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Effects Of β-alanine Supplementation On Human Skeletal Muscle Contractile Properties And Voluntary Muscle Performance

1282 Board #75 May 28, 9

00 AM - 10

30 AM

Stannard, Rebecca L.; Hannah, Ricci; Minshull, Claire; Artioli, Guilherme; Harris, Roger; Sale, Craig

Medicine & Science in Sports & Exercise: May 2015 - Volume 47 - Issue 5S - p 336–337
doi: 10.1249/01.mss.0000477334.63406.fe
C-30 Free Communication/Poster - Ergogenic Aids II Thursday, May 28, 2015, 7: 30 AM - 12: 30 PM Room: Exhibit Hall F
Free

1Nottingham Trent University, Nottingham, United Kingdom. 2University College London, London, United Kingdom. 3University of Edinburgh, Edinburgh, United Kingdom. 4University of São Paulo, São Paulo, Brazil. 5Junipa Ltd, Newmarket, United Kingdom.

Email: rebecca.stannard@ntu.ac.uk

(No relationships reported)

Elevated intramuscular carnosine content achieved via β-alanine supplementation (BA) can improve human exercise performance. This is most likely due to improved intracellular pH regulation and/or enhanced muscle contractile properties as a result of improved calcium (Ca2+) sensitivity.

PURPOSE: To examine the effects of BA on in vivo human skeletal muscle contractile properties and voluntary performance.

METHODS: Twenty-three participants completed two experimental sessions, before and after 28 d supplementation with 6.4 g·d-1 of β-alanine (n=12; 26 ± 7 y) or placebo (PLA; n=11; 25 ± 5 y). Knee extensor force and surface electromyography (EMG) were recorded during a series of voluntary and electrically-evoked (nerve and superficial muscle stimulation) contractions. Data were analysed using repeated measures ANOVA; significance was accepted at P<0.05.

RESULTS: BA had no effect on force-frequency relationship (1 s stimulation, 1-100Hz), or peak force during evoked twitches or octets (8 pulses, 300 Hz). No changes in evoked twitch electromechanical delay (EMD) or time-to-peak tension were shown, although resting and potentiated twitch half-relaxation time (HRT) decreased by 12% and 7% after BA (Table 1). BA did not alter maximal or explosive force (25 ms intervals up to 150 ms from onset) during voluntary contractions.

CONCLUSION: BA had no effect on the force-frequency relationship, supported by lack of change in twitch force data, implying a lack of influence of muscle carnosine elevation on Ca2+ sensitivity. Nevertheless, HRT was reduced after BA, which may be explained by improved cross-bridge detachment rates or reuptake of Ca2+, potentially providing important implications for the efficiency of muscle contraction.

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© 2015 American College of Sports Medicine