The Effect of Static and Dynamic Core Exercises on Serve and Spike Speed in Young Volleyball Players: a Randomized Controlled Trial

Abstract

Background Volleyball is a high-intensity team sport demanding explosive upper-body skills whose performance depends on effective kinetic chain transfer through the core musculature. Although core training is widely incorporated into athletic conditioning, the differential effects of static versus dynamic core protocols on sportspecific ball-velocity outcomes remain insufficiently examined, particularly in adolescent athletes. This study investigated the effects of a six-week supplementary static or dynamic core exercise program on serve speed and spike speed in elite young male volleyball players. Methods Thirty-one male volleyball players (aged 11–14 years) were randomly assigned to a dynamic core exercise group (DCEG, n=15) or a static core exercise group (SCEG, n=16). Both groups continued regular volleyball training and additionally performed a six-week, three-days-per-week core program applied before each training session. Serve and spike speeds were measured with a Bushnell Velocity Gun radar device at pre-test and post-test. Normality was confirmed by the Shapiro-Wilk test. Within-group comparisons used paired t-tests; between-group comparisons used analysis of covariance (ANCOVA) with pre-test values as the covariate. Results Within-group analyses showed a significant improvement in spike speed for SCEG (t(15)=−5.115, p < .001) and a significant improvement in serve speed for DCEG (t(14)=−7.299, p < .001). ANCOVA revealed a significant between-group difference in serve speed (F(1, 28)=31.001, p < .001, partial η² = 0.525) favouring DCEG, while no significant between-group difference was found for spike speed (F(1, 28)=0.250, p = .621, partial η² = 0.009). Conclusions Six weeks of supplementary core training was accompanied by improvements in serve and spike performance in elite young male volleyball players. Dynamic core exercises were more effective for serve speed, whereas static core exercises produced significant gains in spike speed. Because the trial did not include a no-treatment control group and the sample was small, these findings are preliminary and describe a comparison between two active core-training modalities rather than an absolute effect of core training; coaches may consider tailoring core training modality to the specific performance goal, pending confirmation in larger, adequately powered controlled trials.Trial registration ClinicalTrials.gov, NCT07641439. Registered 05 May 2026. Retrospectively registered (recruitment began 23 March 2026; see Methods for justification).