1. School of Education, National and Kapodistrian University of Athens, Athens, Greece
2. Biomedical Research Foundation of the Academy of Athens, Athens, Greece
3. School of Medicine, North Haugh, University of St Andrews, St Andrews, UK
4. Department of Sport Science, University of Konstanz, Konstanz, Germany
5. Department of Psychology, National and Kapodistrian University of Athens, Athens, Greece