Long-term trends in physical fitness and body mass among 10- year-olds in Gdansk: findings from a 12-year intervention programme - Dettlaff-Dunowska, Magdalena; Lemanowicz-Kustra, Aleksandra; Brzeziński, Michał; Sowulewski, Oliver; Plata-Nazar, Katarzyna; Szlagatys-Sidorkiewicz, Agnieszka (Pediatria Polska - Polish Journal of Paediatrics, 2026)