LOCOMOTION: IDLING METABOLISM & GAIT DYNAMICS

这项提议中反映的长期目标没有改变： 1)确定肌肉和种群的方式 肌肉中的纤维在运动过程中被招募； 2)探讨肌肉活动与运动能力的关系 肌肉新陈代谢。 小型猪，越来越被认为是最好的 人类心血管生理学的非灵长类动物模型将是 用于同时测量骨骼肌 活动(肌电和糖原耗竭)、循环(肌肉血液 流动和毛细血管通过时间)和新陈代谢(个体 肌肉VO2和乳酸净释放量) 达到最大耗氧量的速度。这将是 代表着这些关键措施第一次 同时在同一动物(或人类受试者)中制作，以及 将允许直接量化 不同纤维类型组成的肌肉中的变量和 功能。这些测量将允许确定 氧气输送和摄取对有氧能力的限制 单独的肌肉。这些研究的具体目标将是 是直接量化肌肉活动，肌肉氧气输送，和 作为运动功能的运动过程中的肌肉代谢 强度与最大摄氧量之间的关系 变量已经发生了生理性的改变。 变量之间的关系将是生理学的 在两个方面进行了更改。在第一种情况下，这些动物将经历一个 旨在增加有氧能力的延长跑步机训练计划 权力。在第二个实验中，纤维募集的变化， 循环和新陈代谢模式将在 在有无蒸发的情况下进行延长的次极量运动 给动物降温。 这些拟议研究的发现将显著地 加深对潜在机制的理解 个体骨骼的心血管和代谢反应 适合锻炼的不同纤维类型的肌肉 有意识的动物。这些关系以前一直是 仅在“全身”水平或在单独的肌肉中确定。

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.