Effects of lower fatigue protocols on motor neuron excitability in Korea National Team Taekwondo athletes

Abstract

Background and Study Aim: Muscle fatigue and Golgi tendon organ laxity, which also, increases the threshold of muscle spindle discharge and disturbs afferent feedback. The purpose of this study was the effects of fatigue in lower extremities (quadriceps and hamstring) on H-reflex, M-wave, and Hmax/Mmax ratio changes in Korea National Team Taekwondo athletes. Material and Methods: Twelve (7 male, 5 female) Korea National Team Taekwondo athletes were investigated. Participants completed 25 repetitions and 50 repetitions of fatigue protocol by using isokinetic dynamometer. The measured values of H-reflex and M-wave were collected simultaneously by electrical stimulation, and the signals were amplified by the signal converter. Results: Paired t-test showed that the 25 fatigue protocol and 50 fatigue protocol in minimum of knee extension and flexion showed a significant difference. However, no significant difference in 25 fatigue protocol and 50 fatigue protocol in a maximum of knee extension and flexion. The changes of Hmax, Mmax and Hmax/Mmax ratio. There were no significant differences in Hmax, Mmax and Hmax/Mmax ratio. Conclusions: Our fatigue protocols model increased locally fatigued in the quadriceps and hamstring. However, Hmax and Hmax/Mmax ratio of the soleus muscles tend to decrease after the fatigue protocol but did not change.