Caffeine Alters Anaerobic Distribution and Pacing during a 4000-m Cycling Time Trial

Ralmony De Alcantara Santos,Ralmony De Alcantara Santos,Carlos Rafaell Correia-Oliveira,Carlos Rafaell Correia-Oliveira,David John Bishop,Marcos David Silva-Cavalcante,Marcos David Silva-Cavalcante,Adriano Eduardo Lima-Silva,Romulo Bertuzzi,Maria Augusta Peduti Dal Molin Kiss,Manlio Vinciguerra

doi:10.1371/journal.pone.0075399

Ralmony De Alcantara Santos, Ralmony De Alcantara Santos + Show 9 more

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https://doi.org/10.1371/journal.pone.0075399

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Abstract

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.

Highlights

Pacing strategy can be defined as the changes in power output/ velocity that occur throughout a time trial (TT) in order to reach the end point in the fastest possible time [1]
Craig et al [6] found a significant correlation between anaerobic capacity, measured by maximum accumulated oxygen deficit (MAOD), and performance during a 4000-m individual pursuit, suggesting that the maximum amount of ATP potentially supplied by the anaerobic energy system may be an important determinant of performance
Mean power output and time The mean Power output (PO) during the 4000-m cycling TT was significantly greater in the CAF than in the PLA condition [effect size (ES) = 0.60, p = 0.034] (Table 2)

Summary

Introduction

Pacing strategy can be defined as the changes in power output/ velocity that occur throughout a time trial (TT) in order to reach the end point in the fastest possible time [1]. Craig et al [6] found a significant correlation between anaerobic capacity, measured by maximum accumulated oxygen deficit (MAOD) (i.e. total amount of anaerobic work), and performance during a 4000-m individual pursuit, suggesting that the maximum amount of ATP potentially supplied by the anaerobic energy system may be an important determinant of performance. This suggests that any intervention able to increase either moment-by-moment anaerobic power output and/or the total amount of anaerobic work may improve performance during a middle-distance cycling TT

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