title: Mechanomyography energy decreases during muscular fatigue in paraplegics.
abstract: The present work investigated the response of triaxial MMG signals acquired from the rectus femoris muscle of spinal cord injured volunteers during fatigue protocol electrically evoked. A custom functional electrical stimulator voltage-controlled was configured as: pulse frequency set to 1 kHz (20% duty cycle) and burst (modulating) frequency set to 70 Hz (20% active period). The triaxial MMG signal of rectus femoris muscle was processed with third-order 5-50 Hz bandpass Butterworth filter and the values were normalized. A load cell was used to register the force. The stimulator output voltage was increased until the maximal electrically-evoked extension (MEEE) of knee joint. After the load cell placement, the stimuli magnitude required to reach the MEEE was applied and registered by the load cell as muscular force-100% response. Stimuli intensity was increased until and during the control to keep the force in force-100%. Four instants with force functional electrical stimulation (FES)-controlled were selected between force-100% and slope down to force-30%. The MMG energy decreased with FES application due neuromuscular fatigue in paraplegic subjects. X-axis between instant I (1 ± 0) and instant IV (0.74 ± 0.27), and the same tendency was found to Y-axis between instant II (1.14 ± 0.44) and instant IV (0.91 ± 0.3).
authors.forename: Eddy
authors.initials: E
authors.lastname: Krueger
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Scheeren
authors.forename: Guilherme N
authors.initials: GN
authors.lastname: Nogueira-Neto
authors.forename: Percy
authors.initials: P
authors.lastname: Nohama
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D004734:Energy Metabolism; D006801:Humans; D018763:Muscle Fatigue; D053580:Muscle Strength; D009213:Myography; D010264:Paraplegia / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000503:physiopathology; D055815:Young Adult