The differentiated training and its impact on the functional state of the cardiovascular system and the level of endurance development of 13–15-year-old pupils . Sport and Tourism Central European Journal, [S. l.], v. 9, n. 1, p. 111–129, 2026. DOI: 10.16926/sit.2026.01.05. Disponível em: https://czasopisma.ujd.edu.pl/index.php/sport/article/view/3088. Acesso em: 31 mar. 2026.