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Scientific Investigation into the
Rationality of Carbohydrate Researched and Composed by Adam “Old School” Knowlden
Abstract: Analysis of scientific literature regarding post-workout nutrition was reviewed in-depth. An added emphasis was placed upon research pertaining to intelligent carbohydrate consumption post-anaerobic exercise. Vantage points of research included: 1) The scientific background of enhanced recovery, 2) the chemical properties of glycogen, 3) the relationship between the timing of glucose and favorable recuperation, 4) optimizing recovery, 5) methodology of consumption, 6) utilization of the full recovery period. Research topics are discussed in a succession of essays. Carbohydrate metabolic research has validated the necessity of proper glucose feeding post-training bout. Methodologies centered on severely delaying gastric emptying, utilization of inferior sugar sources, and suppressing anabolic hormones are placed under scrutiny. Essay One: Q: What is the Histological Background Linking Optimal Post-Workout Research to Enhanced Recovery? A: J. W. Conn documented the glycemic
response to isoglucogenic quantities of protein and carbohydrate in 1936. Also during this time, research-oriented experiments for the post-workout “window” were catalogued (21, 22). Throughout the 1960s and early ‘70s, Floyd began studying the insulinotropic effect of intravenous amino acid administration. Cocktails of several amino acid samples lead to quantifiable increases in plasma insulin (7-12, 15).
In later studies, Floyd investigated the combined effect of intravenous glucose administrations with the blending of various amino acids and found that arginine-leucine and arginine-phenylalanine resulted in the strongest increase in plasma insulin concentrations (13,14).
More recently, numerous combinations of amino acids were investigated, and it was shown that, when coupled together with glucose, the mixtures resulted in large increases in plasma insulin concentrations. Several in vitro studies using incubated ß-cells of the pancreas showed strong insulinotropic effects of arginine, leucine, phenylalanine, and leucine in combination with glutamine (2, 3, 16, 17, 18, 23, 24, 25, 26, 28). Described later by Nuttall in the 1980s, the synergistic kindling properties of the combined consumption of carbohydrates and protein on plasma insulin concentrations were tested (19, 20). These studies helped confirm that liquid carbohydrate (CHO) ingestion after intense exercise promotes rapid restoration of muscle glycogen (1, 4, 5, 6). Teresa A. Hillier, David A. Fryburg, Linda A. Jahn, and Eugene J. Barrett (27) recently confirmed in vivo that insulin increases protein synthesis.Moreover, the ideology of carbohydrate consumption in conjunction with post-training can be traced back to the ancient Greeks and ancient Hebrews (See: Acute & Chronic Endocrine Responses to Exercise Induced Disruptions in Homeostasis Part One - Exercise Endocrinology Principles and Catecholamines). Subsequent to these earlier reports, considerable amounts of research have been built upon these findings and have been conducted addressing the nutritional concerns of muscle and how various diets impact muscle metabolism and performance post-exercise. In rare instances, unscientific and illogical claims are attributed to liquid and/or high GI carbohydrate utilization post-workout. One such dismissal is reduction of this protocol to nothing more than a tactic of supplement companies in an effort to make money. This is not only scientifically invalid, but furthermore a faulty argument. In logical circles such attacks are called ad hominems, and are highly fallacious. Ad hominems present no real logical argument whatsoever to the topic at hand, but rather attempts to discredit the argument by attacking the person or the person’s circumstances, rather than dealing with the opposing evidence or argument. In layman’s terms, this is referred to as, “Killing the Messenger”. Supplement companies did not invent the usage of high GI carbohydrates post-workout; they marketed the investigations of legitimate research. Albeit, JHR does caution its subscribers to be wary of these marketed products, as they tend to:
Rather, JHR advises its subscribers to home-brew their own post-workout anabolic cocktail, tailored to his or her own individual needs in regards to macro-nutritional content. See: The Window of Opportunity References for essay one: 1.Bergstrom, J, and Hultman E. Muscle glycogen synthesis after exercise: an enhancing factor localized to the muscle cells in man. Nature 210: 309-310, 1966) 2.Blachier F, Mourtada A, Sener A, Malaisse WJ. Stimulus-secretion coupling of arginine-induced insulin release. Uptake of metabolized and nonmetabolized cationic amino acids by pancreatic islets. Endocrinology 1989;124:134–41. 3.Blachier F, Leclercq Meyer V, Marchand J, et al. Stimulus-secretion coupling of arginine-induced insulin release. Functional response of islets to L-arginine and L-ornithine. Biochim Biophys Acta 1989; 1013:144–51. 4.Costill, DL. CHO for exercise dietary
demands for optimal performance. Int J Sports Med 1: 1-18, 1988. 7. Floyd JC Jr, Fajans SS, Conn JW, Knopf RF, Rull J. Stimulation of insulin secretion by amino acids. J Clin Invest 1966;45:1487–502. 8.Floyd JC Jr, Fajans SS, Knopf RF, Conn JW. Evidence that insulin release is the mechanism for experimentally induced leucine hypoglycemia in man. J Clin Invest 1963;42:1714–9. 9. Floyd JC Jr, Fajans SS, Conn JW, Thiffault C, Knopf RF, Guntsche E. Secretion of insulin induced by amino acids and glucose in diabetes mellitus. J Clin Endocrinol Metab 1968;28:266–76. 10.Floyd JC Jr, Fajans SS, Pek S, Thiffault CA, Knopf RF, Conn JW. Synergistic effect of essential amino acids and glucose upon insulin secretion in man. Diabetes 1970;19:109–15. 11.Floyd JC Jr, Fajans SS, Pek S, Thiffault CA, Knopf RF, Conn JW. Synergistic effect of certain amino acid pairs upon insulin secretion in man. Diabetes 1970;19:102–8. 12.Fajans SS, Knopf RF, Floyd JC Jr, Power L, Conn JW. The experimental induction in man of sensitivity to leucine hypoglycemia. J Clin Invest 1962;42:216–29. 13.Floyd JC Jr, Fajans SS, Pek S, Thiffault CA, Knopf RF, Conn JW. Synergistic effect of essential amino acids and glucose upon insulin secretion in man. Diabetes 1970;19:109–15. 14.Floyd JC Jr, Fajans SS, Pek S, Thiffault CA, Knopf RF, Conn JW. Synergistic effect of certain amino acid pairs upon insulin secretion in man. Diabetes 1970;19:102–8. 15.Fajans SS, Knopf RF, Floyd JC Jr, Power L, Conn JW. The experimental induction in man of sensitivity to leucine hypoglycemia. J Clin Invest 1962;42:216–29. 16.Hutton JC, Sener A, Malaisse WJ. Interaction of branched chain amino acids and keto acids upon pancreatic islet metabolism and insulin secretion. J Biol Chem 1980;255:7340–6. 