Department of Training & Exercise Science, Faculty of Sport Science, Ruhr University Bochum, Bochum, Germany. Department of Sport and Exercise Sciences, Durham University, Durham, United Kingdom. Department of Medicine, Training and Health, Institute of Sport Science and Motology, Philipps-University Marburg, Marburg, Germany. German Badminton Association, Saarbrücken, Germany. Institute of Sports and Preventive Medicine, Saarland University, Saarbrücken, Germany. Unit of Sport Psychology, Faculty of Sport Science, Ruhr University Bochum, Bochum, Germany. School of Human Movement and Nutrition Sciences, The University of Queensland, St. Lucia, Australia. Department of Theory and Practice of Sports, Institute of Sport Science, Johannes Gutenberg University Mainz, Mainz, Germany.