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Mouth Rinsing and Ingesting a Bitter Solution Improves Sprint Cycling Performance


Medicine & Science in Sports & Exercise: August 2014 - Volume 46 - Issue 8 - p 1648–1657
doi: 10.1249/MSS.0000000000000271
Applied Sciences

Purpose There is evidence that carbohydrate (CHO) mouth rinsing can improve endurance exercise performance as well as muscle force production and sprint performance. Whether the oral administration of non-CHO tastants also affects exercise performance is not known. The purpose of this study was to investigate whether mouth rinsing and ingesting a bitter-tasting solution of quinine improves maximal sprint cycling performance.

Methods Fourteen competitive male cyclists performed a 30-s maximal cycling sprint immediately after rinsing their mouth for 10 s and then ingesting a 2-mM bitter quinine solution, plain water, a 0.05% (w/v) sweet aspartame solution, or no solution at all (control). Cycling power output was recorded during the sprint. Heart rate, perceived exertion, blood lactate, and blood glucose were measured preexercise, immediately postexercise, and 7 min postexercise.

Results Quinine significantly improved mean power output by 2.4%–3.9% compared with the three other conditions [P ≤ 0.021, effect size (ES) = 0.81–0.85]. Peak power output in the quinine condition was higher compared with the water (3.7%, P = 0.013, ES = 0.71) and control (3.5% P = 0.021, ES = 0.84) conditions but was not significantly different from aspartame (1.9%, P = 0.114, ES = 0.47). There were no significant differences in cycling performance between water, aspartame, and control conditions. There were no differences in heart rate, perceived exertion, or blood variables between any of the conditions.

Conclusion This study shows for the first time that mouth rinsing and ingesting a bitter-tasting solution immediately before a maximal sprint exercise can improve performance.

School of Sport Science, Exercise and Health, University of Western Australia, Crawley, Western Australia, AUSTRALIA

Address for correspondence: Sharon Gam, B.S., School of Sport Science, Exercise and Health, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; E-mail:

Submitted for publication August 2013.

Accepted for publication December 2013.

© 2014 American College of Sports Medicine