17.Malaisse WJ, Plasman PO, Blachier F, Herchuelz A, Sener A. Stimulus-secretion coupling of arginine-induced insulin release: significance of changes in extracellular and intracellular pH. Cell Biochem Funct 1991;9:1–7. 18.Malaisse Lagae F, Brisson GR, Malaisse WJ. The stimulus-secretion coupling of glucose-induced insulin release. VI. Analogy between the insulinotropic mechanisms of sugars and amino acids. Horm Metab Res 1971;3:374–8. 19.Nuttall FQ, Gannon MC, Wald JL, Ahmed M: Plasma glucose and insulin profiles it normal subjects ingesting diets of varying carbohydrate, fat, and protein content J Am Coll Nutr 4:437-450, 1985 20.Nuttall FQ, Mooradian AD, Gannon MC Billington C, Krezowski P: Effect of protein ingestion on the glucose and insulin response to a standardized oraglucose load. Diabetes Care 7:465-470, 1984 21.Pallotta JA, Kennedy PJ: Response of plasma insulin and growth hormone to carbohydrate and protein feeding. Metabolism 17:901-908, 1968 22.Rabinowitz D, Merimee TJ, Maffezzoli R, Burgess JA: Patterns of hormonal release after glucose, protein, and glucose plus protein. Lancet 2:454-456, 1966 23.Sener A, Malaisse WJ. L-Leucine and a nonmetabolized analogue activate pancreatic islet glutamate dehydrogenase. Nature 1980; 288:187–9. 24.Sener A, Hutton JC, Malaisse WJ. The stimulus-secretion coupling of amino acid-induced insulin release. Synergistic effects of L-glutamine and 2-keto acids upon insulin secretion. Biochim Biophys Acta 1981;677:32–8. 25.Sener A, Malaisse WJ. The stimulus-secretion coupling of amino acid-induced insulin release: insulinotropic action of branched-chain amino acids at physiological concentrations of glucose and glutamine. Eur J Clin Invest 1981;11:455–60. 26.Sener A, Blachier F, Rasschaert J, Mourtada A, Malaisse Lagae F, Malaisse WJ. Stimulus-secretion coupling of arginine-induced insulin release: comparison with lysine-induced insulin secretion. Endocrinology 1989;124:2558–67. 27. Teresa A. Hillier, David A. Fryburg, Linda A. Jahn, and Eugene J. Barrett. Extreme hyperinsulinemia unmasks insulin's effect to stimulate protein synthesis in human forearm. Am. J. Physiol. 274 (Endocrinol. Metab. 37): E1067-E1074, 1998 28.Varnier M, Leese GP, Thompson J, Rennie MJ. Stimulatory effect of glutamine on glycogen accumulation in human skeletal muscle. Am J Physiol 1995;269:E309–15 Essay Two: Q: What are the properties of glycogen? And why are these properties so vital post workout? A:
To enhance the progress of muscular strength and size with heavy-resistance body building programs, optimal conditions for recovery from training sessions are imperative, primarily glycogen re-synthesis (22). Recovery occupies the coordinated operation of multiple physiological processes that are heavily influenced by the accessibility and actions of exclusive hormones and nutrients (16, 17). Both qualitative and quantitative modifications in skeletal muscle contractile proteins are all supported and signaled by a horde of systematic -trophic influences from hormones to nutrient availability (18, 19). Markedly, concentric and eccentric contractions disrupt or damage certain muscle fibers that must undertake a remodeling restoration process. Dietary nutrients, hormones, and growth factors interact to regulate this remodeling of skeletal muscle proteins (5). One primal factor associated with muscular fatigue is depletion of muscle glycogen (1). These stores must be replaced rapidly during the post-workout initial recovery phase in order for performance to be reproducible in a subsequent exercise bout(s). Glycogen synthesis may be restricted by blood glucose concentration, glucose transport, and the activity of the enzymes involved in the pathway, particularly glycogen synthase (10). Body building training programs provide conditions within skeletal muscle to support the rapid synthesis of glycogen. Glycogen synthase action is inversely relative to glycogen intensity (23); as a result of the glycogen-depleted state post-training, skeletal muscle (24) and hepatic glycogen synthase activity are raised (13). Basal glucose transport within skeletal muscle occurs via GLUT-4 (A powerhouse effect of insulin is the stimulation of glucose transport via the translocation of the insulin responsive glucose transporter, GLUT4, to the plasma membrane) (14). Nevertheless, the ability of skeletal muscle to take up glucose is relative, due to adjustments in the GLUT-4 content of the sarcolemal membrane.
There are hypothesized to be one or more intracellular pools of GLUT-4 proteins, which are translocated to the sarcolema in response to both increased insulin concentration (20) and prior exercise (9); these effects are additive (6).
The ingestion of high GI carbohydrates increases glycogen synthesis in two ways. The first (12) is increased substrate availability through the increased blood glucose concentration, which results in an increased glucose uptake due to mass action. Moreover, the resultant increase in systemic insulin concentration stimulates the translocation of GLUT-4 transporters from an intracellular pool to the sarcolemal membrane (7). The hormone insulin is also a powerful activator of glycogen synthase and inhibitor of glycogen phosphorylase (2). The effectiveness of a specific carbohydrate in encouraging resynthesis of the carbohydrate stores is reliant on the insulin and glucose response to the carbohydrate load (4). This is directly linked to gastric emptying and intestinal absorption rates. It is also associated with the insulinogenic potential of the carbohydrate, as indicated by the glycemic index (GI) of a carbohydrate. The development of glycogen synthesis relies upon the accessibility of glycogenic substrate (8) and the activity of the enzymes implicated in glycogen synthesis. These include hexokinase and glycogen synthase. Prior exercise enhances skeletal muscle glucose transport (3) because of the translocation of GLUT-4 transporters from an intracellular pool to the sarcolemal membrane.The inclination for skeletal muscle to extort blood glucose will thus be increased, and the glucose will tend to be directed toward glycogen synthesis because glycogen synthase is activated during recovery due to the low intramuscular glycogen concentration (23).These conditions favoring the resynthesis of glycogen can be exploited (8) by the provision of a quality carbohydrate source.The consequential amplification in glucose availability and the insulin response to the glucose load would tend to stimulate (7) a further increase in the GLUT-4 content of the sarcolemal membrane.Research has demonstrated (11) that there is a direct correlation between the rate of glycogen storage during recovery and total muscle GLUT-4 protein content.On a side note, observational and empirical evidence makes it plainly obvious that the endocrinal state of the body builder post-workout is nothing like that of a sedentary individual.
