Exercise anabolic resistance

It is very probable that anabolic resistance to nutrition and/or exercise contributes to age-related muscle loss. More likely, sarcopenia is a very complex process caused by a multiplicity of events, some of... 

Interventions such as leucine supplementation, ingestion of an adequate amount of essential amino acids or protein following traditional resistance exercise, and low-load BFR to prevent and reverse muscle loss with aging seem hopeful. The key to all of these therapeutic techniques is in their ability to overcome anabolic resistance to exercise and nutrients by stimulating muscle protein synthesis and translation initiation through the mTORCl pathway. 

Drummond MJ, Dreyer HC, Pennings B et al. (2008) Skeletal muscle protein anabolic response to resistance exercise and essential amino acids is delayed with aging. J Appl Physiol 104, 1452-1461. 

Rasmussen BB, Tipton KD, Miller SL et al. (2000) An oral essential amino acid-carbohydrate supplement enhances muscle protein anabolism after resistance exercise. J Appl Physiol 88, 386-392. 

West DW, Kujbida GW, Moore DR et al. (2009) Resistance exercise-induced increases in putative anabolic hormones do not enhance muscle protein synthesis or intracellular signalling in young men. J Physiol 587, 5239-5247. 

In contrast to endurance exercise, resistance exercise results in muscle hypertrophy rather than an increase in amino acid oxidation and mitochondrial biogenesis. If, for example, there are no changes in efficiency of amino acid retention, there must, at some point, be a protein intake in excess of basal requirements to provide the amino acids required for anabolism. The extent of this increased need is again a fimction of the basal state of training, the duration, and the intensity of the training program. 

Tipton, K.D., Elliott, T.A., Cree, M.G., Wolf, S.E., Sanford, A.R, and Wolfe, R.R., Ingestion of casein and whey proteins result in muscle anabolism after resistance exercise, Med Sci Sports Exerc, 36, 2073, 2004. 

Tipton, K.D., Rasmussen, B.B., Miller, S.L. et al.. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab, 281, E197, 2001. 

Phillips, S.M., Hartman, J.W., and Wilkinson, S.B. (2(X)5). Dietary protein to support anabolism with resistance exercise in young men. J Am Coll Nutr 24 134S-139S. 

Kraemer WJ, Gordon SE, Fleck SJ, Marchitelli LJ, Mello R, Dziados JE, Friedl K, Harman E, Maresh C, Fry AC. Endogenous anabolic hormonal and growth factor responses to heavy resistance exercise in males and females, Int J Sports Med 1991 12 228-235. 

Overall, the results suggest that older males are more resistant to the anabolic effects of AA feeding, including having a dramatically shorter metabolic window (i.e., the period of heightened nutrient sensitivity to the post-exercise effects of RT). 

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