## 3 Results  
### Punches Performance  
Figure 3 presents the effects of a five-week AEL training program on peak punching force in the AEL, CMJ, and CON groups. The analysis revealed no significant main effects of group for any punch type (\(p>0.28\)), although the partial eta squared values ranged from \(\eta^{2}\)p = 0.02 to 0.09, suggesting small to moderate effects. In contrast, significant main effects of time were observed for all punches (\(p\leq 0.007\)), with \(\eta^{2}\)p ranging from 0.25 to 0.49, indicating large effects and substantial overall improvements over time. Significant  
group \(\times\) time interaction effects were found for the jab (F\({}_{2,26}\) = 5.25; \(p\) = 0.010; \(\eta^{2}\)P = 0.29), straight (F\({}_{2,26}\) = 7.51; \(p\) = 0.002; \(\eta^{2}\)p = 0.37), right cross (F\({}_{2,26}\) = 10.89; \(p\) = 0.004; \(\eta^{2}\)p = 0.46), and left cross punches (F\({}_{2,26}\) = 8.22; \(p\) = 0.002; \(\eta^{2}\)p = 0.39). These represent large interaction effects, suggesting that the magnitude of improvement differed meaningfully between groups, favoring the AEL condition. Post hoc comparisons confirmed that the AEL group demonstrated significant post-intervention improvements across all punch types--jab (\(p\) = 0.005; 95% CI\({}_{\text{diff}}\): 52.63 to 163.5 N), straight (\(p\) = 0.001; 95% CI\({}_{\text{diff}}\): 113.6 to 237.9 N), right cross (\(p\) < 0.001; 95% CI\({}_{\text{diff}}\): 92.80 to 197.5 N), and left cross (\(p\) < 0.001; 95% CI\({}_{\text{diff}}\): 82.59 to 199.7 N). In contrast, no significant changes were observed for the CMJ or CON groups (\(p\) > 0.06 for all comparisons), and the effect sizes for these groups were consistently small or negligible. Additional details on the initial group comparisons and training effects can be found in the Supplementary Materials (Tables S1-S4). Figure 4 presents the distribution of responders (Rs) and non-responders (NRs) to the AEL training program for punching peak force in the AEL, CMJ, and CON groups. For the peak jab punch force, the AEL group showed a small increase (11.1%; d = 0.54) with 66.7% of participants classified as responders (6 out of 9). The CMJ group also exhibited a small effect (4.4%; d = 0.30), with 30% responders (3 out of 10), while the CON group demonstrated a trivial decrease (\(-\)1.1%; d = \(-\)0.06) and no responders. Regarding the peak straight punch force, the AEL group achieved a small improvement (10.5%; d = 0.43) with 44.4% responders (4 out of 9). In contrast, the CMJ (3.5%; d = 0.18) and CON groups (0.9%; d = 0.06) showed trivial changes, with only one responder in the CMJ group and none in the control. For the right cross punch, the AEL group reported a small effect size (7%; d = 0.38) and 66.7% responders. The CMJ group showed a trivial change (2.6%; d = 0.18) with no responders, and the CON group experienced a trivial decrease (\(-\)0.9%; d = \(-\)0.06), also with no responders. Finally, for the left cross punch, the AEL group showed a small improvement (7.1%; d = 0.40) and the highest responder rate of  
Figure 3: Effects of a five-week AEL training program on punching peak force in the AEL, CMJ, and CON groups. Bars represent mean \(\pm\) SD for each punch type pre- and post-intervention. Statistical significance refers to time \(\times\) group interactions. AEL: accentuated eccentric loading; CMJ: countermovement jump; CON: control; N: newton. ***: \(p\) = 0.05; ***: \(p\) = 0.001.  
all punches (77.8%; 7 out of 9). The CMJ group showed a trivial increase (2.8%; d = 0.16) with one responder, whereas the CON group had a trivial decrease (\(-\)1.4%; d = \(-\)0.05) and no responders. These findings suggest that the AEL protocol induced consistent and practically meaningful improvements in punching peak force across all punch types, with particularly high responder rates observed in the jab, right cross, and left cross punches. In contrast, the CMJ and control conditions elicited minimal individual adaptations.