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However, this is hasty generalization (understand also that this is ignoring a host of other benefits glucose feeding post-training has in regards to anabolism). D. L. Costill, D. D. Pascoe, W. J. Fink, R. A. Robergs, S. I. Barr, and D. Pearson reveled in their study, “Impaired muscle glycogen resynthesis after eccentric exercise,” (J Appl Physiol 69: 46-50, 1990) that glycogen synthesis is hindered post-eccentric exercise. The heavy utilization of the eccentric factor in the body builder’s code of behavior makes this study even more imperative for the hypertrophy athlete. In light of this obstruction, it would be foolhardy not to act in a fashion that would allow for the most advantageous recovery, such as is the case with sub-optimal carbohydrate foundations post-workout. But consider that even if an athlete trains his or her shoulders directly only once per week, they are still training chest, back, trapezius, arms, and integrating other various compound exercises that incorporate heavy use of the deltoids, either as prime or secondary movers, synergists or as dynamic stabilizers. No doubt this is supported by DOMS and ingrained through kinesthetic proprioception. The deltoids are taking an extreme breakdown multiple days in a row (and this is the case with a manifold of large and small muscle groups, for example the back, calves, and abdominals). Furthermore, eccentric exercise has been shown to impair glycogen synthesis. Additionally, myofibril hydration is crucial as “glucose and sodium post-exercise greatly enhance intestinal fluid absorption over plain water, due to the Glucose/Sodium co transport system” (See: Effect of Plasma Volume on Myofibril Hydration, Nutrient Delivery, and Athletic Performance).
Furthermore, there is no logical reason not to intake High GI carbohydrates post-workout. Excess fat gain from high GI carbohydrate sources is the only reason asserted, and this is based on ignorance of post-exercise carbohydrate metabolism.
Will one make gains without high GI carbohydrates post-workout? Some progress can be made without these factors. Often proponents of slow burning carbohydrates post-workout will take studies out of context claiming, “Rapid glycogen synthesis via insulin post-workout is unnecessary. Most body building training programs incorporate several rest days before the same muscle group is trained again; therefore, glycogen depletion is not a big issue in bodybuilding. After all, I train my shoulders only once per week; there is plenty of time in between to restore glycogen!” Will optimal performance and maximal potential gains suffer under such a protocol? Science and logic have shown the answer to be an overwhelming and resounding, “yes”. Delaying the consumption of nutrients post-workout, via the intake of low GI carbohydrates like fat and fiber, has been shown to be self-impeding and rationally inconsistent for body building practices. In summary, perhaps no other phrase has been truer than that immortalized by USAF Medical Lab Tech. and ABC Moderator, Seksi, “Not spiking is like letting an open wound bleed for a few hours before doing something about it.” See: Fiber Dynamics Part II, Endocrine Insanity Part III References for essay three: 1.Ahlborg, B, Bergström J, Ekelund LG, and Hultman E. Muscle glycogen and muscle electrolytes during prolonged physical exercise. Acta Physiol Scand 70: 129-142, 1967 2.Balon, T. W., A. Zorzano, J. T. Treadway, M. N. Goodman, and N. B. Ruderman. Effect of insulin on protein synthesis and degradation in skeletal muscle after exercise. Am. J. Physiol. 258 (Endocrinol. Metab. 21): E92-E97, 1990 3.Bennet, W. M., A. A. Connacher, C. M. Scrimgeour, R. T. Jung, and M. J. Rennie. Euglycemic hyperinsulinemia augments amino acid uptake by human leg tissue during hyperaminoacidemia. Am. J. Physiol. 259 (Endocrinol. Metab. 22): E185-E194, 1990 4.Benini L, Castellani G, Brighenti F, Heaton KW, Brentegani MT, Casiraghi MC, Sembenini C, Pellegrini N, Fioretta A, Minniti G, et al. Gastric emptying of a solid meal is accelerated by the removal of dietary fibre naturally present in food. Gut. 1995 Jun; 36(6): 825-30. 5.Bergström, J, Hermansen L, Hultman E, and Saltin B. Diet, muscle glycogen and physical performance. Acta Physiol Scand 71: 140-150, 1967. 6.Bergstrom, J, and Hultman E. Muscle glycogen synthesis after exercise: an enhancing factor localized to the muscle cells in man. Nature 210: 309-310, 1967 7.Biolo, G., S. P. Maggi, B. D. Williams, K. D. Tipton, and R. R. Wolfe. Increased rates of muscle protein turnover and amino acid transport after resistance exercise in humans. Am. J. Physiol. 268 (Endocrinol. Metab. 31): E514-E520, 1995 . 8.Blom, PCS, Høstmark AT, Vaage O, Kardel KR, and Mæhlum S. Effect of different post-exercise sugar diets on the rate of muscle glycogen synthesis. Med Sci Sports Exerc 19: 491-496, 1987 9.Burke, LM, Collier GR, and Hargreaves M. Muscle glycogen storage after prolonged exercise: effect of the glycemic index of carbohydrate feedings. J Appl Physiol 75: 1019-1023, 1993 10.Chesley, A, MacDougall JD, Tarnopolsky MA, Atkinson SA, and Smith K. Changes in human muscle protein synthesis after resistance exercise. J Appl Physiol 73: 1383-1388, 1992 11.Costill, DL, Sherman WM, Fink WJ, Maresh C, Witten M, and Miller JM. The role of dietary carbohydrates in muscle glycogen resynthesis after strenuous running. Am J Clin Nutr 34: 1831, 1981 12.Coyle, EF, Coggan AR, Hemmert MK, and Ivy JL. Muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate. J Appl Physiol 61: 165-172, 1986 13.David S. Ludwig Dietary Glycemic Index
and Obesity 1, 2. 14.Deanna K. Levenhagen1, Jennifer D. Gresham1, Michael G. Carlson3, David J. Maron3, Myfanwy J. Borel1, and Paul J. Flakoll1,2 Postexercise nutrient intake timing in humans is critical to recovery of leg glucose and protein homeostasis. Am J Physiol Endocrinol Metab 280: E982-E993, 2001; 15.Doyle, JA, Sherman WM, and Strauss RL.
