This study aimed to analyze the effects of three off-season training programs on the aerobic capacity, countermovement jump (CMJ), and linear sprint performance of young male soccer players. The study employed a randomized multi-arm design, consisting of three experimental groups: i) a high-intensity interval training (HIIT) group; (ii) a plyometric jump training (PJT) group; and (iii) a HIIT+PJT group; and an inactive control group. Fifty-eight under-19 male soccer players (aged 17.6 ±0.6 years) were randomly assigned to participate in a 3-week offseason training program exclusively performing HIIT, PJT, or a combination of both, while the fourth group remained inactive. Players underwent assessments twice, using the Yo-Yo Intermittent Recovery Test – Level 1 (YYIRT), CMJ, and 30-meter linear sprint. Significant interactions between time and groups were found in CMJ (p<0.001), YYIRT (p<0.001), and 30-m sprint (p<0.001). Group*time interaction revealed that the control group was significantly different from HIIT (p<0.001), PJT (p<0.001), and HIIT+PJT (p<0.001) considering the CMJ. Moreover, the control group was significantly different from HIIT (p=0.037) in YYIRT. Finally, the control group was significantly different from HIIT (p=0.024), PJT (p<0.001), and HIIT+PJT (p=0.021) considering the 30-m sprint. In conclusion, off-season training programs are effective in significantly reducing declines in CMJ and sprint performance compared to maintaining training cessation. However, in the YYIRT, only HIIT seems to be significantly superior to maintaining inactivity. To mitigate aerobic performance declines, incorporating HIIT sessions twice weekly during the offseason is advisable. To enhance or maintain jump performance, integrating at least one session of PJT weekly is beneficial. |