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Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Award

Fall 2009

Document Type


Degree Name

Master of Science (MS)


Department of Kinesiology


Abstract The purpose of this study was to determine the ergogenic response to different caffeine doses of 3 mg/kg and 6 mg/kg consumed by trained cyclists 1 hour prior to a 40 kilometer cycling time trial. It was hypothesized that there would not be a difference in time trial performance following caffeine supplementation of a 3 mg/kg dose as compared to a 6 mg/kg dose. Sixteen male subjects, age 18-40, were initially assessed via a VO2max test on an indoor cycle trainer. Subjects then reported to the lab on 4 separate occasions following a 10 hour fast and a 24 hour period of abstinence from caffeine, for a 40 kilometer time trial on an indoor cycle trainer. One hour before their time trial, subjects were given either 3 mg/kg or 6 mg/kg of caffeine or a placebo in capsule form, administered in double-blind fashion along with 22 ounces of a 6% carbohydrate/electrolyte solution. The effects of the different treatments on 40 kilometer time trial time, average power output, heart rate, rating of perceived exertion, VO2, and respiratory exchange ratio were assessed using Repeated Measures Analysis of Variance with treatment as a within-subjects factor. Caffeine significantly improved 40 kilometer time trial performance with 3mg/kg (P=0.004, 72.7 ± 4.6 min) and 6mg/kg (P=0.001, 71.6 ± 4.7 min) compared to the placebo (74.1 ± 5.4 min). The 6mg/kg dose also resulted in a trend (using Bonferroni correction) to a significantly (P=0.04) improved performance compared to the 3mg/kg dose. Results suggest that both 3 mg/kg and 6 mg/kg doses improve 40K time trial performance, but a dose-response effect may exist such that a 6 mg/kg dose is more effective than a 3 mg/kg dose.

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