Following an intense exercise bout, the body is primarily in a catabolic state. Stress hormones such as cortisol are elevated, and key fuel stores such as muscle glycogen are low or even depleted. For recovery and positive adaptations to occur at the most optimal rate, a shift must be made from this catabolic state to an anabolic one. Ingesting the proper post-exercise nutrition and doing so with optimal timing is critical for this desirable transition to occur.
Nutritional supplementation post exercise is effective for several reasons. Immediately after exercise, the sensitivity of muscle to nutritional stimuli is heightened, remaining maximally elevated for approximately 30-60 minutes. Ingesting nutrients during this time optimizes the rate at which muscle glycogen can be replenished and muscle protein synthesis can be activated. In addition, nutrients can attenuate the catabolic stress hormone response (31) and can help prevent additional protein breakdown (4), thereby accelerating protein accretion. The combination of protein and carbohydrate is more effective than either macronutrient alone because they each activate different but cooperative signaling pathways that serve to regulate carbohydrate and protein metabolism. Enhanced muscle glycogen storage and protein accretion lead to faster recovery and increased muscle mass and strength, key goals of any resistance training program. In addition, appropriate nutrient supplementation during and following exercise can prevent exercise-induced immune system suppression.
While the importance of muscle glycogen is often discussed in the context of endurance exercise, this fuel source is critical for resistance exercise as well. Muscle glycogen stores can be significantly depleted after an intense resistance exercise bout (17), and it is important that glycogen is restored before the next bout to ensure a quality workout. If recovery is more effective, then it is conceivable that the training load can be increased at a faster rate for greater training adaptation.
It has been demonstrated that providing a carbohydrate supplement immediately post exercise results in a doubled rate of glycogen synthesis compared with providing the same supplement 2 hours post exercise (22) and that carbohydrate intake greater than 1.5 g/kg body weight will maximize muscle glycogen storage when provided at 2-hour intervals (23). The addition of more calories will not continue to increase the rate of muscle glycogen resynthesis. In fact, providing 3.0 g CHO/kg body weight immediately post and 2 hours post exercise versus 1.5 g CHO/kg demonstrated the same effect on muscle glycogen resynthesis during a 4-hour recovery period (23). However, it has been shown that more frequent supplementation, such as every 15 to 30 minutes, results in rates of synthesis 25 to 30% higher than when supplementing every 2 hours (11,49). The amount of carbohydrate necessary to maximize glycogen storage when supplementing frequently (1.5 g·kg−1 body weight·h−1) is twice that shown to be most effective when supplementing at 2-hour intervals (0.75 g·kg−1 body weight·h−1). This high amount of carbohydrate could easily be considered excessive for many people to ingest, and the high frequency of supplementation does not reflect a practical post-exercise strategy.
A more practical approach for most exercisers and athletes is to ingest a supplement immediately post exercise and about 2 hours later. A strategy that addresses the practicality of daily training or competitive events and that maximizes muscle glycogen restoration is much more attractive and useful. Rather than providing large boluses of carbohydrate, research suggests that a more moderate amount of carbohydrate with the addition of a small amount of protein can be provided instead. In fact, such carbohydrate plus protein supplementation has been shown to increase muscle glycogen resynthesis post exercise to the same extent as when supplementing frequently with high amounts of carbohydrate (2,20,54). The amount of carbohydrate and protein found to be most effective ranges between 1.2 and 1.5 g CHO/kg body weight and 0.4 to 0.6 g PRO/kg when provided immediately post exercise at 2-hour intervals. For individuals engaging in resistance exercise training, however, the amount of carbohydrate can be reduced to 1.0 to 1.2 g CHO/kg body weight because carbohydrate stores are not as greatly depleted in resistance exercise as occurs with prolonged endurance exercise.
It is important to realize that following glycogen-depleting exercise, there is little if any increase in muscle glycogen storage until adequate carbohydrate is made available (22,23,54). Therefore, early intake of carbohydrate after exercise is advantageous because it provides an immediate source of substrate for muscle to use for glycogen resynthesis, while also taking advantage of an increased muscle insulin sensitivity that develops due to muscle contraction (15,21,39). Furthermore, supplementing immediately after exercise appears to delay the decline in insulin sensitivity, and with supplementation at 2-hour intervals or more frequently, a relatively rapid rate of glycogen storage can be maintained for up to 8 hours post exercise (5,23).
