Creatine supplementation and swimming performance.

The purpose of this study was to determine if oral creatine (CR) ingestion, compared to a placebo (PL), would enable swimmers to maintain a higher swimming velocity across repeated interval sets over 2 weeks of supplementation. Fourteen female and 18 male university swimmers consumed a PL during a 2-week baseline period. Using a randomized, double-blind design, during the next 2 weeks subjects consumed either CR or PL. Swimming velocity was assessed twice weekly during 6 X 50-m swims and once weekly during 10 X 25-yd swims. There was no effect of CR on the 10 X 25-yd interval sets for men and women and no effect on the 6 X 50-m interval sets for women. In contrast, for men, CR significantly improved mean overall swimming velocity in the 6 X 50-m interval after 2 weeks of supplementation, whereas PL had no effect. Although ineffective in women, CR supplementation apparently enables men to maintain a faster mean overall swimming velocity during repeated swims each lasting about 30 s; however, CR was not effective for men in repeated swims each lasting about 10 - 15 s.