Sports Fitness Training

No evidence based on properly conducted, rigorous scientific study suggests that the use of amino acid supplements in conjunction with strength-training increases muscle growth or lean body mass to a greater extent than strength training alone. Two studies that reported greater increases in body mass and reduction in percent body fat, and gains in total body strength, lean body mass, and reduced urinary hydroxyproline excretion as a result of arginine and ornithine supplementation were seriously flawed. In these studies, untrained adult males (mean ages, 38.3 and 37.2 yrs, respectively) trained 3 days per week for 5 weeks. Body composition was assessed using skinfolds and body girths, but not hydrostatic weighing. Subjects in the experimental groups ingested 500 mg each of arginine and ornithine twice daily. In the first study, the statistical procedure used in data analysis was reported as an analysis of variance (ANOVA) using a 2 X 3 factorial design. However, data in the paper were given as absolute change for body mass, percent body fat, and body girths. It appears that each of the dependent variables measured was used within the same ANOVA, thus the “3″ in the 2 X 3 statistical analysis. This is clearly an inappropriate statistical analysis. Furthermore, t-tests of the data shown in the paper show no difference for body mass, percent body fat, and the sum of body girth measurements between placebo and amino acid-supplemented groups. In the second study, only the data collected after 5 weeks of training were used in the analysis. The authors reported using a two-way ANOVA with group (amino acid or placebo) and the dependent variables (strength, lean body mass, hydroxyproline excretion) used in the analysis. Again, this is an incorrect statistical procedure. Although it was suggested that the effects of amino acid supplementation could have been due to the effects of arginine and ornithine on GH, the conclusion is not supported by the data. Again, there are no properly designed studies demonstrating greater gains in strength or lean body mass in individuals using specific amino acids as GH secretagogues in conjunction with strength training.