Effects of dietary nitrate, caffeine, and their combination on 20-km cycling time trial performance
Pattison, John R.
Patterson, Stephen D.
National Strength & Conditioning Association
MetadataDangos cofnod eitem llawn
The 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.
Journal of Strength and Conditioning Research
Glaister, 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
Dynodwr Gwrthrych Digidol (DOI)http://dx.doi.org/10.1519/JSC.0000000000000596
Full version published in Journal of Strength and Conditioning Research - available http://dx.doi.org/10.1519/JSC.0000000000000596
Yn dangos eitemau sy’n perthyn drwy deitl, awdur, pwnc a chrynodeb.
Acute whole body UVA irradiation combined with nitrate ingestion enhances time trial performance in trained cyclists Muggeridge, David; Sculthorpe, Nicholas; Fergal, Grace; Willis, Gareth; Thornhill, Laurence; Weller, Richard; James, Philip; Easton, Chris (Elsevier, 2015-08-01)Abstract Dietary nitrate supplementation has been shown to increase nitric oxide (NO) metabolites, reduce blood pressure (BP) and enhance exercise performance. Acute exposure to ultraviolet (UV)-A light also increases ...
Boulton, James (Cardiff Metropolitan University, 2013)The purpose of this study was to investigate the effects of acute caffeine consumption on jump squat peak power output. Eight resistance-trained university sports students (n=8 21.4 ± 1.2 years, 87.1 ± 9.8 kg and 179.3 ...
Glaister, Mark; Muniz-Pumares, Daniel; Patterson, Stephen D.; Foley, Paul; McInnes, Gillian (Taylor Francis, 2014)The aim of this study was to investigate the effects of caffeine supplementation on peak anaerobic power output (Wmax). Using a counterbalanced, randomised, double-blind, placebo-controlled design, 14 well-trained men ...