1. Institute of Sports and Preventive Medicine, Saarland University, Saarbrücken, Germany
2. Think Tank, German Football Association (Deutscher Fußball-Bund; DFB), Frankfurt, Germany
3. Sport and Exercise Discipline Group, Faculty of Health, University of Technology, Sydney, Australia
4. Performance Diagnostics, TSG 1899 Hoffenheim Fußball-Spielbetriebs GmbH, Zuzenhausen, Germany