This study aimed to determine the acute effects of high-intensity forward-backward and low-intensity side-to-side plyometric jumps performed following the warm-up on sprint (5, 10, and 15 m) and change-of-direction (COD) (T-half test and repeated T-half tests) performance in youth volleyball players. After a familiarization week, 30 male volleyball players (age = 12.04 ± 1.03 years) performed three randomized conditions (no-plyometrics, high-intensity plyometrics, and low-intensity plyometrics) in three sessions. In a within-subject design, three sets of six repetitions of forward-backward 30-cm hurdle jumps (high-intensity) and side-to-side 20-cm hurdle jumps (low-intensity) were completed. Sprint and COD were tested after each of the conditions with a 2-min rest. A significant effect of the plyometric condition was observed on sprint (p < .001, ${\mathrm{\eta }}_{\mathrm{p}}^2$ range: .56–.70) and COD (p < .01, ${\mathrm{\eta }}_{\mathrm{p}}^2=.24$), but not on repeated COD. More specifically, the high-intensity plyometric condition exhibited significantly better results compared with the low-intensity plyometric (Cohen’s d range: 0.73–1.21) and control conditions (Cohen’s d range: 0.91–2.21). Due to the importance of speed and COD in volleyball, these results suggest that young volleyball players may benefit from high-intensity forward-backward plyometric protocols following the warm-up to improve subsequent performance.

本研究旨在确定短跑（5、10 和 15 m）热身和变向（ COD）（T-half 测试和重复 T-half 测试）青少年排球运动员的表现。经过熟悉周后，30 名男子排球运动员（年龄 = 12.04 ± 1.03 岁）在三个疗程中进行了三种随机条件（无增强式训练、高强度增强式训练和低强度增强式训练）。在受试者内部设计中，完成了三组，每组六次重复的前后30厘米跨栏跳（高强度）和左右20厘米跨栏跳（低强度）。在每种条件下休息 2 分钟后测试 Sprint 和 COD。观察到增强式条件对冲刺的显着影响 ( p  < .001，${\mathrm{\eta }}_{\mathrm{p}}^2$范围: .56–.70) 和 COD ( p  < .01,${\mathrm{\eta }}_{\mathrm{p}}^2=.24$），但不适用于重复的 COD。更具体地说，与低强度增强式训练（科恩d范围：0.73–1.21）和对照条件（科恩d范围：0.91–2.21）相比，高强度增强式训练条件表现出明显更好的结果。由于速度和 COD 在排球中的重要性，这些结果表明年轻排球运动员可能会受益于热身后的高强度前后增强训练方案，以提高随后的表现。