Purpose This study aimed to compare the effectiveness of Flywheel Eccentric Overload Training (FT) and Fast Eccentric Resistance Training (RT) on one-repetition maximum (1-RM) back squat performance in resistance-trained university students. Methods 30 resistance-trained male university students were randomly assigned to either an FT group (n = 15) or an RT group (n = 15). Both groups underwent a 6-week training program, with sessions conducted twice per week. The FT group utilized a flywheel-based training system, while the RT group performed traditional resistance training exercises. 1-RM back squat performance was assessed before and after the intervention. Results Both the FT and RT groups demonstrated significant improvements in 1-RM back squat performance (p = 0.001). While the FT group showed a slight improvement compared to the RT group, this difference was not statistically significant (p = 0.410). Conclusion The findings suggest that FT and RT are both effective training modalities for enhancing 1-RM back squat performance in resistance-trained individuals. These results highlight the potential of flywheel training as an effective alternative or supplement to traditional resistance training for improving lower body strength.