Network Interventions for Changing Physical Activity Behaviour in Preadolescents.

"Competing interests: The authors declare no competing interests."

"We thank S. Gächter, A.M. Espin, S. Kriemler, F. Exadaktylos, E. Yoeli, E. Woelbert, S. Stoffel and J. Fooken for invaluable discussions and feedback. We also thank Dr. Claudio Merletti representing the Ufficio Scolastico Territoriale per la Lombardia for his authorization and ethical approval for the realization of this study in schools under his responsibility. We are especially grateful to Mrs. Paula Benetti from the same office for coordinating the communication with all school directors, teachers, parental associations and students' parents. We finally thank all the school directors and teachers involved in the study and all the parents and especially the children who agreed voluntarily to participate in this study (Scuola Primaria "G. Galilei", Ispra; Scuola Primaria "S. Pellico", Ranco; Scuola Primaria "G. Pascoli", Taino; Scuola Primaria "D. Alighieri", Angera; Scuole Primarie "G. Ungaretti" and "G. Matteotti", Sesto Calende; Scuola Primaria "D. Alighieri" Golasecca; Scuola Primaria "A. Manzoni" Mercallo; Scuola Primaria "L. Scotti" Laveno; Scuola Primaria" G. de Amicis" Vergiate; Scuola Primaria "G. Wojtyla" Cimbro; Scuola Primaria "S. Tamborini" Varano Borghi; Scuola Primaria "A. Liborio" Comabbio, Scuola Primaria "A. Manzoni" Malgesso). This research was exclusively funded by European Commission. The supply of the technical equipment (accelerometers) and the contributions of HB and EvS were supported by the Medical Research Council (MC_UU_12015/7), and the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence (RES-590-28-0002). Funding from the British Heart Foundation, Department of Health, Economic and Social Research Council, Medical Research Council, and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration is gratefully acknowledged. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. Any opinions expressed in this article are those of the authors and not of the European Commission or any other involved institute affiliated by the authors. Data on physical activity and bilateral friendships are provided by the authors upon request."