It should be noted that while providing protein in addition to carbohydrate may not increase glycogen synthesis to a greater extent than providing very large boluses of carbohydrate at frequent intervals, the advantages of ingesting a carbohydrate-protein supplement include taking advantage of a rapid rate of muscle glycogen storage without consuming unnecessary additional calories found in large carbohydrate provisions, stimulating a greater effect on protein synthesis, and reducing muscle damage. These benefits can lead to a greater rate of recovery and adaptation to resistance exercise training.
Muscle damage associated with resistance exercise occurs from the mechanical stress placed on the fibers during the eccentric phase of contraction (7,13) as well as the catabolic hormonal environment that increases muscle protein breakdown post exercise. When no supplement is provided post exercise, this catabolic environment predominates, with muscle damage continuing to increase for many hours. In addition, muscle glycogen resynthesis has been shown to be impaired in damaged muscle (9,50), limiting glycogen recovery for several days.
Recently, Baty et al. (1) reported that supplementing with a carbohydrate-protein supplement before, during, and immediately after resistance exercise reduced the appearance of myoglobin and creatine phosphokinase (CPK) in the blood that occurred during and following exercise. These proteins are found in skeletal muscle and leak into the blood circulation when muscle damage occurs. The results of Baty et al. (1) suggest that carbohydrate-protein supplementation can limit muscle damage that occurs both during as well as in the hours after the exercise bout. An earlier investigation by Wojcik et al. (53) reported a trend (p < 0.08) for lower CPK with a milk-based carbohydrate-protein recovery supplement versus a carbohydrate-only beverage following resistance exercise, although no difference in inflammatory markers or in muscle function was reported.
Other investigations using endurance exercise models have demonstrated reduced muscle damage in response to carbohydrate-protein supplementation compared with carbohydrate alone or placebo (8,40-43). Recently, Valentine et al. (48) investigated the responses of trained cyclists to carbohydrate versus carbohydrate-protein supplements. The cyclists performed an intense cycling bout to fatigue while receiving the treatments during the bout. Following a 24-hour recovery period, the cyclists performed a resistance exercise session consisting of leg extensions to fatigue. Not only was time to fatigue during the cycling exercise longer during the carbohydrate-protein treatment, but also the number of leg extension repetitions performed to fatigue 24 hours later was significantly greater compared with the carbohydrate or placebo treatments. The authors also reported a significant decrease in markers of muscle damage with the carbohydrate-protein supplement after the cycling bout (48). The mechanisms by which carbohydrate-protein attenuate muscle damage are yet to be completely elucidated, but the role of insulin in reducing muscle protein degradation is likely to be a key factor, as well as attenuating the catabolic post-exercise hormonal milieu.
At present, few studies have investigated the effects of carbohydrate-protein supplementation on immune function following heavy resistance exercise. The effects of nutritional supplementation on immune function during and after endurance exercise such as cycling and running are better characterized, although the interactions of nutrition, exercise, and the immune system are still a burgeoning and exciting field of research.
The work of Nieman et al. in exercise immunology has illuminated some of the aspects of immune function changes primarily in response to endurance exercise (cycling and running). It is well known that intense and prolonged exercise can negatively impact the immune system, resulting in depressed immune function and higher rates of illnesses such as upper respiratory tract infections (30,35). While the immune response to resistance exercise is far less characterized, it appears that an acute bout of resistance exercise can impact the immune system. Because carbohydrate has been shown to attenuate perturbations in immune cells and cytokines in response to intense endurance exercise (29,33,34,36), Nieman et al. (32) sought to determine if such supplementation could affect cytokine changes in response to a 2-hour resistance exercise bout in trained individuals. Compared with placebo, carbohydrate ingestion did not attenuate the modest increases in the plasma levels of interleukin (IL)-6, IL-10, IL-1ra, and IL-8 or muscle gene expression levels for IL-1β, IL-6, IL-8, and tumor necrosis factor α (32). Given that the subjects were all resistance trained, it is possible that a difference might be found if compared with an untrained group as suggested by the research of Potteiger et al. (37).
