Myoelectric manifestations of fatigue in voluntary and electrically elicited contractions

1990 ◽  
Vol 69 (5) ◽  
pp. 1810-1820 ◽  
Author(s):  
R. Merletti ◽  
M. Knaflitz ◽  
C. J. De Luca
Keyword(s):  
Muscle Fatigue ◽  
Root Mean Square ◽  
Conduction Velocity ◽  
Time Course ◽  
Tibialis Anterior Muscle ◽  
Median Frequency ◽  
Mean Square ◽  
Myoelectric Signal ◽  
Physiological Factor ◽  
Voluntary Contractions

The time course of muscle fiber conduction velocity and surface myoelectric signal spectral (mean and median frequency of the power spectrum) and amplitude (average rectified and root-mean-square value) parameters was studied in 20 experiments on the tibialis anterior muscle of 10 healthy human subjects during sustained isometric voluntary or electrically elicited contractions. Voluntary contractions at 20% maximal voluntary contraction (MVC) and at 80% MVC with duration of 20 s were performed at the beginning of each experiment. Tetanic electrical stimulation was then applied to the main muscle motor point for 20 s with surface electrodes at five stimulation frequencies (20, 25, 30, 35, and 40 Hz). All subjects showed myoelectric manifestations of muscle fatigue consisting of negative trends of spectral variables and conduction velocity and positive trends of amplitude variables. The main findings of this work are 1) myoelectric signal variables obtained from electrically elicited contractions show fluctuations smaller than those observed in voluntary contractions, 2) spectral variables are more sensitive to fatigue than conduction velocity and the average rectified value is more sensitive to fatigue than the root-mean-square value, 3) conduction velocity is not the only physiological factor affecting spectral variables, and 4) contractions elicited at supramaximal stimulation and frequencies greater than 30 Hz demonstrate myoelectric manifestations of muscle fatigue greater than those observed at 80% MVC sustained for the same time.

Effects of electrode location on myoelectric conduction velocity and median frequency estimates

1986 ◽  
Vol 61 (4) ◽  
pp. 1510-1517 ◽  
Author(s):  
S. H. Roy ◽  
C. J. De Luca ◽  
J. Schneider
Keyword(s):  
Conduction Velocity ◽  
Tibialis Anterior Muscle ◽  
Rate Of Change ◽  
Median Frequency ◽  
Myoelectric Signal ◽  
Innervation Zone ◽  
Electrode Location ◽  
Linear Fit ◽  
Distal Tendon ◽  
Effect Of Surface

The effect of surface electrode location on the estimates of the median frequency and conduction velocity of the myoelectric signal was investigated. The locations were identified with respect to the innervation zone and the tendonous portion of the tibialis anterior muscle. Considerable modifications in the median frequency and conduction velocity parameters were noted. The highest values of the median frequency occurred at the region of the innervation zone and tendonous insertion of the muscle, and decreased proportionally with distance from these areas. The rate of change of median frequency was not effected by electrode location. Estimates of conduction velocity were most stable in a region between the distal tendon and the adjacent innervation zone. This region also provided the best linear fit when comparing conduction velocity to median frequency estimates. The implications for signal detection procedures are discussed.

scholarly journals An EMG Patch for the Real-Time Monitoring of Muscle-Fatigue Conditions During Exercise

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3108 ◽  
Author(s):  
Shing-Hong Liu ◽  
Chuan-Bi Lin ◽  
Ying Chen ◽  
Wenxi Chen ◽  
Tai-Shen Huang ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Real Time ◽  
Root Mean Square ◽  
The Body ◽  
Median Frequency ◽  
Mean Square ◽  
Sport Injuries ◽  
Physiological Measurement ◽  
The Real ◽  
Emg Signal

