Static vs Dynamic Core Exercises for Improving Serve and Spike Speed in Elite Young Male Volleyball Players

Volleyball performance at the elite level will depend heavily on the speed and efficiency of overhead actions, particularly the serve and the spike. These skills will rely not only on upper-extremity strength but also on the effective transfer of force through the kinetic chain, in which the core musculature will play a central role. Core stability will contribute to balance, postural control, and coordination of movement, all of which will be essential for producing high ball velocities. However, there is limited evidence directly comparing static (isometric) and dynamic (movement-based) core training approaches in elite young volleyball players. The purpose of this randomized controlled trial will be to investigate and compare the effects of static and dynamic core training programs on serve and spike velocity in elite young male volleyball players aged 11-14 years. The study will aim to determine whether different types of core exercises will lead to specific performance adaptations and whether one method will be more effective than the other for improving particular volleyball skills. A total of 31 elite young male volleyball players will be included in the study. Participants will be randomly assigned to either a Static Core Exercise Group (n = 16) or a Dynamic Core Exercise Group (n = 15). Both groups will participate in a structured six-week training intervention, consisting of three sessions per week, in addition to their regular volleyball training. The static core training program will consist of isometric exercises designed to improve trunk stability and muscular endurance. The dynamic core training program will include multi-planar and rotational exercises aimed at enhancing power, coordination, and force production. All training sessions will be supervised and progressively adjusted throughout the intervention period. Serve and spike velocities will be measured before and after the intervention using a radar-based measurement system under standardized testing conditions. Anthropometric characteristics, including height and body mass, will also be recorded. Statistical analyses will be conducted to evaluate within-group changes and between-group differences following the intervention. The primary research question will be: Will static and dynamic core training programs differentially affect serve and spike velocity in elite young male volleyball players? A secondary objective will be to determine which type of core training will be more effective for improving specific volleyball performance outcomes. It will be hypothesized that both training approaches will lead to improvements in performance. However, dynamic core exercises are expected to result in greater increases in serve velocity due to their emphasis on rotational power and movement specificity, whereas static core exercises are expected to provide greater improvements in spike velocity by enhancing trunk stability during ball contact. The findings of this study will provide practical guidance for coaches and practitioners in designing evidence-based training programs for youth volleyball players and will contribute to more effective performance development and training periodization strategies.

Inclusion Criteria: * male sex; * age 11-14 years; * ≥ 2 years of systematic volleyball training; * club-level competitive participation; * absence of any musculoskeletal injury during the preceding six months. Exclusion Criteria: * chronic pain syndromes; * prior structured core-training intervention within the previous three months; * attendance at fewer than 90% of the supervised sessions during the trial