Effects of eccentric and concentric exercise on muscle glycogen
replenishment. J Appl Physiol 74: 1848-1855, 1993 17.Goldberg, A. L. Influence of insulin and contactile activity on muscle size and protein balance. Diabetes 28: 18-24, 1979 18.Haymond, M. W., F. F. Horber, P. De Feo, S. E. Kahn, and N. Mauras. Effect of human growth hormone and insulin-like growth factor I on whole-body leucine and estimates of protein metabolism. Horm. Res. 40: 92-94, 1993 19.Hermansen, L, Hultman E, and Saltin B. Muscle glycogen during prolonged severe exercise. Acta Physiol Scand 71: 334-346, 1965. 20.Ivy, JL, Katz AL, Cutler CL, Sherman WM, and Coyle EF. Muscle glycogen synthesis after exercise: effect of time of carbohydrate ingestion. J Appl Physiol 64: 1480-1485 21.Ivy, JL. Glycogen resynthesis after exercise: effect of carbohydrate intake. Int J Sports Med 19, Suppl: 142-146, 1998.) 22.Ivy, JL, Lee MC, Brozinick JT, and Reed MJ. Muscle glycogen storage after different amounts of carbohydrate ingestion. J Appl Physiol 65: 2018-2023, 1988 23.Ivy, JL,, Harold W. Goforth Jr.2, Bruce M. Damon3, Thomas R. McCauley3, Edward C. Parsons3, and Thomas B. Price3 J Appl Physiol 93: 1337-1344, 2002. Early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement 24.Johansen, J.N., Knudsen, K.E.B., Sandstrom, B., Skjoth, F. Effects of varying content of soluble dietary fibre from wheat flour and oat milling fractions on gastric emptying in pigs. Br. J. Nutr. 75:339-351, 1996.) 25.Jenkins DJ, Josse RG, Jenkins AL, Wolever TM, Vuksan V. Implications of altering the rate of carbohydrate absorption from the gastrointestinal tract. Clinical Nutrition and Risk Factor Modification Centre, St. Michael's Hospital, Faculty of Medicine, University of Toronto, Ontario. 26.Jentjens, RLPG, van Loon LJC, Mann CH,
Wagenmakers AJM, and Jeukendrup AE. Addition of protein and amino acids to
carbohydrates does not enhance postexercise muscle glycogen synthesis. J
Appl Physiol 91: 839-846, 2001 28.Kadish, AH, and Sternberg JC.
Determination of urine glucose by measurement of rate of oxygen
consumption. Diabetes 18: 467-470, 1969 30.Levenhagen, DK, Gresham JD, Carlson MG, Maron DJ, Borel MJ, and Fakoll PJ. Postexercise nutrient intake timing in humans is critical to recovery of leg glucose and protein homeostasis. Am J Physiol Endocrinol Metab 280: E982-E993, 2001 31.MacDougall, J. D. Hypertrophy or hyperplasia. In: Strength and Power in Sport, edited by P. V. Komi. Boston, MA: Blackwell, 1992, p. 230-238. 32.Phillips SM, Tipton KD, Aarsland A, Wolf SE, and Wolfe RR. Mixed muscle protein synthesis and breakdown after resistance exercise in humans. Am J Physiol Endocrinol Metab 273: E99-E107, 1997. 33.Phillips SM, Tipton KD, Ferrando AA, and Wolfe RR. Resistance training reduces the acute exercise-induced increase in muscle protein turnover. Am J Physiol Endocrinol Metab 276: E118-E124, 1999. 34.Piehl, AK, Soderlund K, and Hultman E. Muscle glycogen resynthesis rate in humans after supplementation of drinks containing carbohydrates with low and high molecular masses. Eur J Appl Physiol 81: 346-351, 2000 35.Pitkanen HT, Nykanen T, Knuutinen J, Lahti K, Keinanen O, Alen M, Komi PV, and Mero AA. Free amino acid pool and muscle protein balance after resistance exercise. Med Sci Sports Exerc 35: 784-792, 2003. 36.Randle, PJ, Garland PB, Hales CN, and Newslome EA. The glucose fatty-acid cycle. Its role in insulin sensitivity and the metabolic disturbances of diabetes mellitus. Lancet 1: 785-789 37.Rasmussen, BB, Tipton KD, Miller SL, Wolf SE, and Wolfe RR. An oral essential amino acid-carbohydrate supplement enhances muscle protein anabolism after resistance exercise. J Appl Physiol 88: 386-392, 2000 38.Reed, MJ, Brozinick JT, Lee MC, and Ivy JL. Muscle glycogen storage postexercise: effect of mode of carbohydrate administration. J Appl Physiol 66: 720-726, 1989 39.Richter, E. A., B. Kiens, B. Saltin, N. J. Christensen, and G. Savard. Skeletal muscle glucose uptake during dynamic exercise in humans: role of muscle mass. Am. J. Physiol. 254 (Endocrinol. Metab. 17): E555-E561, 1988 40.Suzuki, M, Hashiba N, and Kajuu T. Influence of timing of sucrose meal feeding and physical activity on plasma triacylglycerol levels in rat. J Nutr Sci Vitaminol 28: 295-310, 1982 41.Van Loon, LJC, Saris WHS, Kruijshoop M,
and Wagenmakers AJM Maximizing postexercise muscle glycogen synthesis:
carbohydrate supplementation and the application of amino acid and protein
hydrolysate mixtures. Am J Clin Nutr 72: 106-111, 2000 43.Yarasheski, K. E., J. J. Zachwieja, and D. M. Bier. Acute effect of resistance exercise on muscle protein synthesis rate in young and elderly men and women. Am. J. Physiol. 265 (Endocrinol. Metab. 28): E210-E214, 1993 44.Zawadzki, KM, Yaspelkis BB, III, and Ivy JL. Carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise. J Appl Physiol 72: 1854-1859, 1992 Essay Four: Q: What Carbohydrate source is most optimal post-workout? A: Simple carbohydrates (sugar) are referred to as mono- and disaccharides, while complex carbohydrates are referred to as polysaccharides; for instance, starch. The most general disaccharides are sucrose (glucose and fructose); lactose (glucose and galactose), found in milk products; and maltose (glucose and glucose). The most widespread naturally occurring monosaccharide is fructose (found in fruits and vegetables).
Naturally occurring sugar, known as intrinsic, refers to the sugar that is an integral constituent of whole fruit, vegetable, and milk products. Added sugar, or extrinsic, refers to sucrose or other refined sugars in soft drinks and incorporated into food, fruit drinks, and other beverages (1). The rate of muscle glycogen storage after carbohydrate supplementation is related in part to the plasma insulin response (13, 15, 17). Moreover, a distinct advantage in muscle glycogen storage can be achieved after exercise with the addition of protein to a carbohydrate supplement.
