A double blind study investigated the effect of oral creatine supplementation on muscle function, thigh-circumference, and body weight in women. Twenty-two college-age women were assigned to 1 of 2 groups matched for dietary and exercise habits, phase of menstrual cycle, and fat-free mass (FFM).

After familiarization with testing procedures, pretrial measures of muscle function were conducted during maximal voluntary concentric contraction of the quadriceps muscle using an isokinetic dynamometer. Subjects then ingested either CrH2O (0.5 grams per kg of body weight) or placebo (one fourth dosage 4 times daily) for 5 days. Subjects were not allowed to participate in resistance exercise. After the ingestion phase was completed, all pretrial measures were repeated.

Conclusions: Statistical analysis revealed improvements in performance in the group taking creatine, including: -Decreased time to peak torque in quadriceps extension -Average quadriceps power increased. On the other hand, fat free mass, percent body fat, mid-quadriceps circumference, skinfold thckness of the measured thigh, and total body weight did not change for both groups between trials.

Bottom line: Creatine monohydrate improves muscle performance in women without significant gains in muscle volume or body weight.

Source: International Journal of Sport Nutrition and Exercise Metabolism, 2003, 13, 87-96.

Nanci S. Guest is a certified personal trainer & nutritionist, and is completing her Master of Science degree in nutrition this June. She owns "Power Play: Nutrition, Fitness, Performance" in Vancouver, BC, and for the past 8 years she has been providing individuals, sports teams & the community with nutritional consulting & personal training services, as well as research services, seminars and article writing for local & national publications.