Effect of exhaustive stretch-shortening cycle (SSC) exercise on the Education, Associate Professor

本研究旨在探讨拉伸-缩短周期（SSC）疲劳对跳高运动性能的影响机制，包括肌肉损伤的延迟发生和跳高运动的控制。健康男性受试者进行彻底重复的SSC练习，直至精疲力竭。在运动前、运动后以及运动后2天和4天分别进行落差跳（DJ）试验。取血分析肌酸激酶（CK）活性以评估迟发性肌肉损伤。在DJ期间进行了关于刚度和功率调节的动力学和运动学分析。还分析了肌电图（EMG）活动，以评估肌肉的神经活动。与深蹲跳相比，详尽的SSC运动对DJ表现产生了特定的持久疲劳效应。SSC训练后DJ表现的变化呈现双峰模式，即在训练后的第2天出现初始和随后的延迟下降。在运动后2小时，表现出更大衰退的受试者也表现出急性恢复。然而，这些受试者在锻炼后2天出现了DJ表现的二次下降。在运动后2天，在DJ中发现了着陆前关节运动学调节、刚度降低和性能下降之间的相互关系。运动后2天血液CK活性迟发性增高，提示可能存在肌肉损伤并伴有肌肉疼痛。因此，有人认为，损伤引起的疼痛可能会影响落地前关节的运动。运动后2天着陆前肌电活动的延迟下降也提示着陆前运动控制和/或策略可能受到延迟性肌肉损伤和疼痛的影响。综上所述，我们认为力竭重复的SSC运动对跳跃活动产生了特异性疲劳效应，并伴有迟发性肌肉损伤和跳跃运动控制策略的改变。少

The purpose of the present project was to investigate the mechanisms of the stretch-shortening cycle (SSC) fatigue effect on the drop jump performance with respect to the delayed onset of the muscle damage and motor control of drop jump. The healthy male subjects performed exhaustive repeated SSC exercises until exhaustion. Drop jump (DJ) tests were performed before and after exercise as well as 2 days and 4 days after the exercise. Blood samples were taken to analyze creatine kinase (CK) activity for evaluating the delayed muscle damage. Kinetic and kinematic analysis were performed during DJ with respect to stiffness and power regulation. Electromyographic (EMG) activities were also analyzed for evaluate neural activities of the muscles. Exhaustive SSC exercise induced specific long lasting fatigue effect on the DJ performance as compared to the squat jump. Changes in DJ performance after SSC exercise showed bimodal pattern which consists of initial and subsequent delayed decline on … More 2 days after the exercise. Subjects who showed greater initial decline also indicated acute recovery 2 hours after the exercise. However these subjects showed secondary decline in DJ performance 2 days after the exercise. Interrelationships were found between the modulations of pre-landing joint kinematics, decreased stiffness and decreased performance in DJ on 2 days after the exercise. Blood CK activities showed delayed increase 2 days after the exercise which indicates possible muscle damage accompanied with muscle pain. Therefore, it has been suggested that the damage inducing pain could affect pre-landing joint movement. Delayed decrease in pre-landing EMG activities 2 days after exercise also suggest the possible modulation of pre-landing motor control and/or strategy which would be affected by delayed muscle damage and pain. In conclusion, it has been considered that the exhaustive repeated SSC exercise induced specific fatigue effect on the jumping activities accompanied with the delayed muscle damage as well as altered motor control strategy of jumping. Less