The Effect of Creatine Supplementation on Anaerobic Performance in Moderately Active Men

Abstract

The effect of creatine monohydrate (Cr) supplementation on anaerobic performance was investigated in 21 (treatment = 11; placebo = 10) moderately active males. Supplementation included 20 g·d−1 of Cr or a placebo (PLA) for 6 days. Anaerobic performance was assessed by time to fatigue in an anaerobic speed test (AST = 8 mph at a 20% grade). Four 15-second bouts of high-intensity treadmill running preceded the AST to ensure phosphocreatine store depletion. All tests were separated by 30 seconds of passive recovery. Analysis of variance with repeated measures on the time factor demonstrated no significant treatment effects (p > 0.05) in the dependent variables AST performance, body mass, or blood lactate. However, there was a significant interaction for plasma ammonia (p = 0.03), indicating a decreased plasma ammonia in the post-Cr group. Although it is expected that the phosphocreatine, glycolytic, and possibly the aerobic energy pathways contribute to the performance in this exercise protocol, these data suggest that Cr supplementation is ineffective in increasing performance in repeated, short-term, high-intensity anaerobic running.