title: Effects of High-Carbohydrate Versus Mixed-Macronutrient Meals on Soccer Physiology and Performance
Creators: name: Wynne, Jaison Lee
Publisher: name: Old Dominion University Libraries
Year: 2019

description: he purpose of the study was to measure the effects of an acute pre-competition high-carbohydrate (HCHO) meal versus a mixed-macronutrient (MM) meal on physiology, perceptual responses, and performance in 15 division I female collegiate soccer players. Being there are conjectural advantages to pre-exercise meals higher in fiber, fat, and protein, this study was conducted to evaluate the physiological and perceptual effects of pre-competition MM meals. This study used a randomized, investigator-blinded, crossover design involving two dietary interventions – HCHO and MM meals – that were consumed four hours prior to two separate intra-squad soccer scrimmages. Assessments included running metrics via global positioning system (GPS) tracking devices (total distance covered [TDC], high-speed running [HSR], sprint count, and explosive count), heart rate (HR) (average percent of max HR and time spent above 90% of max HR), ratings of perceived exertion (RPE), ratings of fatigue (ROF), gastrointestinal symptoms, and perceptions of satiety, hunger, and fullness. Descriptive statistics are presented as means and standard deviations (SDs) for normally distributed data and medians interquartile ranges (IQRs) for non-normal data. The GPS data were normally distributed, so paired samples t-tests were used to evaluate whether differences existed between the HCHO and MM conditions. Differences in HR, RPE, ROF, and gastrointestinal symptom data between conditions were evaluated with the Wilcoxon signed-rank test due to their non-normal distribution. Data from the hunger, satiety, and fullness scales demonstrated normality and were compared between the two conditions using within-subjects repeated measures ANOVAs involving time (pre-meal, pre-scrimmage, half-time, and end-scrimmage), condition (HCHO vs. MM), and time x condition analysis. Period effects were examined by comparing variables between the two scrimmages regardless of treatment assignment. Significance was set at the p < 0.05 level. No statistically significant differences were found between the two meals with respect to GPS, HR, RPE, ROF, and gut symptom data. Significant main time effects were found for hunger, fullness, and satiety, though there were no significant condition main effects or time x condition interactions. With regard to period effects, TDC (8.0 vs. 7.5 km, p = 0.006), HSR (694 vs. 525 m, p = 0.002), and average percent of max HR (median: 89% vs. 88%, p = 0.038) were higher, while pre-scrimmage ROF was lower (median: 0 vs. 3, p = 0.032), for the second scrimmage than the first scrimmage, which suggests that players were slightly more fatigued going into the first scrimmage. The direction of the period differences in TDC and HSR were consistent regardless of which meal the participants were assigned pre-scrimmage. In total, these findings provide evidence that a meal with moderate amounts of protein, fat, and fiber consumed four hours prior to a 70-minute simulated soccer competition does not lead to more gastrointestinal symptoms and can be equally as ergogenic for performance and perceptual responses as a meal high in carbohydrate.