Author ORCID Identifier


Date of Award

Fall 1-5-2024

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Kinesiology and Health

First Advisor

Jeff Otis

Second Advisor

J. Andrew Doyle

Third Advisor

Kathryn Wilson

Fourth Advisor

Jake Grazer

Fifth Advisor

Rafaela Feresin


There is a growing interest in the use of nutrition and dietary supplements to optimize training and time-trial (TT) cycling performance. Separately, quercetin (Q) and citrulline (CIT) have been used as ergogenic aids to improve oxygen (VO2) kinetics, perceived effort, and cycling TT performance. However, it is currently unknown whether the combination of Q and CIT can provide additive benefits and further enhance cycling performance. We examined 28-days of Q+CIT supplementation on nitric oxide metabolite production (NO) and several physiological measures relevant to time trial (TT) cycling performance. Forty-eight highly trained cyclists were assigned to one of four supplementation groups: (1) Q + CIT (Q: 500 mg, CIT: 3.0 g), (2) Q (500 mg), (3) CIT (3.0 g), or (4) placebo (3.5 g of a zero-calorie flavored crystal light package). Supplements were dissolved in 16 oz. of water and consumed two times per day for 28 consecutive days. Participants performed a 20-km cycling TT race, pre- and post-supplementation to determine the impact of the combined effects of Q + CIT. There were no potential benefits of Q+CIT supplementation on TT performance, NO metabolite production, and several measures of physiological performance. Q+CIT does not seem to be beneficial for 20-km TT performance; further exploration with a focus on an increase in cycling duration or Q+CIT combined with additional polyphenols may amplify any perceived bioactive or metabolic effects on cycling performance. Until such studies are completed, the efficacy of Q+CIT supplementation to improve cycling performance remains ambiguous.


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