Date of Graduation

7-2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Kinesiology (PhD)

Degree Level

Graduate

Department

Health, Human Performance and Recreation

Advisor

Michelle Gray

Committee Member

Ro DiBrezzo

Second Committee Member

Stavros Kavouras

Third Committee Member

Jamie Baum

Fourth Committee Member

Ronna Turner

Keywords

Health and environmental sciences; Aging; Females; Performance; Sport nutrition; Supplementation

Abstract

Within the population of aging individuals exists a subset of competitive seniors or masters athletes (MA). As masters-level competition increases in popularity, MA must find methods to enhance individual athletic performance. Beta-alanine (BA) is an amino acid used to enhance physical capability based on ability increase intramuscular carnosine concentrations. Older adults and females have naturally lower carnosine levels compared to age- and gender-matched counterparts and may experience enhanced benefits from BA supplementation. Purpose: Therefore, the purpose of this investigation was to examine the longitudinal effects of BA supplementation on isometric handgrip strength (HG), time to exhaustion (TTE), total work completed (TWC), and lower-body isokinetic torque (ISO) in female MA. Methods: Twenty-two female MA (age = 53.3 ± 1.0) participated in this double-blind design. Subjects were randomly assigned to BA (n = 11; 800mg BA + 8 g dextrose) or placebo (PLA; n = 11; 8 g dextrose) groups and supplemented 4 times/day over 28 days. HG, TTE, TWC, and ISO were assessed at baseline and each week throughout the intervention. Blood lactate was measured at baseline, immediate post, and 20-minutes after recovery from TTE. Results: No initial significant differences existed between groups for any variable (p > .05). By the 28th day, TTE (23% vs 1% change) and TWC (21% vs 2% change) significantly increased in BA compared to PLA (p < .05). Lactate clearance rate also significantly increased with BA having 24% greater reductions from peak values after the 20-minute recovery. For ISO, work done during the final third (24.0% vs -16.8% change) and average peak torque (5.4% vs 2.9% change) significantly increased in BA compared to PLA (p < .05). When comparing HG and body composition, no significant differences existed at any time point between the two groups (p > .05). No differences existed for any variable during intermittent time points. CONCLUSION: Four-weeks of BA supplementation increased exercise performance and lactate clearance in female MA potentially due to increases in intramuscular carnosine concentrations. Future research should evaluate mechanistic properties influencing these factors as carnosine concentrations can only be evaluated via muscle biopsy analysis or proton magnetic resonance spectroscopy.

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