Abstract

OBJECTIVE: To examine the effect of a relatively low dose of creatine on skeletal muscle metabolism and oxygen supply in a group of training athletes. METHODS: 31P magnetic resonance and near-infrared spectroscopy were used to study calf muscle metabolism in a group of 10 female members of a university swimming team. Studies were performed before and after a six week period of training during which they took either 2 g creatine daily or placebo. Calf muscle metabolism and creatine/choline ratios were studied in resting muscle, during plantar flexion exercise (10-15 min), and during recovery from exercise. RESULTS: There was no effect of creatine on metabolite ratios at rest or on metabolism during exercise and recovery from exercise. Muscle oxygen supply and exercise performance were not improved by creatine if compared to placebo treated subjects. CONCLUSIONS: Oral creatine supplementation at 2 g daily has no effect on muscle creatine concentration, muscle oxygen supply or muscle aerobic or anaerobic metabolism during endurance exercise.