Original Research ARTICLE
The effects of β-alanine supplementation on muscle pH and the power duration relationship during high-intensity exercise
- 1School of Sport and Health Sciences, University of Exeter, United Kingdom
- 2School of Sport, Exercise and Health Sciences, Loughborough University, United Kingdom
- 3NIHR Exeter Clinical Research Facility, University of Exeter, United Kingdom
Purpose: To investigate the influence of β-alanine (BA) supplementation on muscle carnosine content, muscle pH and the power-duration relationship (i.e., critical power and W′). Methods: In a double-blind, randomised, placebo-controlled study, 20 recreationally-active males (22 ± 3 y, V̇O2peak 3.73 ± 0.44 L∙min-1) ingested either BA (6.4 g/d for 28 d) or placebo (PL) (6.4 g/d) for 28 d. Subjects completed an incremental test and two 3-min all-out tests separated by 1 min on a cycle ergometer pre- and post-supplementation. Muscle pH was assessed using 31P-magnetic resonance spectroscopy (MRS) during incremental (INC KEE) and intermittent knee-extension exercise (INT KEE).Muscle carnosine content was determined using 1H-MRS. Results: There were no differences in the change in muscle carnosine content from pre- to post-intervention (PL: 1±16% vs. BA: -4±25%) or in muscle pH during INC KEE or INT KEE (P>0.05) between PL and BA, but blood pH (PL: 0.06±0.10 vs. BA: 0.09±0.13) during the incremental test was elevated post-supplementation in the BA group only (P<0.05). The changes from pre- to post supplementation in critical power (PL: -8±18 W vs. BA: -6±17 W) and W′ (PL: 1.8±3.3 kJ vs. BA: 1.5±1.7 kJ) were not different between groups. No relationships were detected between muscle carnosine content and indices of exercise performance. Conclusions: BA supplementation had no significant effect on muscle carnosine content and no influence on intramuscular pH during incremental or high-intensity intermittent knee-extension exercise. The small increase in blood pH following BA supplementation was not sufficient to significantly alter the power-duration relationship or exercise performance.
Keywords: Muscle pH, beta-Alanine, Carnosine, power-duration relationship, critical power
Received: 17 Oct 2017;
Accepted: 05 Feb 2018.
Edited by:Bruce M. Damon, Vanderbilt University Medical Center, United States
Reviewed by:David Marcinek, University of Washington, United States
Scott Forbes, Brandon University, Canada
Theodore F. Towse, Grand Valley State University, United States
Sean Forbes, University of Florida, United States
Copyright: © 2018 Black, Jones, Morgan, Bailey, Fulford and Vanhatalo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Matthew I. Black, University of Exeter, School of Sport and Health Sciences, Exeter, United Kingdom, firstname.lastname@example.org