title: Single and combined effects of beetroot juice and caffeine supplementation on cycling time trial performance.
abstract: Both caffeine and beetroot juice have ergogenic effects on endurance cycling performance. We investigated whether there is an additive effect of these supplements on the performance of a cycling time trial (TT) simulating the 2012 London Olympic Games course. Twelve male and 12 female competitive cyclists each completed 4 experimental trials in a double-blind Latin square design. Trials were undertaken with a caffeinated gum (CAFF) (3 mg·kg(-1) body mass (BM), 40 min prior to the TT), concentrated beetroot juice supplementation (BJ) (8.4 mmol of nitrate (NO3(-)), 2 h prior to the TT), caffeine plus beetroot juice (CAFF+BJ), or a control (CONT). Subjects completed the TT (females: 29.35 km; males: 43.83 km) on a laboratory cycle ergometer under conditions of best practice nutrition: following a carbohydrate-rich pre-event meal, with the ingestion of a carbohydrate-electrolyte drink and regular oral carbohydrate contact during the TT. Compared with CONT, power output was significantly enhanced after CAFF+BJ and CAFF (3.0% and 3.9%, respectively, p < 0.01). There was no effect of BJ supplementation when used alone (-0.4%, p = 0.6 compared with CONT) or when combined with caffeine (-0.9%, p = 0.4 compared with CAFF). We conclude that caffeine (3 mg·kg(-1) BM) administered in the form of a caffeinated gum increased cycling TT performance lasting ∼50-60 min by ∼3%-4% in both males and females. Beetroot juice supplementation was not ergogenic under the conditions of this study.
authors.affiliation: a Exercise and Nutrition Research Group, School of Medical Sciences, RMIT University, Bundoora, VIC 3083, Australia.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Lane
authors.forename: John A
authors.initials: JA
authors.lastname: Hawley
authors.forename: Ben
authors.initials: B
authors.lastname: Desbrow
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Jones
authors.forename: James R
authors.initials: JR
authors.lastname: Blackwell
authors.forename: Megan L
authors.initials: ML
authors.lastname: Ross
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Zemski
authors.forename: Louise M
authors.initials: LM
authors.lastname: Burke
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D027461:Beta vulgaris; D001628:Beverages; D001642:Bicycling / Q000502:physiology*; D002110:Caffeine / Q000494:pharmacology*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D018517:Plant Roots; D013997:Time Factors
chemical_list: D002110:Caffeine
keywords: caffeine; caféine; carbohydrate; contre-la-montre; cycling performance; ergogenic; ergogène; nitrate; performance cycliste; sucre; time trial