PDF(Pubmed)
Abstract：
The phenomenon of post-activation performance enhancement plays an unidentified role in movement eccentric speed and individual muscle group responses. Therefore, this study aimed to determine whether the loaded front squat (FSq) speed of the eccentric phase would influence the post-activation performance enhancement effect and whether the FSq would elicit similar performance enhancement of knee flexion, knee extension, hip flexion, and hip extension muscles. Twenty resistance-trained handball players performed the FSq under maximum eccentric-concentric speed and 2-s eccentric speed (only the eccentric phase performed), while pre- and post-front squat countermovement jump, knee, and hip isokinetic flexion/extension performance were tested. The FSq conditioning activity was performed in a single set of three repetitions with either 90% (maximum eccentric-concentric speed) or 120% (2-s eccentric speed) of one repetition maximum, and post-performance was measured 4-12 min after the FSq. Athletes randomly changed the FSq eccentric speed and tested the hip or knee isokinetic flexion/extension strength at 180°/s. ANOVA showed that the rate of force development during the jump increased (Cohen d = 0.59-0.77) with no differences between 2-s eccentric and maximum speed eccentric protocols. Isokinetic strength increased after the 2-s eccentric FSq in hip extension (d = 0.76-0.86), knee flexion (d = 0.74-0.88), and hip flexion (d = 0.82), with no differences in knee extension strength. After maximum eccentric-concentric speed, isokinetic strength increased in hip extension (d = 1.25). In conclusion, the FSq conditioning activity enhances hip extensors\' performance more than knee extensors\' performance. Different eccentric types of muscle action during a conditioning activity alter the level of local muscle enhancement.
摘要：
激活后性能增强的现象在运动偏心速度和个体肌肉群反应中起着未知的作用。因此,这项研究旨在确定偏心阶段的前深蹲（FSq）速度是否会影响激活后的性能增强效果，以及FSq是否会引起膝关节屈曲的类似性能增强，膝盖伸展,髋关节屈曲,和臀部伸展肌肉。二十名阻力训练的手球运动员在最大偏心同心速度和2-s偏心速度下执行FSq（仅执行偏心阶段），前蹲和后蹲反移动跳跃时，膝盖,和髋关节等速屈曲/伸展性能进行了测试。FSq调节活动在一组三个重复中进行，其中一个重复最大值的90％（最大偏心同心速度）或120％（2-s偏心速度），并在FSq后4-12分钟测量后性能。运动员随机改变FSq偏心速度，并以180°/s测试髋关节或膝关节等速屈曲/伸展强度。ANOVA表明，跳跃过程中的力发展速率增加（Cohend=0.59-0.77），2-s偏心和最大速度偏心方案之间没有差异。髋部伸展2-s偏心FSq后等速运动强度增加(d=0.76-0.86),膝关节屈曲（d=0.74-0.88），和髋关节屈曲（d=0.82），膝盖伸展力量没有差异。在最大偏心同心速度之后，髋关节伸展的等速肌力增加（d=1.25）。总之,FSq调节活动增强了髋关节伸肌的性能，超过了膝关节伸肌的性能。调节活动期间不同偏心类型的肌肉动作改变局部肌肉增强的水平。
