Plyometrics with reactive agility or isometrics: divergent effects on change-of-direction ability, sprint, and strength adaptations in adolescent female handball players

Introduction: Plyometric training, reactive agility, and isometric training can improve lower limb muscle performance, although the effectiveness of their combination remains unknown in adolescent female handball players. This study compared the effects of 8 weeks of plyometric training combined with either reactive agility or isometrics. Methods: = 12; 13.9 ± 0.5 years) groups. The intervention groups trained twice/week for 8 weeks. Performance was assessed before and after the interventions using: 10 m sprint performance, Repeated-Change-Of-Direction (RCOD), Y-shaped agility, T-half, throwing velocity, countermovement jump (CMJ), maximal isometric force and rate of force development (RFD) of knee extension muscle tests. Upper and lower limb muscle volume was estimated anthropometrically. A 3 × 2 mixed analysis of variance was employed to examine the interaction effects (group x time). Results: CPRAT led to significantly greater RCOD improvements (p < 0.01) and T-half performance (p < 0.001). No significant difference was observed between CPIT vs. CONT. In contrast, (CPIT) showed significantly greater improvements in lower limb muscle volume and knee extension maximal isometric force (p < 0.05) than CPRAT or CONT. Results between experimental groups remained statistically unchanged for Y-Shaped Test, RFD, and lower and upper limb muscle volume. Results for both experimental groups remained statistically unchanged compared to CONT for 10 m sprints, throwing velocity, and CMJ height. Discussion: The CPRAT protocol is superior for developing multidirectional and reactive agility. The CPIT protocol maximizes isometric strength but has limited transfer to high-velocity dynamic tasks. The CPRAT procedure should be selected when the main purpose is to boost agility and COD. However, when developing lower-limb maximal strength is the primary goal, the CPIT treatment should be applied.