LOCOMOTION: IDLING METABOLISM & GAIT DYNAMICS

本提案所反映的长期目标没有改变： 1)以确定肌肉和人口的方式， 肌肉内的纤维在运动过程中被募集;以及 2)研究肌肉活动与 肌肉新陈代谢 小型猪，这是越来越多地被认为是最好的 人类心血管生理学的非灵长类动物模型， 用于同时测量骨骼肌 活动（EMG和糖原消耗）、循环（肌肉血液 流量和毛细血管通过时间）和代谢（个体 肌肉VO 2和净乳酸释放） 达到最大耗氧量的速度。 这将 代表了这些关键措施第一次 在同一时间在同一动物（或人类受试者）中制备，以及 将允许直接量化的相互关系之间的 不同纤维类型组成的肌肉变量， 功能 这些测量将允许确定 氧气输送和吸收对有氧能力的限制， 个别肌肉。 这些研究的具体目标将 直接定量肌肉活动，肌肉O2输送， 运动过程中肌肉代谢作为运动的函数 强度与VO 2 max的关系， 变量在生理上发生了改变 变量之间的关系将是生理上的 以两种方式改变。 首先，动物们将经历一个 长期跑步机训练计划，旨在增加有氧运动 动力. 第二种是纤维补充的改变， 循环和代谢模式将在 长时间亚极量运动伴和不伴蒸发 冷却动物。 这些拟议研究的结果将大大 加深对潜在机制的理解 个体骨骼的心血管和代谢反应 不同纤维类型组成的肌肉进行锻炼 有意识的动物 这些关系以前是 仅在“全身”水平或在分离的肌肉中测定。

The long-term goals reflected in this proposal have not changed: 1) to determine the manner in which muscles and populations of fibers within muscles are recruited during locomotion; and 2) to investigate the relationship between muscular activity and muscular metabolism. Miniature swine, which are increasingly recognized as the best non-primate models for human cardiovascular physiology, will be used to make simultaneous measurements of skeletal muscle activity (EMG and glycogen depletion), circulation (muscle blood flow and capillary transit time), and metabolism (individual muscle VO2 and net lactate release) during treadmill locomotion up to the speed that elicits maximum O2 consumption. This will represent the first time that these critical measures have been made at the same time in the same animal (or human subject), and will permit direct quantitation of the interrelationships among the variables in muscles of differing fiber type composition and function. These measurements will allow determination of limitations to aerobic power imposed by O2 delivery and uptake in individual muscles. The specific objectives of these studies will be to directly quantitate muscle activity, muscle O2 delivery, and muscle metabolism during locomotion as a function of exercise intensity to VO2max which the relationships among the 3 variables have been physiologically altered. The relationships among the variables will be physiologically altered in 2 ways. In the first, the animals will undergo a prolonged treadmill training program designed to increase aerobic power. In the second, alterations in the fiber recruitment, circulatory, and metabolic patterns will be measured during prolonged submaximal exercise with and without evaporative cooling of the animals. The findings from these proposed studies will significantly increase understanding of the mechanisms underlying cardiovascular and metabolic responses of individual skeletal muscles of differing fiber type composition to exercise in conscious animals. These relationships have previously been determined only at the "whole-body" level or in isolated muscle.