## 4 Discussion
### First Serve Analysis  
The analysis of the first serve in U-14 players highlights several key tactical aspects that differentiate them from U-18 and professional players [11]. Regarding service target zones, the data reveal that U-14 players do not show a strong preference for a single service area, as their serves are distributed relatively evenly between the T-zone and wide zone on the deuce side and to the wide zone and body on the advantage side. This contrasts with professional players, who typically show a higher frequency of T-zone serves, as this placement limits the returner's angle and increases the likelihood of an advantageous court position after the serve [19]. Other research [2] found similar trends in U-12 and U-14 players, where junior athletes displayed a less defined preference in serve placement, highlighting a potential developmental difference in tactical awareness and execution.  
The relationship between serve effectiveness and rally length further emphasizes the importance of optimizing the first serve. In our study, short rallies (0-4 strokes) were the most frequent, followed by medium rallies, reinforcing the role of the serve and serve +1 shot in match success. These results align with [PERSON] et al. [20], who demonstrated that players dominating short rallies tend to win matches at a significantly higher rate. However, compared to professional players, U-14 athletes exhibit lower efficiency in capitalizing on strong serves, often leading to extended rallies due to less aggressive serve +1 execution and making more errors [2]. The distribution of impact zones further supports this trend, as U-14 players predominantly hit their first shot after the serve from deep baseline positions. This suggests a reluctance to step into the court and take control of the point, differing from professional players who frequently position themselves more aggressively inside the baseline following their serve. This pattern has been previously noted in junior tennis, where players often lack the physical and tactical development to efficiently transition from serve to an offensive position [21].  
These tactical differences between U-14 and professional players may also be influenced by physical attributes such as strength and neuromuscular coordination. Youngerplayers often have less developed muscle strength and coordination, which may limit their ability to execute more aggressive shots or step inside the baseline after serving. Additionally, these players are still developing the physical endurance required to maintain a more aggressive playing style, which is typical of older players. The physical limitations could partially explain why U-14 players are more likely to engage in extended rallies rather than capitalizing on their first serve. As noted by [PERSON] et al. [22], improvements in motor coordination and tennis skills during early adolescence are crucial for enhancing performance in tennis.  
Finally, an analysis of the final stroke and point-ending zones reveals that U-14 players most frequently finish points in central areas, whereas professional players often finish points by moving the opponent and forcing them to more defensive positions [23]. This difference suggests that junior players may lack the tactical awareness or execution ability to consistently use wide angles to finish points effectively. In contrast, professional players strategically use these zones to maximize offensive opportunities and limit the opponent's recovery time.