EMG spectral indices and muscle power fatigue during dynamic contractions

González-Izal, M.; Malanda, A.; Navarro-Amézqueta, I.; Gorostiaga, E.M.; Mallor, F.; Ibañez, J.; Izquierdo, M.

doi:10.1016/j.jelekin.2009.03.011

« Previous Next »Journal of Electromyography and Kinesiology
Volume 20, Issue 2 , Pages 233-240, April 2010

EMG spectral indices and muscle power fatigue during dynamic contractions

M. González-Izal
- Studies, Research and Sport Medicine Center, Government of Navarre, C/Sanguesa 34, 31005 Pamplona, Navarre, Spain
- Department of Electric and Electronic Engineering, Public University of Navarre, Spain
A. Malanda
- Department of Electric and Electronic Engineering, Public University of Navarre, Spain
I. Navarro-Amézqueta
- Studies, Research and Sport Medicine Center, Government of Navarre, C/Sanguesa 34, 31005 Pamplona, Navarre, Spain
E.M. Gorostiaga
- Studies, Research and Sport Medicine Center, Government of Navarre, C/Sanguesa 34, 31005 Pamplona, Navarre, Spain
F. Mallor
- Department of Statistics and Operations Research, Public University of Navarre, Spain
J. Ibañez
- Studies, Research and Sport Medicine Center, Government of Navarre, C/Sanguesa 34, 31005 Pamplona, Navarre, Spain
M. Izquierdo
- Studies, Research and Sport Medicine Center, Government of Navarre, C/Sanguesa 34, 31005 Pamplona, Navarre, Spain
- Corresponding author. Tel.: +34 948 292623; fax: +34 948 292636.

Received 29 January 2009; received in revised form 24 March 2009; accepted 24 March 2009. published online 30 April 2009.

Abstract

The purpose of this study was to examine acute exercise-induced changes on muscle power output and surface electromyography (sEMG) parameters (amplitude and spectral indices of muscle fatigue) during a dynamic fatiguing protocol. Fifteen trained subjects performed five sets consisting of 10 leg presses (10RM), with 2min rest between sets. Surface electromyography was recorded from vastus medialis (VM) and lateralis (VL) and biceps femoris (BF) muscles. A number of EMG-based parameters were compared for estimation accuracy and sensitivity to detect peripheral muscle fatigue. These were: Mean Average Voltage, median spectral frequency, Dimitrov spectral index of muscle fatigue (FI_nsm5), as well as other parameters obtained from a time–frequency analysis (Choi–Williams distributions) such as mean and variance of the instantaneous frequency and frequency variance. The log FI_nsm5 as a single parameter predictor accounted for 37% of the performance variance of changes in muscle power and the log FI_nsm5 and MFM as a two factor combination predictor accounted for 44%. Peripheral impairments assessed by sEMG spectral index FI_nsm5 may be a relevant factor involved in the loss of power output after dynamic high-loading fatiguing task.