Histological Skeletal Muscle Damage and Surface EMG Relationships Following Eccentric Contractions

The Journal of Physiological Sciences

Hirotaka Furukawa³  Yutaka Kano³  Mizuki Sudo³  Kazuyuki Mito¹  Kazumi Masuda²  Kazuyoshi Sakamoto¹ 

[1] Department of Systems Engineering, University of Electro-Communications;Department of Health Education, Faculty of Education, Kanazawa University;Department of Applied Physics and Chemistry, University of Electro-Communications

关键词: electromyography;    muscle fiber conduction velocity;    integrated EMG;    histology;    electrical stimulation;   

DOI  :  10.2170/physiolsci.RP004908

学科分类：生理学

来源: Springer

【 摘 要 】

References(37)Cited-By(4)This study examined the effects of a different number of eccentric contractions (ECs) on histological characteristics, surface electromyogram (EMG) parameters (integral EMG, iEMG; muscle fiber conduction velocity, MFCV; and action potential waveform), and isometric peak torque using the rat EC model. Male Wistar rats (n = 40) were anesthetized, and ECs were initiated in the tibialis anterior muscle via electrical stimulation while the muscle was being stretched by electromotor. The rats were grouped according to the number of ECs (EC1, EC5, EC10, EC20, EC30, EC40, and EC100). Three days after the ECs, surface EMG signals and isometric peak torque were measured during evoked twitch contractions via electrical stimulation of the peroneal nerve. The muscle damage was evaluated from hematoxylin-eosin (HE) stained cross sections as a relative number of damaged fibers to intact fibers. Intense histological muscle damage (approximately 50% to 70% of the fiber), loss of isometric peak torque, disturbance of action potential waveform, and depression of iEMG (approximately −60% to −70%) were observed at EC20, EC30, EC40, and EC100. On the other hand, the MFCV did not change in any EC group. Although muscle damage and pathological surface EMG signals were not found at EC10, isometric peak torque was reduced significantly. In conclusion, the extent of histological muscle damage is not proportionally related to the number of ECs. Muscle damage was reflected by iEMG and action potential waveforms, but not by MFCV, which remained unaffected even though approximately 50% to 70% of the fiber demonstrated injury.

【 授权许可】

Unknown