Function and position determine relative proportions of different fiber types in limb muscles of the lizard Tropidurus psammonastes

摘要: Skeletal muscles can be classified as flexors or extensors according to their function, and dorsal ventral position. The latter classification evokes embryological origin from muscle masses initially divided during limb development, sharing a given position do not necessarily perform the same function. Here, we compare relative proportions of different fiber types among six in lizard Tropidurus psammonastes. Individual fibers were slow oxidative (SO), fast glycolytic (FG) oxidative-glycolytic (FOG) based on mitochondrial content; Mixed linear models considering one both effects compared using likelihood ratio tests. Variation proportion FG FOG is mainly explained by function (flexor have average lower higher fibers), while variation SO better (they are less abundant than those developed mass). Our results clarify roles determining various provide evidence that these factors may differentially affect distinct types.