A goal of feeding after exercise is to elevate glucose as soon as possible to provide substrate for glycogen synthesis. Glycogen synthesis can occur more rapidly if carbohydrate is consumed quickly and in adequate amounts after exercise (14, 8). Simply put, carbohydrate sources that digest quickly and increase insulin levels are most optimal, and even more so when coupled with protein sources such as hydrolyzed whey, as the two have a synergistic effect. The two prime carbohydrates for achieving this goal are a 50/50 mixture of Dextrose (Glucose) and Maltodextrin. Together these two sources of energy will provide the ultimate anabolic fusion. This topic has been covered extensively. See: Dextrose, Maltodextrin, and Sodium an In Depth Analysis Expanding upon this, however, inferior sources of sugars need to be detailed. Prior exercise enhances skeletal muscle glucose transport because of the translocation of GLUT-4 transporters from an intracellular pool to the sarcolemal membrane (4). The capacity for skeletal muscle to extract blood glucose will thus be increased, and the glucose will tend to be directed toward glycogen synthesis because glycogen synthase is activated during recovery due to the low intramuscular glycogen concentration (16). These conditions favoring the resynthesis of glycogen can be exploited by the provision of carbohydrates. The resultant increase in glucose availability and the insulin response to the glucose load would tend to stimulate a further increase in the GLUT-4 content of the sarcolemmal membrane (6). McCoy et al. (11) demonstrated there is a direct correlation between the rate of glycogen storage during recovery and total muscle GLUT-4 protein content. This increased insulin response will stimulate glycogen synthesis in two ways; first by increasing GLUT-4 translocation (10), which will facilitate increased muscle glucose uptake and thus glycogenic substrate availability, and second by activating glycogen synthase (2). To reiterate, it has been demonstrated by JHR that a 50/50 mixture of Dextrose and Maltodextrin will fulfill these required attributes. However, many post-workout formulas include inferior sugar sources. These can be homemade cocktails prescribed from outdated or ill-informed groups, or recipes sold as marketed supplements in stores. The sources discussed below should be avoided if optimal gains are the objective of the body builders training sessions. In 2000, J. L. Bowtell, K. Gelly, M. L. Jackman, A. Patel, M. Simeoni, and M. J. Rennie (9) reported in their entry, “Effect of different carbohydrate drinks on whole body carbohydrate storage after exhaustive exercise,” that:Fructose is less insulinogenic than glucose; the lower insulin response to the sucrose than to the glucose polymer drinks may be due to the fructose component of sucrose or may be related to a more rapid gastric emptying of the glucose polymer drink. The former explanation is the most feasible, because the calculated gastric emptying times for 330 ml of 18.5% (wt/vol) glucose polymer and sucrose drinks were 69.8 ± 2.9 and 66.5 ± 2.5 min respectively. The low GI of fructose in addition to its preferential uptake by liver makes fructose a poor post-exercise carbohydrate source. Therefore, fructose should be avoided post-training (3). Nilsson and Hultman (12) demonstrated that the infusion of fructose resulted in a fourfold greater increase in liver glycogen than glucose. Fructose is an inferior carbohydrate source to utilize during the window of opportunity; therefore, post-workout blends that include fructose should be avoided (this includes honey and table sugar). Some examples of fructose-containing products that are popular in unscientific post-workout recipes include:
Sucrose is 50% glucose and 50% fructose. Steer clear of recipes that embrace sucrose sources post-workout.
Illustration two-
Sucrose, a 1,2'-glycoside “Sucrose is a disaccharide that yields 1 equiv of glucose and 1 equiv of fructose on acidic hydrolysis. This 1:1 mixture of glucose and fructose is often referred to as invert sugar, since the sign of optical rotation changes (inverts) during the hydrolysis from sucrose ([alpha]D = +66.5o) to a glucose fructose mixture ([alpha]D = -22.0o). Certain insects, particularly honeybees, have enzymes called invertases that catalyze the hydrolysis of sucrose to a glucose-fructose mixture. Honey, in fact, is primarily a mixture of these three sugars.-Photo and explanation compliments of the University of Oxford, Department of Chemistry. J. L. Bowtell, K. Gelly, M. L. Jackman, A. Patel, M. Simeoni, and M. J. Rennie (9) reviewed previous studies of carbohydrate sources post-exercise to confirm the conclusions of their own research: The storage of muscle glycogen was higher during recovery after consumption of the glucose polymer drink than after either of the sucrose drinks. Doyle et al. (18) using multiple regression analysis, found that 94% of the variance in glycogen synthesis rates in the literature could be attributed to variation in plasma glucose and insulin concentrations. In the studies reported in this paper, the glucose response to the carbohydrate supplements was lower in the 12% sucrose trial than in the other two trials during the first hour of recovery. During the second hour of recovery, the plasma glucose response was higher in the glucose polymer trial than in either sucrose trial. The availability of glucose for incorporation into hepatic and skeletal muscle stores was therefore greater in the glucose polymer trial…. In conclusion, consumption of 61 g glucose polymer drink after exhaustive exercise promoted a more rapid storage of carbohydrate during the first 2 h of recovery than did consumption of an isoenergetic sucrose drink, both in the whole body and in skeletal muscle. Oftentimes, articles will illogically assert that the post-workout “window” is a sort of “get out of jail free card,” claiming the post-workout phase presents itself as an opportune time to eat highly processed junk foods, like ice cream or candy bars, as one is unlikely to gain fat. Post-workout is not a time to binge on sucrose-filled junk food; on the contrary, the post-training meal should be taken more seriously than any other serving of food in the day! The idiocy behind prescribing junk food post-workout is self-explanatory from the descriptions of inferior sugars given in this essay, and the fact that these foods do not consider proper carbohydrate ratios or assimilation via gastric emptying. Lactose is also an inferior source of carbohydrates post-workout. Milk sugar has a low GI, and furthermore milk contains casein protein and fat, which will act to delay gastric emptying. Casein is made up of numerous similar proteins, which form a multi-molecular granular structure called a casein micelle. The micellar makeup of milk casein is an important part in the method of milk digestion in the stomach and the basis of many of the milk product industries, such as cheese. In addition to casein molecules, the casein micelles contain water and salts (11). Lactose (disaccharide composed of D-glucose and D-galactose) is the foremost milk carbohydrate in most species. In addition to lactose, milk contains other carbohydrates in small amounts, including glucose, galactose, and oligosaccharides (11). It has been demonstrated that milk should not be blended into a post-workout recipe (5, 7). |
