cfDNA as a potential biomarker of prolonged intense training load in adolescent athletes.

States of pathological fatigue are relativelly common in adolescent athletes. In addition to the higher risk of injury, these states negatively affect further development of the adolescent and due to their complex etiopathogenesis their diagnosing is difficult. Based on studies in adults, cell-free DNA (cfDNA) in the plasma is a promising biomarker, which seems to correlate with the individual response to exercise and according to our knowledge has not been assessed in adolescent athletes.