The effect of creatine supplementation on running economy

Background: Previous studies have reported that creatine (Cr) supplementation causes fluid retention and a consistent increase in body mass (BM) (Easton et al., 2007: International Journal Sports Nutrition and Exercise Metabolism, 17, 70–91). This additional fluid has been shown to attenuate cardiovascular and thermoregulatory responses and improve time to fatigue during cycling exercise in the heat (Kilduff et al., 2004: International Journal of Sports Nutrition and Exercise Metabolism, 14, 446–46). Whilst these physiological effects may be advantageous for endurance athletes who train and compete in hot climates, runners have been advised not to supplement with Cr as the additional BM may increase the energy cost of running (Noakes, 2004: Lore of Running, Champaign, IL: Human Kinetics). However, the effects of Cr on running economy have yet to be determined.