The Yo-Yo lR2 Test: Physiological Response, Reliability, and Application to Elite Soccer.

The article cites a study on the physiological response, reliability and validity of Yo-Yo intermittent recovery level two test (Yo-Yo IR2) in soccer players. Thirteen males carried four Yo-Yo IR2 tests, an incremental treadmill test and various sprint tests. Subjects' muscle biopsies, blood samples and heart rate were measured before, during and after the tests. One-hundred ninety-nine Scandinavian elite soccer players carried out Yo-Yo IR2 test in two or four occasions. The study analyzed that Yo-Yo IR2 test was reproducible and evaluates athletes' ability to perform aerobic or anaerobic exercises. It is concluded that Yo-Yo IR2 test is sensitive tool to differentiate intermittent exercise performance of soccer players.