LOWER EXTREMITY MUSCLE POWER AND FUNCTION IN THE ELDERLY

描述：（逐字引用自申请）虽然下肢肌肉 强度是损伤的可靠量度，也是功能性损伤的指标。 老年人的能力，峰值功率或肌肉的最大能力 单位时间的工作量在功能独立性中可能发挥更重要的作用 和预防残疾的能力。我们最近的工作 实验表明，与下肢功率相比， 肢体力量，是一个更好的预测性能为基础的功能， 一个独立的预测自我报告残疾的体弱老年妇女。 虽然渐进式阻力训练（PRT）在 显着增加肌肉力量和大小，PRT对 基于性能的功能测量没有那么引人注目。拟议 一项研究将检查肌肉力量的生理和功能影响， 培训干预相比，传统的PRT在以社区为基础的 一组老年男性和女性中度行动不便。拟议 这项研究将检验下肢峰值力量训练将 导致功能的更大改善，如物理测试所评估的， 与力量训练相比。我们建议假设的 峰值力量训练发挥这些效果的机制包括： 骨骼肌质量增加较大，肌纤维肥大， 离体单纤维的缩短速度， 具体力量。将进行随机对照干预试验 受试者（N=75）被分配到下肢（膝盖和臀部 伸肌）峰值功率训练干预，PRT或对照组为3 个月将在基线和3个月时评估关注的主要结局 包括：腿部力量、力量、耐力等生理测试; 基于性能的功能测试，平衡和移动性;生化 测量骨骼肌活检，包括组织化学和 收缩特性;以及通过双能X射线评估的身体组成 吸收测定法这项研究的结果将在以下方面产生重要影响： 评估下肢力量训练的效果，一个潜在的更多 改变身体残疾的近端决定因素的有效手段 脆弱的老人。

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.