Forskning
August 30, 2014
Caffeine and performance over consecutive days of simulated competition
H K Stadmeim et al, 2014, Caffeine and performance over consecutive days of simulated competition, Medicine & Science in Sports & Exercise, published online ahead of print.
Human Study/Sports Performance
ABSTRACT: PURPOSE: Performance improvements after caffeine (CAF) ingestion are well documented when using a 1‐d protocol. In numerous competitions such as the Tour de France, Tour de Ski, world championships, and National College Athletic Association championships, athletes compete for several days in a row. To date, no studies have investigated the effects of CAF when competing for consecutive days in a row. This study aimed to investigate the effects of placebo (PLA) and two different CAF doses (3 and 4.5 mg∙kg body mass) on performance in a 10‐min all‐out, cross‐country, double poling ergometer test (C‐PT) 2 d in a row. METHOD: Eight highly trained male cross‐country skiers (V˙O2max‐run, 78.5 ± 1.6 mL∙kg∙min) participated in the study, which was a randomized, double‐blind, PLA‐controlled, crossover design. Performance was assessed as distance covered during a 10‐min all‐out C‐PT. Oral ingestion of CAF or PLA was consumed 75 min before the all‐out C‐PT. RESULTS: Poling distance was improved after CAF ingestions compared with that after PLA on both days. The improvements on day 1 were 4.0% (90% confidence limits, ±3.3) and 4.0% ± 2.9% for both CAF doses, respectively (P < 0.05), whereas improvements on day 2 were 5.0% ± 3.6% and 5.1% ± 2.8% for CAF3 and CAF4.5, respectively, compared with those for PLA. Improved performance was associated with increased HR, adrenaline concentration, blood lactate concentration, and V˙O2 consumption after CAF ingestion. Furthermore, performance was elevated despite higher creatine kinase concentration and muscular pain at arrival on day 2 for both CAF doses. CONCLUSIONS: Both CAF doses improved performance in the 10‐min all‐out C‐PT compared with PLA over two consecutive days. Therefore, CAF seems useful for athletes competing over consecutive days despite higher muscle damage occurring after enhanced performance on the first day.
