Abstract
PURPOSE: As part of a 7-d safety study, we examined the short-term of a dietary pre-workout supplement (PWS) at difference doses on strength and Wingate anaerobic capacity as a secondary outcome. METHODS: We recruited 19 apparently healthy and recreationally active men and women (21.8±2.1 yr, 21.6±8.7 %fat, 26.9±3.8 kg/m2) with at least 6-months of resistance training, to participate in a double-blind, crossover, randomized and placebo-controlled manner. We instructed subjects to maintain their current diet and training regimens throughout the study. Supplements were (1) a dextrose placebo (PLA, 12 g/d); (2) a PWS supplement containing 4.7g B-alanine, 1.6g creatine nitrate, 1.0g arginine AKG, 250mg ascorbic acid, 150mg N-acetyl tyrosine, 150mg caffeine and 5mg tetramethyluric acid; or (3) PWS at ~150% dosage (PWS150) of the base formula for seven days, interspersed with 7-d of washout. On Day 1 (acute) and Day 7 (chronic), subjects were measured fasted (12h), before ingesting their respective supplements. Testing was initiated 30-min after supplement ingestion and strength was assessed as bench and leg press volume, defined as repetitions to fatigue during set three following two sets of 10 reps at 70% of 1RM for each lifting movement. Data were analyzed using a repeated measure MANOVA and are presented as mean change from baseline and 95% CI. RESULTS: No significant effects were noted for strength or Wingate performance including: (1) Bench Press Lifting Volume (kg): PLA (4.9; 95% CI -99.1, 108.9), PWS (-82.0; 95% CI -186.0, 21.9) and PWS150 (85.7; 95% CI -18.2, 189.7); (2) Leg Press Lifting Volume (kg): PLA (174.7; 95% CI -921.9, 1271.2), PWS (670.1; 95% CI -426.5, 1766.6) and PWS150 (789.7; 95% CI -306.9, 1886.2), (3) Wingate Average Power (W): PLA (15.2; 95% CI -9.9, 40.4), PWS (10.7; 95% CI -14.5, 35.9) and PWS150 (17.6; 95% CI -7.6, 42.7) or (4) Wingate Peak Power (W): PLA (-11.0; 95% CI -134.5, 112, 4), PWS (-30.0; 95% CI -153.6, 93.2), and PWS150 (34.9; 95% CI -88.5, 158.3). CONCLUSIONS: The PWS formulae used in this study do not appear to increase various indices of physical performance over a seven day period; it is suggested that a longer period of study is necessary to determine the potential ergogenic benefits of such a supplement regimen. Supported by Nutrabolt Int.
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