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Titolo:
Median frequency of the electromyographic signal: effect of time-window location on brief step contractions
Autore:
Lariviere, C; Arsenault, AB; Gravel, D; Gagnon, D; Loisel, P;
Indirizzi:
Univ Montreal, Sch Rehabil, Montreal, PQ H3C 3J7, Canada Univ Montreal Montreal PQ Canada H3C 3J7 il, Montreal, PQ H3C 3J7, Canada Montreal Rehabil Inst, Res Ctr, Montreal, PQ, Canada Montreal Rehabil Inst Montreal PQ Canada , Res Ctr, Montreal, PQ, Canada Univ Sherbrooke, Dept Kinanthropol, Sherbrooke, PQ J1K 2R1, Canada Univ Sherbrooke Sherbrooke PQ Canada J1K 2R1 erbrooke, PQ J1K 2R1, Canada Univ Sherbrooke, Fac Med, Dept Surg, Sherbrooke, PQ, Canada Univ Sherbrooke Sherbrooke PQ Canada , Dept Surg, Sherbrooke, PQ, Canada
Titolo Testata:
JOURNAL OF ELECTROMYOGRAPHY AND KINESIOLOGY
fascicolo: 1, volume: 11, anno: 2001,
pagine: 65 - 71
SICI:
1050-6411(200102)11:1<65:MFOTES>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
LOW-BACK-PAIN; FIBER CONDUCTION-VELOCITY; MUSCLE FATIGUE; POWER SPECTRUM; MYOELECTRIC SIGNAL; HEALTHY-SUBJECTS; ERECTOR SPINAE; EMG; SIZE; ILIOCOSTALIS;
Keywords:
electromyography; muscle fatigue; power spectrum analysis; back muscles; median frequency; time-window location;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Arsenault, AB Univ Montreal, Sch Rehabil, CP 6128,Succursale Ctr Ville, Montreal, PQ H3C3J7, Canada Univ Montreal CP 6128,Succursale Ctr Ville Montreal PQ Canada H3C 3J7
Citazione:
C. Lariviere et al., "Median frequency of the electromyographic signal: effect of time-window location on brief step contractions", J ELECTROMY, 11(1), 2001, pp. 65-71

Abstract

The purpose of this study was to determine, for different back muscles, ifthe median frequency (MF) of the electromyographic (EMG) power spectrum changes according to the position of the time window during a 5 s step contraction. Twenty males with no known back problems were standing upright in a dynamometer allowing lower limb and pelvis stabilization. Trunk extension efforts were performed by pushing on a force platform positioned at the T4 level while the extension moment at L5/S1 was displayed as visual feedback. The EMG signals from four homologous back muscles (multifidus at L5, ilicostalis lumborum at L3, and longissimus at L1 and T10) were collected using active surface electrodes during two 5 s static step contractions performed at five force levels (10, 20, 40, 60 and 80% of the maximal voluntary contraction). The root mean square (RMS) and MF values of the EMG signals corresponding to three 250 ms time windows (beginning, middle and end of each step contraction) were computed. The RMS values of several back muscles increased from the first to the third time window for contractions performed at high force levels only. However, a concomitant decrease in the MF values wasobserved only for the left multifidus muscle. It was concluded that musclefatigue does not generally manifest itself during 5 s step contractions through the EMG signal. However, it is recommended to use step contractions lasting less than 5 s and to choose a time window located in the first 1-3 sto completely eliminate the possible effects of fatigue. (C) 2001 ElsevierScience Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/01/20 alle ore 20:26:44