PURPOSE: To determine the effects of a caffeine-containing, commercially available energy drink on peak power produced during two, 20-second Wingate tests separated by 150 seconds. Methods In a randomized (order of beverage), double blind, placebo controlled cross-over design, 15 recreationally active subjects (9 males and 6 females; 21.7 ± 1.6 yrs; 172.7 ± 10.3 cm; 75.1 ± 20.2 kg) ingested a commercially available energy drink (containing 160mg of caffeine) or a placebo beverage that was matched for carbohydrate content and was similar in volume and texture. The average relative caffeine dosage for

each participant was 2.1 mg/kg. Approximately 60 minutes following ingestion of the energy drink or MK-1775 ic50 carbohydrate placebo, each participant engaged in two 20-second Wingate tests (Monark 894 E Peak Bike®). Approximately one week later, each participant engaged in the same protocol but ingested the other beverage. To serve as a warm-up prior to the first Wingate test at each trial, each participant was instructed to lightly jog for approximately 90 seconds, perform multiple vertical jumps, and then cycle at a self-selected pace for approximately

5 minutes. Following the warm-up, each participant performed two 20-second Wingate tests with each test separated by approximately 150 seconds. Peak power (measured in watts) for each of the two trials SN-38 chemical structure was recorded for statistical analysis. Peak power performance was analyzed via within-subjects repeated measures ANOVA using SPSS for Windows 15.0. Results The peak power achieved after ingesting the energy drink for the two Wingate tests (separated by 150 seconds) was 786.4 ± 245.9 and 722 ± 242 watts for the first and second tests, respectively. The peak power achieved after ingesting Mannose-binding protein-associated serine protease the carbohydrate

placebo beverage for the two Wingate tests (separated by 150 seconds) was 777.1 ± 276 and 716.7 ± 247.6 watts for the first and second tests, respectively.. The repeated measures ANOVA revealed that there was not a significant main effect for supplement (p = 0.495); but there was a significant main effect for time (the peak power was significantly higher for the first Wingate test as compared to the second Wingate test, irrespective of supplement; p = 0.001). Finally, there was no significant interaction Tideglusib concentration between the energy drink and placebo beverage in relation to peak power production (p = 0.877). Conclusion Ingesting a caffeine-containing energy drink (160 mg of caffeine) 60 minutes prior to performing two 20-second Wingate tests will not improve peak power production. Acknowledgment This investigation was supported by a University of South Florida College of Education Mini-Grant.