The maximal and sub-maximal versions of the Yo-Yo intermittent endurance test level 2 are simply reproducible, sensitive and valid

摘要

We appreciate Drs. Mendez-Villanueva and Buchheit's interest in our work (Bradley et al. 2011b) and agree that the relationship between physical capacity and match performance of soccer players is complex. However, there are several flaws in their critique of our study (Mendez-Villanueva and Buchheit 2011) and some of them need to be corrected as a matter of record.The first point raised by the Letter makes the assertion that our article incorrectly concludes that the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2) is a valid assessment tool for elite soccer populations. Although no exact measure of physical performance in elite soccer matches exists, the total distance and that covered at high-intensity provide useful indicators (Mohr et al. 2003). We observed a significant con-elation between the Yo-Yo IE2 test performance and both total distance (r = 0.74, P < 0.01) and high-intensity running during a game (r = 0.58, P < 0.05). At this point, it is worth reminding the authors of the Letter that the strength of the correlations are large to very large, based on the classifications of Cohen (1988) and Hopkins et al. (2009).