In recent years, wearable monitoring devices have been very popular in the health care field and are being used to avoid sport injuries during exercise. They are usually worn on the wrist, the same as sport watches, or on the chest, like an electrocardiogram patch. Common functions of these wearable devices are that they use real time to display the state of health of the body, and they are all small sized. The electromyogram (EMG) signal is usually used to show muscle activity. Thus, the EMG signal could be used to determine the muscle-fatigue conditions. In this study, the goal is to develop an EMG patch which could be worn on the lower leg, the gastrocnemius muscle, to detect real-time muscle fatigue while exercising. A micro controller unit (MCU) in the EMG patch is part of an ARM Cortex-M4 processor, which is used to measure the median frequency (MF) of an EMG signal in real time. When the muscle starts showing tiredness, the median frequency will shift to a low frequency. In order to delete the noise of the isotonic EMG signal, the EMG patch has to run the empirical mode decomposition algorithm. A two-electrode circuit was designed to measure the EMG signal. The maximum power consumption of the EMG patch was about 39.5 mAh. In order to verify that the real-time MF values measured by the EMG patch were close to the off-line MF values measured by the computer system, we used the root-mean-square value to estimate the difference in the real-time MF values and the off-line MF values. There were 20 participants that rode an exercise bicycle at different speeds. Their EMG signals were recorded with an EMG patch and a physiological measurement system at the same time. Every participant rode the exercise bicycle twice. The averaged root-mean-square values were 2.86 ± 0.86 Hz and 2.56 ± 0.47 Hz for the first and second time, respectively. Moreover, we also developed an application program implemented on a smart phone to display the participants’ muscle-fatigue conditions and information while exercising. Therefore, the EMG patch designed in this study could monitor the muscle-fatigue conditions to avoid sport injuries while exercising.

scholarly journals Computation and Evaluation of Features of Surface Electromyogram to Identify the Force of Muscle Contraction and Muscle Fatigue

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Sridhar P. Arjunan ◽  
Dinesh K. Kumar ◽  
Ganesh Naik
Keyword(s):  
Muscle Contraction ◽  
Muscle Fatigue ◽  
Root Mean Square ◽  
Linear Regression Analysis ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Median Frequency ◽  
Mean Square ◽  
Surface Electromyogram ◽  
The Relationship

The relationship between force of muscle contraction and muscle fatigue with six different features of surface electromyogram (sEMG) was determined by conducting experiments on thirty-five volunteers. The participants performed isometric contractions at 50%, 75%, and 100% of their maximum voluntary contraction (MVC). Six features were considered in this study:normalised spectral index (NSM5), median frequency, root mean square, waveform length, normalised root mean square (NRMS), and increase in synchronization (IIS) index. Analysis of variance (ANOVA) and linear regression analysis were performed to determine the significance of the feature with respect to the three factors: muscle force, muscle fatigue, and subject. The results show that IIS index of sEMG had the highest correlation with muscle fatigue and the relationship was statistically significant (P<0.01), while NSM5 associated best with level of muscle contraction (%MVC) (P<0.01). Both of these features were not affected by the intersubject variations (P>0.05).

The Effect of Heating and Cooling on Time Course of Voluntary and Electrically Induced Muscle Force Variation

Medicina ◽  
2011 ◽  
Vol 47 (1) ◽  
pp. 6 ◽  
Author(s):  
◽  
◽  
◽  
◽  
Keyword(s):  
Muscle Fatigue ◽  
Time Course ◽  
Muscle Force ◽  
Peak Torque ◽  
Voluntary Contraction ◽  
Knee Extensors ◽  
Lower Body ◽  
Heating And Cooling ◽  
Force Variation ◽  
Voluntary Contractions

The aim of this study was to investigate the effect of heating and cooling on time course of voluntary and electrically induced muscle force variation. Material and Methods. Ten volunteers performed 50 maximal voluntary and electrically induced contractions of the knee extensors at an angle of 120 degrees under the control conditions and after passive lower body heating and cooling in the control, heating, and cooling experiments. Peak torque, torque variation, and half-relaxation time were assessed during the exercise. Results. Passive lower body heating increased muscle and core temperatures, while cooling lowered muscle temperature, but did not affect core temperature. We observed significantly lower muscle fatigue during voluntary contraction compared with electrically induced contractions. Body heating (opposite to cooling) increased involuntarily induced muscle force, but caused greater electrically induced muscle fatigue. In the middle of the exercise, the coefficient of correlation for electrically induced muscle torque decreased significantly as compared with the beginning of the exercise, while during maximal voluntary contractions, this relation for torque remained significant until the end of the exercise. Conclusion. It was shown that time course of voluntary contraction was more stable than in electrically induced contractions.

scholarly journals The Time Course of Oxygen Uptake, Aerobic Capacity and Emg during Two Months of Moderate Interval Endurance Training (A Case Study)

