These tests have been shown to be sensitive to training adaptations [13, 14], seasonal variation [13] and differences in

playing position and playing standard [13, 15]. Furthermore, YoYo Intermittent Recovery Test performance is closely related to football match performance, since YoYo IR1 outcomes are correlated with high intensity running and total distance covered during a football match for top class referees [16] and footballers [13]. The highest distance covered in a 5 min period during a game has also been associated with YoYo IR2 performance [12]. These findings suggest that the YoYo IR Tests are appropriate models for examining the effects of interventions designed to manipulate changes in individual performance during team sport exercise. Football is a sport that requires players to perform substantial high-intensity MEK162 research buy running with a large contribution from both aerobic and anaerobic energy pathways. The YoYo IR2 best evaluates an individual’s capacity to perform repeated high-intensity

exercise while simultaneously stimulating both aerobic and anaerobic energy systems [13]. At volitional exhaustion, VS-4718 muscle lactate and glycogen utilisation are higher, and muscle pH is lower, following the YoYo IR2 compared to the YoYo IR1 test [12], suggesting selleck compound a larger activation of the anaerobic energy system towards the end of the YoYo IR2. Interestingly, muscle pH was significantly decreased (and muscle lactate increased) at exhaustion compared with at 85% exhaustion time, while muscle phosphorylcreatine and glycogen were not [13]. This indicates that decreased muscle pH may be a significant contributing factor to fatigue during the YoYo Loperamide IR2, suggesting that the YoYo IR2 is a suitable model to investigate

the effect of increased muscle buffering capacity on team sport specific fitness. No study has examined the effects of supplementation on team sport specific exercise capacity. Therefore, the aim of this investigation was to examine the effect of β-alanine supplementation on YoYo IR2 performance in well-trained amateur footballers throughout a competitive season. We hypothesised that β-alanine would significantly improve the distance covered during the test due to an increase in intracellular pH buffering as the result of muscle carnosine elevation. Methods Subjects Seventeen amateur male footballers (age 22 ± 4 y, height 1.83 ± 0.06 m, mass 76.9 ± 6.6 kg) from the same club competing in the lower divisions of the English football pyramid volunteered for the study and were randomly allocated to either a placebo (PLA) or β-alanine (BA) group. All players were members of the same team and were engaged in an identical team sport specific training regime over the season.