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Effects of dietary leucine supplementation on exercise performance


Branched chain amino acids (BCAA), particularly leucine, have been suggested to be ergogenic for both endurance and strength/power performance. This study investigated the effects of dietary leucine supplementation on the exercise performance of outrigger canoeists. Thirteen (ten female, three male) competitive outrigger canoeists [aged 31.6 (2.2) year, VO2max 47.1 (2.0) ml kg−1 min−1] underwent testing before and after 6-week supplementation with either capsulated L-leucine (45 mg kg−1 d−1; n=6) or placebo (cornflour; n=7). Testing included anthropometry, 10 s upper body power and work and a row to exhaustion at 70–75% maximal aerobic power where perceived exertion (RPE), heart rate (HR) and plasma BCAA and tryptophan concentrations were assessed. Leucine supplementation resulted in significant increases in plasma leucine and total BCAA concentrations. Upper body power and work significantly increased in both groups after supplementation but power was significantly greater after leucine supplementation compared to the placebo [6.7 (0.7) v. 6.0 (0.7) W kg−1]. Rowing time significantly increased [77.6 (6.3)–88.3 (7.3) min] and average RPE significantly decreased [14.5 (1.5)–12.9 (1.4)] with leucine supplementation while these variables were unchanged with the placebo. Leucine supplementation had no effect on the plasma tryptophan to BCAA ratio, HR or anthropometric variables. Six weeks’ dietary leucine supplementation significantly improved endurance performance and upper body power in outrigger canoeists without significant change in the plasma ratio of tryptophan to BCAA.

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  1. American College of Sports Medicine (2000) ACSM’s Guidelines for exercise testing and prescription. Lippincott, Williams and Wilkins, Philadelphia, pp 117

  2. Blomstrand E (2001) Amino acids and central fatigue. Amino Acids 20:25–34

  3. Blomstrand E, Hassmen P, Ekblom B, Newsholme EA (1991) Administration of branched-chain amino acids during sustained exercise-effects on performance and on plasma concentration of some amino acids. Eur J Appl Physiol Occup Physiol 63:83–88

  4. Blomstrand E, Hassmen P, Ek S, Ekblom B, Newsholme EA (1997) Influence of ingesting a solution of branched-chain amino acids on perceived exertion during exercise. Acta Physiol Scand 159:41–49

  5. Borg G (1978) Subjective effort in relation to physical performance and working capacity. In: HL Pick (ed) Psychology: from research to practice. Plenum Publishing Corporation, New York, pp 333–361

  6. Burke LM (2000) Preparation for competition. In: LM Burke, V Deakin (eds) Clinical sports nutrition. McGraw-Hill, Sydney, pp 341–368

  7. Carli G, Bonifazi M, Lodi L, Lupo C, Martelli G, Viti A (1992) Changes in the exercise-induced hormone response to branched chain amino acid administration. Eur J Appl Physiol Occup Physiol 64:272–277

  8. Carroll AR, Feng Y, Bowden BF, Coll JC (1996) Studies of Australian Ascidians. 5. Virenamides A-C, new cytotoxic linear peptides from the Colonial Didemnid Ascidian Diplosoma Virens. J Org Chem 61:4059–4061

  9. Coombes JS, McNaughton LR (2000) Effects of branched-chain amino acid supplementation on serum creatine kinase and lactate dehydrogenase after prolonged exercise. J Sports Med Phys Fitness 40:240–246

  10. Davis JM, Welsh RS, De Volve KL, Alderson NA (1999) Effects of branched-chain amino acids and carbohydrate on fatigue during intermittent, high-intensity running. Int J Sports Med 20:309–314

  11. Davis JM, Alderson NL, Welsh RS (2000) Serotonin and central nervous system fatigue: nutritional considerations. Am J Clin Nutr 72:573S-578S

  12. Godard MP, Williamson DL, Trappe SW (2002) Oral amino-acid provision does not affect muscle strength or size gains in older men. Med Sci Sports Exerc 34:1126–1131

  13. Gratsfield-Hueesgen A (1998) Sensitive and reliable amino acid analysis in protein hydrolysates using the HP1100 series HPLC. Hewlett Packard Technical Note. 12–5966–3110E

