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Comparison of Different Forms of Creatine on Creatine Availability, Retention, and Training Adaptations
The purpose of this study was to determine if a buffered creatine monohydrate (KA) that has been purported to promote greater creatine retention and training adaptations with fewer side effects at lower doses is more efficacious than creatine monohydrate (CrM) supplementation in resistance-trained individuals. In a double-blind manner, 36 resistance-trained participants (20.2±2 years, 181±7 cm, 82.1±12 kg, and 14.7±5 % body fat) were randomly assigned to supplement their diet with CrM or KA at two different dosages. Muscle biopsies from the vastus lateralis, fasting blood samples, body weight, DEXA determined body composition, and Wingate Anaerobic Capacity (WAC) tests were performed at 0, 7, and 28-days while 1RM strength tests were performed at 0 and 28-days. Data were analyzed by a repeated measures multivariate analysis of variance (MANOVA) and are presented as mean ± SD changes from baseline after 7 and 28-days, respectively. Muscle free creatine content obtained in a subgroup of 25 participants increased in all groups over time (p=0.03) after 7 and 28-days, respectively, with no significant differences among groups (p=0.46). Although some significant time effects were observed, no significant group x time interactions (p>0.05) were observed in changes in body mass, fat free mass, fat mass, percent body fat, or total body water; bench press and leg press 1RM strength; WAC mean power, peak power, or total work; serum blood lipids, markers of catabolism and bone status, and serum electrolyte status; or, whole blood markers of lymphocytes and red cells. Neither manufacturers recommended doses (1.5 g/d) or KA with equivalent loading (20 g/d for 7-days) and maintenance doses (5 g/d for 21-days) of CrM promoted greater changes in muscle creatine content, body composition, strength, or anaerobic capacity than CrM (20 g/d for 7-days, 5 g/d for 21-days). There was no evidence that supplementing the diet with a buffered form of creatine resulted in fewer side effects than CrM. These findings do not support claims that consuming a buffered form of creatine is a more efficacious and/or safer form of creatine to consume than creatine monohydrate. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149363
Doctor of Philosophy Texas A & M University 2013 http://hdl.handle.net/1969.1/149363