University of Hertfordshire

  • Michael Tarpey
  • Justin Roberts
  • Lindsy Kass
  • Richard Tarpey
  • Michael Roberts
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Original languageEnglish
Pages (from-to)1245-1253
JournalApplied Physiology, Nutrition, and Metabolism
Volume38
Issue12
DOIs
Publication statusPublished - Dec 2013

Abstract

The study investigated the ingestion of maltodextrin, fructose and protein on exogenous carbohydrate oxidation (CHOEXO) and exercise performance. Seven trained cyclists/triathletes (VO2max: 59.20 ± 9.00 ml •kg-1•min-1) performed three exercise trials consisting of 150 minutes cycling at 50 % Wmax (160 ± 11 W), followed by a 60 km time trial (TT). One of three beverages were randomly assigned during each trial and consumed at 15 minute intervals: (1) 0.84 g•min-1 maltodextrin + 0.52 g•min-1 fructose + 0.34 g•min-1 protein (MD+F+P), (2) 1.10 g•min-1 maltodextrin + 0.60 g•min-1 fructose (MD+F) or (3) 1.70 g•min-1 maltodextrin (MD). CHOEXO and fuel utilisation were assessed via measurement of expired air 13C content and indirect calorimetry, respectively.
Mean total CHO oxidation (CHOTOT) rates were 2.35 ± 0.18, 2.76 ± 0.08 and 2.61 ± 0.17 gmin-1 with MD, MD+F, MD+F+P, respectively, although not significantly different. Peak CHOEXO rates with MD+F were significant greater by 41.4 % (P=0.001) and 45.4 % (P=0.0001) compared to MD+F+P and MD, respectively (1.57 ± 0.22 g•min-1, 1.11 ± 0.08 g•min-1 and 1.08 ± 0.11 g•min-1, respectively). Performance times were 2.2 % and 5.0 % faster with MD+F compared to MD+F+P and MD, respectively, however were not statistically significant. Ingestion of a MD-fructose-protein commercial sports beverage significantly reduced peak and mean CHOEXO rates compared to MD+F, but did not significantly influence CHOTOT. The addition of protein to a MD+F beverage did not enhance performance times.

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