Fig 1. Study protocol and selection of candidate individuals.

Top level Hungarian athletes (n = 145) and healthy control individuals were screened. Athletes above and controls under a VO₂ maximum of 50ml/kg/min were referred to cardiac magnetic resonance (cMRI). Eight athletes were excluded due to low VO₂ maximum (<50ml/kg/min) and eleven athletes did not complete the cMRI examination due to intolerance. Control individuals with higher than 50ml/kg/min VO₂ maximum (n = 3) were also excluded and four volunteers could not tolerate cMRI (n = 4).