Comparison of Fourier and wavelet transform procedures for examining mechanomyographic and electromyographic frequency versus isokinetic torque relationships.
The purpose of this study was to compare the isokinetic torque-related patterns for mechanomyographic (MMG) and electromyographic (EMG) center frequency [wavelet center frequency (CF), mean power frequency (MPF), and median frequency (MDF)] determined by the fast Fourier transform (FFT) and discrete wavelet transform (DWT). Ten adults [mean +/- SD age = 22.0 +/- 3.4 yrs] performed submaximal to maximal, isokinetic muscle actions of the biceps brachii on a Cybex II dynamometer. For both MMG and EMG, the CF, MPF, and MDF values were intercorrelated at (r = 0.91-0.98). Quadratic models provided the best fit for the absolute and normalized CF, MPF, and MDF versus isokinetic torque relationships for MMG (R2 = 0.67-0.83) and EMG (R2 = 0.72-0.90). The similarities among the CF, MPF, and MDF patterns suggested that Fourier or wavelet transform procedures can be used to examine the patterns of MMG and EMG responses during dynamic muscle actions.
Beck
T W
TW
Department of Nutrition and Health Sciences, Human Performance Laboratory, Center for Youth Fitness and Sports Research, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0229, USA. tbeck@unlserve.unl.edu
Housh
T J
TJ
Johnson
G O
GO
Weir
J P
JP
Cramer
J T
JT
Coburn
J W
JW
Malek
M H
MH
D000328:Adult; D001696:Biomechanical Phenomena; D004576:Electromyography; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D012016:Reference Values; D019415:Torque