Study of the Electrically Evoked EMG and Torque Output Dur - ing the Muscle Fatigue Process in FES - Induced Static and Dy - namic Contractions
نویسندگان
چکیده
This study compared the different fatigue processes of electrically elicited static and dynamic muscle contractions of quadriceps in five paraplegic subjects. An electrodynamometer was utilized for recording the generated torque output and controlling the isokinetic dynamic movements. Stimulus-evoked electromyography (EMG), after artifact suppression, was used to observe the fatigue process. Besides torque output, the measured EMG features included peak to peak amplitude, rise time to peak and peak to peak duration. The measurements were modeled by a hyperbolic tangent function, which allowed observance of their time constants, inflection times and relative residual levels during the fatigue process. The time constants as well as the inflection time of torque output and EMG features were compared between static and dynamic contractions. The inflection times of torque output and all EMG features measured during static contraction were found larger than those of dynamic contraction. In EMG temporal features, the inflection times of rise time to peak and peak to peak duration in static contractions were also found significantly larger than those of dynamic contractions. These conditions indicated that, from either contractile (torque curves) or excitation (EMG features) aspects, the electrically elicited muscle contraction in dynamic movement is prone to fatigue earlier and faster.
منابع مشابه
Quantitative Assessment of Muscle Fatigue for FES Research Studies
Background: Muscle fatigue is an important issue in neuromuscular rehabilitation. Better control of this phenomenon would result in better prevention of its consequent physiological damages.Objective: To provide a mathematical representation of muscle fatigue as a function of time.Methods: We conducted this study by combining the EMG-based estimation methods of muscle activation with the availa...
متن کاملTorque assessment based on evoked EMG for FES-induced muscle contractions in SCI patients
In this work a torque assessment approach is presented to estimate FES-induced torque no matter the muscle is fatigued or not in interrupted stimulation. This approach is based on evoked EMG (eEMG) signal and use peakto-peak (PTP) amplitude and second phase area (SPA) to correlate eEMG and torque. The mapping function is built with pooled data of recruitment test and fatigue test in two complet...
متن کاملEvoked EMG versus Muscle Torque during Fatiguing Functional Electrical Stimulation-Evoked Muscle Contractions and Short-Term Recovery in Individuals with Spinal Cord Injury
This study investigated whether the relationship between muscle torque and m-waves remained constant after short recovery periods, between repeated intervals of isometric muscle contractions induced by functional electrical stimulation (FES). Eight subjects with spinal cord injury (SCI) were recruited for the study. All subjects had their quadriceps muscles group stimulated during three session...
متن کاملproduction/torque relationship with onset of fatigue during voluntary muscle contractions and restoration of functional movement in paraplegic patients through FES evoked muscle contraction. Understanding the initiation of movement in animals and central role of muscle
Myoelectric signal remains the gold standard to objectively monitor muscular activities despite the tedious task of separating cross talk from contractions. This work evaluated the signal characteristics during FES-evoked contractions in muscle force and fatigue assessment to reiterate its inherent setbacks despite overwhelming research efforts to improve its signal to noise ratio. It was obser...
متن کاملMechanomyography and Torque during FES-Evoked Muscle Contractions to Fatigue in Individuals with Spinal Cord Injury
A mechanomyography muscle contraction (MC) sensor, affixed to the skin surface, was used to quantify muscle tension during repetitive functional electrical stimulation (FES)-evoked isometric rectus femoris contractions to fatigue in individuals with spinal cord injury (SCI). Nine persons with motor complete SCI were seated on a commercial muscle dynamometer that quantified peak torque and avera...
متن کامل