This study compared muscle stiffness and functional movement quality, assessed using the Functional Movement Screen (FMS), between U-13 and U-14 elite youth soccer players to examine the practical utility of chronological age-based classification in applied settings. Sixteen elite male youth soccer players (U-13, n = 8; U-14, n = 8) with at least two years of systematic training participated in the study. Biological maturation was estimated using a maturity offset equation, and only players classified as mid- or post-peak height velocity (PHV) were included. Muscle stiffness (N/m) of selected lower-limb and trunk muscles and tendons was measured using the MyotonPRO, with the mean value of three trials at each site used for analysis. Functional movement quality was evaluated using the standardized FMS protocol, consisting of seven subtests with a total possible score of 21 points. Between-group differences were analyzed using independent samples t-tests with the significance level set at α = 0.05. The U-14 group demonstrated significantly greater stiffness in the erector spinae, tibialis anterior, and rectus femoris compared with the U-13 group, whereas no significant between-group differences were observed in the remaining muscle and tendon sites (all p > 0.05). In the FMS assessment, the U-14 group scored significantly higher in the Trunk Stability Push-up and Inline Lunge tests, while no significant differences were identified in the remaining FMS subtests (all p > 0.05). These findings suggest that the transition from U-13 to U-14 in elite youth soccer is associated with site-specific increases in muscle stiffness and improvements in trunk stability and movement control. Therefore, chronological age-grouping may represent a practical and feasible approach for monitoring neuromuscular and functional movement characteristics when maturation-based classification is difficult to implement in applied sports settings.
저자
Geon-Byun [ Department of Sports Science, Baekseok University, Chenan, Korea ]
Young-Bae Eum [ Department of Sports Science, Baekseok University, Chenan, Korea ]
Jin-Hee Seo [ Department of Sports Science, Baekseok University, Chenan, Korea ]
Corresponding Author