The effect of an energy drink on cycling performance in male athletes

Abstract

Purpose: The study was designed to determine if the intake of a commerciallyavailable energy drink (ED) improves intermittent cycling performance in male athletes when compared to a placebo beverage (PL). Methods: In a double-blind, crossover randomized design, 7 young trained cyclists (Mean age = 17.14 ± 1.68 yrs. old), participated in three-50 km intermittent cycling trials. A modified version of the test designed by Schabort et al. (1998) was used, and consisted of three 1-km time trials in the 10, 32 and 48 km, as well as two 4-km time trials in the 20 and 40 km. Athletes became familiarized with the test during the first visit to the laboratory. During the second and third occasions, athletes drank 200 ml of either ED or PL every 20 min of the trial. Tests were performed one-week apart. Dependent variables were total time, 1-km time trials, 4-km time trials, ratings of perceived exertion (RPE), and gastrointestinal (GI) symptoms. Statistical analysis using SPSS 8.0 included descriptive statistics, repeated measures analysis of variance, repeated measures t-test, and McNemar X2 tests. Results: Four (36%) out of the eleven initial participants dropped out after the first test due to GI problems (n = 3) and an injury unrelated to the study protocol (n = 1). Therefore, the statistical analysis was performed on the 7 subjects who finished both experimental conditions. There was no significant mean performance time difference between ED (M= 75.29 ± 14.15 min) and PL (M= 74.00 ± 11.39 min) (p = 0.498). A significant mean difference was found in the first 4-km time trial (ED = 5.38 ± 1.00 min vs PL = 5.13 ± 0.83 min, p = 0.030). No significant mean difference in RPE was found at the end of the test (ED = 8.00 ± 2.52 vs PL = 8.00 ± 1.83). No significant associations were found between the type of drink and GI symptoms during the tests (p >.05). During the experimental tests, 5 participants (71. 4%) reported gastrointestinal problems when drinking either ED or PD. Conclusions: Compared to PL the ED did not improve intermittent cycling performance in a 50-km test. Perceived exertion was the same when drinking ED or PL. No associations were found between the type of drink and GI symptoms during the tests.