title: Caffeine-containing energy drink improves sprint performance during an international rugby sevens competition.
abstract: The aim of this study was to determine the effects of a caffeine-containing energy drink on physical performance during a rugby sevens competition. A second purpose was to investigate the post-competition urinary caffeine concentration derived from the energy drink intake. On two non-consecutive days of a friendly tournament, 16 women from the Spanish National rugby sevens Team (mean age and body mass = 23 ± 2 years and 66 ± 7 kg) ingested 3 mg of caffeine per kg of body mass in the form of an energy drink (Fure(®), ProEnergetics) or the same drink without caffeine (placebo). After 60 min for caffeine absorption, participants performed a 15-s maximal jump test, a 6 × 30 m sprint test, and then played three rugby sevens games against another national team. Individual running pace and instantaneous speed during the games were assessed using global positioning satellite (GPS) devices. Urine samples were obtained pre and post-competition. In comparison to the placebo, the ingestion of the energy drink increased muscle power output during the jump series (23.5 ± 10.1 vs. 25.6 ± 11.8 kW, P = 0.05), running pace during the games (87.5 ± 8.3 vs. 95.4 ± 12.7 m/min, P < 0.05), and pace at sprint velocity (4.6 ± 3.3 vs. 6.1 ± 3.4 m/min, P < 0.05). However, the energy drink did not affect maximal running speed during the repeated sprint test (25.0 ± 1.5 vs. 25.0 ± 1.7 km/h). The ingestion of the energy drink resulted in a higher post-competition urine caffeine concentration than the placebo (3.3 ± 0.7 vs. 0.2 ± 0.1 μg/mL; P < 0.05). In summary, 3 mg/kg of caffeine in the form of a commercially available energy drink considerably enhanced physical performance during a women's rugby sevens competition.
authors: Exercise Physiology Laboratory, Camilo José Cela University, C/Castillo de Alarcon, 49, Villafranca del Castillo, 28692, Madrid, Spain. jdelcoso@ucjc.edu
authors: Juan
authors: J
authors: Del Coso
authors: Javier
authors: J
authors: Portillo
authors: Gloria
authors: G
authors: Muñoz
authors: Javier
authors: J
authors: Abián-Vicén
authors: Cristina
authors: C
authors: Gonzalez-Millán
authors: Jesús
authors: J
authors: Muñoz-Guerra
mesh_terms: D000328:Adult; D054874:Athletic Performance; D002110:Caffeine / Q000009:adverse effects / Q000494:pharmacology* / Q000652:urine; D061215:Energy Drinks / Q000009:adverse effects; D005260:Female; D005538:Football; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D058573:Performance-Enhancing Substances; D010807:Physical Endurance / Q000187:drug effects; D010919:Placebos; D012420:Running; D013546:Sweating; D055815:Young Adult
chemical_list: D058573:Performance-Enhancing Substances; D010919:Placebos; D002110:Caffeine