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NAOSITE : Nagasaki University's Academic Output SITE > Institute of Tropical Medicine > Bulletin > Tropical medicine > Volume 23, No. 3 >

熱産生機構の等尺性筋収縮筋電図の解析 : (II)ヒトの筋疲労時の筋電図における群化放電(grouping discharge)の解析

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Title: 熱産生機構の等尺性筋収縮筋電図の解析 : (II)ヒトの筋疲労時の筋電図における群化放電(grouping discharge)の解析
Other Titles: EMG Pattern Analysis of Isometric Muscular Contraction in Themoregulatory Heat Production : (II) Analysis of grouping discharge in EMG during fatigue of maintained voluntary muscle contraction in man
Authors: 大渡, 伸 / 染岡, 慎一 / 近藤, 正行 / 藤本, 博一 / 土屋, 勝彦 / 小坂, 光男
Authors (alternative): Ohwatari, Nobu / Someoka, Shinichi / Kondo, Masayuki / Fujimoto, Hirokazu / Tsuchiya, Katsuhiko / Kosaka, Mitsuo
Issue Date: 30-Sep-1981
Publisher: 長崎大学熱帯医学研究所 / Institute of Tropical Medicine, Nagasaki University
Citation: 熱帯医学 Tropical medicine 23(3). p169-176, 1981
Abstract: 正常ウサギの寒冷ふるえ(cold shivering)筋電図にみられる群化放電(GD)の解析に用いたGDの条件設定値の妥当性を検索するためにヒトの随意・等尺性筋収縮時の筋電図波形にみるGDをデータ処理システム(ATAC450及びPC-8001)にて解析,かつGDの詳細な分析を目的として下記の研究を実施した.(1)室温25℃・湿度65%の常温環境下にて先の論文に記載したと同一の被験者(6名・年令22~33才・体重54~72kg)の上腕二頭筋(M. Biceps branchi)に誘発させた等尺性筋収縮筋電図波形の中にあるGDの構成成分である筋放電を本研究の解析資料とした.(2)上記(1)の方法にて得られた筋電図波形に関して,Cluster分析および因子分析を用い,GDの条件設定値を検索し,連続する2個の筋放電パルス間隔およそ20msec以下を条件設定値と決定した.(3)等尺性収縮負荷による筋疲労の進行過程で記録された筋電図波形を経時的に分画し,GDの周波数,GDを構成する筋放電パルスの数,GDの持続時間及び一定時間内に出現するGDの発生率の4項目について解析し下記の結果を得た.(4)GDの平均周波数は等尺性収縮による筋疲労の初期(25, 40%MVC負荷開始2分目まで)には12~13c/sと比較的高い値を示すが疲労の中期(2分目以後)には10.0c/sとほぼ一定値に収束する.この結果からGDは疲労中期に形成されかつヒトの寒冷ふるえや筋疲労時にみるGDの周波数は10.0c/sである事が判明した.(5)筋疲労中期から極期(2分目~5分目)においてGD構成に参加する筋放電パルスの平均値は負荷開始より次第に増加し,36~38パルスでほぼ一定値を示し,GDの持続時間及び発生率もパルス数の変化とほぼ平行推移した.(6)これらの結果はGDの形成機序およびGDの体温調節上の意義を検索するため重要な資料であり,この点について幾らかの検討が加えられた. / In an environmental control chamber (temperature: 25℃ and humidity: 65%), six healthy human volunteers aged 22-33 years were examined by computer analysis of EMG patterns of dominant biceps brachii muscle during fatiguing voluntray isometric contraction against a constant load. Fatiguing EMG activites of unilateral biceps brachii were recorded during 25 and 40% maximum contraction value (25 and 40% MCV) using fine needle electrodes. Grouping discharge in EMG patterns evoked by cold shivering was identically observed in electrical activity during fatiguing voluntary isometric contraction of human muscles. Following properties such as the interval of consecutive two pulses, mean frequency, mean duration, mean occurrence rate, and pulse numbers of grouping discharge in fatiguing EMG patterns were analyzed by Cluster analysis and Factor analysis using an analogue computer ATAC 450 and personal computer PC-8001. The range of interval of consecutive two pulses of grouping discharge in EMG of cold shivering as well as of isometric muscular contrac ion was conclusively less than about 20 msec. Mean frequency, duration, and occurrence rate of grouping discharge in EMG patterns during middle stage of muscular fatigue were about 10.0c/s, 140.0msec, and 85.5%, respectively. Pulse numbers participated in a certain group of consecutive grouping discharge increased in progress of mscular fatigue and eventually approximated to 36.0 in middle stage of muscular fatigue. These results indicate that various properties observed in grouping discharge of EMG activities evoked by cold shivering and isometric muscular contraction are identical and that rhythm of grouping discharge in their EMG patterns originate in the areas of the motoneuron pools of the spinal cord. Further thermoregulatory significance of grouping discharge during cold shivering and muscular fatigue was discussed in this paper.
URI: http://hdl.handle.net/10069/4309
ISSN: 03855643
Type: Departmental Bulletin Paper
Appears in Collections:Volume 23, No. 3

Citable URI : http://hdl.handle.net/10069/4309

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