Interindividual Variability in Physical Performance Adaptations to Depth Jump Training in Volleyball Players: A Study...

The purpose of this research was to investigate the impact of an 8-week depth jump (DJ) plyometric training using individualized (I-DJT) or traditional DJ training (T-DJT) methods on the physical performance adaptations of male volleyball players.

Twenty-four trained male volleyball players volunteered to participate in the study and were randomly allocated to 3 groups: I-DJT (n = 8), T-DJT (n = 8), and an active control group (n = 8). The T-DJT group underwent an 8-week DJ training from a 45-cm box height, while the I-DJT group integrated DJ training from a personalized box height determined by their power production during the reactive strength index test. Prior to and after the 8-week program, various physical performance variables such as countermovement vertical jump, spike jump, block jump, 10-m sprint, agility T-test, lower-body maximal strength, and the Wingate anaerobic power test were assessed.

After the 8-week training intervention, both training groups observed significant improvements (P = .001) in physical performance, with effect sizes ranging from small to large. A significant group by time interaction (P < .05) indicated that the I-DJT group experienced greater adaptive changes in all physical performance compared with the T-DJT group after the 8-week training period (except block jump). Furthermore, the I-DJT group displayed lower intersubject variability and individual residuals in percent change compared with the T-DJT group.

Individualized DJ training appears to be an effective strategy for enhancing physical performance in volleyball players. By facilitating relatively consistent loading across the training period, it may help to minimize interindividual variability in adaptive outcomes.