Abstract
The purpose of this study was to examine the effects of free leucine supplementation on changes in skeletal muscle mass and strength during a resistance training (RT) program in previously untrained, young subjects. In a double-blind, randomized, placebo-controlled study, 20 healthy young (22 ± 2 years) participants were assigned to two groups: a placebo-supplement group (PLA, N = 10) or a leucine-supplement group (LEU, N = 10). Both groups underwent an 8-week hypertrophic RT program (2 days/week), consuming an equivalent amount of leucine (3.0 g/day in a single post-training dose) or placebo (cornstarch). Quadriceps muscle strength, cross-sectional area (CSA) of the vastus lateralis (VL), and rectus femoris (RF), as well as the habitual dietary intake were assessed before and after the 8-week intervention period. There was a similar improvement in muscle strength (Leg press, LEU: +33% vs. PLA: +37%; P > 0.05, and knee extension, LEU: +31% vs. PLA: 34%; P > 0.05) and CSA (VL, LEU: 8.9% vs. PLA: 9.6%; P > 0.05, and RF, LEU: +21.6% vs. PLA: + 16.4%; P > 0.05) in the both groups from pre- to post-training. In addition, there was no significant (P > 0.05) difference in daily dietary intake between the LEU and PLA groups before and after the intervention period. Free leucine supplementation (3.0 g/day post-training) does not increase muscle strength or CSA during RT in healthy young subjects consuming adequate dietary protein intake.
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References
American College of Sports Medicine (2009) American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Med Sci Sports Exerc 41:687–708
American College of Sports Medicine (2016) American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance. Med Sci Sports Exerc 48:543–568
Anthony JC, Yoshizawa F, Anthony TG, Vary TC, Jefferson LS, Kimball SR (2000) Leucine stimulates translation initiation in skeletal muscle of postabsorptive rats via a rapamycin-sensitive pathway. J Nutr 130:2413–2419
Antonio J, Sanders MS, Ehler LA, Juelmen J, Raether JB, Stout JR (2000) Effects of exercise training and amino-acid supplementation on body composition and physical performance in untrained women. Nutrition 16:1043–1046
Blomstrand E, Eliasson J, Karlsson HK, Köhnke R (2006) Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise. J Nutr 136:269S–273S
Chromiak JA, Smedley B, Carpenter W, Brown R, Koh YS, Lamberth JG, Joe LA, Abadie BR, Altorfer G (2004) Effect of a 10-week strength training program and recovery drink on bodt composition, muscular strength and endurance, and anaerobic power and capacity. Nutrition 20:420–427
Churchward-Venne TA, Burd NA, Mitchell CJ, West DW, Philp A, Marcotte GR, Baker SK, Baar K, Phillips SM (2012) Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. J Physiol 590:2751–2765
Churchward-Venne TA, Breen L, Di Donato DM, Hector AJ, Mitchell CJ, Moore DR (2014) Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: double-blind, randomized trial 1–3. Am J Clin Nutr 99:276–286
Coburn JW, Housh DJ, Housh TJ, Malek MH, Beck TW, Cramer JT, Johnson GO, Donlin PE (2006) Effects of leucine and whey protein supplementation during eight weeks of unilateral resistance training. J Strength Res 20(2):284–291
Cuthbertson D, Smith K, Leese Babraj JG, Waddell T, Atherton P, Wackerhage H, Taylor PM, Rennie MJ (2005) Anabolic signaling deficits underlie amino acid resistance of wasting, aging muscle. FASEB J 19:422–424
Dardevet D, Sornet C, Bayle G, Prugnaud J, Pouyet C, Grizard J (2002) Postprandial stimulation of muscle protein synthesis in old rats can be restored by a leucine-supplemented meal. J Nutr 132:95–100
De Bandt JP (2016) Leucine and mammalian target of rapamycin-dependent activation of muscle protein synthesis in aging. J Nutr 146:2616S–2624S
Dickinson JM, Fry CS, Drummond MJ, Gundermann DM, Walker DK, Glynn EL, Timmerman KL, Dhanani S, Volpi E, Rasmussen BB (2011) Mammalian target of rapamycin complex 1 activation is required for the stimulation of human skeletal muscle protein synthesis by essential amino acids. J Nutr 141:856–862
Dreyer HC, Drummond MJ, Pennings B, Fujita S, Glynn EL, Chinkes DL, Dhanani S, Volpi E, Rasmussen BB (2008) Leucine-enriched essential amino acid and carbohydrate ingestion following resistance exercise enhances mTOR signaling and protein synthesis in human muscle. Am J Physiol Endocrinol Metab 294:E392–E400