Potteiger et al. (37) compared the white blood cell counts and T-cell proliferative responses of resistance trained and untrained women after an acute bout of resistance exercise. While there was no change in these parameters in the trained women, white blood cell counts increased while T-cell proliferative ability significantly decreased in the untrained women during the 3-hour post-exercise period (37). These results suggest that at least these immune parameters adapt to resistance training such that immune function is less perturbed or depressed following each bout in trained individuals compared with the untrained.
To our knowledge, the effects of carbohydrate-protein supplementation and immune function after resistance exercise have not yet been investigated. Given that carbohydrate supplementation has been shown to attenuate immune perturbations in endurance exercise models, and based on the current knowledge of possible immune perturbations in untrained individuals after an acute resistance exercise bout, it is reasonable to hypothesize that nutritional supplementation may be very important in protecting the immune system after each workout, thus being less susceptible to opportunistic infections and illness. This may be especially important for individuals just starting a resistance training program.
An increase in mixed muscle protein is at the very heart of exercise training adaptation. While resistance exercise is associated with hypertrophy of skeletal muscle fibers, endurance exercise is primarily associated with increases in mitochondrial protein. Thus, both types of exercise stimulate mixed muscle protein synthesis, albeit with an exercise phenotype-specific response (51). For the purposes of this review, we will focus primarily on the response to resistance exercise, while drawing insight from endurance studies where applicable.
While an acute bout of resistance exercise increases muscle protein synthesis above the basal rate, it also increases the rate of protein degradation. The balance between degradation and synthesis determines net protein balance, and for strength and mass gains, creating a positive protein balance is essential. Unfortunately, a negative net balance predominates until nutritional intake occurs following a resistance exercise bout.
It has been shown that the addition of adequate protein, especially the essential amino acids, to a post-exercise carbohydrate supplement is vital for optimizing protein synthesis, creating a positive protein balance, repairing muscle damage, and stimulating training adaptations (3,10,14,16,24,25,38,45). In addition, carbohydrate-protein can reduce muscle protein breakdown, largely due to an increase in plasma insulin levels. Insulin is one of the body's most anabolic hormones and exerts its most powerful effect by reducing protein degradation post exercise (4,6). When a supplement containing protein or amino acids is provided post exercise, net protein balance shifts because the rate of synthesis can now exceed that of breakdown (45).
Elevating plasma amino acid levels post exercise by infusion or oral supplementation has been demonstrated to shift the protein balance of the muscle from negative to positive by stimulating protein synthesis (38). Investigations by Levenhagen et al. (25), as well as Miller et al. (27), have demonstrated that the combination of carbohydrate and either protein or amino acids can in fact have an additive effect (25,27), which is likely due in part to a synergistic effect on the plasma insulin response (44,54) and elevated plasma amino acid levels. When amino acids are available, insulin may have an enhanced stimulatory role in protein synthesis (28), yet its most important role in facilitating a positive net protein balance appears to be in reducing degradation (4).
Given that amino acids stimulate protein synthesis, and an increased plasma insulin level reduces protein degradation, the combination of carbohydrate and protein in supplementation can result in a more positive net protein balance. This is due to the synergistic action of carbohydrate and protein on 2 different but cooperative pathways (19,28). Carbohydrate ingestion activates the insulin-signaling pathway, while the amino acids in protein engage the mammalian target of rapamycin (mTOR) pathway. These pathways converge to both increase muscle glycogen synthesis as well as activate messenger RNA translation initiation, which is the rate-limiting step leading to protein synthesis (Figure).
Recently, Howarth and et al. (18) used both stable isotope methodology and muscle biopsy techniques to determine the effect of 3 different carbohydrate or carbohydrate-protein treatments on mixed skeletal muscle fractional synthetic rate (FSR) and whole body protein balance following endurance exercise. The team provided 1.2 g CHO·kg−1·h−1, 1.2 g CHO + 0.4 g PRO·kg−1·h−1, or 1.6 g CHO·kg−1·h−1 for 3 hours of recovery and found that only in the carbohydrate-protein condition was whole body protein balance positive. This was primarily due to reduced protein degradation (18). In addition, biopsies obtained after 4 hours of recovery revealed that muscle FSR was higher in the carbohydrate-protein treatment than the carbohydrate treatments (18). The findings of this study support the hypothesis that a post-exercise carbohydrate-protein supplement is more effective in promoting muscle protein accretion than carbohydrate alone.
