This study is one of the few to investigate how differences in pitch shape during SSG can influence physical fitness adaptation. Our findings revealed that the more elongated pitch (SSGlw2) significantly outperformed the other intervention group (SSGlw1) and the control group in eliciting positive adaptations in sprinting performance. Moreover, both experimental groups exhibited significantly superior improvements in enhancing aerobic capacity compared to the control group, although there was no significant difference between the two experimental groups. This evidence suggests that incorporating SSG promotes positive adaptations at such levels. However, further comparisons in future research are needed to understand whether the primary factor contributing to improvements is the training method itself (SSG) or the supplementation of exercise by adding extra training volume. Research on acute demands induced by SSGs often highlights their limited ability to facilitate stable and significant distances covered at high-speed running and sprinting (Dello Iacono et al., 2023). However, investigations comparing larger pitches, particularly those elongated from goal-to-goal, have provided evidence that this modification significantly increases running speed actions (Castagna et al., 2017). Specifically, players achieve more actions and cover greater distances at faster speeds on larger pitches (Casamichana et al., 2018; Castagna et al., 2019). Building upon these findings, the current study innovated by examining whether this critical modification could enhance the typical adaptations induced by SSGs, which, thus far, have only marginally surpassed control groups in terms of sprint performance adaptations (Clemente et al., 2021b). Interestingly, and in line with our hypothesis, the more elongated condition implemented in the SSGlw2 group significantly improved sprinting performance, surpassing the adaptations induced by both SSGlw1 and control groups. Despite SSGlw1 and SSGlw2 having the same relative area per player, the elongated nature of SSGlw2 likely facilitated more continuous running periods, leading to greater speeds (Casamichana et al., 2018). This contrasts with games played in smaller spaces, where running demands are more associated with frequent changes of direction, acceleration, and deceleration, typically linked to possession-oriented tactics and circulation along the wings (Fradua et al., 2013; Casamichana et al., 2018). The specific tactical behavior observed in SSGs on elongated pitches emphasizes mobility actions, transitions, and exploitation of the longitudinal axis (Silva et al., 2014). By allowing players to explore this axis more frequently, they are exposed to intense running actions, particularly in counter-attacks (Fradua et al., 2013), which may benefit the adaptations observed in this research. Notably, the SSGlw1 group also demonstrated improved sprint performance in within-group analysis, although not significantly surpassing the control group, which only participated in regular in-field sessions. Considering the effects of both SSG training interventions on aerobic capacity, our findings revealed that both significantly promote capacity enhancement, surpassing the control group. The 4v4 format of play, commonly associated with a more metabolic stimulus, effectively targets aerobic and anaerobic metabolisms, favoring aerobic power training (Lacome et al., 2018). Regardless of pitch shape, our results demonstrated that both interventions were equally effective in significantly enhancing aerobic capacity. These findings are consistent with existing literature on SSG interventions, which show comparable adaptations in aerobic capacity to other intense and intermittent methods such as high-intensity interval training (Moran et al., 2019; Clemente et al., 2024). On the other hand, our results contradict a study (Faga et al., 2022) that examined the effects of small (75 m2) and large (300 m2) pitches on maximal aerobic speed. In that study (Faga et al., 2022), it was found that only the largest pitch led to significant improvements in this capacity. The intermittent nature of SSGs, characterized by repeated bursts of high-intensity activity interspersed with brief rests, closely mirrors the demands of aerobic interval training, known for its efficient improvement of cardiovascular fitness (Clemente et al., 2021c). Additionally, the high intensity and varied movement patterns inherent in SSGs, including intense accelerations, decelerations, and changes of direction, engage a larger muscle mass, resulting in greater energy expenditure and cardiovascular demand (Gaudino et al., 2014) compared to traditional continuous exercise. Moreover, the social and competitive aspects of these games often enhance motivation and enjoyment (Selmi et al., 2020; Farhani et al., 2022), further facilitating physiological adaptations associated with improved aerobic capacity. Despite implementing innovative and adhering to recommended practices for randomized experimental studies, our research is not without limitations. One such limitation is the absence of progression in task challenges throughout the study weeks. It would be advisable to explore the potential benefits of incorporating progressive periodization in SSGs, as this may lead to varied adaptations in players. Furthermore, due to methodological limitations, we did not have access to microelectromechanical systems that could aid in monitoring the acute locomotor and mechanical impact during the use of SSGs, nor did we have heart rate sensors to provide information about the players' physiological responses to the games. This lack of instrumentation hindered our ability to gain a comprehensive understanding of the mechanisms contributing to the observed adaptations. Additionally, our study overlooked other physical fitness variables that could be influenced by modifications in pitch size, such as change of direction ability or jumping performance. Furthermore, we chose to conduct in-field tests rather than examining competitive performance measures. While competitive performance is undoubtedly important, some match running performance measures are highly dependent on the context of the game, rather than solely representing specific physical qualities (Buchheit and Simpson, 2017). This led us to focus on a capacity that is not contingent upon the playing dynamics. However, we acknowledge that future studies should also consider employing tests that evaluate performance in matches, while controlling for the influence of game dynamics on these outcomes. Moreover, we only examined a single format of play, neglecting the potential impact of different training formats on the interaction with pitch size. Finally, the experimental groups received an additional 24 minutes of training per week compared to the control group. Therefore, future research should explore alternative training approaches for control groups to match the same training volume. This would ensure that improvements are not solely due to the additional training volume but also to the specific training method employed. Future research should also aim to establish dose-response relationships between accumulated external load demands during games and the resulting adaptations in physical fitness. Despite these limitations, our study is, to the best of our knowledge, the first to investigate the hypothesis that different pitch shapes influence physical fitness adaptations during SSG interventions. Our findings suggest that, from a practical standpoint, coaches should consider employing more elongated games to create conditions conducive to improving sprint performance over time. Merely reducing pitch size along the longitudinal axis may not guarantee to achieve significant improvements in this regard. |