束运动控制策略和肌肉肌腱特性。为了解决这个问题，第一个目标将量化和比较甘蔗蟾蜍长距离、耐力跳跃和古巴树蛙快速、有力跳跃之间的种间运动学变化，以响应环境扰动对基质刚度的影响。第二个目的是测量体内后肢肌肉长度和运动模式对基底刚度的响应，以表征长距离耐力跳虫使用的运动控制机制。第三个目标是通过使用透射电子显微镜和连续块面扫描电子显微镜技术量化胶原纤维组织来表征肌腱的超微结构。最后，将使用体外肌腱组织应力和应变测试来量化肌腱材料特性，以确定不同物种的组织刚度在不同运动和功率输出模式下的作用。拟议的研究将促进对不同运动模式的专业化如何在不同水平的生理组织中提供强大的益处或局限性的理解。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。

The way an organism navigates an environment or habitat can be influenced by an individual’s physiology and the physical properties of its environment. More specifically, the substrate an organism interacts with can pose various challenges during locomotor movements that can impact performance. Adaptations in movement require a dynamic interplay between an organisms’ nervous system, anatomy, and muscle physiology, which together drive whole-body movements. However, the physiological strategies that one animal uses may not be ideally suited for a different habitat or substrate type. This research aims to understand how specialized ways of movement, more specifically, how hopping and jumping may constrain how an organism responds to instantaneous changes in the environment. Frogs and toads provide a unique model to understand variation in movement strategies. This project will investigate whole-body movement and nervous system control of muscle recruitment in response to changes in substrate stiffness. In addition, the project will investigate the mechanics and organization of tendon tissue to better understand the role of tendon stiffness in specialized forms of movement. Such unique adaptations in muscle and tendon physiology can inform the impacts of changing environments across habitats on locomotion, as well as design parameters in engineered systems dealing with environmental disturbance. The broader impacts of this research will increase research opportunities and mentorship of undergraduate students historically underrepresented in STEM, as well as enable the development of educational workshop-based trainings and resources to increase access to STEM research opportunities across the home institution. Throughout history the emergence of new modes of locomotion has played a crucial role in an animal’s ability to navigate new habitats. For example, behavioral transitions between microhabitats may result in more subtle shifts in an animal’s locomotor strategy. In some cases, the locomotor system may be flexible enough to accommodate changes in the physical properties of the environment. The proposed work aims to understand how specialized ways of movement have uniquely constrained motor control strategies and muscle-tendon properties. To address this, the first aim will quantify and compare interspecific kinematic variation between the long distance, endurance hopping of Cane toads, and the fast, powerful jumps of Cuban tree frogs, in response to environmental perturbations in substrate stiffness. The second aim measures in vivo hindlimb muscle length and motor patterns in response to substrate stiffness to characterize the motor control mechanisms used by long distance endurance hoppers. The third aim seeks to characterize tendon ultrastructure by quantifying collagen fibril organization using techniques in transmission electron microscopy and serial block-face scanning electron microscopy. Lastly, tendon material properties will be quantified using in vitro tendon tissue stress and strain tests to determine the role of tissue stiffness across species specialized for differing modes of locomotion and power output. The proposed research will advance understanding of how specialization in different locomotor modes can provide robust benefits or limitations at various levels of physiological organization.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.