Just as skeletal muscle is most sensitive to insulin and nutritional substrate for glycogen resynthesis immediately post exercise, stimulation of protein synthesis by amino acids is most responsive immediately after exercise as well. Levenhagen et al. (26) provided a carbohydrate-protein supplement either immediately or 3 hours after a moderate-intensity cycling exercise bout and found that whole body protein synthesis was increased 300% compared with only 12% when the supplement was delayed by 3 hours (26). While providing a carbohydrate-protein supplement immediately post exercise is more efficacious than delaying a few hours, other investigations have shown that providing a supplement prior to the resistance exercise bout can increase muscle protein synthesis compared with waiting until after exercise (47). Tipton et al. (45) provided a carbohydrate plus essential amino acids supplement before or immediately after resistance exercise and found that muscle protein synthesis was greatest in the before-exercise condition, possibly due to increased amino acid delivery to the muscle because of increased blood flow during exercise. Tipton et al. (46) followed up on these results to determine if whey protein would be as effective as the essential amino acids when provided before exercise. No difference in protein synthesis, however, was found when protein was given before compared with after exercise.
In studies of resistance training over several weeks, carbohydrate-protein supplementation has been shown to increase muscle mass and strength development when taken nearer to the start or end of resistance exercise sessions as opposed to providing the supplementation several hours before or after exercise. Cribb and Hayes (10) recently demonstrated that a significantly greater increase in muscle mass and strength could be achieved during 10 weeks of resistance training if a carbohydrate-protein plus creatine supplement was ingested before and immediately after each daily workout compared with providing the supplement in the morning and at night. This agrees with previous findings of Esmarck et al. (12) who investigated the effects of providing a carbohydrate-protein supplement either immediately post resistance exercise or delayed by 2 hours in a group of elderly men. They found a significant increase in muscle mass and dynamic and isokinetic strength when the supplement was provided immediately post exercise, whereas only a small increase in dynamic strength was observed in the group ingesting the supplement 2 hours post exercise (12). Given that increasing muscle mass and strength are the primary goals of a resistance training program, it seems clear that supplementing with carbohydrate plus protein after each training session is the most effective and advantageous way to accomplish these goals.
In summary, while resistance exercise stimulates muscle growth, the process of muscle protein accretion is greatly limited until a nutritional substrate is provided. In the absence of supplementation, a catabolic state predominates and net protein balance is negative. Providing carbohydrate-protein supplementation immediately and 2 hours post exercise can increase the rate and amount of muscle glycogen replenishment, reduce muscle damage, possibly protect immune function, and increase the rate of muscle protein synthesis to a greater degree than providing carbohydrate or protein alone. Carbohydrate plus protein supplementation leads to greater gains in muscle mass and strength, which is the overarching goal of resistance training programs.
Given our interpretation of the current data on resistance exercise and nutritional supplementation, it is recommended that approximately 1.0 to 1.2 g of carbohydrate plus 0.5 to 0.6 g protein per kg of body weight could be ingested immediately after a resistance exercise session and then again 2 hours later in the form of either a supplement or a meal. The protein source should contain a significant amount of whey as this has been found to be most effective in stimulating protein synthesis (52). For a 70-kg person, each supplement would amount to 70 to 84 g carbohydrate plus 35 to 40 g protein, totaling 400 to 500 kcal. The most practical application of this timing and supplementation strategy is shown in the Table. Following such a nutritional plan can surely set the stage for greater positive adaptations to a resistance training program.
1. Baty JJ, Hwang H, Ding Z, Bernard JR, Wang B, Kwon B, and Ivy JL. The effect of a carbohydrate and protein supplement on resistance exercise
performance, hormonal response, and muscle damage
. J Strength Cond Res
21: 321-329, 2007.
