RACE & GENER DIFFERENCES IN INTRACEREBRAL & CAROTID ARTERIAL VELOCITY--AGING

与年龄相关的肌肉力量变化是导致 老年人的虚弱。这些变化的时间进程和原因是 人们对此知之甚少。这个项目调查了成年人的变化。 生命周期，重点是在中年早期发生的事情 改变开始了。本研究由三部分组成。 首先是BLSA正在进行的一项比较同心(缩写)的研究 和运动的偏心(伸长)阶段评估为慢、快和 零(等长)速度。从20多岁开始，几乎有500名男性和女性受试者 经过80年代的检验和纵向数据收集 开始了。在横断面分析中发现与年龄相关的下降 用于所有肌肉群的向心和偏心测试，以及 速度。横截面确定的下降率在 股四头肌多于二头肌。下降的速度 在向心和偏心方面，男性的力量往往是平行的。 同心比偏心强度下降的幅度要大得多。 女人身上的力量。 其次是对25年来的肌肉和力量的分析。 在BLSA中的测量。最初的分析考察了如何 肌肉质量的质量变化与力量有关。肌酸酐 排泄量下降的方式类似于肌肉力量，而身体 体重指数、横截面积和瘦体重显示较少 这项研究表明，检查肌肉收缩的指标 部件与强度之间的关联可能比交叉部件更强 横断肌区。 第三项是研究外周神经对 力量减退。已经开发出一种协议，用于探测发动机单元 股四头肌不同肌力水平的功能 大腿骨。该技术显示了合理的重测可靠性 .1-.3变异系数。招募的机动部队的规模 随着最大自主收缩百分比的增加而增加。这个 这项研究将考察发动机单元大小和发射模式的影响。

Age-related changes in muscle strength are an important contributor to frailty in the elderly. The time course and causes for these changes are poorly understood. This project examines the changes across the adult life span with an emphasis on what occurs early in middle age when the changes begin. The research consists of three parts. First is an ongoing study in the BLSA comparing concentric (shortening) and eccentric (elongation) phases of movement assessed at slow, fast and zero (isometric) speeds.Almost 500 male and female subjects from the 20s through the 80s have been tested and longitudinal data collection is beginning. Age associated declines are found in cross-sectional analysis for both concentric and eccentric testing for all muscle groups and speeds. The cross-sectionally determined rate of decline is greater in the quadriceps femoris than for the biceps brachii. The rates of decline in concentric and eccentric strength tend to be parallel in men. Concentric strength declined to a much greater extent than eccentric strength in women. Second is an analysis of twenty-five years of muscle and power measurements in the BLSA. The initial analysis examines the issue of how qualitative changes in muscle mass are related to strength. Creatinine excretion declined in a manner similar to muscle strength, while body mass index, cross sectional area and lean body mass showed less change.The study suggests that measures that examine muscle contractile components may show a stronger association with strength than cross sectional muscle area. Third are studies to examine the peripheral nerve contribution to strength loss. A protocol has been developed that explores motor unit function at different levels of muscle exertion in the quadriceps femoris. The technique shows reasonable test-retest reliability with a .1-.3 coefficient of variation. The size of recruited motor units increases at increasing percentage of maximal voluntary contraction. The study will examine the effects of the motor unit size and firing pattern.