J Appl Physiol 2000 May;88(5):1631-6
van Hall G, Shirreffs SM, Calbet JA.
Copenhagen Muscle Research Center, Rigshospitalet, DK-2200 Copenhagen, Denmark. RH01769@RH.DK
In the present study, we have investigated the effect of carbohydrate and protein hydrolysate ingestion on muscle glycogen resynthesis during 4 h of recovery from intense cycle exercise. Five volunteers were studied during recovery while they ingested, immediately after exercise, a 600-ml bolus and then every 15 min a 150-ml bolus containing 1) 1.67 g. kg body wt(-1)of sucrose and 0.5 g. kg body wt(-1) of a whey protein hydrolysate (CHO/protein), 2) 1.67 g. kg body wt(-1)of sucrose (CHO), and 3) water. CHO/protein and CHO ingestion caused an increased arterial glucose concentration compared with water ingestion during 4 h of recovery. With CHO ingestion, glucose concentration was 1-1.5 mmol/l higher during the first hour of recovery compared with CHO/protein ingestion. Leg glucose uptake was initially 0.7 mmol/min with water ingestion and decreased gradually with no measurable glucose uptake observed at 3 h of recovery. Leg glucose uptake was rather constant at 0.9 mmol/min with CHO/protein and CHO ingestion, and insulin levels were stable at 70, 45, and 5 mU/l for CHO/protein, CHO, and water ingestion, respectively. Glycogen resynthesis rates were 52 +/- 7, 48 +/- 5, and 18 +/- 6 for the first 1.5 h of recovery and decreased to 30 +/- 6, 36 +/- 3, and 8 +/- 6 mmol. kg dry muscle(-1). h(-1) between 1.5 and 4 h for CHO/protein, CHO, and water ingestion, respectively. No differences could be observed between CHO/protein and CHO ingestion ingestion. It is concluded that coingestion of carbohydrate and protein, compared with ingestion of carbohydrate alone, did not increase leg glucose uptake or glycogen resynthesis rate further when carbohydrate was ingested in sufficient amounts every 15 min to induce an optimal rate of glycogen resynthesis
Carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise.
J. Appl.Physiol. 72: 1854-1859, 1992
Zawadzki KM, Yaspelkis BB 3rd, Ivy JL.
Department of Kinesiology, University of Texas, Austin 78712
Carbohydrate, protein, and carbohydrate-protein supplements were compared to determine their effects on muscle glycogen storage during recovery from prolonged exhaustive exercise. Nine male subjects cycled for 2 h on three separate occasions to deplete their muscle glycogen stores. 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). Blood samples were drawn before exercise, immediately after exercise, and throughout recovery. Muscle biopsies were taken from the vastus lateralis immediately and 4 h after exercise. 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 postexercise muscle glycogen storage can be enhanced with a carbohydrate-protein supplement as a result of the interaction of carbohydrate and protein on insulin secretion.
Effects of postexercise carbohydrate-protein feedings on muscle glycogen restoration.
J Appl Physiol 2000 Jun;88(6):1976-82
Carrithers JA, Williamson DL, Gallagher PM, Godard MP, Schulze KE, Trappe SW.
Human Performance Laboratory, Ball State University, Muncie, Indiana 47306, USA.
The purpose of this investigation was to determine the effects of postexercise eucaloric carbohydrate-protein feedings on muscle glycogen restoration after an exhaustive cycle ergometer exercise bout. Seven male collegiate cyclists [age = 25.6 +/- 1.3 yr, height = 180.9 +/- 3.2 cm, wt = 75.4 +/- 4.0 kg, peak oxygen uptake (VO(2 peak)) = 4.20 +/- 0.2 l/min] performed three trials, each separated by 1 wk: 1) 100% alpha-D-glucose [carbohydrate (CHO)], 2) 70% carbohydrate-20% protein (PRO)-10% fat, and 3) 86% carbohydrate-14% amino acid (AA). All feedings were eucaloric, based on 1.0 g. kg body wt(-1). h(-1) of CHO, and administered every 30 min during a 4-h muscle glycogen restoration period in an 18% wt/vol solution. Muscle biopsies were obtained immediately and 4 h after exercise. Blood samples were drawn immediately after the exercise bout and every 0.5 h for 4 h during the restoration period. Increases in muscle glycogen concentrations for the three feedings (CHO, CHO-PRO, CHO-AA) were 118 mmol/kg dry wt; however, no differences among the feedings were apparent. The serum glucose and insulin responses did not differ throughout the restoration period among the three feedings. These results suggest that muscle glycogen restoration does not appear to be enhanced with the addition of proteins or amino acids to an eucaloric CHO feeding after exhaustive cycle exercise.
Addition of protein and amino acids to carbohydrates does not enhance postexercise muscle glycogen synthesis.
J Appl Physiol 2001 Aug;91(2):839-46
Jentjens RL, van Loon LJ, Mann CH, Wagenmakers AJ, Jeukendrup AE.
Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
Ingestion of a protein-amino acid mixture (Pro; wheat protein hydrolysate, leucine, and phenylalanine) in combination with carbohydrate (CHO; 0.8 g x kg(-1) x h(-1)) has been shown to increase muscle glycogen synthesis after exercise compared with the same amount of CHO without Pro. The aim of this study was to investigate whether coingestion of Pro also increases muscle glycogen synthesis when 1.2 g CHO. kg(-1). h(-1) is ingested. Eight male cyclists performed two experimental trials separated by 1 wk. After glycogen-depleting exercise, subjects received either CHO (1.2 g x kg(-1) x h(-1)) or CHO+Pro (1.2 g CHO x kg(-1) x h(-1) + 0.4 g Pro x kg(-1) x h(-1)) during a 3-h recovery period. Muscle biopsies were obtained immediately, 1 h, and 3 h after exercise. Blood samples were collected immediately after the exercise bout and every 30 min thereafter. Plasma insulin was significantly higher in the CHO+Pro trial compared with the CHO trial (P < 0.05). No difference was found in plasma glucose or in rate of muscle glycogen synthesis between the CHO and the CHO+Pro trials. Although coingestion of a protein amino acid mixture in combination with a large CHO intake (1.2 g x kg(-1) x h(-1)) increases insulin levels, this does not result in increased muscle glycogen synthesis.
Dietary strategies to promote glycogen synthesis after exercise.
J Appl Physiol 2001;26 Suppl:S236-45
Ivy JL.
Exercise Physiology and Metabolism Laboratory, Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, USA.
Muscle glycogen is an essential fuel for prolonged intense exercise, and therefore it is important that the glycogen stores be copious for competition and strenuous training regimens. While early research focused on means of increasing the muscle glycogen stores in preparation for competition and its day-to-day replenishment, recent research has focused on the most effective means of promoting its replenishment during the early hours of recovery. It has been observed that muscle glycogen synthesis is twice as rapid if carbohydrate is consumed immediately after exercise as opposed to waiting several hours, and that a rapid rate of synthesis can be maintained if carbohydrate is consumed on a regular basis. For example, supplementing at 30-min intervals at a rate of 1.2 to 1.5 g CHO x kg(-1) body wt x h(-1) appears to maximize synthesis for a period of 4- to 5-h post exercise. If a lighter carbohydrate supplement is desired, however, glycogen synthesis can be enhanced with the addition of protein and certain amino acids. Furthermore, the combination of carbohydrate and protein has the added benefit of stimulating amino acid transport, protein synthesis and muscle tissue repair. Research suggests that aerobic performance following recovery is related to the degree of muscle glycogen replenishment.