2. Berardi JM, Price TB, Noreen EE, and Lemon PW. Postexercise muscle glycogen
recovery enhanced with a carbohydrate-protein supplement. Med Sci Sports Exerc
38: 1106-1113, 2006.
3. Biolo G, Tipton KD, Klein S, and Wolfe RR. An abundant supply of amino acids enhances the metabolic effect of exercise on muscle protein. Am J Physiol Endocrinol Metab
273: E122-E129, 1997.
4. Biolo G, Williams BD, Fleming RY, and Wolfe RR. Insulin action on muscle protein kinetics and amino acid transport during recovery after resistance exercise
48: 949-957, 1999.
5. Blom P, Høstmark A, Vaage O, Kardel K, and Maehlum S. Effect of different post-exercise sugar diets on the rate of muscle glycogen
synthesis. Med Sci Sports Exerc
19: 491-496, 1987.
6. Borsheim E, Cree MG, Tipton KD, Elliott TA, Aarsland A, and Wolfe RR. Effect of carbohydrate intake on net muscle protein synthesis
during recovery from resistance exercise
. J Appl Physiol
96: 674-678, 2004.
7. Clarkson PM and Hubal MJ. Exercise-induced muscle damage
in humans. Am J Phys Med Rehabil
81: S52-S69, 2002.
8. Combest T, Saunders M, Kane M, and Todd K. Attenuated CPK following carbohydrate/protein intervention improves subsequent performance. Med Sci Sports Exerc
37: S42, 2005.
9. Costill DL, Pascoe DD, Fink WJ, Robergs RA, Barr SI, and Pearson D. Impaired muscle glycogen
resynthesis after eccentric exercise. J Appl Physiol
69: 46-50, 1990.
10. Cribb PJ and Hayes A. Effects of supplement timing and resistance exercise
on skeletal muscle hypertrophy. Med Sci Sports Exerc
38: 1918-1925, 2006.
11. Doyle JA, Sherman WM, and Strauss RL. Effects of eccentric and concentric exercise on muscle glycogen
replenishment. J Appl Physiol
74: 1848-1855, 1993.
12. Esmarck B, Andersen JL, Olsen S, Richter EA, Mizuno M, and Kjar M. Timing of postexercise protein intake is important for muscle hypertrophy with resistance training in elderly humans. J Physiol
535: 301-311, 2001.
13. Evans WJ, Meredith CN, Cannon JG, Dinarello CA, Frontera WR, Hughes VA, Jones BH, and Knuttgen HG. Metabolic changes following eccentric exercise in trained and untrained men. J Appl Physiol
61: 1864-1868, 1986.
14. Flakoll PJ, Judy T, Flinn K, Carr C, and Flinn S. Postexercise protein supplementation improves health and muscle soreness during basic military training in marine recruits. J Appl Physiol
96: 951-956, 2004.
15. Garetto LP, Richter EA, Goodman MN, and Ruderman NB. Enhanced muscle glucose metabolism after exercise in the rat: The two phases. Am J Physiol Endocrinol Metab
246: E471-E475, 1984.
16. Gautsch TA, Anthony JC, Kimball SR, Paul GL, Layman DK, and Jefferson LS. Availability of eIF4E regulates skeletal muscle protein synthesis
during recovery from exercise. Am J Physiol Cell Physiol
274: C406-C414, 1998.
17. Haff GG, Koch AJ, Potteiger JA, Kuphal KE, Magee LM, Green SB, and Jakicic JJ. Carbohydrate supplementation attenuates muscle glycogen
loss during acute bouts of resistance exercise
. Int J Sport Nutr Exerc Metab
10: 326-339, 2000.
18. Howarth KR, Moreau NA, Phillips SM, and Gibala MJ. Co-ingestion of protein with carbohydrate during recovery from endurance exercise stimulates skeletal muscle protein synthesis
in humans. J Appl Physiol
106: 1394-1402, 2009.
19. Ivy JL, Ding Z, Hwang H, Cialdella-Kam LC, and Morrison PJ. Post exercise carbohydrate-protein supplementation: Phosphorylation of muscle proteins involved in glycogen synthesis and protein translation. Amino Acids
35: 89-97, 2008.
