Exercise training endurance

Fast-twitch muscle fibers have a high capacity for anaerobic glycolysis but are quick to fatigue. They are involved primarily in short-term, high-intensity exercise. Slow-twitch muscle fibers in arm and leg muscles are well vascularized and primarily oxidative. They are used during prolonged, low-to-moderate intensity exercise and resist fatigue. Slow-twitch fibers and the number of their mitochondria increase dramatically in trained endurance athletes. 

Aerobic exercise inyolyes endurance training. As the body performs activities for extended periods, physiological and cellular adaptations occur (10-12). These adaptations focus on the ability of the body to supply oxygen to the muscle cells, the capacity of the cells to utilize oxygen, and a shift in the fuel source to greater use of fatty acids. The magnitude of these changes defines aerobic capacity and endurance. 

GLUT4, which has a AT value of 5 mM, transports glucose into muscle and fat cells. The presence of insulin, which signals the fed state, leads to a rapid increase in the number of GLUT4 transporters in the plasma membrane. Hence, insulin promotes the uptake of glucose by muscle and fat. The amount of this transporter present in muscle membranes increases in response to endurance exercise training. 

Zouhal H, Gratas-Delamarche A, Rannou F, Granier P, Bentue-Ferrer D, Delamarche P. Between 21 and 34 years of age, aging alters the cateholamine responses to supramaximal exercise in endurance trained athletes. Inti J Sports Med 1999 20 343-348. 

The central and peripheral responses of rats were altered due to the interactive effect of acute exercise and endurance training in the presence of physostigmine. The data indicated that endurance training delayed ChE recovery however, there was almost complete recovery in rats given acute exercise plus physostigmine and slower... 

Holloszy JO. Metabolic consequences of endurance exercise training. In Horton ES, Terjung RL, eds. Exercise, nutrition, and energy metabolism. New York Macmillan, 1988, pp. 116-131. 

McKenzie, S., Phillips, S.M., Carter, S.L., Lowther, S., Gibala, M.J., and Tarnopolsky, M.A., Endurance exercise training attenuates leucine oxidation and BCOAD activation during exercise in humans. Am J Physiol Endocrinol Metab, 278, E580, 2000. 

Medved 1, Brown MJ, Bjorksten AR, Murphy KT, Petersen AC, Sostaric S, Gong X, McKenna MJ. N-Acetylcysteine enhances muscle cysteine and glutathione availability and attenuates fatigue during prolonged exercise in endurance-trained individuals. J Appl Physiol 2004 97 1477-1485. 

Acute administration of caffeine produces a 5-25% increase in the basal metabolic rate. Inactive subjects exhibit a greater increase in resting metabolic rate than do exercise-trained subjects. It is concluded that endurance training seems to result in a reduced thermogenic response to a caffeine challenge. 

Healy, M.L., Gibney, J., Russell-Jones, D.L., et aL (2003) High dose growth hormone exerts an anabolic effect at rest and during exercise in endurance-trained athletes./owma/ of Clinical Endocrinology and Metabolism,... 

Denis, C., Linossier, M.-T, Dormois, D., Cottier-Perrin, M., Geyssant, A., and Lacour, J,-R. (1989). Effects of endurance training on hyperammonaemia during a 45-min constant exercise intensity. Eur. J. Appi Physiol. 59, 268-272. 

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