Effect of Red Bull Energy Drink on Repeated Wingate Cycle Performance and Bench-Press Muscle Endurance Scott C. Forbes, Darren G. Candow, Jonathan P. Little, Charlene Magnus, and Philip D. Chilibeck The purpose of this study was to determine the effects of Red Bull energy drink on Wingate cycle performance and muscle endurance. Healthy young adults (N = 15, 11 men, 4 women, 21 ± 5 y old) participated in a crossover study in which they were randomized to supplement with Red Bull (2 mg/kg body mass of caffeine) or isoenergetic, isovolumetric, noncaffeinated placebo, separated by 7 d. Muscle endurance (bench press) was assessed by the maximum number of repetitions over 3 sets (separated by 1-min rest intervals) at an intensity corresponding to 70% of baseline 1-repetition maximum. Three 30-s Wingate cycling tests (load = 0.075 kp/kg body mass), with 2 min recovery between tests, were used to assess peak and average power output. Red Bull energy drink significantly increased total bench-press repetitions over 3 sets (Red Bull = 34 ± 9 vs. placebo = 32 ± 8, P < 0.05) but had no effect on Wingate peak or average power (Red Bull = 701 ± 124 W vs. placebo = 700 ± 132 W, Red Bull = 479 ± 74 W vs. placebo = 471 ± 74 W, respectively). Red Bull energy drink significantly increased upper body muscle endurance but had no effect on anaerobic peak or average power during repeated Wingate cycling tests in young healthy adults. Key Words: anaerobic power, caffeine, exercise
Red Bull energy drink is purported to improve some aspects of performance (i.e., reaction time, concentration, and alertness) in exercising individuals (1). The primary ergogenic ingredient in Red Bull is caffeine. Acute caffeine ingestion of 2–9 mg/kg body weight during aerobic exercise increases endurance and reduces fatigue (11, 12, 25, 37, 46). Most research on caffeine ingestion has focused primarily on its effects during short-term or extended aerobic exercise (23), with numerous studies supporting an ergogenic effect from caffeine on exercise time to exhaustion (17, 22, 29, 46, 48), maximal power output (32, 37), and performance time (9, 41). The effects of caffeine ingestion on anaerobic performance (i.e., Wingate cycle power) and muscle endurance Forbes, Little, Magnus, and Chilibeck are with the College of Kinesiology, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B2. Candow is with the Faculty of Kinesiology and Health Studies, University of Regina, Regina, SK, Canada S4S 0A2. 433
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(i.e., total repetitions for lifting a given resistance over multiple sets) are less evident, however. Regarding anaerobic performance, Collump et al. (16) showed that caffeine ingestion (250 mg) 1 h before 100-m freestyle swimming significantly improved performance time. In addition, caffeine ingestion (250 mg) 30 min before exercise resulted in significant improvements during a maximum-power 6-s cycle sprint against various loads (2). Greer et al. (28), however, observed no improvement in maximum force output or reduced fatigue during repeated Wingate anaerobic tests with 6 mg/kg of caffeine 1 h before exercise; Collomp et al. (15) found no improvement during a single 30-s Wingate test with 5 mg/kg of caffeine 60 min before exercise; and Crowe et al. (18) found that 6 mg/kg of caffeine given 90 min before two 60-s cycling bouts had no effect on peak power or work output. Regarding muscle endurance, Kalmar and Cafarelli (35) reported that 6 mg/kg of caffeine given 1 h before exercise significantly increased submaximal isometric-contraction time. In contrast, Beck et al. (7) and Jacobs et al. (34) found no improvement in bench-press or leg-press muscle endurance (i.e., total repetitions of lifting a weight corresponding to 70–80% one-repetition maximum [1-RM]) 60–90 min after subjects consumed ~2.5–4 mg/kg of caffeine. Although...