title: Caffeine supplementation does not affect match activities and fatigue resistance during match play in young football players.
abstract: Abstract The study examined the effect of caffeine supplementation on match activities and development of fatigue during a football match. In a randomised, double-blind cross-over design, two experimental football games separated by 7 days were organised between the junior teams of two professional football clubs (17.6 ± 1.1 years (±s), 71.7 ± 6.9 kg, 13.9% ± 5.0% body fat). The players ingested either a capsule of 6 mg · kg-1b.w. caffeine or placebo (dextrose) 65 min prior to the matches. Match activities were assessed using the ZXY match analysis system, and a Yo-Yo intermittent recovery test-level 2 (Yo-Yo IR2) was conducted immediately post-game. Heart rate was monitored throughout the game, and blood samples were obtained at baseline, half-time and after the game. There were no differences between caffeine and placebo regarding total distance covered (10,062 ± 916 vs 9854 ± 901 m), high-intensity running (557 ± 178 vs 642 ± 240 m), sprinting distance (109 ± 58 vs 112 ± 69 m) or acceleration counts (123 ± 31 vs 126 ± 24). In both trials, players displayed lower (P < 0.05) values in total distance and acceleration counts in the last 15 min compared to all other 15-min periods of the matches. Post-game Yo-Yo IR2 performance was not different between game trials (caffeine: 829 ± 322 m; placebo 819 ± 289 m). In conclusion, oral caffeine administration does not appear to have an ergogenic effect in young football players during match play.
authors.affiliation: a Faculty of Health Sciences , The Regional Centre for Sport, Exercise and Health-North, University of Tromsoe , Tromso , Norway.
authors.forename: Svein Arne
authors.initials: SA
authors.lastname: Pettersen
authors.forename: Peter
authors.initials: P
authors.lastname: Krustrup
authors.forename: Mads
authors.initials: M
authors.lastname: Bendiksen
authors.forename: Morten Bredsgaard
authors.initials: MB
authors.lastname: Randers
authors.forename: Joao
authors.initials: J
authors.lastname: Brito
authors.forename: Jens
authors.initials: J
authors.lastname: Bangsbo
authors.forename: Yun
authors.initials: Y
authors.lastname: Jin
authors.forename: Magni
authors.initials: M
authors.lastname: Mohr
keywords: Yo-Yo IR2 test; blood lactate; ergogenic effect; intermittent exercise performance; match analysis; soccer