Properties and distributions of the fiber types in the locomotory muscles of mammals

摘要

Mammalian locomotory muscles contain mixtures of fibers with different contractile and metabolic properties. The presence of these various fiber types within the same muscle permits it to generate forces over a broad range of shortening velocities with varying degrees of resistance to fatigue. Unlike the muscles of most lower vertebrates and invertebrates, which tend to have more homogeneous fiber compositions, mammalian muscles possess an amazing degree of versatility in meeting their contractile requirements. In fact, the heterogenous fiber composition in the skeletal muscles of mammals reflects the complexity of the innervating motor components of the nervous system.