title: Effects of high-dose large neutral amino acid supplementation on exercise, motor skill, and mental performance in Australian Rules Football players.
abstract: This study investigated the effects of high-dose large neutral amino acid (LNAA) supplementation on attenuating fatigue-induced decrements in exercise and motor skill performance in Australian Rules Football (ARF) players. Fifteen subelite ARF players participated in 3 testing sessions separated by 7 days. Players completed an initial control trial involving a reactive motor skills test (RMST) and a reactive agility test (RAT) carried out before and after fatiguing exercise. In the subsequent experimental trials, players ingested a serotonin-depleting or protein control (PC) LNAA mixture 3 h before testing, allocated in a double-blind randomized cross-over design. Blood samples were taken at presupplementation and pre- and postexercise for analysis of plasma amino acid, insulin, and metabolite concentrations. The effect of the LNAA was established as the difference in the change in the mean RMST and RAT test scores among the depleting, PC, and baseline (BL) trials. Mean overall repetition time of the RAT was moderately improved by -5.2% ± 3.4% (mean ± 90% confidence limits; effect size -0.45 ± 0.28) after ingestion of the serotonin-depleting mixture compared with the BL trial. Serotonin-depleting and PC supplements had a divergent effect on mean repetition time after fatiguing exercise in RMST: depleting serotonin elicited a small improvement (-3.0% ± 2.7%) in motor skill performance in contrast to a small decrement (2.4% ± 2.7%) after ingestion of the PC mixture, when compared to the BL. High-dose serotonin-"depleting" LNAA supplementation given 3 h prior to intermittent high-intensity exercise improved reactive motor skill and agility performance in ARF players.
authors: Institute of Sport Exercise and Active Learning, Victoria University, Melbourne, Victoria, Australia. Nigel.Stepto@vu.edu.au
authors: Nigel K
authors: NK
authors: Stepto
authors: Benjamin B
authors: BB
authors: Shipperd
authors: Graeme
authors: G
authors: Hyman
authors: Bernie
authors: B
authors: McInerney
authors: David B
authors: DB
authors: Pyne
mesh_terms: D000328:Adult; D021542:Amino Acids, Neutral / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D056352:Athletes / Q000523:psychology; D054874:Athletic Performance / Q000523:psychology; D001315:Australia; D003071:Cognition; D018592:Cross-Over Studies; D003657:Decision Making; D004044:Dietary Proteins / Q000008:administration & dosage / Q000627:therapeutic use; D019587:Dietary Supplements; D004311:Double-Blind Method; D005221:Fatigue / Q000097:blood / Q000503:physiopathology / Q000517:prevention & control* / Q000523:psychology; D005538:Football; D006801:Humans; D008297:Male; D009048:Motor Skills; D010807:Physical Endurance; D012702:Serotonin Antagonists / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use; D014364:Tryptophan / Q000037:antagonists & inhibitors / Q000097:blood; D055815:Young Adult
chemical_list: D021542:Amino Acids, Neutral; D004044:Dietary Proteins; D012702:Serotonin Antagonists; D014364:Tryptophan