title: Sub-maximal and maximal Yo-Yo intermittent endurance test level 2: heart rate response, reproducibility and application to elite soccer.
abstract: The aims of this study were to (1) determine the reproducibility of sub-maximal and maximal versions of the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2 test), (2) assess the relationship between the Yo-Yo IE2 test and match performance and (3) quantify the sensitivity of the Yo-Yo IE2 test to detect test-retest changes and discriminate between performance for different playing standards and positions in elite soccer. Elite (n = 148) and sub-elite male (n = 14) soccer players carried out the Yo-Yo IE2 test on several occasions over consecutive seasons. Test-retest coefficient of variation (CV) in Yo-Yo IE2 test performance and heart rate after 6 min were 3.9% (n = 37) and 1.4% (n = 32), respectively. Elite male senior and youth U19 players Yo-Yo IE2 performances were better (P < 0.01) than elite youth U16s and sub-elite players (2,603 ± 451 and 2,534 ± 549 vs. 1,855 ± 535 vs. 1,749 ± 382 m). The intra- and inter-season CV for Yo-Yo IE2 test performance were 4.2 and 5.6%, respectively. A correlation was observed (P < 0.05) between Yo-Yo IE2 test performance and the total (r = 0.74) and high-intensity (r = 0.58) running distance covered in a match. A correlation was also evident (P < 0.01) between Yo-Yo IE2 test heart rate after 6 min expressed in percentage of maximal heart rate and the peak values for high-intensity running performed by midfielders in 5-min (r = -0.71), 15-min (r = -0.75) and 45-min periods (r = -0.77). The present data demonstrate that the Yo-Yo IE2 test is reproducible and can be used to determine the capacity of elite soccer players to perform intense intermittent exercise. Furthermore, the Yo-Yo IE2 test was shown to be a sensitive tool that not only relates to match performance but can also differentiate between intermittent exercise performance of players in various standards, stages of the season and playing positions.
authors.affiliation: Department of Sport and Exercise Sciences, Soccer Research Group, University of Sunderland, Sunderland, UK. paul.s.bradley@sunderland.ac.uk
authors.forename: Paul S
authors.initials: PS
authors.lastname: Bradley
authors.forename: M
authors.initials: M
authors.lastname: Mohr
authors.forename: M
authors.initials: M
authors.lastname: Bendiksen
authors.forename: M B
authors.initials: MB
authors.lastname: Randers
authors.forename: M
authors.initials: M
authors.lastname: Flindt
authors.forename: C
authors.initials: C
authors.lastname: Barnes
authors.forename: P
authors.initials: P
authors.lastname: Hood
authors.forename: A
authors.initials: A
authors.lastname: Gomez
authors.forename: Jesper L
authors.initials: JL
authors.lastname: Andersen
authors.forename: M
authors.initials: M
authors.lastname: Di Mascio
authors.forename: J
authors.initials: J
authors.lastname: Bangsbo
authors.forename: P
authors.initials: P
authors.lastname: Krustrup
mesh_terms: D000328:Adult; D056352:Athletes; D054874:Athletic Performance / Q000502:physiology; D005080:Exercise Test / Q000145:classification / Q000379:methods*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D015203:Reproducibility of Results; D012916:Soccer / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult