Actua High-volume and high-intensity exercise improve BA induced muscle carnosine loading Authors: Lievens Eline, Bex Tine, Derave Wim Affiliation. Department of movement and sport sciences, Ghent University, Ghent Belgium Abstract Purpose Muscle carnosine loading through beta-alanine (BA) supplementation has been shown to be beneficial for high intensity exercise performance. As only 2,8% of ingested BA is actually incorporated into muscle carnosine1 , it is important to identify parameters to optimize the BA supplementation strategies. Although research of Bex et al.2 showed that carnosine loading was higher in trained muscle than in untrained muscle, it remains unclear whether this is due to acute or chronic adaptations on exercise. Therefore the main purpose of this study was to investigate whether acute exercise can enhance the efficacy of BA supplementation. Moreover the effect of high volume (HV) and high intensity (HI) exercise combined with BA was investigated to understand in which way these factors affect exercise-induced carnosine loading. Methods 28 untrained participants were assigned to either control (n=10), HV-training (n=9) or HI-training (n=9) and were all supplemented with 6,4g/day of BA for 23 days. For the HV and the HI group, the training consisted of 9 exercise sessions with respectively 75-90 min continuous cycling at 35-45% Wmax or 3-5 repeated 30 s maximal cycling bouts at 165% Wmax. Muscle carnosine concentration was measured in the soleus and gastrocnemius before and after supplementation by proton magnetic resonance spectroscopy (1H-MRS). Results When compared to the control group, the increase in carnosine concentration in the entire training group trended to be higher in the soleus muscle (2.95 vs. 2.13 mM, P=0.07) and was significantly higher in the gastrocnemius muscle (3.27 vs. 1.70 mM, P=0.03). Though, when comparing HV and HI, no significant difference was found in the increase of muscle carnosine content in both muscles. Conclusion This study showed that the efficiency of carnosine loading by BA is enhanced by repeated acute exercise. Moreover, these findings suggest that both exercise duration and intensity have a positive effect on the BA uptake. Athletes can take BA tablets before the training sessions to optimize their BA supplementation protocol. References 1. Stegen S, Blancquaert L, Everaert I, et al. Meal and beta-alanine coingestion enhances muscle carnosine loading. Med. Sci. Sports Exerc. 2013;45(8):1478–85 2. Bex T, Chung W, Baguet A, et al. Muscle carnosine loading by beta-alanine supplementation is more pronounced in trained vs. untrained muscles. J. Appl. Physiol. 2014;116(2):204–9. 48 Sport & Geneeskunde | maart 2015 | nummer 1 Pagina 47
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