Ingesting a pre-workout supplement containing caffeine, B-vitamins, amino acids, creatine, and beta-alanine before exercise delays fatigue while improving reaction time and muscular endurance
Journal Title (Medline/Pubmed accepted abbreviation):  Nutr. Metab.
Year: 2012
Volume: 9
Number: 3
First page:28
doi: 10.1186/1743-7075-9-28

Summary of background and research design:

Background: Several ergogenic aids (compounds that enhance sports performance) have been identified as effective for most athletes. Among these ingredients are caffeine, creatine, branched chain amino acids (BCAAs), B-vitamins, and beta-alanine.

Hypothesis: An acute dose of the pre-workout supplement Assault will improve performance on resistance training exercises.

Subjects: 12 active males, age 28 ± 5 y. Some were moderate caffeine users.

Experimental Design: randomized, placebo-controlled, double-blinded, cross-over

SUP: One scoop (2 servings) of Assault mixed with about 16 oz. of water. This supplement contained 6 g BCAA, 5 g creatine, 4 g beta-alanine, 1.5 g citrulline malate, and 300 mg caffeine per scoop.
PL: placebo, maltodextrin colored and flavored so that it resembled SUP

Protocol: On their first trip to the laboratory, the participants were familiarized with the exercises and assessed for VO2max and 1 repetition maxima (1RM) for bench press and leg press. On visits 2 and 3, the participants consumed one of the 2 treatments. On the days of the trials, the participants arrived to the laboratory after an overnight fast. They were assessed for blood pressure and heart rate before supplement (or placebo) ingestion, then again after a 20 min rest. A questionnaire was completed regarding perceived energy level and focus. In the approximate 90 min to follow, reaction time (audio and visual) was assessed 4 times, Intermittent Critical Velocity was assessed 3 times on a treadmill (at 110%, 100%, and 90% of their peak velocity at their previously determined VO2max), and 75% 1RM to failure was completed twice for leg press and bench press. Blood pressure and heart rate were completed at the end.

Summary of research findings:
  • The supplement increased heart rate, perceived energy, alertness, and focus and decreased fatigue compared to the placebo.
  • The supplement improved performance on the leg press (13 ± 6 reps with the supplement vs. 11 ± 3 reps with the placebo).
  • There were several parameters assessed for reaction time. When the participants consumed the supplement they either performed the same or better with the supplement compared to the placebo.
  • There were no differences between the supplement and the placebo for critical velocity, suggesting that the supplement works best for anaerobic exercise compared to aerobic exercise.

Key practice applications: The combination of ingredients present in two servings of “Assault” (creatine, BCAAs, beta-alanine, B-vitamins, and caffeine) was effective at increasing energy, focus, and performance in these athletes, especially in regard to anaerobic exercise, when consumed 20 min before exercise. The results are mostly attributed to caffeine, and perhaps B-vitamins. Creatine and beta-alanine have traditionally been shown to be effective only after consumption for several weeks.

Limitations It is unknown which ingredients were responsible for the positive effects and which are superfluous. Also, the day-to-day caffeine usage of the participants was not accounted for. There are large individual differences in caffeine sensitivity and tolerance. Given the well known positive effects of caffeine on performance, it would have been better to have the placebo beverage contain an equivalent amount of caffeine. This improved design would make it easier to delineate if the test product provide benefits that were in addition to what was provided by caffeine. The study, as it was originally designed, is of limited usefulness.

Key search terms for this article (5-7 terms):caffeine, pre-workout, creatine, Assault, BCAAs, beta-alanine, β-alanine

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