Muscle Energetics during Fatiguing Contractions in Young and Old Men

年轻人和老年人疲劳收缩期间的肌肉能量

• 批准号: 7781821
• 负责人: Thorsten Rudroff
• 金额: $ 18.28万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7781821
• 关键词: Advisory Committees; Aging; Blood flow; Computers; Consumption; Educational workshop; Elbow; Elderly; Failure; Fatigue; Flexor; Heart Rate; Image; Individual; Institutes; Intervention; Measures; Muscle; National Institute on Aging; Oxygen Consumption; Participant; Performance; Positioning Attribute; Positron-Emission Tomography; Relative (related person); Research; Resistance; Role; Signal Transduction; Time; Torque; Variant; age group; age related; arm; glucose uptake; men; older men; public health relevance; restraint; tomography; young adult

DESCRIPTION (provided by applicant): Although old adults are often more fatigable than young adults, this is not a universal finding. As suggested in an exploratory workshop by the National Institute of Aging (NIA) on unexplained fatigue in the elderly, such differences in performance between young and old adults may be related to muscle energetics. We propose to compare the distribution of activation and energy utilization among a group of synergist, antagonist, and accessory muscles in young and old men during two types of fatiguing contractions with the elbow flexor muscles. The difference between the two contractions will be the type of load supported by the arm muscles: one fatiguing contraction will require an individual to sustain a submaximal force (force task) and the other fatiguing contraction will involve supporting an equivalent inertial load and keeping the position of the arm constant (position task). Although the net muscle torque exerted during the two contractions will be similar for each subject, the position task is more difficult and cannot be sustained for as long as the force task. The central hypothesis of the research plan is that differences in energetics of arm and accessory muscles during the two tasks can explain the age-related differences in times to task failure. Positron emission tomography (PET) will be combined with computer tomography (CT) to measure blood flow and oxygen consumption in arm muscles during force and position tasks, and PET images will provide information about the glucose uptake in individual muscles to estimate cumulative levels of muscle activity. The research plan involves first comparing blood flow and oxygen consumption in arm muscles of old and young men during two types of fatiguing contractions (Aim 1) and then comparing glucose uptake in arm and accessory muscles of old and young men after two types of fatiguing contractions (Aim 2). Although the relative performance of young and old men during a position task is unknown, we expect to explain any differences in time to failure for both tasks by differences in muscle energetics. By understanding the task dependent role of muscle energetics, specific interventions can be developed to maximize fatigue resistance in older adults. Public Health Relevance: Young and old men will perform two types of fatiguing contractions that differ in difficulty. The plan is to determine if differences in performance between the two groups of participants can be explained by variation in blood flow and energy consumption in the involved muscles.

描述（由申请人提供）：虽然老年人通常比年轻人更容易疲劳，但这并不是一个普遍的发现。正如国家老龄化研究所（NIA）关于老年人不明原因疲劳的探索性研讨会所建议的那样，年轻人和老年人之间的这种表现差异可能与肌肉能量有关。我们建议比较年轻和老年男性在两种类型的肘屈肌疲劳收缩期间，一组增效肌、拮抗肌和辅助肌的激活和能量利用分布。两种收缩之间的区别在于手臂肌肉支撑的负载类型：一种疲劳收缩需要个人维持次最大力（力任务），另一种疲劳收缩将涉及支撑等效惯性负载并保持位置臂常数（位置任务）。尽管每个受试者在两次收缩期间施加的净肌肉扭矩相似，但姿势任务更加困难，并且不能像力量任务那样持续那么久。该研究计划的中心假设是，在两项任务期间手臂和辅助肌肉的能量差异可以解释与年龄相关的任务失败时间差异。正电子发射断层扫描 (PET) 将与计算机断层扫描 (CT) 相结合，测量力量和位置任务期间手臂肌肉的血流量和耗氧量，PET 图像将提供有关单个肌肉中葡萄糖摄取的信息，以估计肌肉的累积水平活动。研究计划首先比较老年人和年轻男性在两种类型的疲劳收缩期间手臂肌肉的血流量和耗氧量（目标1），然后比较老年人和年轻男性在两种类型的疲劳收缩后手臂和辅助肌肉的葡萄糖摄取量（目标 2）。尽管年轻人和老年人在位置任务中的相对表现尚不清楚，但我们希望通过肌肉能量的差异来解释这两项任务的失败时间差异。通过了解肌肉能量学的任务依赖性作用，可以制定具体的干预措施，以最大限度地提高老年人的抗疲劳能力。 公共健康相关性：年轻人和老年人会进行两种难度不同的疲劳收缩。该计划是为了确定两组参与者之间的表现差异是否可以通过相关肌肉的血流量和能量消耗的变化来解释。