RUI Collaborative: Biomechanics and Control of Landing in Toads

青蛙和蟾蜍的后肢肌肉已经成为理解肌肉的典型模型。在为跳跃等推进运动提供动力方面的作用。任何跳跃的东西最终都必须着陆，但与跳跃时肌肉产生能量来加速身体不同，控制着陆需要肌肉消耗能量来减速身体。肌肉在能量耗散中的作用仍然知之甚少。这项研究将揭示与这种运动活动相关的重要原理。陆生蟾蜍在着陆方面非常出色，它们只用前肢给身体减速。拟议的工作将使用蟾蜍着地作为模型系统，以了解肌肉在撞击期间和之后如何控制前肢关节运动（肩部，肘部和腕部）。在人类跳跃过程中，腿部肌肉的落地前活动用于使关节僵硬，为落地做准备，并根据预期的时间和冲击力进行调整。最近的研究表明，在半空中跳跃的蟾蜍肘关节处的肌肉也有类似的先见之明活动。拟议的工作将解决在其他前肢关节的这种调整的，着陆前的活动的普遍性，并将特别验证其效用在于防止参与能量消耗的肌肉在着陆时拉伸到太长，这是最可能发生伤害的地方。我们还将研究视觉和本体感觉反馈在帮助动物调整肌肉活动以协调不同高度和距离跳跃后着陆的重要性。通过整合生物力学、肌肉生理学和感觉生物学，这项工作将强调控制减速的基本原理，这是大多数运动系统共同的动作。本科生对这项工作的执行和展示至关重要，通过让当地社区学院的学生和教师参与进来，我们将扩大对前沿研究的直接参与。

The hindlimb muscles of frogs and toads have served as an exemplary model for understanding muscle?s role in powering propulsive movements like jumping. Anything that jumps must ultimately land, but unlike during jumping, where muscles produce the energy to accelerate the body, controlled landing requires muscles to dissipate energy to decelerate the body. The role of muscles during energy dissipation remains poorly understood. This research will reveal important principles associated with this locomotor activity. Terrestrial toads are outstanding at landing, using their forelimbs exclusively to decelerate their bodies. The proposed work will use toad landing as a model system for understanding how muscles control forelimb joint movements (shoulder, elbow and wrist) during and after impact. During human jumps, pre-landing activity in leg muscles is used to stiffen joints in preparation for landing, and is tuned to the expected time and magnitude of impact. Recent work demonstrates similarly prescient activity in muscles acting at the elbow joints of hopping toads in mid-air. The proposed work will address the generality of such tuned, pre-landing activity at other forelimb joints, and will specifically test the hypothesis that its utility lies in preventing muscles involved in energy dissipation from stretching to overly long lengths during landing, where injuries are most likely to occur. We will also examine the importance of visual and proprioceptive feedback in helping animals tune muscle activity to coordinate landing after hops of variable height and distance. By integrating biomechanics, muscle physiology and sensory biology this work will highlight fundamental principles governing controlled deceleration, an action common to most locomotor systems. Undergraduate students will be essential to the execution and presentation of this work, and by involving students and faculty from local community colleges, we will broaden direct participation in cutting-edge research.