title: Reliability and validity of a soccer-specific test of prolonged repeated-sprint ability.
abstract: OBJECTIVE
  The purpose of the study was to assess the reliability and validity of a newly developed laboratory protocol to measure prolonged repeated-sprint ability (RSA) during soccer-specific exercise.
  
  
  METHODS
  To assess reliability, 12 youth soccer players age 15.2 +/- 0.3 y performed 2 trials of a soccer-specific intermittent-exercise test (SSIET) separated by 3 months. The test was performed on a nonmotorized treadmill. A separate sample of 12 youth soccer players (15.2 +/- 0.3 y) completed the SSIET while simultaneously HR, VO2, and blood lactate (BLa) were monitored. The SSIET was designed to replicate the demands of competing in one half of a soccer match while sprint performance was monitored. The test included a 5-s sprint every 2 min.
  
  
  RESULTS
  The mean coefficient of variation was 2.5% for the total distance covered during the SSIET and 3.8% for the total distance sprinted; measures of power output were less reliable (=5.9%). Participants covered 4851 +/- 251 m during the SSIET, working at an average intensity of 87.5% +/- 3.2% HRpeak and 70.2% +/- 3.1% VO2peak, with ~7mmol/L BLa accumulation. A significant reduction (P < .05) in sprint performance was observed over the course of the SSIET.
  
  
  CONCLUSIONS
  The SSIET provided a reliable method of assessing prolonged RSA in the laboratory. The distance covered and the physiological responses during the SSIET successfully recreated the demands of competing in a soccer match.
authors.affiliation: Cardiff School of Sport, University of Wales Institute, Cardiff, Wales.
authors.forename: Jon L
authors.initials: JL
authors.lastname: Oliver
authors.forename: Neil
authors.initials: N
authors.lastname: Armstrong
authors.forename: Craig A
authors.initials: CA
authors.lastname: Williams
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D005080:Exercise Test; D017079:Exercise Tolerance; D006339:Heart Rate; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption; D015203:Reproducibility of Results; D012916:Soccer / Q000502:physiology*; D013997:Time Factors
chemical_list: D019344:Lactic Acid