A long-duration race induces a decrease of left ventricular strains, twisting mechanics and myocardial work in trained adolescents

We investigated the acute cardiac consequences of a long-duration (>5 h) adventure race in adolescent athletes from evaluations of left ventricular (LV) strains and myocardial work. Twenty trained male adolescents (i.e. 8 +/- 4 h.week(-1) of endurance sports) aged 14-17 years participated in a competitive long-duration adventure race. Blood samples were collected before, immediately and 24 h after the race to determine the time course of troponin I (cTnI) considered a myocardial damage biomarker. Resting echocardiography was conducted before and after the race to assess myocardial regional strains, LV twisting mechanics and myocardial work using speckle tracking echocardiography. The mean completion time of the race was 05:38 +/- 00:20 h, with a mean heart rate (HR) of 83 +/- 5% of maximal HR. cTnI concentration significantly increased in 16/20 participants after the race (pre: 0.001 +/- 0.002 vs. post: 0.244 +/- 0.203 ng.dL(-1), p < .001) and returned to baseline within 24 h. Stroke volume, ejection fraction and global longitudinal strains remained unchanged after the race, while LV twist and global myocardial work significantly decreased (8.6 +/- 3.3 vs. 6.3 +/- 3.3 deg and 2080 +/- 250 vs. 1781 +/- 334 mmHg%, p < .05). Diastolic function, indexes of myocardial relaxation and LV untwisting rate (-91.0 +/- 19.0 vs. -56.4 +/- 29.1 deg.s(-1), p < .001) were affected after the race. We demonstrated that in trained adolescents, a high-intensity endurance exercise of several hours induced an increase of the cTnI concentration associated with an alteration of myocardial function.