β-alanine supplementation enhances human skeletal muscle relaxation speed but not force production capacity
Authors
Hannah, RicciJones, Rebecca Louise
Minshull, Claire
Artioli, Guilherme Giannini
Harris, Roger C.
Sale, Craig
Issue Date
2015-03-01Subjects
beta-alaninemuscle contractile properties
electrical stimulation
force-frequency relationship
C600 Sports Science
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β-alanine supplementation and muscle contractile propertiesAbstract
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.Citation
Hannah R., Stannard R.L., Minshull C., Artioli G.G., Harris R.C, Sale C (2015) 'β-alanine supplementation enhances human skeletal muscle relaxation speed but not force production capacity', Journal of Applied Physiology, 118 (5), pp.604-612.Publisher
American Physiological SocietyJournal
Journal of Applied PhysiologyAdditional Links
http://jap.physiology.org/content/118/5/604Type
ArticleLanguage
enISSN
8750-7587EISSN
1522-1601ae974a485f413a2113503eed53cd6c53
10.1152/japplphysiol.00991.2014
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