Chu, Ba Binh (1996) The effects of creatine supplementation on performance and metabolism during brief, intermittent, high-intensity exercise. Research Master thesis, Victoria University of Technology.

Abstract

This study investigated the ergogenic and metabolic effects of creatine supplementation during two series of 10 x 6 s of "all out" cycling sprints, interrupted by either 30 s rest intervals (RI). Both sprint series were performed before and after five days of oral supplementation with either creatine (CrS, n = 7) or placebo (CON, n = 7), using a randomised double-blind design. To evaluate the effects of CrS on exercise performance, peak power (PPO) and mean power (MPO) were determined during the 30 s and 6 min RI sprint series. To monitor the metabolic effects of CrS, arterialised venous blood was sampled at rest, immediately after the fifth and tenth sprints and during 20 min of recovery; these were analysed for plasma ammonia, lactate and hydrogen ion concentrations. PPO was maintained at near constant levels for 6 min RI for both supplementation groups, but decreased progressively for 30 s RI, regardless of supplementation. Following CrS, PPO. and MPO increased (P < 0.05) during both RI trials, but not with CON. Plasma ammonia concentrations ([NH3 +]) were significantly lower after CrS for 6 min RI, and tended to be lower for 30 s RI. For CON, [NH3 +] was not significantly different after supplementation. Plasma lactate and hydrogen ion concentrations were similar before and after CrS for both RI, despite the higher power after CrS. The corresponding responses CON were similar to CrS, with the exception that [La"] was significantly lower after supplementation for 30 s RI. Oral creatine supplementation enhanced performance during repeated "all out" sprints of short duration, for a wide range of rest intervals between sprints. The ergogenic effects CrS were probably associated with decreased degradation of adenine nucleotides, reflected by lower plasma [NH3 +], and greater ATP turnover, caused by an increase pre-exercise PCr availability.

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