Before players start participating in any sport, they should be medically examined to ensure that they are sufficiently healthy to cope with the demands of training and playing. Therefore, medical assessments aimed at risk factor and disease detection are generally advocated by physicians and sports organisations. The aims of the pre-competition assessment are to prevent harm and to identify potentially significant medical conditions that might make playing football dangerous. A very small number of individuals have unknown or undiagnosed heart conditions, such as congenital cardiomyopathy, and may be at risk as exercise might trigger the manifestation of their disease or at least of associated symptoms like cardiac arrhythmia and might, in the worst case, cause sudden cardiac death. This small part of the population should be identified in order not to expose a player to any disproportionate risk.