Caffeine alters anaerobic distribution and pacing during a 4000-m cycling time trial.
The purpose of the present study was to investigate the effects of caffeine ingestion on pacing strategy and energy expenditure during a 4000-m cycling time-trial (TT). Eight recreationally-trained male cyclists volunteered and performed a maximal incremental test and a familiarization test on their first and second visits, respectively. On the third and fourth visits, the participants performed a 4000-m cycling TT after ingesting capsules containing either caffeine (5 mg.kg(-1) of body weight, CAF) or cellulose (PLA). The tests were applied in a double-blind, randomized, repeated-measures, cross-over design. When compared to PLA, CAF ingestion increased mean power output [219.1±18.6 vs. 232.8±21.4 W; effect size (ES)  = 0.60 (95% CI = 0.05 to 1.16), p = 0.034] and reduced the total time [419±13 vs. 409±12 s; ES = -0.71 (95% CI = -0.09 to -1.13), p = 0.026]. Furthermore, anaerobic contribution during the 2200-, 2400-, and 2600-m intervals was significantly greater in CAF than in PLA (p<0.05). However, the mean anaerobic [64.9±20.1 vs. 57.3±17.5 W] and aerobic [167.9±4.3 vs. 161.8±11.2 W] contributions were similar between conditions (p>0.05). Similarly, there were no significant differences between CAF and PLA for anaerobic work (26363±7361 vs. 23888±6795 J), aerobic work (68709±2118 vs. 67739±3912 J), or total work (95245±8593 vs. 91789±7709 J), respectively. There was no difference for integrated electromyography, blood lactate concentration, heart rate, and ratings of perceived exertion between the conditions. These results suggest that caffeine increases the anaerobic contribution in the middle of the time trial, resulting in enhanced overall performance.
Sports Science Research Group, Department of Physical Education and Sports Science (CAV), Federal University of Pernambuco, Vitoria de Santo Antão, Pernambuco, Brazil ; Nephrology Division, Department of Medicine, Federal University of São Paulo, São Paulo, São Paulo, Brazil.
Ralmony de Alcantara
Rde A
Santos
Maria Augusta Peduti Dal Molin
MA
Kiss
Marcos David
MD
Silva-Cavalcante
Carlos Rafaell
CR
Correia-Oliveira
Romulo
R
Bertuzzi
David John
DJ
Bishop
Adriano Eduardo
AE
Lima-Silva
D000328:Adult; D015308:Anaerobic Threshold / Q000187:drug effects*; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D018592:Cross-Over Studies; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D013997:Time Factors
D000697:Central Nervous System Stimulants; D002110:Caffeine