Faculty Collaboration Database

EMG frequency content changes with increasing force and during fatigue in the quadriceps femoris muscle of men and women. J Electromyogr Kinesiol 2003 Feb;13(1):83-92

Date

12/19/2002

Pubmed ID

12488090

DOI

10.1016/s1050-6411(02)00050-0

Scopus ID

2-s2.0-0037290922 (requires institutional sign-in at Scopus site)   182 Citations

Abstract

The purpose of this study was to determine the effect of gender on changes in electromyographic (EMG) signal characteristics of the quadriceps muscles with increasing force and with fatigue. A total of fourteen healthy adults (seven men, seven women) participated in the study. Subjects had to perform isometric ramp contractions in knee extension with the force gradually increasing from 0 to 100% of the maximal voluntary contraction (MVC) in a 6-s period. Subjects then performed a fatigue task, consisting of a sustained maximum isometric knee extension contraction held until force decreased below 50% of the pre-fatigue MVC. Subjects also performed a single ramp contraction immediately after the fatigue task. The Root Mean Square (RMS) amplitude, mean power frequency (MPF) and median frequency (MF) of EMG signals obtained from the vastus lateralis, vastus medialis and rectus femoris were calculated at nine different force levels from the ramp contractions (10, 20, 30, 40, 50, 60, 70, 80 and 90% MVC), as well as every 5 s during the fatigue task. The main results were a more pronounced increase in EMG RMS amplitude for the three muscles and in MPF for the VL muscle with force in men compared with women. No significant effect of gender was found with regards to fatigue. These observations most likely reflect a moderately greater type II fiber content and/or area in the VL muscle of men compared to that of women.

Author List

Bilodeau M, Schindler-Ivens S, Williams DM, Chandran R, Sharma SS

Author

Sheila Schindler-Ivens PhD Assistant Professor in the Physical Therapy department at Marquette University

MESH terms used to index this publication - Major topics in bold

Adult
Electromyography
Female
Fourier Analysis
Hip Joint
Humans
Isometric Contraction
Knee Joint
Male
Muscle Fatigue
Muscle Fibers, Skeletal
Muscle, Skeletal
Sex Factors