title: Effects of 28-Day Beta-Alanine Supplementation on Isokinetic Exercise Performance and Body Composition in Female Masters Athletes.
abstract: Beta-alanine (BA) supplementation increases exercise performance due to increases in the intramuscular lactate buffer, carnosine. Females are more sensitive to these increases and results are further pronounced in trained individuals. Baseline intramuscular carnosine levels also naturally decrease with age; therefore, trained older females may experience augmented benefits from BA supplementation. However, the ability of BA to increase lower-body isokinetic strength (ISO) in female masters athletes (MA) is unknown. The purpose of this study was to examine the longitudinal effects of BA supplementation on ISO, handgrip strength (HG), and body composition in female MA cyclists. Twenty-two subjects participated in this double-blind randomized study. Subjects were randomized into 2 groups (placebo [PLA] = 8 g dextrose; BA = 800 mg + 8 g dextrose) and supplemented 4 times per day for 28 days. ISO, HG, and body composition were evaluated at baseline and at the same day/time each week over the 28-day intervention. No differences existed between groups at baseline or at the 7, 14, and 21 days time points for any variables (p > 0.05). When evaluating ISO (isokinetic) after 28 days, total work performed during the final third of the assessment (24.0 vs. -16.8% change) in flexion and average peak torque (5.4 vs. 2.9% change) in extension were significantly increased from baseline in BA compared with PLA (p ≤ 0.05). No differences existed for HG or body composition after supplementation. Twenty-eight days of BA supplementation increased peak torque and work completed, indicating BA improves lower-body exercise performance in female MA.
authors.affiliation: 1Human Performance Laboratory, University of Arkansas, Fayetteville, Arkansas; 2Office for Studies on Aging, University of Arkansas, Fayetteville, Arkansas; 3Office of the Provost and Vice Chancellor for Academic Affairs, University of Arkansas, Fayetteville, Arkansas; 4Psychometric and Educational Evaluation Research Office, University of Arkansas, Fayetteville, Arkansas; and 5Department of Food Science, University of Arkansas, Fayetteville, Arkansas.
authors.forename: Jordan M
authors.initials: JM
authors.lastname: Glenn
authors.forename: Michelle
authors.initials: M
authors.lastname: Gray
authors.forename: Rodger W
authors.initials: RW
authors.lastname: Stewart
authors.forename: Nicole E
authors.initials: NE
authors.lastname: Moyen
authors.forename: Stavros A
authors.initials: SA
authors.lastname: Kavouras
authors.forename: Ro
authors.initials: R
authors.lastname: DiBrezzo
authors.forename: Ronna
authors.initials: R
authors.lastname: Turner
authors.forename: Jamie I
authors.initials: JI
authors.lastname: Baum
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Stone
mesh_terms: D054874:Athletic Performance; D001823:Body Composition / Q000187:drug effects*; D019587:Dietary Supplements; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005080:Exercise Test; D005260:Female; D018737:Hand Strength; D006801:Humans; D008875:Middle Aged; D053580:Muscle Strength / Q000187:drug effects* / Q000502:physiology; D058573:Performance-Enhancing Substances / Q000008:administration & dosage / Q000494:pharmacology*; D015091:beta-Alanine / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D058573:Performance-Enhancing Substances; D015091:beta-Alanine