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Performance and muscle fiber adaptations to creatine supplementation and heavy resistance training

VOLEK, JEFF S.; DUNCAN, NOEL D.; MAZZETTI, SCOTT A.; STARON, ROBERT S.; PUTUKIAN, MARGOT; GÓMEZ, ANA L.; PEARSON, DAVID R.; FINK, WILLIAM J.; KRAEMER, WILLIAM J.

Medicine & Science in Sports & Exercise: August 1999 - Volume 31 - Issue 8 - pp 1147-1156
Basic Sciences: Original Investigations

Performance and muscle fiber adaptations to creatine supplementation and heavy resistance training. Med. Sci. Sports Exerc., Vol. 31, No. 8, pp. 1147-1156, 1999.

Purpose: The purpose of this study was to examine the effect of creatine supplementation in conjunction with resistance training on physiological adaptations including muscle fiber hypertrophy and muscle creatine accumulation.

Methods: Nineteen healthy resistance-trained men were matched and then randomly assigned in a double-blind fashion to either a creatine (N = 10) or placebo (N = 9) group. Periodized heavy resistance training was performed for 12 wk. Creatine or placebo capsules were consumed (25 g·d−1) for 1 wk followed by a maintenance dose (5 g·d−1) for the remainder of the training.

Results: After 12 wk, significant (P ≤ 0.05) increases in body mass and fat-free mass were greater in creatine (6.3% and 6.3%, respectively) than placebo (3.6% and 3.1%, respectively) subjects. After 12 wk, increases in bench press and squat were greater in creatine (24% and 32%, respectively) than placebo (16% and 24%, respectively) subjects. Compared with placebo subjects, creatine subjects demonstrated significantly greater increases in Type I (35% vs 11%), IIA (36% vs 15%), and IIAB (35% vs 6%) muscle fiber cross-sectional areas. Muscle total creatine concentrations were unchanged in placebo subjects. Muscle creatine was significantly elevated after 1 wk in creatine subjects (22%), and values remained significantly greater than placebo subjects after 12 wk. Average volume lifted in the bench press during training was significantly greater in creatine subjects during weeks 5-8. No negative side effects to the supplementation were reported.

Conclusion: Creatine supplementation enhanced fat-free mass, physical performance, and muscle morphology in response to heavy resistance training, presumably mediated via higher quality training sessions.

Laboratory for Sports Medicine/Department of Kinesiology/Center for Sports Medicine, The Pennsylvania State University, University Park, PA 16802; The Human Performance Laboratory, Ball State University, Muncie, IN 47306; Department of Biological Sciences, College of Osteopathic Medicine, and School of Physical Therapy, Ohio University, Athens, OH 45701; and Department of Physiology, The University of Melbourne, Melbourne, AUSTRALIA

Submitted for publication November 1998.

Accepted for publication January 1999.

Address for correspondence: William J. Kraemer, Ph.D., Professor/Director, The Human Performance Laboratory, Ball State University, Muncie, IN 47306. E-mail: wkraemer@bsu.edu.

© 1999 Lippincott Williams & Wilkins, Inc.