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Effects of dietary nitrate, caffeine, and their combination on 20-km cycling time trial performance.

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contributor authorGlaister, Mark
contributor authorPattison, John R
contributor authorMuniz, Daniel
contributor authorPatterson, Stephen D
contributor authorFoley, Paul
date accessioned2017-07-14T14:40:41Z
date available2017-07-14T14:40:41Z
date issued2015-01-29
identifier citationGlaister , M , Pattison , J R , Muniz , D , Patterson , S D & Foley , P 2015 , ' Effects of dietary nitrate, caffeine, and their combination on 20-km cycling time trial performance. ' Journal of Strength and Conditioning Research , vol 29 , no. 1 , pp. 165-174 . DOI: 10.1519/JSC.0000000000000596en
identifier issn1064-8011
identifier otherPURE: 11686741
identifier otherPURE UUID: 01a4bb73-8dff-41d5-9744-77591748341d
identifier uri
descriptionThis is the accepted manuscript version of the following article: M. Glaister, J. R. Pattison, D. Muniz-Pumares, S. D. Patterson, and P. Foley, “Effects of Dietary Nitrate, Caffeine, and Their Combination on 20-km Cycling Time Trial Performance”, The Journal of Strength and Conditioning Research,Vol. 29(1): 165-174, January 2015. The final published version is available at: ©2015 by the National Strength & Conditioning Association.en
description abstractThe aim of this study was to examine the acute supplementation effects of dietary nitrate, caffeine, and their combination on 20-km cycling time trial performance. Using a randomized, counterbalanced, double-blind Latin-square design, 14 competitive female cyclists (age: 31 ± 7 years; height: 1.69 ± 0.07 m; body mass: 61.6 ± 6.0 kg) completed four 20-km time trials on a racing bicycle fitted to a turbo trainer. Approximately 2.5 hours before each trial, subjects consumed a 70-ml dose of concentrated beetroot juice containing either 0.45 g of dietary nitrate or with the nitrate content removed (placebo). One hour before each trial, subjects consumed a capsule containing either 5 mg·kg of caffeine or maltodextrin (placebo). There was a significant effect of supplementation on power output (p = 0.001), with post hoc tests revealing higher power outputs in caffeine (205 ± 21 W) vs. nitrate (194 ± 22 W) and placebo (194 ± 25 W) trials only. Caffeine-induced improvements in power output corresponded with significantly higher measures of heart rate (caffeine: 166 ± 12 b·min vs. placebo: 159 ± 15 b·min; p = 0.02), blood lactate (caffeine: 6.54 ± 2.40 mmol·L vs. placebo: 4.50 ± 2.11 mmol·L; p < 0.001), and respiratory exchange ratio (caffeine: 0.95 ± 0.04 vs. placebo: 0.91 ± 0.05; p = 0.03). There were no effects (p ≥ 0.05) of supplementation on cycling cadence, rating of perceived exertion, (Equation is included in full-text article.), or integrated electromyographic activity. The results of this study support the well-established beneficial effects of caffeine supplementation on endurance performance. In contrast, acute supplementation with dietary nitrate seems to have no effect on endurance performance and adds nothing to the benefits afforded by caffeine supplementation.en
format extent10en
language isoeng
relation ispartofJournal of Strength and Conditioning Researchen
subjectAthletic Performanceen
subjectDietary Supplementsen
subjectDouble-Blind Methoden
subjectHeart Rateen
subjectOxygen Consumptionen
subjectPhysical Enduranceen
subjectPhysical Exertionen
subjectJournal Articleen
subjectRandomized Controlled Trialen
subjectResearch Support, Non-U.S. Gov'ten
titleEffects of dietary nitrate, caffeine, and their combination on 20-km cycling time trial performance.en
contributor institutionSchool of Life and Medical Sciencesen
contributor institutionDepartment of Psychology and Sports Sciencesen
identifier doi
description versionauthorsversionen
description statusPeer revieweden
date embargoedUntil29-01-20

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