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Sports Medicine

, Volume 41, Issue 9, pp 773–792 | Cite as

Effects of Acute Carbohydrate Supplementation on Endurance Performance

A Meta-Analysis
  • Tom J. Vandenbogaerde
  • Will G. HopkinsEmail author
Research Review Article

Abstract

Research on the performance effects of acute carbohydrate supplementation is comprehensive. Here we present the first meta-analytic review of this research.

Methods: Eighty-eight randomized crossover studies in which carbohydrate supplements were consumed with or without protein before and/or during exercise provided 155 estimates for performance effects in time-to-exhaustion tests or in time trials with or without a preload. For the mixed-model metaanalysis, all effects were converted into percentage changes in mean power in a non-preloaded time trial and weighted using percentage standard errors derived from exact p-values (in a minority of studies) or from estimated errors of measurement (in all other studies). Publication bias was assessed with a plot of t-values for the random-effect solutions versus standard errors. Probabilistic inferences were derived with reference to thresholds for small, moderate and large effects on performance of 0.5, 1.5 and 2.7%.

Results: Publication bias was reduced by excluding studies with a standard error >1.25%. In the remaining 73 studies and 122 estimates, the meta-analysed performance effects of carbohydrate supplements ranged from clear large improvements of ~6% to clear moderate impairments of ~2%. The best supplement inferred from the analysis consisted of a ~3–10% carbohydrate plus-protein drink providing ~0.7 g/kg/h glucose polymers, ~0.2 g/kg/h fructose and ~0.2 g/kg/h protein. Substantial increases in the benefit of a supplement were probably small with an additional 9-hour fast and with the inclusion of ~0.2 g/kg/h of protein, probably small to moderate with ingesting the first bolus not at the start of exercise but 14 hours before exercise, and possibly small with increasing the frequency of ingestion by three boluses per hour. Substantial reductions in the benefit of a supplement were possibly moderate with a supplement providing >0.25 g/kg/h fructose, and possibly small with an increase in ambient temperature of 10°C. The effect in subjects with maximal oxygen consumption higher by 10mL/kg/min was probably trivial, and the effects of exercise duration were dependent on the concentration of carbohydrate plus protein in the supplement. The effect of including salt was unexpectedly trivial, and the effect of gender was unclear.

Conclusions: Carbohydrate supplements with an appropriate composition and administration regimen can have large benefits on endurance performance. More research and better reporting are required to investigate the moderating effects of gender and salt.

Keywords

Fructose Time Trial Performance Effect Carbohydrate Ingestion Exercise Duration 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

No funding additional to government occupational salaries was provided for the preparation of this review. The authors have no conflicts of interest. No other people made substantial contributions worthy of acknowledgement.

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© Adis Data Information BV 2011

Authors and Affiliations

  1. 1.Sport Performance Research Institute of NZAUT UniversityAucklandNew Zealand

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