Uebersax J Roth R Bächle T Faude O 2020 We evaluated the structure (i.e., the different training parts), contents (i.e., the various activities used), intensity and occurrence of contact situations and headers during training sessions in under-13 football in Switzerland. A total of 242 players from 20 different teams on average aged 11.4 (SD 0.7) years participated. The participants were filmed during a typical training session while they were equipped with a heart rate sensor. The sessions were systematically recorded to allow for detailed analyses. Furthermore, a preliminary and explorative analysis of the influence of the level of play on these results was conducted. The overall findings indicated that training included 33.4% playing forms, 29.5% training forms, 28.4% inactivity time and 8.7% athletics. The highest heart rates were achieved in the playing forms (166 min-1, 83% HRmax) compared to the other two activities (training forms 154 min-1, 77% HRmax; athletics 150 min-1, 75% HRmax). Each player had 12.8 duels and 0.6 headers per training. Overall, most duels were conducted from the anterior direction. Playing forms induce higher cardio-circulatory load as well as a better learning environment. Potentially dangerous situations like contact with other players or headers occurred in a single player on average every six min during a training session. application/pdf https://sonar.ch/global/documents/189344 eng info:eu-repo/semantics/altIdentifier/doi/10.3390/ijerph17228351 info:eu-repo/semantics/altIdentifier/pmid/33187381 info:eu-repo/semantics/openAccess International journal of environmental research and public health. - 2020 children health soccer training programming youth Structure, Intensity and Player Duels in Under-13 Football Training in Switzerland. http://purl.org/coar/resource_type/c_6501