Introduction:
Soccer requires a combination of high-intensity physical, technical, and tactical skills, with a particular emphasis on anaerobic endurance.

Aim of the study:
This study aims to develop and test the effectiveness of the weighted-vestbased (WV) anaerobic soccer training (AnST) model as an integrated approach to improving players’ anaerobic endurance without increasing training volume.

Material and methods:
This study involved 33 male amateur soccer players randomly assigned to three groups: Group A with a WV of 12.40 ± 0.13% body mass, Group B with 7.88 ± 0.08%, and Group C without additional load. Participants had an average weight of 61.75 ± 6.22 kg, height of 164.88 ± 5.39 cm, age of 19.94 ± 1.03 years, and BMI of 22.73 ± 2.24 kg/m2. Anaerobic endurance was assessed using the running-based anaerobic sprint test (RAST) for peak power (PP), average power (AP), and fatigue index (FI). ANCOVA with pretest covariates was used for PP and FI, and Quade’s nonparametric ANCOVA for AP due to nonhomogeneous slopes. Post hoc comparisons employed Tukey’s tests (PP, FI), and pairwise Quade tests (AP), with Cohen’s d effect sizes.

Results:
ANCOVA results showed significant differences between groups for PP (p = 0.006) and FI (p = 0.033), with pretest scores also significantly influencing the outcomes (p < 0.001). Post hoc tests indicated that Group A had significantly higher PP (p = 0.004) and lower FI (p = 0.020) compared to Group C. For AP, Quade-adjusted ranks showed Group A was significantly higher than Group C (p = 0.007). Effect sizes were large (Cohen’s d = 1.53, 1.24, and 1.05), highlighting the substantial impact of WV training on anaerobic performance.

Conclusions:
A WV corresponding to 12.40 ± 0.13% of body mass produced the greatest improvement in soccer players’ anaerobic endurance compared with lighter or no load.