Skeletal Muscle Fiber Size and Capillarity 1

Summary The ATPase technique following preincubation in an acid medium (pH 3.8–4.0) was used to visualize capillaries. After preincubation at a pH of 4.5, in combination with the DPNH tetrazolium reductase, it was used to identify fiber types. A positive correlation has been demonstrated between fiber cross sectional area and C:F, indicating that large fibers are surrounded by more capillaries. The increase in fiber size may or may not be associated with changes in capillary density.