# Age-Related Changes in Landing Mechanics in Elite Male Youth Soccer Players: A Longitudinal Study
## 4 Discussion
Although the players in our study demonstrated positive age-related changes in landing technique, the average LESS score was greater than five points in each year of observation, except the third year of measurement for U16 players (4.9 \(\pm\) 1.4 points), who can be considered post-PHV (maturity offset = 3.3 \(\pm\) 0.6) [34]. This suggests that during nearly the whole observed period, players may be considered \"at-risk\". [PERSON] et al. [16] also indicated that in elite youth soccer players aged 14 years, a LESS score of six or more was related to a greater risk of injury compared with individuals with a value of four or less. Values of 7.1 \(\pm\) 1.7 in the U14 group in the first year of the study and 6.4 \(\pm\) 1.2 in the U16 group in the first year of the study place these players above the cut-off suggested for low risk. Regarding the injury risk, it was also suggested that the period of PHV or post-PHV was an ACL rupture risk factor due to impaired knee joint mechanics when landing [51]. This suggestion is concerning for players in the U14 group who can be considered circa-PHV in the first year of observation (maturity offset = \(-\)0.3 \(\pm\) 0.7 years) [34]. Poor landing mechanics at this developmental phase might be attributed to the phenomenon of \"adolescent awkwardness\", which is a temporary impairment of motor coordination explained by the rapid growth of bones during PHV not followed by equally rapid soft tissue adaptation. This discrepancy phenomenon results in reduced tendon muscle flexibility, leading to a significant reduction in joint range and the development of abnormal movement patterns and, consequently, increased susceptibility to lower limb injuries in soccer players [35; 37; 52]. On the other hand, it should be mentioned that no players monitored in this study suffered from an ACL injury during the observed period. It is assumed that the main reason was that the group of players in our study was small, and the incidence of ACL injury is not high and is lower in males compared with females. Our findings concerning the poor landing technique in PHV players and gradual improvement during adolescence support the findings of a recent cross-sectional study on soccer players by [PERSON] et al. [34]. The authors observed 10-18-year-old soccer players and found that the decrease in pVGRF did not occur linearly with increasing chronological or biological age, but there was a temporary increase in landing stiffness during PHV. Unfortunately, the players in our study were not measured in the previous stage of maturation (i.e., pre-PHV period), and thus, it is not possible to compare the data from the first year with the data from the pre-PHV stage to confirm a potential decrease in landing technique around PHV. Similarly, the results of the current study indicate that although the players were involved in a systematic training process within a professional academy soccer club for at least six years at the beginning of the study, the training program applied in these years of elite developmental pathway did not effectively influence players' neuromuscular system to assure better landing technique quality. As the movement pattern of jump landing pertains to the controllable risk factors for injury, and can be, to a large extent, modified, it is suggested that more attention should be paid to the quality of landing mechanics in the training process before PHV to improve players' landing mechanics and to decrease the incidence of ACL injury, especially in the subsequent \"at-risk\" periods. Research has shown that a properly designed 4-week neuromuscular training program reduced LESS scores and improved landing mechanics in both pre-PHV and post-PHV male cricket players [53]. The finding concerning improved jump-landing mechanics with age indicated by the changes in the LESS score in the soccer players observed is also supported by the decline in the SPJD score.