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Illustrations collage- Examples of sugar sources to avoid post workout. References for essay four: 1.Circulation. 2002;106:523.Sugar and Cardiovascular Disease 2.Cohen, P. Muscle glycogen synthase. Enzymes 17: 461-497, 1986. 3.Conlee RK, Lawler RM, Ross PE Effects of glucose or fructose feeding on glycogen repletion in muscle and liver after exercise or fasting Ann Nutr Metab. 1987;31(2):126-32 4.Douen, AG, Ramlal T, Rastogi S, Bilan PJ, Cartee GD, Vranic M, Holloszy JO, and Klip A. Exercise induces recruitment of the "insulin-responsive" glucose transporter. J Biol Chem 124: 13427-13430, 1990. 5. Ercan N, Nuttall FQ, Gannon MC, Redmon JB, Sheridan KJ. Effects of glucose, galactose, and lactose ingestion on the plasma glucose and insulin response in persons with non-insulin-dependent diabetes mellitus. Metabolism 42(12):1560-7, 1993 6.Goodyear, LJ, Hirshman MF, Napoli R, Calles J, Markuns JF, Ljungqvist O, and Horton ES. Glucose ingestion causes Glut 4 translocation in human skeletal muscle. Diabetes 45: 1051-1056, 1996 7.Hugi D, Tappy L, Sauerwein RM, Bruckmaier RM, Blum JW. Insulin-dependent glucose utilization in intensively milk-fed veal calves is modulated by supplementing lactose in an age-depenedent manner. J Nutr 128:1023-30, 1998 8.Ivy, JL,, Harold W. Goforth Jr.2, Bruce M. Damon3, Thomas R. McCauley3, Edward C. Parsons3, and Thomas B. Price3 J Appl Physiol 93: 1337-1344, 2002. Early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement 9.J. L. Bowtell, K. Gelly, M. L. Jackman, A. Patel, M. Simeoni, and M. J. Rennie “Effect of different carbohydrate drinks on whole body carbohydrate storage after exhaustive exercise”. Appl Physiol 88: 1529-1536, 2000; 10.Klip, A, Ramlal T, Young DA, and Holloszy JO. Insulin-induced translocation of glucose transporters in rat hind-limb muscles. FEBS Lett 224: 224-230, 1987 11.McCoy, M, Proietto J, and Hargreaves M. Skeletal muscle GLUT-4 and post-exercise muscle glycogen storage in humans. J Appl Physiol 80: 411-415, 1996 12.Nilsson, LH, and Hultman E. Liver and muscle glycogen in man after glucose and fructose infusion. Scand J Clin Lab Invest 33: 5-10, 1974 13.Reed, MJ, Brozinick JT, Lee MC, and Ivy JL. Muscle glycogen storage postexercise: effect of mode of carbohydrate administration. J Appl Physiol 66: 720-726, 1989 14.Robergs, R.A. (1991). Nutrition and exercise determinants of postexercise glycogen synthesis. Int. J. Sport Nutr. 1:307-337. 15.Van Loon, LJC, Saris WHS, Kruijshoop M, and Wagenmakers AJM Maximizing postexercise muscle glycogen synthesis: carbohydrate supplementation and the application of amino acid and protein hydrolysate mixtures. Am J Clin Nutr 72: 106-111, 2000 16.Yan, Z, Spencer MK, and Katz A. Effect of low glycogen on glycogen synthase in human muscle during and after exercise. Acta Physiol Scand 145: 345-352, 1992 17.Zawadzki, KM, Yaspelkis BB, III, and Ivy JL. Carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise. J Appl Physiol 72: 1854-1859, 1992 Essay Five: Q: What is the proper ratio of carbohydrates to consume post-exercise? A: Scientific evidence (4, 27, 34) suggests that irregular activities can stimulate significant glycogenolytic effects (such as body building shock training protocols, i.e. various angles, targeting different muscle fibers, enhanced eccentric training, etc.).
These examinations show that muscle glycogen is an imperative fuel source during body building performances. Moreover, reductions in muscle glycogen concentration have resulted in:
Glycogenolysis has proved itself to be an essential energy supplier during high-intensity intermittent exercises, such as those required by body building training styles (21, 30, 31). Haff et al. (12) reported that 3 sets of isokinetic leg extensions performed at 120°·s–1 can reduce the muscle glycogen content of the vastus lateralis by 17%. Additionally, in the same investigation, a multiple-set resistance-training session (back squats, speed squats, 1-leg squats) performed at 65, 45, and 10 percent of 1 repetition maximum (1RM) back squat resulted in a 26.7% decrease in muscle glycogen of the vastus lateralis. Tesch et al. (31) have also reported a 40% reduction in muscle glycogen in response to the performance of 5 sets of 10 repetitions of concentric knee extensions performed at 60% of 1RM. A 30% decrease in the muscle glycogen content of type IIab and IIb fibers in response to this protocol was also reported. Muscle glycogen concentration was also reported to decrease by 20% in response to the performance of 5 sets of 10 repetitions at 45% of 1RM. Similarly, Robergs et al. (26) have shown that 6 sets of 6 repetitions of leg extensions performed at 70 and 35% of 1RM can elicit a significant glycogenolytic effect resulting in 39 and 38% reductions in glycogen, respectively. Type II fibers were also demonstrated to have a greater glycogen loss when compared with type I fibers. Tesch et al. (32) also reported that a 26% decrease in the muscle glycogen content of the vastus lateralis can occur in response to a resistance-training regimen consisting of 5 sets of front squats, back squats, leg presses, and knee extensions. One set of 10 repetitions of biceps curls can also reduce muscle glycogen by 13%, whereas 3 sets of 10 can result in a 25% reduction in muscle glycogen. Pascoe et al. (25) have reported a 31% reduction in muscle glycogen content in response to leg extensions performed to muscular failure (sets: 8.0 ± 0.7). The results of these studies clearly show that muscle glycogen is an encompassing source of energy required throughout training. The studies also suggest that glycogen depletion is dependent upon the total amount of work completed. Body building sessions which focus on higher repetition schemes (8–12 repetitions), specific time under tensions, and moderate loads such as those incorporated during the hypertrophy/hyperplasia phase of bodybuilders, has an even greater effect on muscle glycogen concentration than those of lower repetition formats (13). Type II fibers, which are heavily targeted for hypertrophy exercise, tend to express higher glycolytic enzyme activity than type I fibers; therefore, a preferential depletion of muscle glycogen may not be totally unexpected. The favored depletion of type II fibers during high-intensity training compromises the performance of subsequent and exercises in the session, and will ultimately lead to a decrease in performance (10, 11, 34). Costill et al. (8) has undoubtedly shown that minimal glycogen synthesis occurs after exercise in the absence of carbohydrate consumption. Furthermore, the amount of muscle glycogen synthesis in the 24-hour period post-exercise is also directly correlated (r = 0.84) to the amount of carbohydrate ingested and the timing of that ingestion (15, 17, 22). When carbohydrates are given immediately after and 1 hour after resistance exercise, the muscle glycogen content of the vastus lateralis is returned to 91% of resting values compared with 75% of pre-exercise values in 6 hours when only water is given (25). Thus, it can be logically demonstrated that delaying the ingestion of carbohydrates after exercise by a time frame of two hours can significantly decrease the amount of glycogen resynthesis, such as would be the case in the intake of slow burning, low GI, carbohydrate foods post-exercise. This decrease is even more important to body builders who perform multiple training sessions in one day, known as an AM/PM split (13). If the trainee can increase his or her amount of resynthesis between training sessions, an increase in performance will occur during the second bout of exercise on a given training day. Cortisol has been shown to be highly catabolic in type II fibers (19). The multitude of catabolic effects stimulated by cortisol occur in order to stimulate gluconeogenesis (23). Additionally, Dinan, T.G., J. Thakore, and V. O'Keane, in their study, “Lowering cortisol enhances growth hormone response to growth hormone releasing hormone in healthy subjects,” (Acta Physiol. Scand. 