18Objectives: The physiological and performance effects of carbohydrate-electrolyte gels consumed 19 before the 30 min extra-time period of prolonged soccer-specific exercise were investigated. 20Design: Randomised, double-blind, crossover.

This study investigated the changes in indices of acid-base balance during 120 minutes of simulated soccer match play that included a 30 minute extra-time (ET) period. Eight English Premier League academy soccer players participated in a simulated soccer match that required varying intensities of intermittent exercise including 15-m sprints and soccer dribbling throughout. Blood samples were obtained before (i.e., baseline and pre-exercise) and throughout exercise (i.e., 15, 30, 45, 60, 75, 90, 105, and 120 minutes), and at half time. Sprint speeds over 15 m reduced in ET compared to the first half (-0.39 ± 0.37 m·s, -7 ± 6%, p = 0.021) but not the second half (-0.18 ± 0.25 m·s, -3 ± 4%, p = 0.086). At 105 minutes, blood lactate concentrations reduced compared with that in the opening 30 minutes (-0.9 to -1.2 mmol·L, p ≤ 0.05). Blood pH (-0.03 to -0.04 units), base excess (-0.95 to -1.48 mmol·L), and bicarbonate concentrations (-0.9 ± 0.8 mmol·L) were depressed at 120 minutes compared with those at 105 minutes, baseline and half time (all p ≤ 0.05). There were no significant correlations between changes in acid-base balance and sprint speed (all p > 0.05). Although the perturbations in acid-base balance during ET were statistically significant, the decreases in blood pH, lactate, base excess, and bicarbonate concentrations may not represent metabolic acidosis or impairments in buffering capacity that are likely to explain reduced physical performance. Further research is warranted to investigate mechanisms of fatigue during ET and to develop interventions that attenuate decrements in performance.

4Dietary analysis of Academy soccer players' highlights that total energy and carbohydrate 5 intakes are less than optimal; especially, on match-days. As UK Academy matches 6 predominantly kick-off at ~11:00 h, breakfast is likely the last pre-exercise meal and thus 7 may provide an intervention opportunity on match-day. Accordingly, the physiological and 8 performance effects of an increased calorie breakfast consumed ~135-min before soccer-9 specific exercise were investigated. English Premier League Academy soccer players (n=7) 10 repeated a 90-min soccer-match-simulation on two occasions after consumption of habitual 11 (Bhab; ~1100 kJ) or increased (Binc; ~2100 kJ) energy breakfasts standardised for 12 macronutrient contributions (~60% carbohydrates, ~15% proteins and ~25% fats). increased dribbling speed was identified, which may be of benefit to match-play.