## 4 Discussion
In Zone 3, a decline in performance was noted for the CDs, while the CMs exhibited an increase in distance covered. These results are partially consistent with prior studies, which have shown decreased second-half performance for CDs, SDs, and CMs [12; 27; 29; 50]. In Z4, the present study identified reduced performance among CDs and Forwards, while CMs demonstrated improvements in both Z4 and Z5. Previous research has often reported performance declines in high-intensity zones for CMs and CDs during the second half [12], though other studies have found no such reductions [13; 27; 28; 50]. Finally, in the sprint zone (Z6), a decrease in performance was observed for the CMs, contrasting with findings from [PERSON] et al. (2020) [12], who reported that only the SDs failed to maintain sprint performance. Several other studies also reported consistent sprint performance throughout both halves of play [13; 27; 28; 29]. The decrease in performance in the second half can be explained by fatigue, the team's tactics [51], and the match outcome [24]. The scoreline of a soccer match can significantly influence the running performance of players, as it often dictates the tactical demands placed on individuals and the team as a whole. For instance, when a team is trailing, players are typically required to adopt a more aggressive and high-intensity approach, often leading to increased sprinting and total distance covered as they attempt to regain possession and create scoring opportunities. Conversely, teams in the lead may adopt a more conservative strategy, focusing on maintaining possession and defensive shape, which can reduce the physical demands on players, especially in high-intensity efforts [52]. Studies have shown that contextual factors such as match status (winning, drawing, or losing) can alter players' physical output, with higher physical performances often observed during periods when teams are losing [53]. Therefore, understanding the influence of scoreline dynamics is crucial for coaches and performance analysts when interpreting match data and planning training sessions. In the present study, considering that in 14 out of the 18 games, the study team won, and of these, 8 were with a goal difference greater than two, this may partially explain the decline in performance in the second half. Fatigue is another factor that could affect running performance in the second half, but since fatigue assessment measurements were not taken, only assumptions can be made. As mentioned earlier, this is one of the few studies that depict the running performance profile of high-level young football players in the 1-4-3-3 formation. The differences between playing positions in the formation suggest the impact of the tactical role on external load. Knowledge of the demands of the position helps coaches in personalizing the external load of players throughout the weekly cycle, aiming to improve performance and prevent injuries. Although this study provides important information, it has some limitations. The study involved only one football team, which limits the ability to generalize the results. Additionally, matches from only one competitive season were used. Furthermore, contextual variables (score, home or away match) that could influence running performance were not taken into account in this study. The team's philosophy, playing style, and the individual instructions given to players during matches were also not considered. A further potential limitation of this study is the use of both parametric and non-parametric tests across variables, which, although based on distributional assumptions, may affect analytical consistency and could be addressed in future research through the application of mixed models or generalized linear models. Therefore, future research on larger samples of young players, where contextual variables that could affect running performance are also considered, will provide a more complete picture of the running profile in this formation.