## 4 Discussion  
The present study aimed to evaluate the effects of school-based endurance and strength exercise interventions designed to improve body composition, physical fitness and cognitive functions in adolescents. Our findings provide critical information about how school-based endurance and strength exercise intervention can influence these key health parameters. Our results showed the significant effects of group \(\times\) moment interaction on cognitive function, weight, waist circumference and body mass index (BMI). Specifically, a significant interaction between weight and waist circumference was observed, suggesting that the intervention program produced differential effects in different intervention groups (i.e., endurance and strength groups). Post hoc analyses revealed significant differences between the resistance group and the control group in terms of improvements in aerobiccapacity, while the strength group demonstrated greater gains in muscle strength compared to the control group. The analysis of cognitive parameters revealed significant effects on the reduction of omissions and commissions, as well as improvements in reaction time and a decrease in slow reactions. Specifically, EG demonstrated a greater reduction in omissions and commissions, while the SG resulted in more notable improvements in reaction time. Additionally, both the strength and endurance interventions contributed to a decrease in slow reactions, with the effect being more pronounced in the endurance group. The analysis of anthropometric measures, including weight, waist circumference and BMI, showed significant improvements in the group \(\times\) moment interaction. The SG had a greater impact on increasing weight and BMI, while showing a smaller gain in waist circumference compared to the other groups. This suggests that the strength intervention not only contributed to increased body mass, but also helped maintain a more favorable distribution of body fat around the waist. In the physical fitness parameters, the group \(\times\) moment interaction indicated significant improvements in grip strength, agility and VO\({}_{2}\) max. The SG resulted in the greatest improvements in grip strength and agility. On the other hand, the EG had a more notable effect on improving VO\({}_{2}\) max, reflecting a significant increase in participants in the Course Navette. These differences underscore the importance of choosing the appropriate type of physical intervention based on the specific physical improvement goal. The ALPHA-Fitness battery included measures such as body composition, horizontal jump, grip strength, 4 \(\times\) 10-m and Course Navette (VO\({}_{2}\) max). Notably, the Course Navette showed a significant group \(\times\) main effect, indicating that different training modalities had distinct impacts on cardiovascular fitness. The absence of significant primary effects or interactions in the other fitness tests suggests that, although overall fitness improved, the EG may have been particularly effective in improving aerobic capacity compared to SG and CG. Several studies corroborate our findings on the effectiveness of physical activity interventions improving physical fitness. A study [34] found that a 12-week resistance training program significantly improved the VO\({}_{2}\) max and aerobic capacity in adolescents. Similarly, another study [35] reported significant improvements in cardiovascular capacity and muscle strength following a structured physical activity program, aligning with the best performance in the Course Navette observed in our EG. There were no differences or main effects observed in the rest of the physical fitness domains or body composition. A possible reason for this could be the short duration of the intervention. However, as an example, the previous literature observed expected strength gains of 30-40% in untrained youth following their participation in an introductory (8-20 weeks) resistance training program [36].