Effects of loaded vs unloaded plyometric training combined with change-of-direction sprints on neuromuscular performance in elite U-18 female basketball players: a randomized controlled study

Objectives: Elite basketball performance in adolescent female players is characterized by high-intensity intermittent activities, including an average of 44 jumps per game and spending 8.8% of live time in explosive movements, such as sprinting, change-of-direction (COD), and vertical jumping. This study investigated the impact of 8-week loaded and unloaded plyometric exercises combined with COD drills on performance parameters in female basketball players. Methods: Forty-two elite under-18 female basketball players competing at national championship level were randomly assigned to loaded plyometric with COD training (LDPLYO) (n = 12; age = 16.6 ± 1.1 years; body mass = 65.9 ± 11.8 kg; body height = 173.4 ± 4.9 cm), unloaded plyometric with COD training (UNLPLYO) (n = 15; age = 17.1 ± 0.19 years; body mass = 65.5 ± 9.9 kg; body height = 167.9 ± 7.4 cm), or control groups (n = 15; age = 17.1 ± 0.53 years; body mass = 63.9 ± 11.1 kg; body height = 168.3 ± 9.9 cm). Sprint performance (5, 10, 20 m), COD (Y-agility test and T test), repeated-sprint-ability (RSA), and vertical-jump performance (squat jump—SJ, countermovement jump—CMJ) were assessed pre- and post-intervention. Results: LDPLYO intervention elicited significant improvements in 5 m sprint time (−10.6%, p = 0.005, d = 0.77), COD speed (Y-agility: −12.4%, p < 0.001, d = 0.37; T test: −12.6%, p = 0.005, d = 1.13), RSA (worst time: −2.6%, p < 0.001, d = 2.88; best time: −1.5%, p < 0.001, d = 2.61), and vertical-jump performance (CMJ: +7.5%, p = 0.004, d = 0.22; SJ: +14.6%, p = 0.032, d = 0.06). UNLPLYO demonstrated significant improvements in sprint times (5m: −13.1%, 10m: -6.2%) and jump performance (CMJ: +8.2%, SJ: +13.4%). Conclusions: Bi-weekly loaded plyometric training (8% body mass) with COD effectively enhances multiple neuromuscular performance parameters in elite adolescent female basketball players. Loaded protocols demonstrate superior adaptations in repeated-sprint ability and change-of-direction speed compared to unloaded training, providing practical evidence to support the implementation of loaded plyometric training in female youth basketball.