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Aim. Creatine monohydrate supplementation is beneficial for enhancing high-intensity exercise performance, especially activities that involve repeated sprints. Creatine monohydrate supplementation is common in ice-hockey players. The purpose of this study was to determine the effect of creatine monohydrate supplementation on sprint skating performance in Junior B and collegiate ice-hockey players.
Methods. Seventeen ice-hockey players were randomly assigned to receive creatine (0.3 g/kg body mass/day for 5 days) or placebo. Before and after supplementation players performed repeated sprints to exhaustion on a skating treadmill (repeated 10-s sprints; 30-s rest between sprints) while blood lactate was simultaneously collected. The time to exhaustion on the treadmill test was calculated as total amount of time, including partial intervals, before the player reached exhaustion. Players were also tested for peak torque and average power during knee extension/flexion (3 sets of 10 reps; 60-s rest between sets) on an isokinetic dynamometer at 60 degrees/s.
Results. The change in time to exhaustion from before to after supplementation averaged 20.6±7 s in the creatine group and 21.9±13 s in the placebo group, with no differences between groups. Likewise, there were no differences between groups for changes in isokinetic peak torque and average power. There were no differences between groups over time for blood lactate changes during the repeated sprints on the treadmill.
Conclusion. We conclude that creatine was not effective for improving performance in these ice-hockey players.
KEY WORDS: Strength * Exercise * Phosphocreatine.
Creatine monohydrate supplementation has become popular for athletes in strength and power sports.1 Creatine supplementation increases phosphocreatine (PCr) stores within muscle with a corresponding increase in the ability of muscle to sustain high intensity, anaerobic type exercise.2·3 Creatine monohydrate especially has the potential for enhancing performance of activities that involve repeated intervals of sprinttype exercise, interspersed with short rest intervals. This may occur through a variety of mechanisms. First, an increase in PCr stores should increase the relative contribution from PCr for resynthesis of ATP 4 and decrease the contribution from glycolysis at the start of exercise resulting in a smaller lactic acid accumulation.2 secondly, when PCr is broken down to rephosphorylate ADP, a hydrogen ion is consumed in the reaction.5 An increase in PCr could therefore delay the onset of acidosis and fatigue. Lastly, creatine supplementation has...