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 performedtreadmill 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.
RCT Entities:
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.
Authors: Christopher J Womack; Michael J Saunders; Marta K Bechtel; David J Bolton; Michael Martin; Nicholas D Luden; Wade Dunham; Melyssa Hancock Journal: J Int Soc Sports Nutr Date: 2012-03-15 Impact factor: 5.150
Authors: Nanci S Guest; Trisha A VanDusseldorp; Michael T Nelson; Jozo Grgic; Brad J Schoenfeld; Nathaniel D M Jenkins; Shawn M Arent; Jose Antonio; Jeffrey R Stout; Eric T Trexler; Abbie E Smith-Ryan; Erica R Goldstein; Douglas S Kalman; Bill I Campbell Journal: J Int Soc Sports Nutr Date: 2021-01-02 Impact factor: 5.150