MUSCLE QUALITY IN SARCOPENIA

描述(改编自申请者摘要)：与年龄相关 肌肉质量和力量下降，称为骨质疏松症，这是一种 导致老年人身体虚弱和残疾的重要原因。有一个 随着年龄的增长，肌肉纤维的数量和大小都会下降 导致骨骼肌衰老时的虚弱。然而， 骨质疏松症患者肌肉细胞水平的功能改变没有 已经被彻底研究过了。唯一被证明可以扭转 到目前为止，骨质疏松症造成的弱点是渐进性抵抗训练 (PRT)。没有报告研究了以下变化的相对贡献 单纤维收缩能力(即肌肉质量)与肌肉质量(即， 肌肉数量)在石棺减少的病因或治疗中。在这 探索性拨款，我们建议首次评估 单个肌纤维的收缩特性随年龄的变化及其反应 对骨质疏松症的老年妇女进行PRT治疗。他们假设衰老是 与最大力、比力的降低有关 (力/面积)，以及I型和IIA型肌纤维的缩短速度； 单一肌肉纤维产生的最大力量和比力量相关 对青年和老年受试者的肌力进行活体测量； 而PRT将刺激单位力量生产的增长 纤维和活体中也是如此。他们建议招募8名健康的年轻人 久坐不动的妇女(18-30岁)和16名老年健康妇女(70-85岁)和 通过CT扫描评估肌力、活体肌肉CSA和比力 他们的股四头肌肌群。到那时，老年妇女将被 随机分配到力量训练组(n=8)或控制活动组(n=8) 已经12周了。这些数据将被用作后续研究的基础 探讨肌肉纤维品质与机能的关系 老年石棺减少症患者的状况。此外，这些方法将 允许独立于中枢神经评估肌肉细胞功能 系统影响，为未来的研究更好地定义 外周机制与中枢机制在病因和治疗中的作用 骨质疏松症。

DESCRIPTION (Adapted from the Applicant's Abstract): Aging is associated with a decline in muscle mass and strength, called sarcopenia, which is an important cause of frailty and disability in the elderly. There is a decline in both the number and size of muscle fibers with age which contributes to the weakness seen in aging skeletal muscle. However, functional alterations at the muscle cell level with sarcopenia have not been studied thoroughly. The only intervention proven to reverse the weakness caused by sarcopenia to date is progressive resistance training (PRT). No reports have examined the relative contribution of changes in single fiber contractility (i.e., muscle quality) versus muscle mass (i.e., muscle quantity) in the etiology or treatment of sarcopenia. In this exploratory grant, we propose to assess for the first time changes in the contractile properties of single muscle fibers with age, and their response to PRT in sarcopenic elderly women. They hypothesize that aging is associated with a decrease in the maximal force, specific force (force/area), and shortening velocity of type I and IIA muscle fibers; that maximal and specific force production by single muscle fibers correlates with in vivo measurements of muscle strength in young and elderly subject; and that PRT will stimulate gains in specific force production in single fibers as well as in vivo. They propose to recruit 8 young healthy sedentary women (ages 18-30) and 16 elderly, healthy women (ages 70-85) and evaluate the strength, in vivo muscle CSA by CT scan, and specific force of their quadriceps femoris muscle group. The elderly women will then be randomly assigned to strength training (n = 8) or control activity (n = 8) for 12 weeks. These data will be used as the basis for subsequent studies examining the relationship between muscle fiber quality and functional status of elderly adults with sarcopenia. In addition, these methods will allow assessment of muscle cell function independently of central nervous system influence, setting the stage for future studies to better define the role of peripheral versus central mechanisms in the etiology and treatment of sarcopenia.