LOWER EXTREMITY MUSCLE POWER AND FUNCTION IN THE ELDERLY

描述：(一字不差)虽然是腿部肌肉 力量是损伤的可靠量度，也是功能的指标 老年人的能力、峰值功率或最大肌肉能力 单位时间的工作量在功能独立性中可能起到更重要的作用 和残疾预防，而不仅仅是肌肉力量。来自我们的最新工作 实验室提示，相比于较低的峰值， 四肢力量是基于性能的功能的更好的预测因子，并且 虚弱老年妇女自我报告残疾的独立预测因子。 尽管渐进式阻力训练(PRT)在 显著增加肌肉力量和大小，PRT对 以绩效为基础的功能衡量则没有那么戏剧性。建议数 这项研究将检验肌肉力量的生理和功能效应。 社区培训干预与传统PRT的比较研究 一组行动能力中等受限的老年男女。建议数 研究将验证这样的假设，即下肢峰值力量训练将 通过物理测试评估，导致功能上的更大改善 表现，与力量训练相比。我们认为，假设 峰值功率训练发挥这些作用的机制包括：a 骨骼肌质量增加较大，肌纤维肥大， 离体单纤维的体外缩短速度不变 特定力。将进行随机对照干预试验 受试者(N=75)被分配到下肢(膝盖和髋部 伸肌)峰值功率训练干预，PRT，或对照组3人 月份。感兴趣的主要结果将在基线和3个月进行评估 包括：腿部力量、力量和耐力的生理学测试； 基于性能的功能测试、平衡性和移动性；生化 骨骼肌活检的测量，包括组织化学和 收缩性能；以及用双能x射线评估的身体成分 吸光度测定法。这项研究的结果将对 评估下肢力量训练的效果，一种潜在的 修改身体残疾的近端决定因素的有效手段 在虚弱的老年人中。

DESCRIPTION: (verbatim from application) Although lower extremity muscle strength is a reliable measure of impairment and an index of functional capacity in the elderly, peak power or the maximum capacity to perform muscular work per unit of time may play a more important role in functional independence and disability prevention than muscle strength alone. Recent work from our laboratory suggests that peak lower extremity power, compared to lower extremity strength, is a better predictor of performance-based function and is an independent predictor of self-reported disability in frail elderly women. Although progressive resistance training (PRT) has been effective in significantly increasing muscle strength and size, the effects of PRT on performance-based measures of function have been less dramatic. The proposed study will examine the physiologic and functional effects of a muscle power training intervention in comparison to traditional PRT in a community-based group of elderly men and women with moderate mobility limitation. The proposed study will test the hypothesis that lower extremity peak power training will result in greater improvements in function, as assessed by tests of physical performance, compared to strength training. We propose that the hypothesized mechanisms by which peak power training will exert these effects include: a larger increase in skeletal muscle mass, muscle fiber hypertrophy, an increased in vitro shortening velocity of isolated single fibers with no change in specific force. A randomized controlled intervention trial will be conducted with subjects (N=75) being assigned to a lower extremity (knee and hip extensors) peak power training intervention, PRT, or control group for 3 months. Primary outcomes of interest will be assessed at baseline, and 3 months and include: physiological tests of leg strength, power, and endurance; performance-based functional tests, balance and mobility; biochemical measurements of skeletal muscle biopsies including histochemical and contractile properties; and body composition assessed by dual energy x-ray absorptiometry. The results of this study will have important implications in evaluating the effects of lower extremity power training, a potentially more effective means of modifying the proximal determinants of physical disability in the frail elderly.