  14. Henderson SA, Black AL, Brooks GA (1985) Leucine turnover and oxidation in trained rats during exercise. Am J Physiol Endocrinol Metab 249:E137–E144

  15. Howell DC (1992) Statistical methods for psychology. Duxbury Press, Belmont, pp 178–180, 213, 363–364, 431–483

  16. Lamont LS, McCullough AJ, Kalhan SC (2001) Gender differences in leucine, but not lysine, kinetics. J Appl Physiol 91:357–362

  17. Layman DK (2002) Role of leucine in protein metabolism during exercise and recovery. Can J Appl Physiol 27:646–663

  18. Madsen KD, MacLean A, Kiens B, Christensen D (1996) Effects of glucose, glucose plus branched-chain amino acids, or placebo on bike performance over 100 km. J Appl Physiol 81:2644–2650

  19. Mero A, Pitkanen H, Oja SS, Komi PV, Pontinen P, Takala T (1997) Leucine supplementation and serum amino acids, testosterone, cortisol and growth hormone in male power athletes during training. J Sports Med Phys Fitness 37:137–145

  20. Mittleman KD, Ricci MR, Bailey SP (1998) Branched-chain amino acids prolong exercise during heat stress in men and women. Med Sci Sports Exerc 30:83–91

  21. Mourier AA, Bigard X, de Kerviler E, Roger B, Legrand H, Guezennec CY (1997) Combined effects of caloric restriction and branched-chain amino acid supplementation on body composition and exercise performance in elite wrestlers. Int J Sports Med 18:47–55

  22. Norton K, Olds T (1996) Anthropometrica. UNSW Press, Sydney

  23. Pardridge WM, Oldendorf WH (1975) Kinetic analysis of blood-brain barrier transport of amino acids. Biochim Biophys Acta 401:128–136

  24. Pitkanen HT, Oja SS, Rusko H, Nummela A, Komi PV, Saransaari P, Takala T, Mero AA (2003) Leucine supplementation does not enhance acute strength or running performance but affects serum amino acid concentration. Amino Acids 25:85–94

  25. Rennie MJ, Edwards RH, Krywawych S, Davies CT, Halliday D, Waterlow JC, Millward DJ (1981) Effect of exercise on protein turnover in man. Clin Sci (Lond) 61:627–639

  26. Tarnopolsky M (2000) Protein and amino acid needs for training and bulking up. In: LM Burke and V Deakin (eds) Clinical sports nutrition. McGraw-Hill, Sydney, pp 106–109

  27. Varnier M, Sarto P, Martines D, Lora L, Carmignoto F, Leese GP, Naccarato R (1994) Effect of infusing branched-chain amino acid during incremental exercise with reduced muscle glycogen content. Eur J Appl Physiol Occup Physiol 69:26–31

  28. Verger P, Aymard P, Cynobert L, Anton G, Luigi R (1994) Effects of administration of branched-chain amino acids vs. glucose during acute exercise in the rat. Physiol Behav 55:523–526

  29. Watson P, Shirreffs SM, Maughan RJ (2004) The effect of acute branched-chain amino acid supplementation on prolonged exercise capacity in a warm environment. Eur J Appl Physiol Sep 2 (Epub ahead of print)

  30. Yoshiga CC, Higuchi M (2003) Oxygen uptake and ventilation during rowing and running in females and males. Scand J Med Sci Sports 13:359–363

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Correspondence to Melissa J. Crowe.

Additional information

Parts of this work have previously been presented in abstract form: Crowe MJ, Weatherson JN (2002) The effects of dietary L-leucine supplementation on exercise performance. Sports Medicine and Science at the Extremes. Australian Conference of Science and Medicine in Sport. 12–16 October, Melbourne, Australia

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Crowe, M.J., Weatherson, J.N. & Bowden, B.F. Effects of dietary leucine supplementation on exercise performance. Eur J Appl Physiol 97, 664–672 (2006).

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  • Branched-chain amino acids
  • Central fatigue
  • Supplements
  • Tryptophan