Negligible effects of fructose-glucose composite carbohydrates on performance across a prolonged soccer match simulation compared with a glucose-only control in semi-professional soccer players

Higher carbohydrate availability, achieved through combined intake of glucose and fructose, has shown to enhance endurance performance. This study examined the effects of higher carbohydrate doses containing a fructose–glucose mixture (1:2 ratio) on performance during a 120-min simulated soccer match, compared to lower doses containing only glucose. Fifteen semi-professional soccer players (7 males, 8 females) completed two 120-min soccer-specific exercise sessions in a randomised and crossover design. Participants consumed either 60 g·h⁻¹ glucose, or a combination of 0.5 g∙min-1 fructose and 1.0 g∙min-1 glucose (90 g·h⁻¹) at pre-exercise, halftime, full-time, and midway through extra-time. Measures including gastrointestinal (GI) discomfort, mental fatigue, passing accuracy, neuromuscular performance (reactive strength index, countermovement jump height, peak power output), and sprint performance (15 and 30m sprints), were assessed at 0-min, 45-min, 90-min, and 120-min. Blood glucose and lactate concentrations were assessed every 15 min. Fructose–glucose co-ingestion elevated blood glucose concentration from 105 min (p=0.006, d=1.2), but did not maintain performance (p>0.05). GI symptoms of gastric reflux at 45-min (p=0.011, d=0.9), fullness at 90-min (p=0.013, d=0.9), and flatulence at 120-min worsened in glucose (p=0.003, d=1.1). Abdominal cramps were greater in fructose–glucose at 45-min (p<0.001, d=1.7) and 90-min (p<0.001, d=1.6). Although supplementation did not influence any other variables (p<0.05), countermovement jump height, peak power output and sprint performance was negatively influenced by exercise in both conditions (p<0.05). A higher carbohydrate dosage of fructose–glucose co-ingestion increases blood glucose concentrations but does not mitigate technical and neuromuscular performance impairments during a prolonged simulated soccer match.