The Effects of Pre-Game Carbohydrate Intake on Running Performance and Substrate Utilisation during Simulated Gaelic Football Match Play

Background: Previous research has reported that elite Gaelic football players' carbohydrate (CHO) intakes are sub-optimal, especially, in the lead up to competitive matches. Despite clear decrements in running performance across elite Gaelic football matches, there are no studies that have investigated nutrition interventions on match-related Gaelic football performance. The aim of this study was to determine whether a higher-CHO diet in line with sports nutrition guidelines can improve Gaelic football-related performance compared to lower CHO intakes previously observed in Gaelic footballers. Methods: Twelve Gaelic football players completed a Gaelic football simulation protocol (GFSP) on two occasions after consuming a high-CHO diet (7 g center dot kg(-1)) (HCHO) or an energy-matched lower-CHO diet (3.5 g center dot kg(-1)) (L-CHO) for 48 h. Movement demands and heart rate were measured using portable global positioning systems devices. Countermovement jump height (CMJ) and repeated-sprint ability (RSA) were measured throughout each trial. Expired respiratory gases were collected throughout the trial using a portable gas analyser. Blood samples were taken at rest, half-time, and post-simulation. Results: There was no significant difference in total distance (p = 0.811; eta(2) = 0.005) or high-speed running distance (HSRD) covered between both trials. However, in the second half of the HCHO trial, HSRD was significantly greater compared to the second half of the LCHO trial (p = 0.015). Sprint distance covered during GFSP was significantly greater in HCHO (8.1 +/- 3.5 m center dot min(-1)) compared with LCHO (6.4 +/- 3.2 m center dot min(-1)) (p = 0.011; eta(2) = 0.445). RSA performance (p < 0.0001; eta(2) = 0.735) and lower body power (CMJ) (p < 0.0001; eta(2) = 0.683) were significantly greater during the HCHO trial compared to LCHO. Overall CHO oxidation rates were significantly greater under HCHO conditions compared to LCHO (3.3 +/- 0.5 vs. 2.7 +/- 0.6 g center dot min(-1)) (p < 0.001; eta(2) = 0.798). Blood lactate concentrations were significantly higher during HCHO trial versus LCHO (p = 0.026; eta(2) = 0.375). There were no significant differences in plasma glucose, non-esterified fatty acids (NEFAs), and glycerol concentration between trials. In both trials, all blood metabolites were significantly elevated at half-time and post-trial compared to pre-trial. Conclusion: These findings indicate that a higher-CHO diet can reduce declines in physical performance during simulated Gaelic football match play.