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

本研究的目的是从肌肉损伤的延迟发生和运动控制两个方面来研究拉伸缩短周期(SSC)疲劳对跳高成绩的影响机制。健康男性受试者进行重复的力竭SSC运动，直到筋疲力尽。分别于运动前、运动后、运动后2d、4d进行跳跃试验。取血检测肌酸激酶(CK)活性，以评估延迟性肌肉损伤。在DJ过程中进行了关于刚度和功率调节的运动学和运动学分析。肌电(EMG)活动也用于评估肌肉的神经活动。与深蹲跳跃相比，力竭性SSC运动对DJ成绩产生了特定的持久疲劳效应。潜伏期运动后DJ成绩的变化呈双峰模式，由…的初始和随后延迟下降组成运动后2天以上。表现出较大初始下降的受试者也表明在锻炼2小时后迅速恢复。然而，这些受试者在锻炼2天后表现出DJ表现的继发性下降。在运动后2天，DJ的着陆前关节运动学调制、僵硬降低和运动能力降低之间存在相互关系。运动后第2天，血CK活性出现延迟性升高，提示可能存在肌肉损伤并伴有肌肉疼痛。因此，损伤引起的疼痛可能会影响着陆前的关节运动。运动后2天着陆前肌电活动的延迟下降也表明着陆前运动控制和/或策略可能受到延迟性肌肉损伤和疼痛的影响。综上所述，反复SSC力竭运动对跳跃活动产生了特异性的疲劳效应，并伴随着延迟性肌肉损伤，改变了跳跃的运动控制策略。较少

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