Forbes et al., (2007) International Journal Of Sports Nutrition and Exercise Metabolism, 17, p433-444

Methodology In this study, 15 healthy young adults (average age 21) were randomised to receive either a Red Bull energy drink (the quantity consumed was equivalent to a dosage of 2mg caffeine per kg body weight, e.g. for a 75kg individual this equated to 2 red bull drinks) or an isoenergetic non-caffeinated placebo drink. Muscle endurance in the bench press exercise was assessed by the maximum number of repetitions performed over 3 sets with a weight which corresponded to 70% of the subjects predetermined 1 rep max (maximal weight for 1 repetition). Results The results showed that Red Bull energy drink significantly increased total bench-press repetitions over the three sets, e.g. the placebo group achieved an average of 32 reps over three sets whereas the red bull group achieved 34 reps (P < 0.05).

Discussion

The results of this study suggest that Red Bull might be an effective sports supplement for those individuals who perform repeated upper body anaerobic endurance exercises. It is plausible that a red-bull induced gain of 2 reps over three sets, repeated on a weekly basis, may will lead to increases in size and strength. Future research is required to verify this.

Although the researchers cannot conclude with certainty it was caffeine producing the ergogenic effect, it would seem likely that caffeine is the candidate compound. This is based on a lack of evidence in the literature for other compounds found present in the drink having any influence on strength parameters (such as Taurine, Carnitine, B-vitamins). Although the mechanisms explaining the possible ergogenic effects of caffeine remains to be fully elucidated, plausible theories relate to both increased central nervous system activation, raised adrenaline concentrations and alterations in cell membrane excitability.

So, can the results of this study be generalised to you? Well, interestingly the study revealed no differences in response to the red bull drink between caffeine-consuming subjects and caffeine naïve subjects. This result is in agreement with other studies, in which habitual caffeine intake has not been shown to effect the acute ergogenic effects of caffeine ingestion. So whether you do drink coffee/tea or don’t, Red Bull is still likely to exert an acute effect on strength.

Rather encouragingly, the outcome of this study is in agreement with other studies looking at caffeine and anaerobic exercise performance. Alford et al., (2000) also examined the effects of Red Bull on anaerobic exercise performance and showed a significant increase in maximum speed during an all out cycling test. More recently, Researchers from the University of Nebraska demonstrated that weight-trained men who consumed a caffeine supplement one hour before working out increased the number of reps they could perform (2.1% increase) on the bench press using 80% of their one-rep max (or their 8RM). In a follow-up study, the same lab reported that weight-trained subjects taking one dose of caffeine before workouts increased their maximum bench-press weight by about 5 pounds. In another study, conducted by the University of Alabama, it was found that when subjects took caffeine one hour before a weight-training workout they completed more reps on biceps curls (using their 12-rep max) and reported significantly less muscle pain on the fourth set of curls compared to when they took a placebo or aspirin.

Alford et al., (2000) The effect of red bull energy drink on human performance and mood. Amino acids, 21, p139-150.

Beck, T.W., et al (2006) The acute effects of a caffeine-containing supplement on strength, muscular endurance, and anaerobic capabilities. Journal of Strength and Conditioning Research 20(3):506-510

Hudson, G.M., et al (2007) Effects of caffeine and aspirin on resistance training performance, RPE, and pain perception. Medicine & Science in Sports & Exercise 39(5 suppl.):S248