[1] Heidelberg Univ Educ, Dept Nat & Human Sci, Heidelberg, Germany
[2] PJ Safarik Univ Kosice, Fac Med, Kosice Inst Soc & Hlth, Dept Hlth Psychol, Kosice, Slovakia
[3] Univ St Andrews, Sch Med, Child & Adolescent Hlth Res Unit, St Andrews, Fife, Scotland
[4] Univ Massachusetts, Dept Exercise & Hlth Sci, Boston, MA 02125 USA
[5] Univ Tubingen, Inst Sport Sci, Tubingen, Germany
[6] Palacky Univ Olomouc, Fac Phys Culture, Inst Act Lifestyle, Olomouc, Czech Republic
[7] Jozef Pilsudski Univ Phys Educ, Warsaw, Poland
[8] Univ Torino, Dept Publ Hlth & Pediat, Turin, Italy
[9] Palacky Univ Olomouc, Fac Phys Culture, Dept Recreat & Leisure Studies, Olomouc, Czech Republic