Subjects had not taken any supplement in the 3 months prior to the study and had not taken β-alanine for at least 6 months. None of the subjects were vegetarian and,

therefore, would have encountered small amounts of β-alanine in their diet from the hydrolysis BI 10773 concentration of carnosine and its methyl derivatives in meat. The study was approved by the institution’s Ethical Advisory Committee. Study design All subjects had performed the YoYo IR2 on a minimum of two previous occasions, and were aware of the requirements of the protocol. Subjects were required to perform the YoYo IR2 on two separate occasions, separated by 12 weeks of supplementation. Subjects maintained a food diary in the 24 h period before the first main trial, and this was subsequently used to replicate the diet prior to the second main trial. Subjects were supplemented with either 3.2 g·day-1 of β-alanine (CarnoSynTM, NAI, USA) or placebo (maltodextrin, NAI, USA), provided in the form of 800 mg sustained-release tablets, over a 12 week period. Players were supplemented from early to mid-season (PLA: N = 5; BA: N = 6) or mid- to the end of the season (PLA: check details N = 3; BA: N = 3). There were no differences in YoYo IR2 performance prior to supplementation between players starting early season and mid-season for either group (PLA: P = 0.38, 1128 ± 241 and 1280 ± 160 m; BA: P = 0.48, 1120

± 143 and 1040 ± 174 m). The dosing regimen consisted of one 800 mg β-alanine or placebo tablet ingested four times per day at 3 – 4 h intervals. see more compliance with the supplementation regimen was monitored using supplementation logs, with a high degree of compliance being reported in both groups (Placebo: 89%; β-alanine: 90%). There were no reports of symptoms of paraesthesia from any of the subjects in

either group. All supplements were tested by HFL Sports Science prior Phosphoprotein phosphatase to use to ensure no contamination with steroids or stimulants according to ISO 17025 accredited tests. YoYo intermittent recovery test level 2 All tests were performed indoor on an artificial running track in ambient conditions (temperature 21.0 ± 0.7°C, relative humidity 52.4 ± 0.8%). Upon arrival, subjects performed a 5 min standardised warm-up, consisting of light jogging and running, followed by 5 min of self-selected stretching. The YoYo IR2 consists of repeated 40 m (2 x 20 m) runs between markers set 20 m apart, at progressively increasing speeds dictated by an audio signal [11]. Subjects perform 10 s of active recovery between each running bout, consisting of a 10 m (2 x 5 m) walk. The test was ended if the player failed to reach the finish line within the given time frame on two consecutive occasions or if the player felt unable to continue (volitional exhaustion). The total number of levels was recorded and used to determine total distance covered (m) during the test.