Task Dependence of Muscle Fatigue in Older Adults

老年人肌肉疲劳的任务依赖性

• 批准号: 6828507
• 负责人: SANDRA K HUNTER
• 金额: $ 6.03万
• 依托单位: MARQUETTE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-15 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6828507
• 关键词: biomechanics; blood pressure; clinical research; computer program /software; elbow; electromyography; electronic recording system; environmental adaptation; fatigue; gender difference; heart rate; human old age (65+); human subject; muscle contraction; muscle strength; neuromuscular function; shear stress; statistics /biometry; young adult human (21-34)

DESCRIPTION (provided by applicant): NIA Pilot Research Program, Topic 14: Sensory and Motor Processing The endurance capacity of a muscle will vary with the task performed. However, the influence of age-related changes within the neuromuscular system on the task-dependent nature of muscle fatigue is unexplored in older adults. This raises the following question: Does age alter the ability of the neuromuscular system to adapt to different fatiguing tasks? In young adults, the endurance time when performing a submaximal isometric contraction was longer when maintaining a force and pushing against a force transducer (force task) compared with maintaining a constant elbow angle while supporting an equivalent inertial load at the wrist (position task) (Hunter et al. 2002). The briefer endurance time for the position task was attributable to neural mechanisms including a greater rate of descending drive. Given that age-related changes in the neuromuscular system will predispose the older adult to impairment within the nervous system during a fatiguing task, this RO3 application examines the following hypothesis: the difference in endurance time of a submaximal fatiguing contraction for a position task compared with a force task, will be greater in older adults compared with young adults due to age-related impairment in neural mechanisms. There are three specific aims to test this hypothesis. The first aim will compare the endurance time and muscle activation patterns of the elbow flexor muscles in young and older adults for a position task and force task. Aims 2 and 3 will evaluate potential mechanisms for the age-related differences in muscle fatigue of the two tasks, by measuring indices of descending drive and peripheral afferent feedback from the muscle during the fatiguing contractions. These measures include muscle sympathetic nerve activity, heart rate, fluctuations in motor Output, sense of effort and the pressor response. This application proposes a novel approach to examine muscle fatigue in older adults. The findings will provide preliminary information on the type of load and support preferred by older adults for long-duration submaximal tasks during daily tasks. This will constitute new information on the task-dependent nature of muscle fatigue in older adults. These preliminary findings will form the foundation for an RO 1 application that will further explore the mechanisms and task dependency of muscle fatigue in older adults.

描述（由申请人提供）：NIA 试点研究计划，主题 14：感觉和运动处理 肌肉的耐力会随着执行的任务而变化。然而，在老年人中，神经肌肉系统内与年龄相关的变化对肌肉疲劳的任务依赖性的影响尚未得到探索。这就提出了以下问题：年龄是否会改变神经肌肉系统适应不同疲劳任务的能力？在年轻人中，与保持恒定的肘部角度同时支撑手腕处的等效惯性负载（位置任务）相比，在保持力并推力传感器（力任务）时进行次最大等长收缩时的耐力时间更长（亨特等人，2002）。位置任务的较短耐力时间可归因于神经机制，包括较高的下降驱动力。鉴于神经肌肉系统中与年龄相关的变化将使老年人在疲劳任务期间容易受到神经系统损伤，该 RO3 应用程序检验了以下假设：与姿势任务相比，次最大疲劳收缩的耐力时间差异由于与年龄相关的神经机制损伤，与年轻人相比，老年人的力量任务会更大。检验这一假设有三个具体目标。第一个目标将比较年轻人和老年人在位置任务和力量任务中的肘部屈肌的耐力时间和肌肉激活模式。目标 2 和 3 将通过测量疲劳收缩期间肌肉的下降驱动指数和外周传入反馈来评估这两项任务的肌肉疲劳与年龄相关的差异的潜在机制。这些测量包括肌肉交感神经活动、心率、运动输出波动、努力感和加压反应。该应用提出了一种检查老年人肌肉疲劳的新方法。研究结果将提供有关老年人在日常任务中进行长时间次最大任务时首选的负荷和支持类型的初步信息。这将构成关于老年人肌肉疲劳的任务依赖性性质的新信息。这些初步发现将为 RO 1 应用奠定基础，进一步探索老年人肌肉疲劳的机制和任务依赖性。