title: Effect of creatine and beta-alanine supplementation on performance and endocrine responses in strength/power athletes.
abstract: The effects of creatine and creatine plus beta-alanine on strength, power, body composition, and endocrine changes were examined during a 10-wk resistance training program in collegiate football players. Thirty-three male subjects were randomly assigned to either a placebo (P), creatine (C), or creatine plus beta-alanine (CA) group. During each testing session subjects were assessed for strength (maximum bench press and squat), power (Wingate anaerobic power test, 20-jump test), and body composition. Resting blood samples were analyzed for total testosterone, cortisol, growth hormone, IGF-1, and sex hormone binding globulin. Changes in lean body mass and percent body fat were greater (P < 0.05) in CA compared to C or P. Significantly greater strength improvements were seen in CA and C compared to P. Resting testosterone concentrations were elevated in C, however, no other significant endocrine changes were noted. Results of this study demonstrate the efficacy of creatine and creatine plus beta-alanine on strength performance. Creatine plus beta-alanine supplementation appeared to have the greatest effect on lean tissue accruement and body fat composition.
authors.affiliation: Dept. of Health and Exercise Science, The College of New Jersey, Ewing, NJ 08628, USA.
authors.forename: Jay
authors.initials: J
authors.lastname: Hoffman
authors.forename: Nicholas
authors.initials: N
authors.lastname: Ratamess
authors.forename: Jie
authors.initials: J
authors.lastname: Kang
authors.forename: Gerald
authors.initials: G
authors.lastname: Mangine
authors.forename: Avery
authors.initials: A
authors.lastname: Faigenbaum
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Stout
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold; D001823:Body Composition / Q000187:drug effects*; D003401:Creatine / Q000008:administration & dosage* / Q000494:pharmacology; D019587:Dietary Supplements; D004311:Double-Blind Method; D004357:Drug Synergism; D005538:Football; D013006:Growth Hormone / Q000097:blood; D006339:Heart Rate; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000097:blood; D016896:Treatment Outcome; D014891:Weight Lifting; D015091:beta-Alanine / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D012738:Sex Hormone-Binding Globulin; D015091:beta-Alanine; D013739:Testosterone; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D003401:Creatine; D006854:Hydrocortisone