Exercise training resistance

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. 

Duncan, N.D., D.A. Williams, and G.S. Lynch (1998). Adaptations in rat skeletal muscle following long-term resistance exercise training. Eur. J. Appl. Physiol. Occupat. Physiol. 77 372-8. 

Fairey, A.S. et al.. Effects of exercise training on fasting insulin, insulin resistance, insulin-like growth factor binding proteins in postmenopausal breast cancer survivors a randomized controlled trial. Cancer Epidemiol Biomarkers Prev., 12, 721, 2003. 

Increased serum RBP4 levels are associated with insulin resistance in postmenopausal and elderly women (An et al. 2009 Suh et al. 2010). In addition, elevated serum RBP4 is coupled with metabolic syndrome components, such as increased BMI, waist-to-hip ratio, serum triglycerides, and systolic blood pressure. Interestingly, exercise training is accompanied by a reduction of serum RBP4 only in subjects in whom insulin resistance improved. Interventions that ameliorated insulin resistance... 

Yarasheski KB, Pak-Loduca J, Hasten DL et al. (1999) Resistance exercise training increases mixed muscle protein synthesis rate in frail women and men >/=76 yr old. Am J Physiol Endocrinol Metab 2.T1, B118-B125. 

Even withont resistance exercise, testosterone administration can increase lean body mass,and a resistance exercise training program can magnify these effects. 

Gaine, FC., Viesselman, C.T., Pikosky, M.A. et al.. Aerobic exercise training decreases leucine oxidation at rest in healthy adults, J Nutr, 135, 1088, 2005. Campbell, W.W., Crim, M.C., Young, V.R., Joseph, L.J., and Evans, W.J., Effects of resistance training and dietary protein intake on protein metabolism in older adults. Am J Physiol, 268, El 143, 1995. 

Nissen S, Sharp R, Ray M, Rathmacher JA, Rice J, Fuller JC, Jr., Connelly AS, Abumrad N. The effect of the leucine metabolite P-hydroxy-fi-methylbutyrate on muscle metabolism during resistance-exercise training. J Appl Physiol 1996 81 2095-2104. 

Endurance training also has a noteworthy effect on fat metabolism. In sedentary individuals, especially those who have undergone calorie-restricted diets, adipocytes are resistant to the stimulation by the sympathetic nervous system that accompanies physical exercise. For reasons that are still poorly understood, endurance training results in an increased sensitivity of adipocytes to these hormones. This is an important point, because the amount of fatty acids transported into muscle cells and used to drive muscle contraction is directly related to their concentration in blood. Trained muscle can generate more energy by oxidizing ketone bodies. 

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