Convertino V A
National Aeronautics and Space Administration, Biomedical Operations and Research Office, Kennedy Space Center, FL 32899.
Physiologist. 1991 Feb;34(1 Suppl):S125-8.
Based on the results generated from experiments conducted by our investigators, it is clear that prolonged exposure to microgravity environments can induce ultrastructural abnormalities and atrophy of muscle and impair muscle function, especially upon return to terrestrial gravity. It is also apparent that ground-base models can be effectively used to study these changes. This provides a less expensive and more controlled laboratory condition in order to conduct experiments. The use of animal models must be more closely examined. In the case of muscle adaptations to microgravity, the data from flight experiments which have used rodents might suggest the use of exercise with characteristics contrary to those which would be most appropriate to defend against atrophy and dysfunction in human muscle. Although many spaceflight experiments may be limited to the use of animal models, the results of the studies reviewed in this paper emphasize the importance of using human models in order to provide the most accurate interpretation of data for the development of exercise countermeasures for spaceflight. If maintenance of muscle structure, size and function is perceived as operationally necessary, the results from the studies conducted by our investigators indicate that the use of more resistive exercise must be given greater consideration as part of the development of future exercise countermeasure programs for spaceflight. The advantages of incorporating resistive exercise with a strong emphasis on the use of eccentric muscle actions in addition to concentric actions may prove most effective as a countermeasure against the muscle atrophy and dysfunction caused by long-duration exposure to microgravity environments.
根据我们的研究人员所进行实验得出的结果，很明显，长时间暴露于微重力环境会诱发肌肉的超微结构异常和萎缩，并损害肌肉功能，尤其是在返回地球重力环境时。同样明显的是，地面模型可有效地用于研究这些变化。这提供了一种成本较低且可控性更强的实验室条件来进行实验。动物模型的使用必须得到更严格的审视。就肌肉对微重力的适应性而言，使用啮齿动物的飞行实验数据可能表明，所采用的运动特征与预防人类肌肉萎缩和功能障碍最适宜的运动特征相反。尽管许多太空飞行实验可能限于使用动物模型，但本文所综述研究的结果强调了使用人体模型的重要性，以便为制定太空飞行运动对策提供最准确的数据解读。如果认为维持肌肉结构、大小和功能在操作上是必要的，我们研究人员所开展研究的结果表明，在制定未来太空飞行运动对策计划时，必须更多地考虑采用阻力更大的运动。除了向心动作外，大力强调离心肌肉动作的阻力运动相结合，其优势可能证明是预防因长时间暴露于微重力环境而导致的肌肉萎缩和功能障碍的最有效对策。
