PPARGC1A and atrial fibrillation: Due to the potential influence of these candidate genetic variants on endurance performance in athletic pursuits and non-elite AF populations, the primary purpose of this study was to investigate any associations of the ACE (rs4343), ACTN3 (rs1815739), ADRB1 (rs1801253), and PPARGC1A (rs8192678) polymorphisms with two-kilometre time-trial endurance test performance in elite AF players.