ISSN 1750-9823 (print) International Journal of Sports Science and Engineering Vol. 02 (2008) No. 04, pp. 223-230 The Comparative Effects of Oral Creatine Supplementation and High Protein on Muscular Strength and Body Composition Farhad Rahmani-Nia 1 , Nader Rahnama 2, + and Yaser Garazhian 2 1 Department of Sport Sciences, University of Guilan, Rasht, Iran 2 Faculty of Physical Education & Sport Sciences, Isfahan University, Isfahan, Iran (Received June 20, 2008, accepted September 18, 2008) Abstract. The purpose of this study was to examine the effects of 6 weeks of oral creatine supplementation and a high-protein diet on muscular strength and body composition. Thirty-six college athletes (at least 1 year of weight training experience) volunteered to take part in the study. They were randomly assigned to one of four groups: creatine and protein (Cr + Pro, n=9), creatine (Cr, n=9), protein (Pro, n=9), and placebo (P, n=9). They showed no significant difference in their pretest values. Cr consumed 5 g of creatine monohydrate in a flavored sucrose drink four times per day for 6 day. After 6 days, supplementation was reduced to 5 g.d-1.Cr +Pro ingested Cr in a same procedure plus a high protein diet (1.6 g.kg/day).Pro ingested placebo plus a high protein diet (1.6 g.kg /day). Placebo ingested a starched, sucrose drink. 1RM strength of arm flexors, bench press, squat and body composition was measured before and after a 6-wk resistance training program. The subjects trained (3 day.Week-1) with determined training loads. Results showed that body mass and lean tissue mass increased to a greater extent with training in Cr + Pro compared to the other groups, and in Cr compared to P group (p< 0.05). There were no significant changes in percent body fat for groups. Cr + Pro group demonstrated greater improvement in 1RM of squat, bench press and arm flexors than other groups. Also, subjects who supplemented with Cr + Pro had similar increases in 1RM of squat, bench press compared to placebo group (p< 0.05). There were not significant differences between Cr supplementation and high protein diet on muscular strength and body composition. Keywords: Supplementation; Weight training; Creatine monohydrate; High protein diet. 1. Introduction National and biochemical supplements are continually introduced into sport and physical fitness. As the use of these nutritional supplements continues to increase for promoting sporting performance . Creatine (Cr×H2o) supplementation is one form of ergogenic aid that has gained popularity as a supplement to resistance-training programs. Creatine is an amino acid derived [ (α- methyl guanidine ) acetic Acid] that occurs naturally to small extant in human body . Approximately 2% of total body Cr is synthesized in the liver, pancreas and kidneys, and about 60% of Cr found in the body is in form of creatine phosphate . Found primarily in skeletal muscle, creatine in its free and phosphorylated forms plays a crucial role in skeletal muscle energy metabolism . Anecdotal reports of ergogenic value have been supported by significantly controlled studies investigating its effect on strength , power , speed and fatigue , however, not all the findings support ergogenic claims . Rawson and Volek (20) showed that Cr supplementation improved the capacity at which subjects could maintain high intensity exercise. ] 2 , 1 [ ] 2 [ ] 3 [ ] 4 [ ] 14 5 [ − ] 18 , 17 , 16 , 15 , 1 [ ] 15 [ ] 12 [ ] 19 , 16 [ Protein needs of individuals engaged in strength training have been shown to be up to two times more than that of sedentary individuals . Protein turnover is elevated substantially following training exercise, and the rate of protein synthesis following exercise is enhanced with oral consumption of amino acids . Protein requirements of individuals engaged in strength training are related to the intensity and volume of training intensity and volume of acute bouts of exercise are augmented with creatine monohydrate ] 21 [ ] 23 , 22 [ + Dr Nader Rahnama, Faculty of Physical Education & Sport Sciences, Isfahan University, Isfahan, Iran Tel: 0098 (0) 311 7932195; Fax: 0098 (0) 311 6687572; Email: rahnamanader@yahoo.com Published by World Academic Press, World Academic Union