Heritability assessment of contractile properties: insight from monozygotic twins' national youth track and field champions

Heritability estimates for various traits were previously obtained in large-scale twin studies as well as in genomic analyses, which have been used more frequently recently. The potential for heritability in studies of twin athletes has never been observed for tensiomyography (TMG)-derived contractile properties. Accordingly, the aim of this study was to investigate the hereditary capabilities (HC) of lower-limb contractile properties using a twin case study design performed on a pair of monozygotic (MZ) track and field youth champions from Croatia. The results showed high HC values for contraction time, time delay, and contraction velocity, which measure the absolute (Tc, Td) and relative (Vc) velocity of the lower limb muscles. Very high HC values of the listed contractile properties indicate a strong influence of heritability on selected, mainly velocity-related properties, whereas Td-variable related to the peripheral nervous system is the most affected. Second, the muscle morphology of vastus lateralis, vastus medialis, and rectus femoris also appears to be subject to a strong heritable influence. In conclusion, the HC estimates presented, together with the heritability coefficients, can be used as guidelines for talent identification processes, especially when combined with TMG, a suitable non-invasive alternative for estimating lower-limb contractile properties in adolescent athletes.