Estimating diffusion distances in muscle.

Models of fibers and capillaries in cross sections of muscle were used to quantify the relationships between diffusion distances and tissue capillarity. The fibers were constructed as square and hexagonal arrays, and the placement of capillaries around the perimeters of the fibers ordered them in similar arrays. Diffusion distances were measured as the percent cumulative frequency of fiber area within a given distance of a capillary when capillary-to-fiber ratio was increased from 0.5 to 4.0. Equations fitted to the data make it possible to estimate diffusion distances in muscle and to correlate changes in diffusion distances with fiber growth, capillary growth, and the geometrical arrangement of capillaries in the muscle bed.