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The authors aimed to examine the acute hormonal and performance responses to resistance exercise with and without prior consumption of an amino acid/creatine/energy supplement. Eight men performed a resistance-exercise protocol at baseline (BL), 20 min after consuming a supplement (S) consisting of essential amino acids, creatine, taurine, caffeine, and glucuronolactone or a maltodextrin placebo (P). Venous blood samples were obtained before and immediately after (IP), 15 min (15P), and 30 min (30P) after each protocol. Area under the curve of resistance-exercise volume revealed that BL was significantly less than S (10%) and P (8.6%). For fatigue rate, only S (18.4% ± 12.0%) was significantly lower than BL (32.9% ± 8.4%). Total testosterone (TT) and growth hormone (GH) were significantly elevated at IP and 15P in all conditions. The GH response was significantly lower, however, in S and P than in BL. The TT and GH responses did not differ between S and P. These results indicated that a supplement consisting of amino acids, creatine, taurine, caffeine, and glucuronolactone can modestly improve high-intensity endurance; however, the anabolic-hormonal response was not augmented.
The authors are with the Dept. of Health and Exercise Science, The College of New Jersey, Ewing, NJ 08628.