As requested, a brief compilation of some of the study info relating to the benefits of using EAAs around resistance training. There are a few other good studies that I have saved somewhere on my disorganised hard drive but just can't find right now... will add when i find them again.
The first study suggests that EAAs on their own are sufficient to induce MPS, and that the presence of NEAAs is not required:
Postexercise net protein synthesis in human muscle from orally administered amino acids
Kevin D. Tipton, Arny A. Ferrando, Stuart M. Phillips, David Doyle Jr., and Robert R. Wolfe
Metabolism Unit, Shriners Burns Institute, and Departments of Surgery and Anesthesiology, University of Texas Medical Branch, Galveston, Texas 77550
We examined the response of net muscle protein synthesis to ingestion of amino acids after a bout of resistance exercise. A primed, constant infusion of L-[ring-2H5]phenylalanine was used to measure net muscle protein balance in three male and three female volunteers on three occasions. Subjects consumed in random order 1 liter of 1) a mixed amino acid (40 g) solution (MAA), 2) an essential amino acid (40 g) solution (EAA), and 3) a placebo solution (PLA). Arterial amino acid concentrations increased ~150-640% above baseline during ingestion of MAA and EAA. Net muscle protein balance was significantly increased from negative during PLA ingestion ( 50 ± 23 nmol • min 1 • 100 ml leg volume 1) to positive during MAA ingestion (17 ± 13 nmol • min 1 • 100 ml leg volume 1) and EAA (29 ± 14 nmol • min 1 • 100 ml leg volume 1; P < 0.05).
Because net balance was similar for MAA and EAA, it does not appear necessary to include nonessential amino acids in a formulation designed to elicit an anabolic response from muscle after exercise. We concluded that ingestion of oral essential amino acids results in a change from net muscle protein degradation to net muscle protein synthesis after heavy resistance exercise in humans similar to that seen when the amino acids were infused.
Full study: http://ajpendo.physiology.org/cgi/conte ... 276/4/E628
The following study shows that EAAs taken combination with carbohydrate (CHO) around a workout has superior anti-catabolic benefits to either consuming just EAAs or CHO alone.
Liquid carbohydrate/essential amino acid ingestion during a short-term bout of resistance exercise suppresses myofibrillar protein degradation.
Bird SP, Tarpenning KM, Marino FE.
School of Human Movement Studies, Charles Sturt University, Bathurst, NSW 2795, Australia. sbird@csu.edu.au
A number of physiological events including the level of contractile activity, nutrient status, and hormonal action influence the magnitude of exercise-induced skeletal muscle growth. However, it is not the independent action of a single mechanism, but the complex interaction between events that enhance the long-term adaptations to resistance training. The purpose of the present investigation was to examine the influence of liquid carbohydrate (CHO) and essential amino acid (EAA) ingestion during resistance exercise and modification of the immediate hormonal response on myofibrillar protein degradation as assessed by 3-methylhistidine (3-MH) excretion. After a 4-hour fast, 32 untrained young men (18-29 years) performed a single bout of resistance exercise (complete body; 3 setsx10 repetitions at 75% of 1-repetition maximum; 1-minute rest between sets), during which they consumed a 6% CHO (n=8) solution, a 6-g EAA (n=8) mixture, a combined CHO+EAA (n=8) supplement, or placebo (PLA; n=8) beverage. Resistance exercise performed in conjunction with CHO and CHO+EAA ingestion resulted in significantly elevated (P<.001) glucose and insulin concentrations above baseline, whereas EAA ingestion only increased the postexercise insulin response (P<.05). Time matched at 60 minutes, the PLA group exhibited a peak cortisol increase of 105% (P<.001) with no significant change in glucose or insulin concentrations. Conversely, the CHO and CHO+EAA groups displayed a decrease in cortisol levels of 11% and 7%, respectively. Coinciding with these hormonal response patterns were significant differences in myofibrillar protein degradation. Ingestion of the EAA and CHO treatments attenuated 3-MH excretion 48 hours after the exercise bout. Moreover, this response was synergistically potentiated when the 2 treatments were combined, with CHO+EAA ingestion resulting in a 27% reduction (P<.01) in 3-MH excretion. In contrast, the PLA group displayed a 56% increase (P<.01) in 3-MH excretion.
These data demonstrate that not only does CHO and EAA ingestion during the exercise bout suppress exercise-induced cortisol release; the stimulatory effect of resistance exercise on myofibrillar protein degradation can be attenuated, most dramatically when the treatments are combined (CHO+EAA). Through an "anticatabolic effect," this altered balance may better favor the conservation of myofibrillar protein.
http://www.ncbi.nlm.nih.gov/pubmed/1663 ... t=Abstract
Another similar study showing the immediate post workout hormonal response of a EAA + CHO drink:
Effects of liquid carbohydrate/essential amino acid ingestion on acute hormonal response during a single bout of resistance exercise in untrained men.
Bird SP, Tarpenning KM, Marino FE.
