**7. New biomarkers capable of evaluating exercise performance capacity and progress in training**


miRNAs meet most of the requirements for good biomarkers, such as easily accessible sample collection, minimally invasive and remarkable stability in body fluids. In addition, miRNAs affect many processes and play a crucial role not only in cell differentiation, proliferation and apoptosis, but also affect extracellular matrix composition and maintaining processes of homeostasis. They play significant role in the regulation of physiological adaptation to exercise, such as skeletal muscle and cardiomyocyte hypertrophy, mitochondrial biogenesis, vascular angiogenesis and metabolic processes [33].
