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Titolo:
Influence of contraction intensity, muscle, and gender on median frequencyof the quadriceps femoris
Autore:
Pincivero, DM; Campy, RM; Salfetnikov, Y; Bright, A; Coelho, AJ;
Indirizzi:
Eastern Washington Univ, Dept Phys Therapy, Human Performance & Fatigue Lab, Cheney, WA 99004 USA Eastern Washington Univ Cheney WA USA 99004 gue Lab, Cheney, WA 99004 USA Eastern Washington Univ, Dept Phys Educ Hlth & Recreat, Cheney, WA 99004 USA Eastern Washington Univ Cheney WA USA 99004 Recreat, Cheney, WA 99004 USA
Titolo Testata:
JOURNAL OF APPLIED PHYSIOLOGY
fascicolo: 3, volume: 90, anno: 2001,
pagine: 804 - 810
SICI:
8750-7587(200103)90:3<804:IOCIMA>2.0.ZU;2-6
Fonte:
ISI
Lingua:
ENG
Soggetto:
KNEE EXTENSOR MUSCLES; CONDUCTION-VELOCITY; POWER SPECTRUM; SURFACE ELECTROMYOGRAM; MYOELECTRIC SIGNAL; FIBER COMPOSITION; MOTOR UNITS; FORCE; EMG; FATIGUE;
Keywords:
vastus medialis; vastus lateralis; rectus femoris; electromyography;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Pincivero, DM Eastern Washington Univ, Dept Phys Therapy, Human Performance & Fatigue Lab, Mail Stop 4,526 5th St, Cheney, WA 99004 USA Eastern Washington Univ Mail Stop 4,526 5th St Cheney WA USA 99004
Citazione:
D.M. Pincivero et al., "Influence of contraction intensity, muscle, and gender on median frequencyof the quadriceps femoris", J APP PHYSL, 90(3), 2001, pp. 804-810

Abstract

The purpose of this study was to assess the effects of contraction intensity, gender, and muscle on median frequency of the three superficial portions of the quadriceps femoris muscle. Thirty healthy volunteers were assessedfor isometric electromyogram activity of the vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscles with the knee at 60 degreesflexion. Subjects performed 5-s isometric contractions at 10, 20, 30, 40, 50, 60, 70, 80, and 90% of the average of three maximal voluntary contractions. Median frequency (f(med)) of the three muscles was assessed through a power spectral analysis performed over 11 consecutive 512-ms epochs overlapping each other by one-half their length. The f(med) for each of the 11 epochs was then determined, followed by calculation of the mean and SD. The major findings of this study demonstrated that overall f(med) was significantly highest for the VL and lowest for the VM, whereas RF f(med) was between that of the other two muscles. Similar findings were observed for f(med) variability as the VL was significantly higher than the VM and RF, with no gender differences or differences between the latter two muscles. he results demonstrate that the largest change in f(med) as a function Of contraction intensity occurred for the VL in men (18.6%) and women (7.6%). These findings suggest that muscle fiber-type homogeneity may exist in the VM and RF, which displayed negligible changes in f(med), whereas the VL may possess greater morphological variability.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/04/20 alle ore 17:29:32