Schematic representation of the control of muscle glucose uptake during exercise. Schematic representation of the control of muscle glucose uptake during exercise. Control of glucose is distributed between three serial steps. These are extracellular glucose delivery from blood to muscle membrane, muscle membrane glucose transport, and intracellular glucose phosphorylation. Below each gear are known mechanisms of regulation. Arrows associated with those mechanisms reflect exercise adaptations. Note that acute exercise increases hexokinase II protein; however, this adaptation is slow in onset. Modified from Wasserman and Halseth (47). Ronald J. Sigal et al. Dia Care 2004;27:2518-2539 ©2004 by American Diabetes Association