20. Ivy JL, Goforth HW Jr, Damon BM, McCauley TR, Parsons EC, and Price TB. Early postexercise muscle glycogen
recovery is enhanced with a carbohydrate-protein supplement. J Appl Physiol
93: 1337-1344, 2002.
21. Ivy JL and Holloszy JO. Persistent increase in glucose uptake by rat skeletal muscle following exercise. Am J Physiol Cell Physiol
241: C200-C203, 1981.
22. 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, 1988.
23. Ivy JL, Lee MC, Brozinick JT Jr, and Reed MJ. Muscle glycogen
storage after different amounts of carbohydrate ingestion. J Appl Physiol
65: 2018-2023, 1988.
24. Koopman R, Pannemans DLE, Jeukendrup AE, Gijsen AP, Senden JMG, Halliday D, Saris WHM, van Loon LJC, and Wagenmakers AJM. Combined ingestion of protein and carbohydrate improves protein balance during ultra-endurance exercise. Am J Physiol Endocrinol Metab
287: E712-E720, 2004.
25. Levenhagen DK, Carr C, Carlson MG, Maron DJ, Borel MJ, and Flakoll PJ. Postexercise protein intake enhances whole-body and leg protein accretion in humans. Med Sci Sports Exerc
34: 828-837, 2002.
26. Levenhagen DK, Gresham JD, Carlson MG, Maron DJ, Borel MJ, and Flakoll 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.
27. Miller SL, Tipton KD, Chinkes DL, Wolf SE, and Wolfe RR. Independent and combined effects of amino acids and glucose after resistance exercise
. Med Sci Sports Exerc
35: 449-455, 2003.
28. Morrison PJ, Hara D, Ding Z, and Ivy JL. Adding protein to a carbohydrate supplement provided after endurance exercise enhances 4E-BP1 and RPS6 signaling in skeletal muscle. J Appl Physiol
104: 1029-1036, 2008.
29. Nehlsen-Cannarella SL, Fagoaga OR, Nieman DC, Henson DA, Butterworth DE, Schmitt RL, Bailey EM, Warren BJ, Utter A, and Davis JM. Carbohydrate and the cytokine response to 2.5 h of running. J Appl Physiol
82: 1662-1667, 1997.
30. Nieman DC, Berk LS, Simpson-Westerber M, Arabatzis K, Youngberg S, Tan SA, Lee JW, and Eby WC. Effects of long-endurance running on immune system parameters and lymphocyte function in experienced marathoners. Int J Sports Med
10: 317-323, 1989.
31. Nieman DC. Immune response to heavy exertion. J Appl Physiol
82: 1385-1394, 1997.
32. Nieman DC, Davis JM, Brown VA, Henson DA, Dumke CL, Utter AC, Vinci DM, Downs MF, Smith JC, Carson J, Brown A, McAnulty SR, and McAnulty LS. Influence of carbohydrate ingestion on immune changes after 2 h of intensive resistance training. J Appl Physiol
96: 1292-1298, 2004.
33. Nieman DC, Davis JM, Henson DA, Walberg-Rankin J, Shute M, Dumke CL, Utter AC, Vinci DM, Carson JA, Brown A, Lee WJ, McAnulty SR, and McAnulty LS. Carbohydrate ingestion influences skeletal muscle cytokine mRNA and plasma cytokine levels after a 3-h run. J Appl Physiol
94: 1917-1925, 2003.
34. Nieman DC, Fagoaga OR, Butterworth DE, Warren BJ, Utter A, Davis JM, Henson DA, and Nehlsen-Cannarella SL. Carbohydrate supplementation affects blood granulocyte and monocyte trafficking but not function after 2.5 h or running. Am J Clin Nutr
66: 153-159, 1997.
35. Nieman DC, Johanssen LM, Lee JW, and Arabatzis K. Infectious episodes in runners before and after the Los Angeles Marathon. J Sports Med Phys Fitness
30: 316-328, 1990.
36. Nieman DC, Nehlsen-Cannarella SL, Fagoaga OR, Henson DA, Utter A, Davis JM, Williams F, and Butterworth DE. Effects of mode and carbohydrate on the granulocyte and monocyte response to intensive, prolonged exercise. J Appl Physiol
84: 1252-1259, 1998.
