In the last years sports physiologists have tried to decipher the inherited component of physical performance amongst others to improve the selection of potential top athletes. The currently most employed method to gain information about the perfect sports genome is the association study that screens the genome of athlete groups to identify overrepresented polymorphisms that might be supportive on the way to the winners' rostrum. Problems with reproducibility or improper test groups not representative for a desired phenotypic trait often enforce a rejection of the postulated sports polymorphisms. The concept of association studies is challenged by difficulties to evaluate the potential combined impact of the different polymorphisms or the low impact of a single polymorphism on the phenotype. Amongst others the poor reproducibility might be due to epigenetic factors such as DNA methylation, histone modification or chromatin modeling. Epigenetic modification of DNA serves as a switch to control transcription of genes or DNA sections. Epigenetic marks are determined through environmental impact over the entire lifetime as proved by twin studies but most effectively during gestation and lactation period and many of them are immutable. Mouse model studies indicated that some epigenetic marks are even inherited, although this could not yet be confirmed by studies in humans. Therefore epigenetics could play a considerable role in the determination of the athletic potential of the individual that can not be assessed by transgenerational study approaches in quantitative genetics. Taken together, the role of epigenetic status and its influence on physical performance traits needs to be further explored. So far it has to be regarded as speculative that genome screening for sequence variation alone can really deliver information about athletic potential.