Introduction: Energy drinks are one of the most popular supplements among young elite athletes (Hoffman, 2010). These drinks represent a relatively new category of commercially available beverages that contain caffeine. However, the effects of the energy drinks on sports performance have not been properly investigated. The purpose of this study was to investigate the possible ergogenic effect of a caffeinated energy drink on a 50-m simulated swimming competition as well as on swimming-specific tests. Methods: We recruited 14 male elite swimmers (age = 20.2±2.6 years; weight =, 73.9±8.3 kg). They performed two experimental trials separated by one week: on one occasion, the swimmers ingested a caffeinated energy drink (3 mg of caffeine per kg of body weight) and on another occasion they ingested the same drink but without caffeine content (0 mg/kg; placebo). The order of the trials was randomized and counterbalanced. Sixty minutes after ingestion, the swimmers performed a countermovement jump (CMJ), a manual maximal dynamometry test, a 50-m simulated competition (with their preferred style) and 45-s test at maximal intensity in a swimming ergometer. A blood sample was withdrawn 1-min after completion of the ergometer test to assess blood lactate concentration. After the trials, participants completed a questionnaire about side-effects derived from the intake of the beverages. Results: In comparison to the placebo drink, the intake of the caffeinated energy drink increased the height in the CMJ (49.4±5.3 vs 50.9±5.2 cm; P<0.05) and the maximal force during the handgrip test with the right hand (49.2±5.1 vs 50.9±4.4 kg; P<0.05). Besides, the caffeinated energy drink reduced the time to complete the 50-m swimming competition (27.7±3.4 vs 27.5±3.1 s; P<0.05) and it produced greater peak power (272.6±55.2 vs. 303.2±49.1 W; P<0.05) and blood lactate concentration (11.0±2.0 vs 11.7±2.1 mM; P<0.05) during the ergometer test. However, the caffeinated energy drink did not modify the prevalence insomnia (7% vs 7%) or self-reported fatigue (0% vs 0%) and muscle pain (28% vs 28%) during the hours following to the ingestion of the drinks (P>0.05). Discussion: Our study suggests that caffeine (3 mg/kg) increases swimming-specific performance when ingested via commercial energy drinks. The use of caffeinated energy drinks might represent a potent ergogenic method for speed swimmers. Besides, the sides-effects derived from these beverages are marginal.
© Copyright 2014 19th Annual Congress of the European College of Sport Science (ECSS), Amsterdam, 2. - 5. July 2014. Veröffentlicht von VU University Amsterdam. Alle Rechte vorbehalten.