The effects of glucose-fructose co-ingestion on repeated performance during a day of intensified rugby union training in professional academy players: Fructose and rugby recovery

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Abstract

Glucose-fructose co-ingestion can accelerate recovery of endurance capacity when compared to ingestion of isocaloric glucose-based carbohydrates alone. The effects of glucose-fructose co-ingestion on recovery of intermittent exercise performance, such as that seen in Rugby Union, is currently unknown. The present study assessed the effects of glucose-fructose co-ingestion during recovery from high-intensity rugby training on performance during high-intensity rugby training later the same day. Nine professional, senior academy Rugby Union players performed two trials in a double-blind, randomized, crossover design. Trials consisted of two identical rugby training sessions separated by a 3-hour recovery period, during which participants ingested protein (0.3 gkg BMh-1) and carbohydrate-containing (0.8 gkg BMh-1) recovery drinks, which were either glucose-based (maltodextrin and dextrose; GLUCOSE ONLY) or a glucose-fructose mixture (GLUCOSE+FRUCTOSE). Performance outcomes [mean speed, mean heart rate, and rate of accelerations] were determined from global positioning systems combined with accelerometry and heart rate monitoring. Mean speed during sessions 1 (morning, am) and 2 (afternoon, pm) of the GLUCOSE ONLY trial was (mean±SD) 118±6 and 117±4 mmin-1, respectively. During the GLUCOSE+FRUCTOSE trial, mean speed during session 1 and 2 was 117±4 and 116±5 mmin-1, respectively (time x trial interaction, p = 0.61). Blood lactate concentrations were higher throughout recovery in the GLUCOSE+FRUCTOSE trial (mean ±SD: 1-h 3.2 ±2.0 mmolL-1; 2-h 2.9 ±2.1 mmolL-1; 3-h 2.1 ±1.2 mmolL-1) compared to GLUCOSE ONLY (1-h 2.0 ±1.0 mmolL-1; 2-h 2.3 ±1.2 mmolL-1; 3-h 1.4 ±1.0 mmolL-1; trial effect p = 0.05). Gastrointestinal discomfort remained below the moderate discomfort threshold in both conditions and there were no differences between trials. These data suggest that glucose-fructose mixtures consumed as part of a protein-carbohydrate recovery drink following ~60 minutes of rugby training do not enhance performance later in the day compared to glucose-based recovery drinks.
Original languageEnglish
JournalJournal of Sports Sciences
Early online date15 Dec 2020
DOIs
Publication statusE-pub ahead of print - 15 Dec 2020

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