The Application of the Yo-Yo Intermittent Endurance Level 2 Test to Elite Female Soccer Populations

The aim of this study was to evaluate the application of the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2) to elite female soccer populations. Elite senior (n=92), youth (n=42), domestic (n=46) and sub-elite female soccer players (n=19) carried out the Yo-Yo IE2 test on numerous occasions across the season. Test-retest coefficient of variation (CV) in Yo-Yo IE2 test performance in domestic female players was 4.5%. Elite senior female players' Yo-Yo IE2 test performances were better (P<0.01) than elite youth, domestic and sub-elite players (mean +/- standard deviation; 1774 +/- 532 vs 1490 +/- 447, 1261 +/- 449, and 994 +/- 373m). For elite senior female players, wide midfielders (2057 +/- 550m) had a higher Yo-Yo IE2 test performance (P<0.05) than central defenders (1588 +/- 534m) and attackers (1516 +/- 401m), but not central midfielders (1764 +/- 473m) or full-backs (1964 +/- 522m). Large correlations were observed between Yo-Yo IE2 test performance and the total and high-intensity distance covered (r=0.55; P<0.05) during elite senior soccer matches (r=0.70; P<0.01). A large correlation was also obtained between Yo-Yo IE2 test performance and (r=0.68; P<0.01). Performances in the Yo-Yo IE2 test were greater (P<0.05) in the middle and the end of the season compared with the preparation period for elite youth female players (1767 +/- 539 and 1742 +/- 503 vs 1564 +/- 504m) and in elite senior female players, Yo-Yo IE2 test performance increased by 14% (P<0.01) after completing 4 weeks of intense training prior to the FIFA Women's World Cup Finals (2049 +/- 283 vs 1803 +/- 342m). The data demonstrate that the Yo-Yo IE2 test is reproducible and is an indicator of the match-specific physical capacity of female soccer players. Furthermore, the Yo-Yo IE2 test illustrates sensitivity by differentiating intermittent exercise performance of female players in various competitive levels, stages of the season and playing positions.