Introduction:
Explosive power is essential for volleyball performance, underpinning rapid movements such as spiking, blocking, and jumping. Specialized strength training to enhance explosive power is thus critical for optimal athletic performance.

Aim of the study:
This study examined whether a targeted strength training program could significantly improve the explosive power of male volleyball students at Vietnam National University, Ho Chi Minh City (VNU-HCM) compared to conventional training methods.

Material and methods:
Twenty-four male volleyball students were randomly assigned to an experimental group (EG) or a control group (CG). The EG completed a 12-week specialized explosive strength training regimen, while the CG maintained their standard training protocol. Pre- and postintervention performance was assessed using standardized tests: 10-second push-up, 30-meter sprint, pro-agility shuttle run, 20-second chair stand, 10-second crunch, and standing vertical jump. A two-way ANOVA evaluated the interaction between time (pre vs post) and group (EG vs CG), with paired t-tests used for within-group comparisons. Effect sizes were estimated using Cohen’s d and partial η², with significance set at p < 0.05.

Results:
The EG demonstrated significant improvements across all tests. For instance, the 10-second push-up test increased from 13.92 ± 1.22 to 16.00 ± 1.47 repetitions (p < 0.001; Cohen’s d = 1.50; partial η2 = 0.65). Similar significant gains (p < 0.001) were observed in the 30-meter sprint, pro-agility shuttle run, chair stand test, crunch test, and standing vertical jump, while the CG showed only modest or non-significant changes. The ANOVA confirmed a significant time × group interaction, indicating that the EG outperformed the CG across all variables.

Conclusions:
A specialized explosive strength training regimen significantly enhances the explosive power of male volleyball players, exceeding improvements observed with conventional training. The robust statistical significance and large effect sizes support the efficacy of targeted training programs for optimizing athletic performance.