The UNIL Center for Interdisciplinary Research on Sport (CIRSport) have granted support for a joint effort at CHUV-UNIL between Stanislas Rapacchi and Prof. Matthias Stuber from the CIBM – Radiology Department and Simon Oestreicher and Prof. Aaron Baggish from the Cardiology Department to develop and validate an exercise cardiac MRI protocol and perform a pilot study on cardiac adaptation in prepuberty athletes. This one-year Seed Grant will propel their efforts to propose here an original and mechanistic approach to develop, implement, optimize and validate needle-free in-bore cardiac stress MRI, with 2D and then 3D whole organ coverage for the first time to eventually study the cardiac adaptation and growth trajectory in young pre-puberty athletes using exercise MRI.