151:413–416. 1994) verified that the lowering of cortisol levels enhances the release of growth hormone in reaction to growth hormone–releasing hormone. Kraemer et al. (20) have demonstrated in their entry suppressed cortisol levels in response to three days of carbohydrate supplementation and a heavy resistance-training regime. Additionally, increases in growth hormone were reported in concurrence with these suppressed cortisol levels. This promotes the claim that insulin-mediated suppression of cortisol may result in increases in growth hormone concentration, and thus lead to an ergogenic effect (an ability to enhance sports performance) (27, 29). Additionally, cortisol has been exposed to reduce nucleic acid and protein synthesis in thymocytes (7). A very similar outcome would be expected with body building resistance exercises. In fact, Nieman et al. (24) have reported that back squats executed to muscular failure can result in an immune response that is highly comparable to that seen with endurance exercise. A report by Zawadzki (36) stated that the combination of protein to a carbohydrate solution produced higher glycogen synthesis rates in subjects after exercise than did ingestion of a carbohydrate only solution,, and even more so in relation to a protein only solution. Immediately and 2 h after each exercise bout, they ingested 112.0 g carbohydrate (CHO), 40.7 g protein (PRO), or 112.0 g carbohydrate and 40.7 g protein (CHO-PRO). During recovery the plasma glucose response of the CHO treatment was significantly greater than that of the CHO-PRO treatment, but the plasma insulin response of the CHO-PRO treatment was significantly greater than that of the CHO treatment. Both the CHO and CHO-PRO treatments produced plasma glucose and insulin responses that were greater than those produced by the PRO treatment (P less than 0.05). The rate of muscle glycogen storage during the CHO-PRO treatment [35.5 +/- 3.3 (SE) mumol.g protein-1.h-1] was significantly faster than during the CHO treatment (25.6 +/- 2.3 mumol.g protein-1.h-1), which was significantly faster than during the PRO treatment (7.6 +/- 1.4 mumol.g protein-1.h-1). The results suggest that post-exercise muscle glycogen storage can be enhanced with a carbohydrate-protein supplement as a result of the interaction of carbohydrate and protein on insulin secretion. Therefore, the proper amount of carbohydrates to consume post workout must take into consideration: Lean Body Mass (LBM), volume of training, size of muscle being trained, and intensity; the latter of which stimulates a release in cortisol. Considering all of these variables, it becomes obvious that the amount of carbohydrates to consume post-workout is going to be relative to each person. A myriad of studies has shown the anabolic effects of various measures of carbohydrates post-workout (1, 3, 9, 15-17, 33, 36). Its important to note that the optimization of glycogen synthesis rates requires adequate amounts of carbohydrate ingestion (2, 5, 15). Studies have revealed that most athletes can ingest carbohydrate at a maximum rate of 1.2 grams per minute without noticing the effects of gastrointestinal distress (6). However, this can vary from individual to individual. A collaboration of the research brings about a general consensus for the macros needed in the post-workout cocktail:
These numbers are calculated based on Lean Body Mass. It is evident that a 300lb. man with 25% body fat will not need 150 grams of carbohydrates post-workout. Instead, he should find his LBM and compute his requirements from those numbers. (To calculate lean body mass, take body fat percent minus total weight. See: The Ultimate Guide to Body fat Testing! ) Provided here are standard ranges; the maximums and minimums should be the starting points of personal ideal intakes. Again, recognize these are relative ratios, and that the intake of carbohydrates post-workout needs to stay consistent and reflect the athletes daily macro nutritional percentages along with the athlete’s insulin sensitivity (See: 13 Weeks To Hardcore Fat Burning - " The Diet ") For example, during a mass phase, carbohydrate intake tends to be higher. During this time, the upper end of the scale should be adhered to. When cutting body fat, daily carbohydrate consumption is more liable to be reduced, thus the lower end of the range would be a desirable starting point. The actual amount each individual consumes is subject to fall between the max and min range given. In the Journal of Sports Sciences, January 2004, vol. 22, no. 1, pp. 15-30, Burke L., Kiens B., and Ivy J. recommend the following advice in their entry, “Carbohydrates and fat for training and recovery”: An important goal of the athlete's everyday diet is to provide the muscle with substrates to fuel the training programme that will achieve optimal adaptation for performance enhancements. In reviewing the scientific literature on post-exercise glycogen storage since 1991, the following guidelines for the training diet are proposed. Athletes should aim to achieve carbohydrate intakes to meet the fuel requirements of their training programme and to optimize restoration of muscle glycogen stores between workouts. General recommendations can be provided, preferably in terms of grams of carbohydrate per kilogram of the athlete's body mass, but should be fine-tuned with individual consideration of total energy needs, specific training needs and feedback from training performance… Carbohydrate-rich foods with a moderate to high glycaemic index provide a readily available source of carbohydrate for muscle glycogen synthesis, and should be the major carbohydrate choices in recovery meals. This is sound counsel. Furthermore, total daily carbohydrate and protein calories percent ratios should be factored into the equation. The post-workout formula is considered a full meal. My personal recommendation is to keep a detailed training journal, paying close attention to post-training nutritional intake and compare that with success rates and goals reached at the end of a bulk-up or cut-down cycle (See: Muscle Mind Doctrine - Theoretical Concepts of Strategization ). If needed, this can help hone in and tweak a more precise number of adequate carbohydrates for each individual’s needs. In general, I recommend a 2:1 Carb/Pro ratio during a mass gaining phase and a 1:1 Carb/Pro ratio during a cutting or maintenance phase in the brew, which will be consumed over the space of one hour (tapering discussed in the next essay). For pre-contest or carbohydrate depletion, refer to: Pre Contest Week - An In Depth Analysis I advocate using the maximum number of .50g of carbohydrates per pound of LBM for a mass cycle, and the minimum number of .25 carbohydrates per pound of LBM for a leaning out/ maintenance cycle as solid starting ratios.