Katsanos CS, Kobayashi H, Sheffield-Moore M, Aarsland A, Wolfe RR (2006) A high proportion of leucine is required for optimal stimulation of the rate of muscle protein synthesis by essential amino acids in the elderly. Am J Physiol Endocrinol Metab 291:E381–E387
Koopman R, Verdijk L, Manders RJ, Gijsen AP, Gorselink M, Pijpers E, Wagenmakers AJ, van Loon LJ (2006) Co-ingestion of protein and leucine stimulates muscle protein synthesis rates to the same extent in young and elderly lean men. Am J Clin Nutr 84:623–632
Leenders M, Verdijk LB, van der Hoeven L, van Kranenburg J, Hartgens F, Wodzig HKWH, Saris WHM, van Loon LJC (2011) Prolonged leucine supplementation does not augment muscle mass or affect glycemic control in elderly type 2 diabetic men 1–3. J Nutr 141:1070–1076
Lixandrão ME, Ugrinowitsch C, Bottaro M, Chacon-Mikahil MP, Cavaglieri CR, Min LL, de Souza EO, Laurentino GC, Libardi CA (2014) Vastus lateralis muscle cross-sectional area ultrasonography validity for image fitting in humans. J Strength Cond Res 28(11):3293–3297
Luiking YC, Deutz NE, Memelink RG, Verlaan S, Wolfe RR (2014) Postprandial muscle protein synthesis is higher after a high whey protein, leucine-enriched supplement than after a dairy-like product in healthy older people: a randomized controlled trial. Nutr J 13:9
Norton LE, Layman DK (2006) Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise. J Nutr 136:533S–537S
Norton LE, Wilson GJ, Moulton CJ, Layman DK (2017) Meal distribution of dietary protein and leucine influences long-term muscle mass and body composition in adult rats. J Nutr 147:195–201
Peters SJ, van Helvoort A, Kegler D, Argiles JM, Luiking YC, Laviano A, van Bergenhenegouwen J, Deutz NE, Haagsman HP, Gorselink M, van Norren K (2011) Dose-dependent effects of leucine supplementation on preservation of muscle mass in cancer cachectic mice. Oncol Rep 26:247–254
Ratamess NA, Kraemer WJ, Volek JS, Rubin MR, Gómez AL, French DN, Sharman MJ, McGuigan MM, Scheett T, Häkkinen K, Newton RU, Dioguardi F (2003) The effects of amino acid supplementation on muscular performance during resistance training over reaching. J Strength Cond Res 17:250–258
Rennie MJ (2005) A role for leucine in rejuvenating the anabolic effects of food in old rats. J Physiol 569:357
Schoenfeld BJ, Peterson MD, Ogborn D, Contreras B, Sonmez GT (2015a) Effects of low- versus high-load resistance training on muscle strength and hypertrophy in well-trained men. J Strength Cond Res 29:2954–2963
Schoenfeld BJ, Ratamess NA, Peterson MD, Contreras B, Tiryaki-Sonmez G (2015b) Influence of resistance training frequency on muscular adaptations in well-trained men. J Strength Cond Res 29:1821–1829
Stark M, Lukaszuk J, Prawitz A, Salacinski A (2012) Protein timing and its effects on muscular hypertrophy and strength in individuals engaged in weight-training. J Int Soc Sports Nutr 9:54
Verhoeven S, Vanschoonbeek K, Verdijk LB, Koopman R, Wodzig WK, Dendale P, van Loon LJ (2009) Long-term leucine supplementation does not increase muscle mass or strength in healthy elderly men. Am J Clin Nutr 89:1468–1475
Wang X, Proud CG (2006) The mTOR pathway in the control of protein synthesis. Physiology (Bethesda) 21:362–369
Wilkinson DJ, Hossain T, Hill DS, Phillips BE, Crossland H, Williams J, Loughna P, Churchward-Venne TA, Breen L, Phillips SM, Etheridge T, Rathmacher JA, Smith K, Szewczyk NJ, Atherton PJ (2013) Effects of leucine and its metabolite b-hydroxy-b-methylbutyrate on human skeletal muscle protein metabolism. J Physiol 591:2911e23
Williams AG, Van Den Oord M, Sharma A, Jones DA (2001) Is glucose/amino acid supplementation after exercise an aid to strength training? Br J Sports Med 35:109–113
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This research involved human participants, who were carefully informed of the purpose, procedures, benefits, risks, and discomfort of the investigation, and signed an informed consent document approved by the Institutional Review Board of the University (Protocol No: 44487715.6.0000.0108–CAAE).
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Aguiar, A.F., Grala, A.P., da Silva, R.A. et al. Free leucine supplementation during an 8-week resistance training program does not increase muscle mass and strength in untrained young adult subjects. Amino Acids 49, 1255–1262 (2017). https://doi.org/10.1007/s00726-017-2427-0
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DOI: https://doi.org/10.1007/s00726-017-2427-0
Keywords
- Nutritional supplementation
- Hypertrophy
- Cross-sectional area
- Ergogenic
- Skeletal muscle