title: β-alanine supplementation improves YoYo intermittent recovery test performance.
abstract: BACKGROUND
  β-alanine supplementation has been shown to improve high-intensity exercise performance and capacity. However, the effects on intermittent exercise are less clear, with no effect shown on repeated sprint activity. The aim of this study was to investigate the effects of β-alanine supplementation on YoYo Intermittent Recovery Test Level 2 (YoYo IR2) performance.
  
  
  METHODS
  Seventeen amateur footballers were allocated to either a placebo (PLA; N = 8) or β-alanine (BA; N = 9) supplementation group, and performed the YoYo IR2 on two separate occasions, pre and post 12 weeks of supplementation during a competitive season. Specifically, players were supplemented from early to mid-season (PLA: N = 5; BA: N = 6) or mid- to the end of the season (PLA: N = 3; BA: N = 3). Data were analysed using a two factor ANOVA with Tukey post-hoc analyses.
  
  
  RESULTS
  Pre supplementation scores were 1185 ± 216 and 1093 ± 148 m for PLA and BA, with no differences between groups (P = 0.41). YoYo performance was significantly improved for BA (+34.3%, P ≤ 0.001) but not PLA (-7.3%, P = 0.24) following supplementation. 2 of 8 (Early - Mid: 2 of 5; Mid - End: 0 of 3) players improved their YoYo scores in PLA (Range: -37.5 to + 14.7%) and 8 of 9 (Early - Mid: 6 of 6; Mid - End: 2 of 3) improved for BA (Range: +0.0 to +72.7%).
  
  
  CONCLUSIONS
  12 weeks of β-alanine supplementation improved YoYo IR2 performance, likely due to an increased muscle buffering capacity resulting in an attenuation of the reduction in intracellular pH during high-intensity intermittent exercise.
authors.affiliation: Sport, Health and Performance Enhancement (SHAPE) Research Group, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK. caroline.sunderland@ntu.ac.uk.
authors.forename: Bryan
authors.initials: B
authors.lastname: Saunders
authors.forename: Caroline
authors.initials: C
authors.lastname: Sunderland
authors.forename: Roger C
authors.initials: RC
authors.lastname: Harris
authors.forename: Craig
authors.initials: C
authors.lastname: Sale