37. Potteiger JA, Chan MA, Haff GG, Mathew S, Schroeder CA, Haub MD, Chirathaworn C, Tibbetts SA, McDonald J, Omoike O, and Benedict SH. Training status influences T-cell responses in women following acute resistance exercise
. J Strength Cond Res
15: 185-191, 2001.
38. 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.
39. Richter EA, Garetto LP, Goodman MN, and Ruderman NB. Enhanced muscle glucose metabolism after exercise: Modulation by local factors. Am J Physiol Endocrinol Metab
246: E476-E482, 1984.
40. Romano B, Todd M, and Saunders M. Effect of a 4:1 ratio carbohydrate/protein beverage on endurance performance, muscle damage
and recovery. Med Sci Sports Exerc
36: S126, 2004.
41. Romano-Ely B, Todd M, Saunders M, and St. Laurent T. Effect of an isocaloric carbohydrate-protein-antioxidant drink on cycling performance. Med Sci Sports Exerc
38: 1608-1616, 2006.
42. Saunders M, Kane M, and Todd K. Effects of a carbohydrate-protein beverage on cycling endurance and muscle damage
. Med Sci Sports Exerc
36: 1233-1238, 2004.
43. Saunders MJ, Luden ND, and Herrick JE. Consumption of an oral carbohydrate-protein gel improves cycling endurance and prevents postexercise muscle damage
. J Strength Cond Res
21: 678-684, 2007.
44. Spiller GA, Jensen CD, Pattison TS, Chuck CS, Whittam JH, and Scala J. Effect of protein dose on serum glucose and insulin response to sugars. Am J Clin Nutr
46: 474-480, 1987.
45. Tipton KD, Borsheim E, Wolf SE, Sanford AP, and Wolfe RR. Acute response of net muscle protein balance reflects 24-h balance after exercise and amino acid ingestion. Am J Physiol Endocrinol Metab
284: E76-E89, 2003.
46. Tipton KD, Elliott TA, Cree MG, Aarsland AA, Sanford AP, and Wolfe RR. Stimulation of net muscle protein synthesis
by whey protein ingestion before and after exercise. Am J Physiol Endocrinol Metab
292: E71-E76, 2007.
47. Tipton KD, Rasmussen BB, Miller SL, Wolf SE, Owens-Stovall SK, Petrini BE, and Wolfe RR. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise
. Am J Physiol Endocrinol Metab
281: E197-E206, 2001.
48. Valentine RJ, Saunders MJ, Todd MK, and St. Laurent TG. Influence of carbohydrate-protein beverage on cycling endurance and indices of muscle disruption. Int J Sport Nutr Exerc Metab
18: 363-378, 2008.
49. van Hall G, Shirreffs SM, and Calbet JAL. Muscle glycogen
resynthesis during recovery from cycle exercise: No effect of additional protein ingestion. J Appl Physiol
88: 1631-1636, 2000.
50. Widrick JJ, Costill DL, McConell GK, Anderson DE, Pearson DR, and Zachwieja JJ. Time course of glycogen accumulation after eccentric exercise. J Appl Physiol
72: 1999-2004, 1992.
51. Wilkinson SB, Phillips SM, Atherton PJ, Patel R, Yarasheski KE, Tarnopolsky MA, and Rennie MJ. Differential effects of resistance and endurance exercise in the fed state on signalling molecule phosphorylation and protein synthesis
in human muscle. J Physiol
586: 3701-3717, 2008.
52. Wilkinson SB, Tarnopolsky MA, MacDonald MJ, MacDonald JR, Armstrong D, and Phillips SM. Consumption of fluid skim milk promotes greater muscle protein accretion after resistance exercise
than does consumption of an isonitrogenous and isoenergetic soy-protein beverage. Am J Clin Nutr
85: 1031-1040, 2007.
53. Wojcik JR, Walber-Rankin J, Smith LL, and Gwazdauskas FC. Comparison of carbohydrate and milk-based beverages on muscle damage
and glycogen following exercise. Int J Sport Nutr Exerc Metab
11: 406-419, 2001.
54. 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.