β–alanine: performance effects, usage and side effects

Abstract

β-alanine is a relatively new ergogenic aid and a number of questions relating to its effectiveness in enhancing high intensity exercise performance remain to be addressed. The five studies described in this thesis examined the influence of β-alanine supplementation and high intensity training on exercise capacity and considered factors that potentially influence dosage compliance and side effects -factors that may impact on the ergogenic value of β-alanine supplementation. Study 1 examined the efficacy of β-alanine supplementation in conjunction with repeated sprint and sprint interval training (and combined with a pre-exercise dose of sodium bicarbonate), on repeated-sprint ability and high intensity cycling capacity (time to fatigue at 110% of maximum power output). β-alanine supplementation, when combined with sprint and interval training, improved repeated sprint ability but did not influence high intensity cycle capacity. Furthermore, acute sodium bicarbonate ingestion improved high intensity cycle capacity before training but had no influence on either repeated sprint ability or exercise capacity after training. It is likely that intramuscular buffer capacity increased as a result of training and that this may have outweighed the potential ergogenic buffering effects of β-alanine and sodium bicarbonate (i.e., both alone and in combination).Study 2 investigated β-alanine supplementation use and level of knowledge amongst professional rugby union (n = 87), rugby league (n = 180) and Australian Rules Football (n = 303) players. Over half the professional footballers surveyed used β-alanine, yet most supplemented in a manner inconsistent with recommendations. A better understanding of the environment and culture within professional football codes is required before supplement use aligns with evidence-based β-alanine supplementation recommendations. In light of these findings, Study 3 examined compliance levels to β-alanine supplementation in an applied setting. Compliance over a 28 day period was 59% (± 24%) which was significantly lower than the mean compliance rate reported by others (96%) (p < 0.0001). It was concluded that the determinants of β-alanine (non-) compliance in athletes needed to be further investigated. Study 4 examined potential relationships between different β-alanine dosages and side effects. Healthy male participants were divided into low (< 75 kg) and high (> 85kg) body mass groups and completed three supplementation treatments: 1. a placebo, 2. β-alanine as a relative dose of 0.02 g·kgBM -1 and 3. β-alanine as an absolute dose of 1.6 g. For 90 min following supplementation in each condition, participants completed a questionnaire that sought responses to side effects. It was found that lighter individuals iii experienced fewer side effects when they supplemented with β-alanine as a dose relative to body mass; heavier individuals experienced fewer side effects when they consumed an absolute dose of 1.6 g. It was concluded that individualising the supplementation of β-alanine is...