LOCOMOTION: IDLING METABOLISM AND GAIT DYNAMICS

本建议中反映的长期目标是：1）确定 肌肉和肌肉内的纤维群被 在运动过程中招募;和2）调查之间的关系 肌肉活动和肌肉代谢。 在以前的工作中， 描述了发生在内部和之间的空间招聘模式， 哺乳动物的肌肉在运动。 此外，我们最近发现， 肌肉内和肌肉间血流的大小和分布模式 的大鼠不同的纤维类型组成的肌肉和 运动速度，肌肉血流量随着时间的推移而增加， 以恒定的速度运动至疲劳。 我们从这项工作中得出结论， 肌肉血流模式与肌肉纤维密切相关 招募模式。 两个直接的问题源于我们以前的 工作：1）血流的绝对大小和模式 在代表其他哺乳动物的大鼠肌肉内和之间观察到， 还是实验室啮齿动物独有的 2)是渐进的变化， 肌纤维募集负责肌肉中的逐渐升高 在运动过程中随着时间的推移发生的血液流动，或者是其他机制 参与？ 为了回答第一个问题，血液在体内流动， 在猪和狗的肌肉之间将在运动过程中确定。 到 回答第二个问题，我们将测试三个假设，可以解释 随着时间的推移，肌肉血流量逐渐增加， 运动：a）由于逐渐招募 作为纤维疲劳的肌肉中的额外运动单位; B）升高 由体温逐渐升高引起;或c）升高 由于血管扩张物质在血管中的逐渐积累， 肌肉. 这些问题的答案将大大促进我们的 了解肌肉纤维活动的模式， 运动和伴随的肌肉活动的代谢支持。

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.