title: Physiological and performance effects of carbohydrate gels consumed prior to the extra-time period of prolonged simulated soccer match-play.
abstract: OBJECTIVE
  The physiological and performance effects of carbohydrate-electrolyte gels consumed before the 30min extra-time period of prolonged soccer-specific exercise were investigated.
  
  
  METHODS
  Randomised, double-blind, crossover.
  
  
  METHODS
  Eight English Premier League academy soccer players performed 120min of soccer-specific exercise on two occasions while consuming fluid-electrolyte beverages before exercise, at half-time and 90min. Carbohydrate-electrolyte (0.7±0.1gkg(-1) BM) or energy-free placebo gels were consumed ∼5min before extra-time. Blood samples were taken before exercise, at half-time and every 15min during exercise. Physical (15-m and 30-m sprint speed, 30-m sprint maintenance and countermovement jump height) and technical (soccer dribbling) performance was assessed throughout each trial.
  
  
  RESULTS
  Carbohydrate-electrolyte gels improved dribbling precision (+29±20%) and raised blood glucose concentrations by 0.7±0.8mmoll(-1) during extra-time (both p<0.01). Supplementation did not affect sprint velocities (15m and 30m), 30-m sprint maintenance or dribbling speed as reductions compared to 0-15min values occurred at 105-120min irrespective of trial (all p<0.05). Plasma osmolality and blood sodium concentrations increased post-exercise vs. the opening 15min (p<0.05) but no effect of supplementation existed. Selected markers of physical performance (jump height, 30-m sprint velocity and 30-m repeated sprint maintenance) also reduced by >3% during half-time (all p<0.05).
  
  
  CONCLUSIONS
  Carbohydrate-electrolyte gel ingestion raised blood glucose concentrations and improved dribbling performance during the extra-time period of simulated soccer match-play. Supplementation did not attenuate reductions in physical performance and hydration status that occurred during extra-time.
authors.affiliation: Sport, Exercise and Rehabilitation, Health and Life Sciences, Northumbria University, UK.
authors.forename: Liam D
authors.initials: LD
authors.lastname: Harper
authors.affiliation: Sport, Exercise and Rehabilitation, Health and Life Sciences, Northumbria University, UK.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Briggs
authors.affiliation: The Academy of Light, Sunderland Association Football Club, UK.
authors.forename: Ged
authors.initials: G
authors.lastname: McNamee
authors.affiliation: Sport, Exercise and Rehabilitation, Health and Life Sciences, Northumbria University, UK.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: West
authors.affiliation: Applied Sports Technology Exercise and Medicine Research Centre (A-STEM), Health and Sport Portfolio, Swansea University, UK; Welsh Institute of Performance Sciences (WIPS), Swansea University, UK.
authors.forename: Liam P
authors.initials: LP
authors.lastname: Kilduff
authors.affiliation: Sport, Exercise and Rehabilitation, Health and Life Sciences, Northumbria University, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Stevenson
authors.affiliation: Sport, Exercise and Rehabilitation, Health and Life Sciences, Northumbria University, UK. Electronic address: mark.russell@northumbria.ac.uk.
authors.forename: Mark
authors.initials: M
authors.lastname: Russell
mesh_terms: D000293:Adolescent; D056352:Athletes; D054874:Athletic Performance / Q000502:physiology*; D001786:Blood Glucose / Q000378:metabolism*; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage* / Q000097:blood; D019587:Dietary Supplements; D004311:Double-Blind Method; D004573:Electrolytes / Q000008:administration & dosage* / Q000097:blood; D061215:Energy Drinks; D006801:Humans; D008297:Male; D012916:Soccer / Q000502:physiology*
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004573:Electrolytes
keywords: Fatigue; Football; Glucose; Hydration; Intermittent; Skill