Furthermore, distance covered during the YoYo IR2 has been associated with high-intensity running performed during competitive games play [12, 13]. Therefore, the results of the present investigation suggest that β-alanine supplementation is effective at improving team sport

specific exercise capacity. Blood measures were not taken in the current investigation, although others have reported lactate values in excess of 10 mmol·L-1 at exhaustion [13], which is higher than the values shown in repeated sprint activity studies that have shown a correlation to H+ buffering capacity (~8 mmol·L-1; [5, 18]). Although the rate of muscle phosphorylcreatine and glycogen utilisation are high during SCH727965 chemical structure the YoYo IR2 [13], there is no difference in muscle concentrations of these substrates between 85% and 100% of exhaustion time, indicating that depletion of these substrates is not a main contributing factor to fatigue. Interestingly, muscle pH was significantly lower at exhaustion compared with at 85% of exhaustion time, which suggests increasing muscle acidity is a limiting factor to YoYo IR2 performance. Although muscle carnosine concentrations were not directly determined in this study, Stellingwerff et al. [19] showed that

as little as two weeks of β-alanine supplementation at half the dose used in the current study was sufficient to increase muscle carnosine by 11.8 ± 7.4% in the selleck chemicals tibialis anterior. Therefore, it can by hypothesised that 12 weeks of β-alanine supplementation at 3.2 g·day-1 significantly increased muscle carnosine concentrations in the current population. As MG-132 cost such, since one of the undisputed roles of muscle carnosine is in muscle buffering, the most likely explanation O-methylated flavonoid for the improvement in YoYo IR2 performance is due to an increase in intracellular buffering capacity, resulting in an attenuation of the reduction in intracellular

pH during high-intensity exercise. The YoYo IR2 has been shown to be a highly reproducible capacity test, with a CV of ~10% for two tests performed within a one week period [13]. In addition, the test is sensitive to detect training adaptions, with performance improvements of approximately 42% shown following pre-season training. In the present investigation, players in the placebo group showed a ~7% decline in performance while β-alanine supplementation improved YoYo IR2 performance by ~34%, which compares favourably with the effects of pre-season training, and exceeds the expected CV of the test. Furthermore, all 8 of the players who improved with β-alanine did so above this expected CV, while the placebo group showed more variation with 3 players exceeding the CV (1 improved and 2 decreased their performance), which suggests that performance improvements in the β-alanine group can be attributed to the nutritional intervention employed in the current investigation.