Malleability of skeletal muscle in overcoming limitations: structural elements

Muscles allow animals to interact mechanically with their environment. The basic processes concerned with motion as well as the structure of the sliding filaments in muscle cells are found with little modification throughout the animal kingdom (Huxley, 1973). However, the energetic demand imposed on a muscle by the organism may vary greatly depending on the specific function of that muscle. Thus, both the heart and the diaphragm have to deliver high rates of mechanical energy continuously during the whole life-span of an animal, whereas other muscles, such as the gastrocnemius, are only briefly activated every once in a while. The present review analyses the malleability of the structural components of the energetic machinery of skeletal muscle cells with regard to the energetic demand placed upon them by the organism.