Histological skeletal muscle damage and surface EMG relationships following eccentric contractions

フォーマット:

論文

責任表示:

Kano, Yutaka ; Masuda, Kazumi ; Furukawa, Hirotaka ; Sudo, Mizuki ; Mito, Kazuyuki ; Sakamoto, Kazuyoshi

言語:

英語

出版情報:

日本生理学会, 2008-10-01

著者名:

Kano, Yutaka

Masuda, Kazumi

Furukawa, Hirotaka

Sudo, Mizuki

Mito, Kazuyuki

Sakamoto, Kazuyoshi

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掲載情報:

Journal of Physiological Sciences

ISSN:

1880-6546      

巻:

58

通号:

5

開始ページ:

349

終了ページ:

355

バージョン:

publisher

概要:

金沢大学人間社会研究域人間科学系<br />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.全文公開200911 続きを見る

URL:

http://hdl.handle.net/2297/12404