Effect of Plyometric Training on Smash Performance in Extracurricular Volleyball Students at SMP Negeri 3 Sembawa

Abstract

This research examines the effect of plyometric training on smash performance improvement in extracurricular volleyball students at SMP Negeri 3 Sembawa. Low smash ability marked by insufficient hitting power, directional inaccuracy, and attack ineffectiveness is the main problem in school extracurricular coaching. The research method used a quantitative experiment with a pre-experimental one-group pretest-posttest design. The sample consisted of 10 male students selected through purposive sampling with criteria of age 11–15 years and active participation in volleyball extracurricular activities for a minimum of six months. The treatment was a plyometric training program consisting of basic box jump, burpee, and depth jump for 16 sessions with a frequency of four times per week. Measurement instruments used a volleyball smash skill test with scoring technique toward target areas. Data analysis included Shapiro-Wilk normality test and paired sample t-test hypothesis testing using IBM SPSS 26. The results showed an increase in the average value from 9.80 (pretest) to 14.00 (posttest) with a percentage increase of 42.85%. The paired sample t-test obtained a value of t = −31.500, p = 0.000 (< 0.05), with Cohen's d = 2.91 effect size classified as very large. The conclusion indicates that plyometric training has a significant effect on improving smash performance in extracurricular volleyball students at SMP Negeri 3 Sembawa. This finding provides a recommendation for coaches and physical education teachers to integrate plyometric training programs systematically into smash technique training design.