Creatine kinase, encoded by the CKM gene, is an enzyme which influences the energy systems used in your cells. Your FitnessGenes result tells you whether you carry a CKM genotype that is found more commonly in endurance or strength athletes. CKM levels are also related to the ability to process oxygen which is important for speed and endurance.
Source: 1000 Genome Project. Global averages for both sexes