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dc.contributor.authorGlaister, Mark
dc.contributor.authorPattison, John R.
dc.contributor.authorMuniz-Pumares, Daniel
dc.contributor.authorPatterson, Stephen D.
dc.contributor.authorFoley, Paul
dc.date.accessioned2016-06-22T15:32:14Z
dc.date.available2016-06-22T15:32:14Z
dc.date.issued2015-01
dc.identifier.citationGlaister, M., Pattison, J.R., Muniz-Pumares, D., Patterson, S.D. and Foley, P. (2015) 'Effects of dietary nitrate, caffeine, and their combination on 20-km cycling time trial performance', Journal of Strength & Conditioning Research, 29(1), pp. 165-174
dc.identifier.issn1064-8011
dc.identifier.urihttp://hdl.handle.net/10369/7942
dc.identifier.urihttp://dx.doi.org/10.1519/JSC.0000000000000596
dc.descriptionFull version published in Journal of Strength and Conditioning Research - available http://dx.doi.org/10.1519/JSC.0000000000000596
dc.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_US
dc.publisherNational Strength & Conditioning Associationen_US
dc.relation.ispartofseriesJournal of Strength and Conditioning Research
dc.subjectcycling performanceen_US
dc.subjectcaffeineen_US
dc.subjectdietary nitrateen_US
dc.subjecttime trialsen_US
dc.subjectfemale cyclistsen_US
dc.subjectenduranceen_US
dc.titleEffects of dietary nitrate, caffeine, and their combination on 20-km cycling time trial performanceen_US
dc.typeArticleen_US
dc.identifier.doihttp://dx.doi.org/10.1519/JSC.0000000000000596
dc.date.dateAccepted2014-01-15


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