Muscle Adaptations Permitting Fatigue-Resistant Exercise.

摘要

Fatigue-resistant endurance exercise is achieved by developing sustainable patterns of substrate provision to the working muscle and of waste product elimination from the working muscle. Endurance sled dogs demonstrate marked fatigue resistance at high levels of exercise. The studies of sled dog metabolism demonstrated several noteworthy patterns of substrate delivery to the muscle, including extremely high capacity for muscle uptake of glucose, fatty acid, and lactate. In the case of glucose and fatty acid uptake, the increase in transport capacity appears to be due to increased intrinsic capacity of these transporters, rather than synthesis of additional transporter, thus increasing the efficiency of insulin- and contraction-stimulated substrate uptake.