LOCOMOTION: IDLING METABOLISM AND GAIT DYNAMICS

这项提案所反映的长期目标是：1)确定 肌肉和肌肉内纤维数量的方式 在运动中招募；以及2)调查两者之间的关系 肌肉活动和肌肉新陈代谢。在以前的工作中，我们有 描述了发生在内部和之间的空间招聘模式 运动中的哺乳动物肌肉。另外，我们最近发现， 肌肉内部和肌肉间血流的大小和分布模式 大鼠的肌肉纤维类型组成和 运动速度，肌肉血流量随着时间的推移而增加 以恒定的速度运动到疲劳。我们从这项工作中得出了结论 肌肉血液流动模式与肌肉纤维密切相关 招聘模式。两个直接的问题源于我们之前的 功：1)是血流的绝对大小和模式 在代表其他哺乳动物的老鼠肌肉内和之间观察到， 或者它们是实验室啮齿动物独有的？2)是渐进式的变化 肌肉纤维的募集与肌肉的逐渐抬高有关 在运动过程中随着时间的推移而产生的血液流动，或者是其他机制 有牵连吗？为了回答第一个问题，血液在和 将在运动中测定猪和狗的肌肉中的蛋白质。至 回答第二个问题，我们将测试三个可能解释 随着时间的推移，肌肉血流量逐渐增加 练习：a)晋升是由于循序渐进地征聘 肌肉中额外的运动单位，如纤维疲劳；b)隆起 由体温逐渐升高所致；或c)海拔 血管扩张剂物质在脑内逐渐积累所致 肌肉。对这些问题的回答将大大推动我们的 对肌肉纤维活动模式的理解 运动和伴随的新陈代谢支持肌肉活动。

The long-term goals reflected in this proposal are: 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. In previous work we have described the spatial recruitment patterns that occur within and among mammalian muscles during exercise. Also, we recently have found that the magnitude and distribution patterns of blood flow within and among muscles of rats vary with the fiber type composition of the muscles and with locomotory speed, and that muscle blood flow increases with time during exercise to fatigue at a constant speed. We have concluded from this work that muscle blood flow patterns are closely related to muscle fiber recruitment patterns. Two immediate questions emanate from our previous work: 1) Are the absolute magnitudes and the patterns of blood flow observed within and among the rat muscles representative of other mammals, or are they unique to laboratory rodents? 2) Are progressive changes in muscle fiber recruitment responsible for the gradual elevations in muscle blood flow that occur over time during exercise, or are other mechanisms involved? To answer the first of these questions, blood flows within and among the muscles of pigs and dogs will be determined during exercise. To answer the second, we will test three hypotheses that may explain the progressive increases in muscle blood flow that occur with time during exercise: a) the elevations rsult from progressive recruitment of additional motor units in the muscles as fibers fatigue; b) the elevations result from a progressive rise in body temperature; or c) the elevations result from progressive accumulation of vasodilator substance in the muscles. Answers to these questions will significantly further our understanding of the patterns of muscle fiber activity that occur during exercise and the accompanying metabolic support of the muscular activity.