School of Human Movement Studies, Charles Sturt University, Bathurst, New South Wales, Australia. sbirg@csu.edu.au
OBJECTIVE: The primary objective of this study was to investigate the influence of nutritive interventions on acute hormonal responses to a single bout of resistance exercise in untrained young men. Specifically, the aim was to determine whether the acute hormonal milieu conducive to enhancing skeletal muscle hypertrophic adaptation to resistance training could be created. The potential role of cortisol in inhibiting training-induced muscle growth is of particular interest, as is whether exercise-induced cortisol release can be attenuated by nutritive interventions. METHODS: After a 4-h fast, 32 subjects performed a single bout of resistance exercise ( approximately 60 min), during which they consumed a 6% carbohydrate (CHO) solution, a 6-g essential amino acid (EAA) mixture, a combined CHO+EAA supplement, or a placebo beverage. Blood samples were collected every 15 min throughout the exercise bout, immediately after exercise, and 15 and 30 min after exercise for analysis of total testosterone, cortisol, growth hormone, insulin, and glucose. RESULTS: No significant change in glucose or insulin was observed for placebo. CHO and CHO+EAA ingestion resulted in significantly (P < 0.001) increased glucose and insulin concentrations above baseline, whereas EAA resulted in significant postexercise increases (P < 0.05) in insulin only. Placebo exhibited a significant increase in cortisol within 30 min (P < 0.01), with a peak increase of 105% (P < 0.001) immediately after exercise, and cortisol remained 54% above baseline at 30 min after exercise (P < 0.05). Conversely, the treatment groups displayed no significant change in cortisol during the exercise bout, with CHO and CHO+EAA finishing 27% (P < 0.01) and 23% (P < 0.05), respectively, below baseline at 30 min after exercise. No between-group differences in exercise-induced growth hormone or testosterone concentrations after nutritive intervention were present.
CONCLUSION: These data indicate that CHO and/or EAA ingestion during a single bout of resistance exercise suppresses the exercise-induced cortisol response, in addition to stimulating insulin release. We conclude that the exercise-induced hormonal profile can be influenced by nutritive interventions toward a profile more favorable for anabolism.
http://www.ncbi.nlm.nih.gov/pubmed/1647 ... t=Abstract
A study which suggests that while EAAs work well post workout, taking them pre workout may actually be more effective for improving anabolism:
Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise.
Tipton KD, Rasmussen BB, Miller SL, Wolf SE, Owens-Stovall SK, Petrini BE, Wolfe RR.
Department of Surgery, University of Texas Medical Branch, Galveston, Texas 77550, USA. ktipton@utmb.edu
The present study was designed to determine whether consumption of an oral essential amino acid-carbohydrate supplement (EAC) before exercise results in a greater anabolic response than supplementation after resistance exercise. Six healthy human subjects participated in two trials in random order, PRE (EAC consumed immediately before exercise), and POST (EAC consumed immediately after exercise). A primed, continuous infusion of L-[ring-(2)H(5)]phenylalanine, femoral arteriovenous catheterization, and muscle biopsies from the vastus lateralis were used to determine phenylalanine concentrations, enrichments, and net uptake across the leg. Blood and muscle phenylalanine concentrations were increased by approximately 130% after drink consumption in both trials. Amino acid delivery to the leg was increased during exercise and remained elevated for the 2 h after exercise in both trials. Delivery of amino acids (amino acid concentration times blood flow) was significantly greater in PRE than in POST during the exercise bout and in the 1st h after exercise (P < 0.05). Total net phenylalanine uptake across the leg was greater (P = 0.0002) during PRE (209 +/- 42 mg) than during POST (81 +/- 19). Phenylalanine disappearance rate, an indicator of muscle protein synthesis from blood amino acids, increased after EAC consumption in both trials.
These results indicate that the response of net muscle protein synthesis to consumption of an EAC solution immediately before resistance exercise is greater than that when the solution is consumed after exercise, primarily because of an increase in muscle protein synthesis as a result of increased delivery of amino acids to the leg.
Full study: http://ajpendo.physiology.org/cgi/conte ... 281/2/E197
Finally some more info regarding a secondary anti catabolic marker which suggests that catabolism is still reduced at 48 hours post workout when EAAs + CHO are consumed:
Changes In 3-Methyl Histidine Excretion
Another important finding of this study is that EAA and carb ingestion minimized 3-methylhistidine excretion 48 hours after exercising. Now what does this mean? 3-methylhistidine (3-MH) is an important indicator of protein catabolism in muscle. Increases in urinary 3-methylhistidine levels indicate muscle tissue catabolism.
Since muscle contains the largest level of 3-methylhistidine in the body, urinary levels relate directly to muscle breakdown... In other words, the more of it in your piss, the more catabolic you are.
The EAA and carbohydrate blend showed a 26% decrease in 3-methylhistidine while the placebo showed an increase of 52%. Once again, this shows that EAA's and carbs, working together, have a positive anabolic effect by blunting protein breakdown.
http://www.bodybuilding.com/fun/animalpak83.htm
