MUSCULOSKELETAL STIFFNESS AND LOCOMOTION

肌肉、肌腱和韧带具有类似弹簧的特性。 因为 当关节弯曲或伸展时，这些肌肉骨骼元件会改变长度， 接头表现出类似弹簧的特性并不奇怪。的 肌肉骨骼僵硬度的控制是复杂的，有许多因素 从而影响每个关节的刚度。然而，在一些多关节 运动，包括哺乳动物运行，元素的 肌肉骨骼系统整合在一起， 肌肉骨骼系统表现出类似弹簧的行为。实验 关于跑步步态的研究结果表明， 肌肉骨骼系统的行为就像一个单一的线性弹簧在所有的 迄今为止研究的哺乳动物，包括奔跑的人类，小跑的狗和 马和跳跃的袋鼠。这一观察导致了 一个弹簧质量模型的运行，由一个单一的线性无质量 “腿弹簧”和质量。“腿弹簧”代表弹簧般的 整体综合肌肉骨骼系统的特点， 运动，质量等于动物的质量。的 拟议研究的总体目标是了解 肌肉骨骼僵硬和运动生物力学之间的联系。 考虑到控制单个肌肉的刚度的复杂性， 联合，这是不现实的，使用前向动力学的方法，开始 单块肌肉的僵硬程度，并试图解释 跑步的技巧我们建议使用逆动力学方法 它首先关注运动力学和 整体肌肉骨骼僵硬。在具体目标1的保护伞下， 调整整体刚度的重要性 肌肉骨骼系统，以适应不同的地形运行， 考察这项研究将涉及审查调整， 在不同硬度的表面上跑步时的肌肉骨骼硬度 和不同可预测性的表面。在具体目标的保护伞下 2.我们将进行一系列相互关联的研究， 用于调节整个肌肉骨骼系统的刚度， 运行.这些研究将包括检查 腿的单个关节的刚度可以在运动期间调节。 此外，还将涉及审查变革的相对重要性 以关节的刚度和姿势来调整整体的刚度 跑步时的肌肉骨骼系统。两个具体实验 目标1和2将涉及组合动力学和运动学分析， 跑步以确定整体肌肉骨骼刚度和关节 刚度研究结果将为优化设计提供新的信息 地板和轨道，以尽量减少过度使用的伤害， 负重有氧活动，并优化设计了弹簧式 假肢和机器人腿。最后，我们的研究将开始 将关节刚度的神经控制知识应用于 理解自然活动的机制， 有腿的动物，运动

Muscles, tendons, and ligaments have spring-like characteristics. Because these musculoskeletal elements change length when joints flex or extend, it is not surprising that joints exhibit spring-like characteristics. The control of musculoskeletal stiffness is complex with many factors affecting the stiffness of each joint. However, in some multi-jointed movements, including mammalian running, the elements of the musculoskeletal system are integrated together so that the overall musculoskeletal system exhibits spring-like behavior. Experimental findings on the mechanics of running gaits have revealed that the overall musculoskeletal system behaves like a single linear spring in all of the mammals studied to date, including running humans, trotting dogs and horses, and hopping kangaroos. This observation has led to the development of a spring-mass model for running, consisting of a single linear massless "leg spring" and a mass. The "leg spring" represents the spring-like characteristics of the overall integrated musculoskeletal system during locomotion, and the mass is equivalent to the mass of the animal. The general objective of the proposed research is to gain an understanding of the link between musculoskeletal stiffness and locomotion biomechanics. Given the complexity of the control of the stiffness of a single muscle or joint, it is not realistic to use a forward dynamics approach that begins at the level of the stiffness-of a single muscle and attempts to explain the mechanics of running. We propose to use an inverse dynamics approach that begins by focusing on the link between locomotion mechanics and overall musculoskeletal stiffness. Under the umbrella of Specific Aim 1, the importance of adjustments to the stiffness of the overall musculoskeletal system to accommodate running on varied terrain is examined. This research will involve examining the adjustments to musculoskeletal stiffness for running on surfaces of different stiffnesses and surfaces of varying predictability. Under the umbrella of Specific Aim 2, we will do a series of interrelated studies examining the mechanisms for adjusting the stiffness of the overall musculoskeletal system during running. These studies will include examining the range over which the stiffness of a single joint of the leg can be adjusted during locomotion. In addition, it will involve examining the relative importance of changes to joint stiffness and posture in adjusting the stiffness of the overall musculoskeletal system during running. The experiments under both Specific Aims l and 2 will involve a combined kinetic and kinematic analysis of running to determine overall musculoskeletal stiffness and joint stiffness. The findings will give new information about the optimal design of floors and tracks for minimizing overuse injuries during sustained weight-bearing aerobic activities, and the optimal design of spring-based prosthetic legs and robotic legs. Finally, our research will begin applying knowledge of the neural control of joint stiffness to understanding the mechanics of a natural activity that is performed by all legged animals, locomotion.