Lower Extremity Muscle Power and Function in the Elderly

老年人下肢肌肉的力量和功能

• 批准号: 6930285
• 负责人: Roger A. Fielding
• 金额: $ 42.72万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-15 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6930285
• 关键词: balance; body composition; body movement; clinical research; disease /disorder prevention /control; exercise; human middle age (35-64); human old age (65+); human subject; limbs; longitudinal human study; muscle contraction; muscle function; muscle strength; outcomes research; performance; person with disability; striated muscles; training

DESCRIPTION (provided by applicant): This proposal is for the competitive renewal of RO1 AG018844, which is in its third year of funding and is submitted in response to PAS-03-122 "Frailty in Old Age: Pathophysiology and Interventions". The focus of this research has been to examine the physiologic and functional effects of a muscle power training intervention in comparison to traditional progressive resistance training in a community-based group of elderly men and women with moderate mobility limitations. During the current project period, we have successfully demonstrated that peak lower extremity power is closely associated with functional limitations and self-reported disability in older community dwelling men and women. We propose to extend our previous findings by examining the physiological mechanisms that contribute to the age and gender-related declines in peak muscle power. To compliment our existing data on skeletal muscle fiber contractile properties, we will assess the neural contributions to the generation of muscle power with advancing age. We will test the hypothesis that skeletal muscle single fiber contractile properties (i.e. single fiber power, shortening velocity, specific force), neural factors (i.e. intermuscular coordination patterns, central activation ratios/and motor unit control properties) and lower extremity power will be reduced with advancing age and degree of risk for mobility disability, and these differences will be attenuated in women compared to men. Middle-aged healthy (40-55 yrs.), older healthy (70-85 yrs), and older (70-85 yrs) men and women at risk for mobility disability will be studied under controlled conditions (Study 1). In addition, in light of our recent observations that differences in lower extremity maximal velocity occur at relatively low external forces (eg: 40% 1 RM) and are most closely associated with gait velocity in older individuals, we propose conducting a randomized controlled trial of high velocity low resistance exercise training in individuals at risk for mobility disability to test the hypothesis that a short-term resistance training intervention performed against a low external force and at maximum voluntary velocity will induce significant reductions in mobility disability as evidenced by improvements in gait velocity during performance of a 400 M walk in older individuals at risk for mobility disability (SPPB score <_9, 70 - 85 yrs) (Study 2). The results of these studies will have important implications in understanding the proximal determinants of physical disability in the frail elderly and in designing intervention strategies targeted at improving mobility.

描述（由申请人提供）：本提案是针对 RO1 AG018844 的竞争性更新，该提案已进入资助的第三年，是为了响应 PAS-03-122“老年衰弱：病理生理学和干预措施”而提交的。这项研究的重点是在社区中度行动不便的老年男性和女性群体中检查肌肉力量训练干预措施与传统渐进式阻力训练相比的生理和功能效果。在当前项目期间，我们已成功证明下肢力量峰值与老年社区居住男性和女性的功能限制和自我报告的残疾密切相关。我们建议通过检查导致年龄和性别相关的峰值肌肉力量下降的生理机制来扩展我们之前的发现。为了补充我们关于骨骼肌纤维收缩特性的现有数据，我们将评估随着年龄的增长神经对肌肉力量产生的贡献。我们将测试骨骼肌单纤维收缩特性（即单纤维功率、缩短速度、比力）、神经因素（即肌间协调模式、中枢激活比率/和运动单位控制特性）和下肢功率将降低的假设随着年龄的增长和行动障碍风险程度的增加，与男性相比，女性的这些差异将会减弱。将在受控条件下对存在行动障碍风险的中年健康（40-55 岁）、老年健康（70-85 岁）和老年（70-85 岁）男性和女性进行研究（研究 1）。此外，根据我们最近的观察，下肢最大速度的差异发生在相对较低的外力（例如：40％1 RM）下，并且与老年人的步态速度最密切相关，我们建议进行一项随机对照试验对有行动障碍风险的个体进行高速低阻力运动训练，以检验以下假设：针对低外力和以最大自愿速度进行的短期阻力训练干预将导致行动障碍显着减少，如步态速度的改善所证明表演期间有行动障碍风险的老年人（SPPB 评分 <_9，70 - 85 岁）步行 400 M 的距离（研究 2）。这些研究的结果对于了解体弱老年人身体残疾的直接决定因素以及设计旨在改善活动能力的干预策略具有重要意义。