Begin with those macro proportions, and adjust accordingly based on individual circumstances, using a personal training journal to tweak the macro nutrient percentages further. I also recommend utilizing the lower end of the spectrum for a less intense or lower volume training session. Logically, the more severe the body builder’s training session is, or even the greater the amount of volumes which is used, the greater the demand your body would place on glycogen restoration due to depletion and the post-workout shake should reflect that.
For example, Ilias Smilios, Theophiolos Piliandis, Michalis Karamouzis, and Savvas P. Tokmakidis, in their study, “Hormonal Responses after Various Resistance Exercise Protocols” (Medicine & Science in Sports & Exercise 35(4): 644-654; Apr 2003), concluded: This study examined the effects of the number of sets on testosterone, cortisol, and growth hormone (hGH) responses after maximum strength (MS), muscular hypertrophy (MH), and strength endurance (SE) protocols. The number of sets functions up to a point as a stimulus for increased hormonal concentrations in order to optimize adaptations with MH and SE protocols, and has no effect on a MS protocol. Furthermore, the number of sets may differentiate long-term adaptations with MS, MH, and SE protocols causing distinct hormonal responses. This same ideology can be applied to working smaller muscle groups. Often body builders will prioritize (See: Priority Training Principle ), for example, biceps or calves and enter the gym with the sole intent of training a smaller muscle group. In such an event, the carbohydrate ratio post-workout should reflect the fact that a smaller muscle group is being exhausted, as compared to back or legs. During such an episode, the general carbohydrate recommendation for cutting ratios would suffice post-workout. On the opposite end, a shocking principle like the Austrian or Zane blitz, or high volume training, would require greater carbohydrate demands post-drill, and should be acted upon correspondingly during the window of opportunity. References for essay five: 1.Bak JF, Moller N, Schmitz O, Richter EA, Pedersen O. Effects of hyperinsulinemia and hyperglycemia on insulin receptor function and glycogen synthase activation in skeletal muscle of normal man. Metabolism 1991;40:830–5 2.Bergstrom J, Hultman E. Muscle glycogen synthesis after exercise: an enhancing factor localized to the muscle cells in man. Nature 1966;210:309–10 3.Blom PC, Hostmark AT, Vaage O, Kardel KR, Maehlum S. Effect of different post-exercise sugar diets on the rate of muscle glycogen synthesis. Med Sci Sports Exerc 1987;19:491–6 4.Boobis, I., C. Williams, and S.N. Wooten. Influence of sprint training on muscle metabolism during maximal exercise in man. J. Appl. Physiol. 342:36–37P. 1983. 5.Brozinick JT Jr, Lee MC, Ivy JL. Muscle glycogen storage postexercise: effect of mode of carbohydrate administration. J Appl Physiol 1989;66:720–6. 6.Coggan, A. R. and E. E. Coyle. Carbohydrate ingestion during prolonged exercise: effects on metabolism and performance. Exercise and Sports Science Review. 19: 1-40, 1991. 7.Chow, J.W., W.G. Darling, and J.G. Hay. Mechanical characteristics of knee extension exercises performed on an isokinetic dynamometer. Med. Sci. Sports Exerc. 29:794–803. 1997 8.Costill, D.L., W.M. Sherman, W.J. Fink, C. Maresh, M. Witten, and J.M. Miller. The role of dietary carbohydrates in muscle glycogen resynthesis after strenuous running. Am. J. Clin. Nutr. 34:1831–1836. 1981 9.Doyle JA, Sherman WM, Strauss RL. Effects of eccentric and concentric exercise on muscle glycogen replenishment. J Appl Physiol 1993;74:1848–55. 10.Gollnick, P.D., K.
Piehl, and B. Saltin. Selective glycogen depletion pattern in human muscle
fibres after exercise of varying intensity and at varying pedaling rates.
J. Physiol. Lond. 241:45–57. 1974. 12.Haff, G.G. Carbohydrate supplementation attenuates muscle glycogen loss during acute bouts of resistance training exercise. Doctoral dissertation, University of Kansas, Lawrence, 1999. 13.Haff GG, Lehmkuhl MJ, McCoy LB, Stone MH. “Carbohydrate Supplementation and Resistance Training.” Journal of Strength and Conditioning Research, 2003 Feb; 17(1): 187-196. 14.Hepburn, D., and R.J. Maughan. Glycogen availability as a limiting factor in performance of isometric exercise. J. Physiol. 342:52–53P. 1982. 15.Ivy JL, Lee MC, Brozinick JT Jr, Reed MJ. Muscle glycogen storage after different amounts of carbohydrate ing | |||||||
Additionally,
during these experiments Floyd observed a synergistic effect
when glucose was administered intravenously with these various
amino acid groupings.
Glycogen
is a polysaccharide, (C
In the
post-workout period, therefore, muscle membrane permeability to
glucose is high, thus favoring the accretion of glycogen
replacement. However, if rapid carbohydrate distribution is not provided
during recovery, glycogen synthesis will be limited
because the rate of endogenous glucose production from gluconeogenic
precursors such as alanine and glycerol is inadequate to support
maximal rates of glycogen synthesis (15). 
Body builders
are focused on lifting progressively heavier weights under longer time
under tensions.
Once
glycogen stores are depleted, the capacity to perform exercise
at full potential is lost or severely limited. Glycogen depletion has a
direct impact on decreasing the levels of maximum intensity that can be
dispersed during training (1, 5, 12, 15, 19, 21).
Figure
1. Gastric emptying is
Replacing
glycogen stores rapidly as possible is the most logical conclusion for
body builders who train multiple days or follow typical body building
splits and exercise programs.
The word
dextrose is a term used for glucose. 
