Purpose: Performance improvements after caffeine (CAF) ingestion are well documented when using a one day protocol. In numerous competitions such as the Tour de France, Tour de Ski, World Championships and NCAA Championships, athletes compete several days in a row. To date no studies have investigated the effects of CAF when competing consecutive days in a row.
Aim: Investigate the effects of placebo (PLA) and two different CAF doses (3 and 4.5 mg [middle dot] kg-1 body mass) on performance in a 10-min all-out cross-country double poling ergometer test (C-PT) two days in a row.
Method: 8 highly trained male cross-country skiers (V[spacing dot above]O2max-run 78.5+/-1.6 ml[middle dot]kg1[middle dot]min-1) participated in the study which was a randomized double-blinded, placebo-controlled, cross-over-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 to PLA both days. The improvements on day one were 4.0% (90% confidence limits: +/- 3.3) and 4.0% +/- 2.9 for both CAF doses respectively (P< 0.05), while improvements on day two were 5.0 +/- 3.6 and 5.1% +/- 2.8 for CAF3 and CAF4.5 compared to PLA. Improved performance was associated with increased heart rate, adrenaline, blood lactate and V[spacing dot above]O2 consumption after CAF ingestion. Furthermore, performance was elevated despite higher creatine kinase and muscular pain at arrival on day two for both CAF doses.
Conclusion: 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 the first day.
(C) 2014 American College of Sports Medicine