Neuromuscular Profile of Top-Level Youth Taekwondo Competitors Assessed Through Tensiomyography - Croatian National Youth Taekwondo Team Example

Purpose: This study aimed to investigate the neuromuscular profile of elite youth Taekwondo (TKD) athletes using tensiomyography (TMG) to assess lower-limb muscle contractile properties and estimate muscle fiber composition. Methods: Seventeen members of the Croatian national junior TKD team (10 males, 7 females) participated in this crosssectional study. Anthropometric characteristics and age at peak height velocity (APHV) were assessed, and TMG measurements were performed bilaterally on the vastus lateralis (VL) muscle to obtain contraction time (Tc), delay time (Td), sustain time (Tr), and estimated percentage of type I muscle fibers (MHC-I%). The average chronological age of participants was 16.3 ± 0.9 years, with an average APHV of 13.4 ± 0.7 years. Results: Males were taller and heavier than females, and females showed earlier biological maturation. No significant differences were found between the left and right VL for Tc (21.5 ± 2.6 ms vs. 22.2 ± 2.8 ms; P = .29) or MHC-I% (15.4 ± 9.5% vs. 14.4 ± 11.7%; P = .69). However, a significant side-to-side difference was observed in Td (t = 2.43, P = .03), suggesting asymmetries in neuromuscular activation onset. Substantial intra-individual variability in MHC-I% distribution was also observed. Conclusions: These findings provide novel insight into the contractile characteristics of adolescent TKD athletes and highlight the utility of TMG as a non-invasive profiling tool. The results may inform individualized training design, injury prevention strategies, and athlete development models in youth combat sports. Keywords: talent identification, muscle fiber typology, elite athletes, biological maturation, non-invasive muscle assessment.