Document Type

Article

Publication Title

Nutrients

Abstract

Background: The purpose of this study was to examine the effects of acute dietary nitrate (NO3−) and caffeine (CAF) supplementation on end power (EP) and work performed above EP (WEP) in trained male cyclists during a 3 min all-out test (3MT) on a cycle ergometer.

Methods: Fifteen healthy, trained male cyclists (28.5 ± 5.3 years, 79.2 ± 9.1 kg, VO2peak 55.2 ± 5.6 mL·kg−1·min−1) completed four exercise trials in a randomized, double-blind, placebo-controlled, crossover study design separated by 3–7 days. The four experimental conditions were placebo beverage (nitrate-depleted) + placebo capsule, nitrate-rich beetroot juice + placebo capsule (BR), placebo beverage + caffeine capsule (CAF), and nitrate-rich beetroot juice + caffeine capsule (BR + CAF). Participants consumed nitrate-rich beetroot juice (~13 mmol NO3−) or nitrate-depleted placebo three hours before exercise, and caffeine (5 mg∙kg−1) or maltodextrin placebo one hour before testing. EP and WEP were determined from the 3MT. Secondary outcomes included peak and mean power output. Data were analyzed using a repeated-measures ANOVA with repeated measures on condition. A p-value of 0.05 was used to determine statistical significance. Effect size was evaluated using partial eta squared.

Results: No significant effect of condition was observed for EP (p = 0.401, ηp2 = 0.056), WEP (p = 0.580, ηp2 = 0.048), peak power (p = 0.642, ηp2 = 0.046), mean power (p = 0.212, ηp2 = 0.108), or total work (p = 0.217, ηp2 = 0.107).

Conclusions: No statistically significant differences between conditions were detected under the conditions of the present study.

Research Highlights

  • The Problem: The study examined the effects of acute dietary nitrate and caffeine supplementation on end power and work performed above end power in trained male cyclists during a 3-minute all-out test on a cycle ergometer.

  • The Method: Fifteen healthy, trained male cyclists completed four exercise trials in a randomized, double-blind, placebo-controlled crossover study; the four experimental conditions included a nitrate-depleted placebo beverage with a placebo capsule, nitrate-rich beetroot juice with a placebo capsule, a placebo beverage with a caffeine capsule, and nitrate-rich beetroot juice with a caffeine capsule.

  • Quantitative Finding: No significant effect of condition was observed for end power (p=0.401) or work performed above end power (p=0.580); furthermore, no significant effect was observed for peak power (p=0.642), mean power (p=0.212), or total work (p=0.217).

  • Finding: No statistically significant performance differences between the supplementation conditions were detected under the parameters of the present study.

Publication Date

5-2026

Creative Commons License

Creative Commons Attribution-NonCommercial 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

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