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β-Alanine supplementation enhances human skeletal muscle relaxation speed but not force production capacity

  • Rebecca Jones
    ,
  • Ricci Hannah
    ,
  • Claire Minshull
    ,
  • Guilherme Giannini Artioli
    ,
  • Roger C. Harris
    ,
  • Craig Sale
  • Nottingham Trent University
    ,
  • University College London
    ,
  • Queen Margaret University
    ,
  • University of Edinburgh
    ,
  • Universidade de São Paulo
Research Output: Contribution to journal Article Peer-review

Open access

Abstract

PURPOSE: β-alanine (BA) supplementation improves human exercise performance. One possible explanation for this is an enhancement of muscle contractile properties, occurring via elevated intramuscular carnosine resulting in improved calcium sensitivity and handling. This study investigated the effect of BA supplementation on in vivo contractile properties and voluntary neuromuscular performance. METHODS: Twenty-three men completed two experimental sessions, pre- and post-28 days supplementation with 6.4 g·d-1 39 of BA (n = 12) or placebo (PLA; n = 11). During each session, force was recorded during a series of knee extensor contractions: resting and potentiated twitches and octet (8 pulses, 300 Hz) contractions elicited via femoral nerve stimulation; tetanic contractions (1 s, 1 – 100 Hz) via superficial muscle stimulation; and maximum and explosive voluntary contractions. RESULTS: BA supplementation had no effect on the force-frequency relationship, or the force responses (force at 25 ms and 50 ms from onset, peak force) of resting or potentiated twitches, and octet contractions (P > 0.05). Resting and potentiated twitch electromechanical delay and time-to-peak tension were unaffected by BA supplementation (P > 0.05), although half-relaxation time declined by 7-12% (P < 0.05). Maximum and explosive voluntary forces were unchanged after BA supplementation. CONCLUSION: BA supplementation had no effect on evoked force responses, implying that altered calcium sensitivity and/or release are not the mechanisms by which BA supplementation influences exercise performance. The reduced half-relaxation time with BA supplementation might, however, be explained by enhanced reuptake of calcium, which has implications for the efficiency of muscle contraction following BA supplementation.

Publication Information

Output type

Research Output: Contribution to journal Article Peer-review

Original language

English

Pages from-to (Number of pages)

Pages 604-612

Journal (Volume, Issue Number)

Journal of Applied Physiology (Volume 118, Issue 5)

Publication milestones

  • Published - 01/03/2015

Publication status

Published - 01/03/2015

ISSN

8750-7587

External Publication IDs

  • handle.net: 10547/622223
  • Scopus: 84925357457

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