![Sample our Medicine, Dentistry, Nursing & Allied Health journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/5944/TOC-Subject-Sample-2021-Medicine-Dentistry-Nursing-Allied-Health.jpg"})
Abstract
Background
The objective of this study was to analyze the effect of caffeine ingestion on the performance and physiological variables associated with fatigue in 20-km cycling time trials.
Methods
In a double-blind placebo-controlled crossover study, 13 male cyclists (26–10 y, 71–9 kg, 176–6 cm) were randomized into 2 groups and received caffeine (CAF) capsules (6 mg.kg–1) or placebo (PLA) 60 min before performing 20-km time trials. Distance, speed, power, rpm, rating of perceived exertion (RPE), electromyography (EMG) of the quadriceps muscles and heart rate (HR) were continuously measured during the tests. In addition, BRUMS questionnaire was applied before and after the tests.
Results
Significant interactions were found in power and speed (P=0.001), which were significantly higher at the end of the test (final 2 km) after CAF condition. A main effect of time (P=0.001) was observed for RPE and HR, which increased linearly until the end of exercise in both conditions. The time taken to complete the test was similar in both conditions (PLA=2191–158 s vs. CAF=2181–194 s, P=0.61). No significant differences between CAF and PLA conditions were identified for speed, power, rpm, RPE, EMG, HR, and BRUMS (P>0.05).
Conclusion
The results suggest that caffeine intake 60 min before 20-km time trials has no effect on the performance or physiological responses of cyclists.
Electronic supplementary material
The online version of this article (doi:10.1186/s12970-014-0045-8) contains supplementary material, which is available to authorized users.
Copyright comment
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Electronic supplementary material
The online version of this article (doi:10.1186/s12970-014-0045-8) contains supplementary material, which is available to authorized users.
Copyright comment
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Acknowledgments
We would like to express thanks to all the participants for their engagement in this study and also the Coordination of Improvement of Higher Education Personnel (CAPES/Brazil) for the master scholarship conferred to H.B. and M.V.C. and the National Council of Technological and Scientific Development (CNPq/Brazil) for the grants conceded to E.S.C. and L.R.A.
Competing interests
The authors declare that they have no competing of interests.
Authors’ contributions
HB, LRA, MVC and ESC were significant manuscript writers; HB, LRA and ESC participated in the concept and design; HB and MVC were responsible for data acquisition; HB, LRA, MVC and ESC participated in data analysis and interpretation. All authors read and approved the final manuscript.