Authors:
Eddy Krueger
1
;
Eduardo M. Scheeren
2
;
Guilherme N. Nogueira-Neto
2
;
Agnelo Denis Vieira
2
and
Percy Nohama
1
Affiliations:
1
Universidade Tecnológica Federal do Paraná, Brazil
;
2
Pontifícia Universidade Católica do Paraná, Brazil
Keyword(s):
Mechanomyography, Fatigue, Functional Electrical Stimulation, Spinal Cord Injury, Cauchy Wavelet.
Related
Ontology
Subjects/Areas/Topics:
Applications and Services
;
Biomedical Engineering
;
Biomedical Signal Processing
;
Computer Vision, Visualization and Computer Graphics
;
Medical Image Detection, Acquisition, Analysis and Processing
;
Wavelet Transform
Abstract:
The purpose of this study is the evaluation of mechanomyographic (MMG) time-frequency response of rectus femoris muscle of a paraplegic subject during an isometric electrically-elapsed fatigue protocol. An accelerometer sensor was used to measure the vibration of muscle during voltage-controlled functional electrical stimulation application at 1 kHz pulse frequency (20% duty cycle) 70 Hz modulated frequency (20% duty cycle). A load cell (50 kgf) measured the force signal with the participant seated on a bench with the hip and knee angle set to 90º. During the protocol the electrical output voltage was adjusted to keep the force at 30% of maximal stimulated contraction (MSC). When the electrical stimulation was unable to keep the force above approximately 10% of MSC the protocol was ceased. Ten seconds with unfatigued (initial period) and fatigued (final period) muscle, MMG signal was processed with Cauchy wavelet transformation (bandpass 5-100 Hz). For fatigue conditions of paraplegi
c subject, MMG signal presents concentration energy to lower frequencies mainly to 11.31 Hz band frequency.
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