title: Ingesting a high-dose carbohydrate solution during the cycle section of a simulated Olympic-distance triathlon improves subsequent run performance.
abstract: The well-established ergogenic benefit of ingesting carbohydrates during single-discipline endurance sports has only been tested once within an Olympic-distance (OD) triathlon. The aim of the present study was to compare the effect of ingesting a 2:1 maltodextrin/fructose solution with a placebo on simulated OD triathlon performance. Six male and 4 female amateur triathletes (age, 25 ± 7 years; body mass, 66.8 ± 9.2 kg; peak oxygen uptake, 4.2 ± 0.6 L·min(-1)) completed a 1500-m swim time-trial and an incremental cycle test to determine peak oxygen uptake before performing 2 simulated OD triathlons. The swim and cycle sections of the main trials were of fixed intensities, while the run section was completed as a time-trial. Two minutes prior to completing every quarter of the cycle participants consumed 202 ± 20 mL of either a solution containing 1.2 g·min(-1) of maltodextrin plus 0.6 g·min(-1) of fructose at 14.4% concentration (CHO) or a sugar-free, fruit-flavored drink (PLA). The time-trial was 4.0% ± 1.3% faster during the CHO versus PLA trial, with run times of 38:43 ± 1:10 min:s and 40:22 ± 1:18 min:s, respectively (p = 0.010). Blood glucose concentrations were higher in the CHO versus PLA trial (p < 0.001), while perceived stomach upset did not differ between trials (p = 0.555). The current findings show that a 2:1 maltodextrin/fructose solution (1.8 g·min(-1) at 14.4%) ingested throughout the cycle section of a simulated OD triathlon enhances subsequent 10-km run performance in triathletes.
authors.affiliation: Department for Health, University of Bath, Claverton Down, Bath, UK. kerry.mcgawley@miun.se
authors.forename: Kerry
authors.initials: K
authors.lastname: McGawley
authors.forename: Oliver
authors.initials: O
authors.lastname: Shannon
authors.forename: James
authors.initials: J
authors.lastname: Betts
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology; D004040:Dietary Carbohydrates / Q000008:administration & dosage* / Q000009:adverse effects; D004415:Dyspepsia / Q000139:chemically induced; D061215:Energy Drinks; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005632:Fructose / Q000008:administration & dosage / Q000009:adverse effects; D006801:Humans; D008297:Male; D011134:Polysaccharides / Q000008:administration & dosage / Q000009:adverse effects; D012420:Running / Q000502:physiology*; D013550:Swimming / Q000502:physiology; D055815:Young Adult
chemical_list: D004040:Dietary Carbohydrates; D011134:Polysaccharides; D005632:Fructose; C008315:maltodextrin