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

Abstract

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·kg^-1) (HCHO) or an energy-matched lower-CHO diet (3.5 g·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; η² = 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·min^-1) compared with LCHO (6.4 ± 3.2 m·min^-1) (p = 0.011; η² = 0.445). RSA performance (p < 0.0001; η² = 0.735) and lower body power (CMJ) (p < 0.0001; η² = 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·min^-1) (p < 0.001; η² = 0.798). Blood lactate concentrations were significantly higher during HCHO trial versus LCHO (p = 0.026; η² = 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.

Keywords: Gaelic games; carbohydrate; running performance; substrate utilisation.

Figure 1

An overview of trial procedures.

Figure 2

Total distance covered (A), high-speed running distance (HSRD) covered (B) and sprint distance (C) in total and in each half of HCHO and LCHO. # Significant main effect for condition between HCHO and LCHO (p < 0.05). * Significant difference from the first half (p < 0.05). † Significant different from second half in LCHO (p < 0.05). Values are presented as the mean ± SD. HCHO = high-carbohydrate trial; LCHO = low-carbohydrate trial.

Figure 3

Mean anaerobic power during each Repeated Anaerobic Sprint Test (RAST) throughout both HCHO and LCHO trials. # Significant main effect for condition between HCHO and LCHO (p < 0.05). * Significant difference from all other time points in both groups (p < 0.05). ‡ Significant difference between HCHO and LCHO at corresponding time point (p < 0.05). Values are presented as the mean ± SD. HCHO = high-carbohydrate trial; LCHO = low-carbohydrate trial.

Figure 4

Peak countermovement jump (CMJ) height throughout both HCHO and LCHO trials. # Significant main effect for condition between HCHO and LCHO (p < 0.05). ‡ Significant difference between HCHO and LCHO at corresponding time point (p < 0.05). † Significantly different compared to pre-trial in LCHO condition (p = 0.01). Values are presented as the mean ± SD. HCHO = high-carbohydrate trial; LCHO = low-carbohydrate trial.

Figure 5

Carbohydrate (CHO) oxidation (A), fat oxidation (B) and respiratory exchange ratio (RER) (C) in total and in each half during HCHO and LCHO trials. # Significant main effect for condition between HCHO and LCHO (p < 0.05). * Significant difference from the first half (p < 0.05). Values are presented as the mean ± SD. HCHO = high-carbohydrate trial; LCHO = low-carbohydrate trial.

Figure 6

Plasma glucose (A), lactate (B), glycerol (C) and non-esterified fatty acids (NEFAs) (D) throughout both HCHO and LCHO trials. # Significant main effect for condition between HCHO and LCHO (p < 0.05). * Significant difference from pre-trial in both conditions (p < 0.05). ‡ Significant difference between HCHO and LCHO at corresponding time point (p < 0.05). † Significantly different compared to post-trial in HCHO condition (p < 0.05). Values are presented as the mean ± SD. HCHO = high-carbohydrate trial; LCHO = low-carbohydrate trial.