Purpose: This study is presented as an effort to provide more information on the effects of energy drinks (ED) on intermittent exercise, and add to the published research in Caffeine (CAF) combined with Carbohydrate (CHO) as an ergogenic aid compared to CAF alone. Methods: In three trials, each separated by seven days, seven healthy male and seven healthy female collegiate soccer players randomly ingested an ED, a sugar-free ED, or a placebo beverage 40 minutes before performing a Loughborough Intermittent Shuttle Test (LIST). Rate of perceived exertion (RPE) and heart rate (HR) were measured through the LIST. Results: There were significant differences in weight, height, estimated VO, and daily CAFintake between males and females. TTE during was 16.18 plus or minus 8.26, 17.71 plus or minus 11.64, and 12.43 plus or minus 5.99 for the ED, sugar-free ED, and placebo respectively. No significant differences were found between the trials after an ANCOVA with CAF intake, gender, and weight as covariates. There were no significant differences between RPE scores for the ED, sugar-free ED, and placebo trials. An ANCOVA with CAF intake, gender, and weight as covariates did no result in significant differences. A significant correlation between RPE and HR was found throughout the trials. Conclusions: These results demonstrate no significant improvements in collegiate soccer players for performance of extended duration intermittent exercise or RPE after ingesting an ED or sugar-free ED when compared with a placebo.
