Age-Related Changes in Landing Mechanics in Elite Male Youth Soccer Players: A Longitudinal Study

The aim of this longitudinal observational study was to examine the age differences in jump landing kinematics in 13-17-year-old male soccer players. Landing technique was evaluated in three consecutive seasons in U14 (n = 15) and the U16 (n = 10) competition age groups using the Landing Error Scoring System (LESS). For the LESS, ANOVA revealed no significant interaction effect (p = 0.81, eta(2) = 0.009) or main effect for groups (p = 0.15, eta(2) = 0.086), but a significant year effect was observed (p < 0.001, eta(2) = 0.265). The LESS score in the U14 group decreased significantly in the second year (5.7 +/- 1.9, p = 0.006, d = 0.84) and in the third year (5.9 +/- 2.0, p = 0.020, d = 0.70) compared to the first year (7.1 +/- 1.7). The LESS score in the U16 group decreased significantly in the second year (5.1 +/- 0.9 points, p = 0.034, d = 0.77) and in the third year (4.9 +/- 1.4, p = 0.013, d = 0.92) compared to the first year (6.4 +/- 1.2). This trend was supported by the results of the separate assessment of the sagittal plane joint displacement. These findings support previous limited findings from cross-sectional studies, which point to improved landing mechanics during maturation. However, the LESS scores in both groups indicate that players who were around and/or post-peak height velocity during the observed periods may be considered "at-risk", and suggest that preventive training programs should be introduced at earlier stages of players' development.