Scaling of the Mechanics and Energetics of Mammalian Muscle Fibers with Body Size

9514383罗马 经验表明，小动物（例如小鼠和大鼠）的肢体运动频率高于大型动物（人或马），并且小动物移动给定距离的每克能量消耗高于大型动物。 在该提案中，主要研究者（PI）将提出“肌肉系统是如何设计的，以允许小动物更快的运动，为什么小动物跑起来比大动物消耗更多的能量？“据推测，差异在于肌肉纤维的性质。 小动物的肌肉纤维被认为要快得多--这是这些动物奔跑时高频率的必要条件。 但这是有代价的：非常快的肌肉纤维使用更多的能量来产生力量，这可能解释了为什么小动物跑步的成本更高。 PI将通过测量从大鼠到马的动物中不同纤维类型产生力的速度和能量成本如何随体型缩放来检验上述假设。 PI研究的长期目标是了解肌肉系统的设计。 这涉及执行特定的实验，促进分子，细胞和整个动物研究信息的整合。 这种方法是至关重要的，因为我们对动物使用肌肉的原理的认识存在很大的差距。 此外，阐明健康运动系统如何工作的原理可能在人类和其他动物的健康和运动表现方面具有深远的应用。 例如，从这些研究中获得的信息可用于1）理解运动/心血管系统的疾病/损伤; 2）设计用于辅助残疾人运动的计算机系统; 3）设计用于肌肉疾病状态的药理学和遗传学干预; 4）理解训练/康复的功能基础;以及5）选择用于心脏泵送辅助的适当骨骼肌。 随着最近尝试在人类中使用非人类物种的组织，这些研究将特别重要，因为它们将提供肌肉速度的数据库，医生可能能够从中选择与人类特定功能相匹配的肌肉。 这些信息对兽医学也很重要。 ***

9514383 Rome It has been empirically shown that small animals (e.g. mice and rats) move their limbs at higher frequencies than large animals (man or horses) and that it costs more energy per gram for a small animal to move a given distance than for a large one. In this proposal, the principal investigator (PI) will ask "how is the muscular system designed to permit much faster movements in small animals and why does it cost much more energy for small animals to run than large ones?" It has been hypothesized that the difference lies in the properties of the muscle fibers. The muscle fibers of the small animals are thought to be much faster--a necessity for the high frequencies at which these animals run. But there is a price: very fast muscle fibers use far more energy to generate force, thus potentially explaining why it is more costly for small animals to run. The PI will test the above hypothesis by measuring how speed and the energetic cost of generating force of different fiber types scales with body size in animals ranging from rats to horses. The long-term goal of the PI's research is to understand the design of muscular systems. This involves performing specific experiments that facilitate the integration of information from molecular, cellular and whole animal studies. This approach is crucial because there are large gaps in our knowledge of the principles by which animals use their muscles. Further, elucidation of the principles of how healthy motor systems work may have far-reaching application in terms of health and athletic performance of humans and other animals. For instance, the information obtained from these studies may be useful in 1) understanding disease/injuries of the motor/cardiovascular systems; 2) designing computer systems for aiding movement in the handicapped; 3) designing pharmacological and genetic interventions for muscle disease states; 4) understanding the functional basis of training/rehabilitation; and 5) choosing appropriate skeletal muscle fo r heart pumping assist. With recent attempts to use tissue from non-human species in man, these studies would be particularly important as they will provide a data base of muscle speeds from which physicians might be able to choose a good match for a particular function in humans. This information will also be important for veterinary medicine. ***