Rodger Wayne Stewart Jr1,2, Jordan McKenzie Glenn1,2, Keyona Smith1,2, Nicole Elizabeth Moyen1, Madeline Galey1,2 & Michelle Gray1,2

University of Arkansas – 1Human Performance Lab, 2Office for Studies on Aging, Fayetteville, Arkansas

Beta-alanine (BA) supplementation increases the intramuscular pH buffer, carnosine, and is suggested to increase anaerobic exercise performance. When supplemented alongside BA, creatine-monohydrate (CrM) has a synergistic effect for further increasing exercise performance in males; however, these effects have not been evaluated in females. Females experience greater relative increases in carnosine from BA supplementation and these effects are further augmented in trained muscle. Therefore, when combined with CrM, an acute BA dose may produce performance increases in trained females; however, the effects of an acute BA and/or CrM dose on performance in females remain unknown. PURPOSE: To evaluate the effects of an acute dose of BA and/or CrM on repeated anaerobic cycling performance in females. METHODS: Twelve females (age = 26.6 ± 1.3 years) with at least two years of competitive riding experience (3.92 ± 0.64 years training at 125.83 ± 5.37 miles/week) volunteered to participate in this randomized, double-blind study. All subjects completed four supplement trials: 1) PLA = 34g dextrose, 2) BA = 1.6g BA + 34g dextrose, 3) CrM = 5.25g CrM + 34g dextrose, and 4) BA-CrM = 1.6g BA + 5.25g CrM + 34g dextrose. Thirty-minutes after supplementation, subjects performed three repeated 30 second Wingate cycling tests with 2-min active rest between each. Fatigue index, mean power, and peak power were measured during each Wingate. Lactate, heart rate, and rating of perceived exertion (RPE) were measured at rest, immediately after each Wingate, and after the completion of each active rest period. All trials were separated by at least 72 hours to ensure that adequate rest was achieved. RESULTS: Repeated measures ANOVA revealed no significant effect of supplementation on any of the performance variables during any of the three Wingates (p > .05). RPE significantly decreased (p < .001) immediately following Wingates 1 and 2, and after each 2-minute rest period for the BA and BA-CrM trials; however, no differences were observed immediately after Wingate 3. DISCUSSION: An acute dose of BA and/or CrM did not improve anaerobic performance in young trained female cyclists. Acute supplementation of 1.6g BA did, however, significantly decrease feelings of perceived exertion immediately post Wingate performance and after 2-minute recovery intervals; these decreases in RPE were present despite similar power output and fatigue index across Wingate trials. This study demonstrates that acute BA supplementation can decrease feelings of exertion, but does not improve anaerobic cycling performance.

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