IEICE Workshop of Technical Committee on Medical Imaging

摘要

This study measured potentiation mechanisms of plyometric training (normalized electromyography in triceps surae, stiffness and elastic energy utilization of Achilles tendon) and investigated correlations between the mechanisms and performances (voluntary electromechanical delay and jump height). Twenty-one subjects were randomly assigned to either the control group (10 subjects: age 22.3 ±1.6 years) or to a training group (11 subjects: age 22.1 ± 1.6 years) that performed an eight-week plyometric training. Results: As compared with the performances before training, normalized electromyographies in soleus were significantly increased after four weeks and eight weeks of training (p<0.001). Tendon stiffness, elastic energy storage, release and jump height collected after training were significantly increased (p<0.05), with a concomitant reduced voluntary electromechanical delay (p=0.01). These changed variables also showed significant differences to the control group (all p <0.05). Other variables remained unchanged. Correlations were observed between the tendon stiffness and either voluntary electromechanical delay (r=-0. 77, p=0.014) or jump height (r=0.54, p=0.031). Conclusions: Early soleus muscle activation from spinal and/or supraspinal center potentiated by plyometric training is a possible preparatory mechanism for performance augmentation. Increases of tendon stiffness correlating with reduced voluntary electromechanical delay may lead to a movement re-organization of sport activities after plyometric training.