1. Frahsa Institute of Sport Science, University of Tübingen, Wilhelmstr. 124, 72074 Tübingen
2. Institute of Social and Preventive Medicine, University of Bern, Mittelstrasse 43, 3012 Bern, Switzerland
3. Department of Sport Science and Sport, Friedrich-Alexander University Erlangen-Nuremberg, Gebbertstraße 123b, 91058 Erlangen, Germany