MUSCLE QUALITY IN SARCOPENIA

描述（改编自申请人摘要）：老化与 肌肉质量和力量下降，称为肌肉减少症，这是一种 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， 导致了骨骼肌老化后的虚弱 然而，在这方面， 肌肉减少症的肌细胞水平的功能改变 被彻底研究。 唯一被证明可以逆转 到目前为止，由肌肉减少症引起的虚弱是渐进式阻力训练 （PRT）。 没有任何报告审查了下列变化的相对贡献： 单纤维收缩性（即，肌肉质量）与肌肉质量（即， 肌肉量）在肌肉减少症的病因学或治疗中的作用。 在这 探索性赠款，我们建议首次评估的变化， 单根肌纤维随年龄的收缩特性及其反应 在肌肉减少的老年女性中的PRT。 他们假设衰老是 与最大力、比力、 （力/面积）和I型和IIA型肌纤维的缩短速度; 单根肌纤维产生的最大和比力与 对年轻和老年受试者的肌肉力量进行体内测量; 而PRT将刺激在单一的特定部队生产的收益， 纤维，以及在体内。 他们计划招募8名年轻健康的 久坐妇女（18-30岁）和16名老年健康妇女（70-85岁）， 通过CT扫描评估强度、体内肌肉CSA和比力， 他们的股四头肌群。 然后，老年妇女将 随机分配至力量训练组（n = 8）或对照组（n = 8） 12周 这些数据将作为后续研究的基础 研究肌纤维质量和功能之间的关系， 老年人肌肉减少症的状态。 此外，这些方法将 允许独立于中枢神经系统评估肌细胞功能 系统的影响，为未来的研究奠定基础，以更好地确定 外周机制与中枢机制在病因学和治疗中的作用 肌肉减少症

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.