The effect of rugby sevens on cardiac biomarkers in elite female athletes

Rugby is a sport characterized by high-intensity anaerobic interval runs alongside aerobic exertion. During matches, sudden accelerations, intense isometric contractions due to pushing and pulling, and heavy physical contact require players to exert maximum strength throughout the game. Consequently, rugby matches are known to increase serum levels of CK and Mb. Although these increases are often attributed to skeletal muscle damage, these markers can also rise as a result of myocardial injury. Sports with high levels of isometric contractions can lead to concentric left ventricular hypertrophy due to increased systemic arterial pressure. In this context, rugby is thought to impose significant cardiac stress, making it essential to investigate its effects on cardiac damage biomarkers. This study aims to determine whether rugby sevens, an Olympic sport played in three matches a day, induces cardiac damage. A total of 28 licensed female rugby players participating in the Turkey Rugby Sevens Championship were included. Blood samples were collected twice: before warm-up exercises and at the end of the championship. Serum levels of hs-cTnI, NT-proBNP, BNP, CK-MB, Mb, and hs-CRP were analyzed using immunoassay methods. At the end of the championship, significant increases were observed in all cardiac biomarkers (hs-cTnI, p<0.001; NT-proBNP, p<0.001; BNP, p<0.01; CK-MB, p<0.001; Mb, p<0.001; and hs-CRP, p<0.001). Post-championship, CK-MB, and Mb concentrations exceeded reference limits in 12 and 23 players, respectively, while increases in other biomarkers remained within reference ranges. A positive correlation was found between the duration of physical activity and the increases in Mb and CK-MB levels (r=0.659, p<0.001; r=0.663, p<0.001, respectively). Considering that Mb and CK-MB can also increase due to skeletal muscle damage, these findings suggest that rugby sevens does not cause cardiac damage. Keywords: Cardiac Damage, Rugby as a Sport, Hs-cTnI, CK-MB, Hs-CRP