Negligible Effects of Fructose-Glucose Composite Carbohydrates on Performance Across a Prolonged Soccer Match...

Higher carbohydrate availability, achieved through combined intake of glucose and fructose, has been shown to enhance endurance performance. This study examined the effects of higher carbohydrate doses containing a fructose-glucose mixture (1:2 ratio) compared with lower doses containing only glucose on performance during a 120-min simulated soccer match. Fifteen semiprofessional soccer players (seven males and eight females) completed two 120-min soccer-specific exercise sessions in a randomized and crossover design. Participants consumed either 60 g/hr glucose or a combination of 0.5 g/min fructose and 1.0 g/min glucose (90 g/hr) at preexercise, halftime, full time, and midway through extra time. Measures, including gastrointestinal discomfort, mental fatigue, passing accuracy, neuromuscular performance (reactive strength index, countermovement jump height, and peak power output), and sprint performance (15- and 30-m sprints), were assessed at 0, 45, 90, and 120 min. Blood glucose and lactate concentrations were assessed every 15 min. Fructose-glucose coingestion elevated blood glucose concentration from 105 min (p = .006, d = 1.2) but did not maintain performance (p > .05). Gastrointestinal symptoms of gastric reflux at 45 min (p = .011, d = 0.9), fullness at 90 min (p = .013, d = 0.9), and flatulence at 120 min worsened in the glucose group (p = .003, d = 1.1). Abdominal cramps were greater in the fructose-glucose group at 45 (p < .001, d = 1.7) and 90 min (p < .001, d = 1.6). Although supplementation did not influence any other variables (p > .05), countermovement jump height, peak power output, and sprint performance were negatively influenced by exercise in both conditions (p < .05). A higher carbohydrate dosage of fructose-glucose coingestion increases blood glucose concentrations but does not mitigate technical and neuromuscular performance impairments during a prolonged simulated soccer match.