Caffeine is ergogenic after supplementation of oral creatine monohydrate

Mike Doherty, Paul M. Smith, R.C. Richard Davison, Michael G. Hughes

Research output: Contribution to journalArticle

59 Citations (Scopus)

Abstract

PURPOSE: The purpose of this investigation was to assess the acute effects of caffeine ingestion on short-term, high-intensity exercise (ST) after a period of oral creatine supplementation and caffeine abstinence.

METHODS: Fourteen trained male subjects performed treadmill running to volitional exhaustion (T(lim)) at an exercise intensity equivalent to 125% VO(2max). Three trials were performed, one before 6 d of creatine loading (0.3 g x kg x d(-1) baseline), and two further trials after the loading period. One hour before the postloading trials, caffeine (5 mg x kg(-1)) or placebo was orally ingested in a cross-over, double-blind fashion. Four measurements of rating of perceived exertion were taken, one every 30 s, during the first 120 s of the exercise. Blood samples were assayed for lactate, glucose, potassium, and catecholamines, immediately before and after exercise.

RESULTS: Body mass increased (P < 0.05) over the creatine supplementation period, and this increase was maintained for both caffeine and placebo trials. There was no increase in the maximal accumulated oxygen deficit between trials; however, total VO(2) was significantly increased in the caffeine trial in comparison with the placebo trial (13.35 +/- 3.89 L vs 11.67 +/- 3.61 L). In addition, caffeine T(lim) (222.1 +/- 48.9 s) was significantly greater (P < 0.05) than both baseline (200.8 +/- 33.4 s) and placebo (198.3 +/- 45.4 s) T(lim). RPE was also lower at 90 s in the caffeine treatment (13.8 +/- 1.8 RPE points) in comparison with baseline (14.6 +/- 1.9 RPE points).

CONCLUSION: As indicated by a greater T(lim), acute caffeine ingestion was found to be ergogenic after 6-d of creatine supplementation and caffeine abstinence.

Original languageEnglish
Pages (from-to)1785-1792
Number of pages8
JournalMedicine & Science in Sports & Exercise
Volume34
Issue number11
Publication statusPublished - Nov 2002
Externally publishedYes

Keywords

  • Adult
  • Anaerobic Threshold
  • Analysis of Variance
  • Blood Chemical Analysis
  • Blood Gas Analysis
  • Caffeine
  • Central Nervous System Stimulants
  • Creatine
  • Dietary Supplements
  • Double-Blind Method
  • Energy Metabolism
  • Exercise Test
  • Humans
  • Male
  • Muscle Fatigue
  • Physical Endurance
  • Physical Exertion
  • Probability
  • Reference Values
  • Running
  • Sensitivity and Specificity
  • Clinical Trial
  • Comparative Study
  • Journal Article
  • Randomized Controlled Trial

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