Abstract
The concurrent development of strength and power is considered effective for improving jump performance in athletes.Although previous studies have examined the effects of unilateral and bilateral training, there is a lack of systematic research comparing the impact of these two training modes within the framework of Complex-Contrast Training (CCT) on female volleyball players. This study aimed to compare the effects of Unilateral Complex-Contrast Training (UCCT) and Bilateral Complex-Contrast Training (BCCT) on lower limb strength and jump performance in collegiate female volleyball athletes. A total of 16 female volleyball players were randomly assigned to either the UCCT group (n = 8) or the BCCT group (n = 8) using a random number-based randomization method. The training intervention consisted of 2 sessions per week for 8 weeks.Before and after the intervention, participants underwent a series of standardized tests, including Countermovement Jump (CMJ), Squat Jump (SJ), Drop Jump (DJ), Eccentric Utilization Rate (EUR), Standing Long Jump (SLJ), and one-repetition maximum (1-RM) squat. Statistical analysis was conducted using JASP version 0.18.3.0 with a 2 (group) × 2 (time) two-way repeated measures ANOVA. The results showed significant main effects of time (p < 0.001) for CMJ, DJ, SLJ, and 1-RM squat, while SJ and EUR did not exhibit significant improvements. A significant time × group interaction was found for CMJ (p = 0.009), and simple effects analysis indicated that the UCCT group showed a more pronounced improvement. No significant main effects of group or time × group interaction effects were observed for the other variables. Overall, UCCT demonstrated similar effects to BCCT in improving horizontal jump performance and maximal lower limb strength, but showed a greater advantage in enhancing vertical jump performance.