Mechanics of In Vivo Muscle Function During Locomotion

运动过程中体内肌肉功能的力学

• 批准号: 9306793
• 负责人: Andrew Biewener
• 金额: $ 21.5万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-10-01 至 1997-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9306793&HistoricalAwards=false
• 关键词: Mechanics; Vivo; Muscle; Function; During

9306793 Biewener The main objective of this research is to record directly how limb muscles function during the locomotion of animals. Despite the considerable interest and extensive research that has been carried out on the physiology, biochemistry and mechanical properties of vertebrate skeletal muscles, little direct data exist concerning the in vivo mechanics of muscle of function during normal locomotor activity. In particular, studies of human limb muscles necessarily rely on the indirect assessments of muscle force and lengthening . By making direct in vivo measurements of the forces exerted by select muscles and length changes that they undergone different animal species, we can better understand how muscles function dynamically to support and power the movement of an animal. Measurements of muscle force will be made by using either implanted tendon force tranducers or by making force-calibrated in vivo skeletal strain recordings at the muscle's attachment site on the bone. In vivo measurements of muscle fiber length change will be made using ultrasound emitting sonomicrometry electrodes implanted within the muscle. In this proposal, we will examine the in vivo performance of muscles in two terrestrial and two flying species. In studies of ankle extensor muscles of wallabies, these measurements will enable us to explore how requirements for elastic energy storage in muscle-tendon 'springs' to conserve energy expenditure affect how the nervous system activates these muscles to power hopping versus the animal's need to accelerate and change direction. In studies of the medial(MG) and lateral(LG) gastrocnemius muscles in white leghorn chickens, we will study the recruitment of muscle force generation in relation to shortening during walking and running. The differing fiber characteristics of these two muscles (LG: mainly fast and MG: mainly slow), combined with independent recordings of force output, provides a unique opportunity to study recr uitment within a single muscle. I a third set of experiments we will obtain direct measurements of force generation and fiber shortening in the pectoralis muscle of pigeons and crows during flight. These measurements will provide the first direct measurement of muscle mechanical power, as well as whole animal power, during locomotion in a vertebrate species. These studies will extend our previous work, which developed the skeletal strain approach to measure in vivo force generation directly by the pectoralis during flight i starlings and pigeons. In summary, most studies of skeletal muscle mechanics have relied either on experimentally controlled simulations of shortening and force development isolated whole muscles or muscle fiber bundles under quasi-static conditions that are unlikely to apply to muscles performing normal movements. The results obtained from the proposed studies, therefore, will provide valuable information concerning the dynamic force-velocity properties of muscles under normal functional conditions. The results obtained from these studies will help to better establish general principles underlying muscle function in animal locomotion, as well as have relevance for motor control and robotics research. ***

9306793比温纳这项研究的主要目的是直接记录动物在运动过程中四肢肌肉的功能。尽管人们对脊椎动物骨骼肌的生理、生化和力学特性进行了广泛的研究，但关于正常运动活动中肌肉功能的活体力学方面的直接数据很少。特别是，对人类四肢肌肉的研究必然依赖于对肌肉力量和伸长的间接评估。通过在体内直接测量选定肌肉施加的力量和它们经历不同动物物种的长度变化，我们可以更好地了解肌肉如何动态地支持和推动动物的运动。肌力的测量将通过使用植入的肌腱力传感器或通过在骨骼上的肌肉附着位置进行力校准的活体骨骼应变记录来进行。肌纤维长度变化的活体测量将使用植入肌肉内的超声波发射声学测量电极进行。在这项提案中，我们将检查两个陆生物种和两个飞行物种的肌肉在体内的表现。在对沙袋鼠脚踝伸展肌肉的研究中，这些测量将使我们能够探索肌肉-肌腱‘弹簧’中弹性能量存储的要求如何影响神经系统如何激活这些肌肉来为跳跃提供动力，而不是动物加速和改变方向的需要。在对白色来航鸡的内侧(MG)和外侧(LG)腓肠肌的研究中，我们将研究步行和跑步时肌肉力量生成与缩短的关系。这两块肌肉不同的纤维特征(LG：主要是快的，MG：主要是慢的)，结合独立的力量输出记录，为研究单一肌肉内的调节提供了一个独特的机会。在第三组实验中，我们将直接测量鸽子和乌鸦在飞行过程中胸肌的力量产生和纤维缩短。这些测量将首次直接测量脊椎动物在运动过程中的肌肉机械动力以及整个动物的动力。这些研究将扩展我们之前的工作，该工作开发了骨骼应变方法来测量在I号飞行中直接由胸肌产生的力量。总而言之，骨骼肌力学的大多数研究要么依赖于对孤立的整个肌肉的缩短和力量发展的实验控制模拟，要么依赖于准静态条件下的肌肉纤维束，这不太可能适用于执行正常运动的肌肉。因此，所提出的研究结果将提供关于正常功能条件下肌肉的动态力-速度特性的有价值的信息。这些研究的结果将有助于更好地建立动物运动中肌肉功能的一般原理，并对运动控制和机器人学研究具有重要意义。***