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ID 11716
JaLCDOI
Sort Key
5
Title Alternative
Variations of parameters of bioelectrical impedance during upper limb movement
FullText URL
Author
Yamamoto, Yoshitake
Abstract
これまでに生体電気インピーダンスを用いて身体運動の解析を行ってきた。インピーダンスの変動原因は測定部位の等価断面積変化および貯血量変化と説明できるが,直接的に断面積変化や貯血量変化を測定することは困難であるため,その変動原因の定量的な検討は不十分であった。そこで,本研究では上肢運動に伴う生体電気インピーダンスの変動原因を生体の等価回路のパラメータの変動で説明する。インピーダンスのモデルはCole-Cole型であり,等価回路は,細胞外液抵抗Re,細胞内液抵抗Ri,分散の特性周波fm fm,緩和時間の分布の程度を表すα,βの独立した5パラメータで表現した。 上肢の肘関節および手関節の屈曲運動野に伴う前腕部および上腕部の電気インピーダンスを測定した。まず,電気インピーダンスの等価直列抵抗Rの変動率をパラメータの変動率で線形近似し,その信頼性と各パラメータ変動のRへの影響を確認した。Rへの影響はReとRiが支配的であるが,測定部位や運動の違いにより,それぞれの影響が異なることを示した。これは測定部位の筋活動状態の違いを表すものである。さらに,肘関節最大屈曲におけるRの変化にはfmの変化が大きく依存しており,上肢運動のインピーダンス変化には細胞膜の分極特性の変化も影響していることを明らかにした。本研究の結果は,運動強度の違いや疲労状態における身体運動評価に有意義である。
Abstract Alternative
We have proposed new biodynamic analysis methods using bioelectrical impedance. Variations of human limb electrical impedance during biodynamics were caused by variations of equivalent cross sectional area of muscle and variations of blood volume. However these variations could not be directly measured. Therefore quantitative discussions about relation between the impedance and these variations have been insufficient. In this work, we explained variations of the impedance with variations of parameters of an equivalent circuit. The model of impedance was Cole-Cole type. The equivalent circuit consisted of five individual parameters as follows : extracellular fluid resistance, 'Re', intracellular fluid resistance, 'Ri', characteristic frequency of dispersion, 'fm' and parameters of dispersion of relaxation time, 'α' and 'β'. Impedances of forearm and upper arm were measured with four electrode method during flexion and extension of joints in upper limb. The ratio of variations of equivalent series resistance R was linear-approximated using the above mentioned parameters. The influences of parameters on variations of R was confirmed. R was strongly influenced by Re and Ri, However there were differences between influence of Re and that of Ri in difference measured part and difference joint movement. This showed the conditibn of the muscle. In case of the maximum flexion of the elbow joint, R of upper arm was influenced by fm. This means that a polarization of cell membrane changes and influences impedance during movement. These results are significant in evaluation of biodynamics including difference of strength of movement and condition of exhaustion.
Keywords
生体電気インピーダンス (bioelectrical impedance)
等価回路 (equivalent circuit)
Cole-Cole円弧 (Cole-Cole circular loci)
上肢運動 (upper limb movement)
4電極法 (four electrode method)
Publication Title
岡山大学医学部保健学科紀要
Published Date
1999-12-20
Volume
volume10
Issue
issue1
Publisher
岡山大学医学部保健学科
Publisher Alternative
Faculty of Health Sciences Okayama University Medical School
Start Page
15
End Page
22
ISSN
1345-0948
NCID
AA11403004
Content Type
Departmental Bulletin Paper
OAI-PMH Set
岡山大学
language
日本語
File Version
publisher
NAID
Eprints Journal Name
fhs