2018 ◽  
Vol 4 (91) ◽  
Author(s):  
Sandra Raubaitė ◽  
Neringa Baranauskienė ◽  
Arvydas Stasiulis
Keyword(s):  
Body Composition ◽  
Oxygen Uptake ◽  
Endurance Training ◽  
Root Mean Square ◽  
Aerobic Capacity ◽  
Time Course ◽  
Oxygen Uptake Kinetics ◽  
Moderate Intensity ◽  
Mean Square ◽  
Ventilation Threshold

Research  background  and  hypothesis. The  low-moderate-intensity  continuous endurance training improved body composition, aerobic capacity and overall health-related parameters in healthy persons. However, we could not find publications about the effect of moderate interval aerobic endurance training (IET) on body composition,  2 OV&  kinetics, aerobic capacity and EMG parameters. Research aim. The main purpose of this study was to examine the effect of interval endurance training (IET) on oxygen uptake kinetics, aerobic capacity, body composition and EMG parameters. Research methods. A 26-year-old, sedentary obese female (stature – 1.80 m; weight – 99.2 kg; VO 2 max – 37.2 ml/kg -1 /min -1 ) was involved in two-month moderate interval endurance training (IET). The subject performed three training sessions a week separated by one or two days of rest. The initial intensity of training was 90% of the first ventilation threshold (VT1). The VT1 and second ventilation threshold (VT2) ware estimated after completion of incremental running test until exhaustion on a LE 200 CE treadmill (VIASYS, Germany). Research results. We determined that after two months IET subject’ body mass decreased by 10%, the training had an effect on aerobic capacity parameters as well. The running speed at VT1 and VT2 increased by 8.1% and 10.2%  respectively  after  the  two-month  IET  programme. The  heart  rate  (165.9  beats/min -1 )  and  oxygen  uptake (2.583 l/min -1 ) significantly decreased respectively (150.4 beats/min -1 ) (2.285 l/min -1 ) after IET period compared with pre-training testing. To indicate the total muscle activity we measured integrated EMG (iEMG) and root mean square (RMS). We also determined changes on EMG parameters after four, six and eight weeks IET.Discussion and conclusions. Two-month moderate interval endurance training has significant effect on aerobic capacity, anthropometrics, EMG parameters and VO 2  kinetics.Keywords: ventilatory thresholds, maximal oxygen uptake, EMG root mean square.

scholarly journals Muscular Behavior during Inspiratory Training in Patients with a Complete Cervical Spinal Cord Injury: Pilot Study

2016 ◽  
Vol 85 (3) ◽  
Author(s):  
Tomás Santibáñez Arellano
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Root Mean Square ◽  
Cervical Spinal Cord ◽  
Training Session ◽  
Cervical Spinal Cord Injury ◽  
Median Frequency ◽  
Mean Square ◽  
Muscle Training ◽  
Cord Injury

Introduction: There is a huge variety of inspiratory muscle training protocols in patients with complete cervical spinal cord injury. None of them provide information about muscle behavior and its relationship with effort and fatigue sensation perceived by the subject.Objective: Analyze the relationship between the behavior of the Median Frequency (MF) and the Root Mean Square (RMS) of diaphragm (DPH) and sternocleidomastoid (ECOM) muscles and Subjective Fatigue Sensation (SFS) during an inspiratory muscle training session using a threshold valve in patients with CCSCI.Methods: Electromyographic activity of the DPH and ECOM during a fifteen minutes training session using a threshold valve with a Maximum Inspiratory Pressure (MIP) of 30% was recorded. Median Frequency average and the Root Mean Square of DPH and ECOM was calculated. SFS was recorded every minute. The correlation between variables was determined by Spearman rho.Results: The correlation between SFS and MF of the DPH was 0.22. The correlation between SFS and MF of the ECOM was 0.36. The correlation between SF and RMS_INDEX was -0.09.Conclusion: There is no correlation between the variables studied. The RMS_INDEX is presented as a useful tool to describe the muscle behavior during training with threshold valve.Results: The correlation between SFS and MF of the DPH was 0.22. The correlation between SFS and MF of the ECOM was 0.36. The correlation between SF and RMS_INDEX was -0.09.Results: The correlation between SFS and MF of the DPH was 0.22. The correlation between SFS and MF of the ECOM was 0.36. The correlation between SF and RMS_INDEX was -0.09.Comportamento muscular durante treino inspiratório em pacientes com lesão medular cervical completa: estudo pilotoIntrodução: Existe uma grande variedade de protocolos de treinos inspiratórios em pacientes com lesão medular cervical completa. Nenhum deles passa informação a respeito do comportamento muscular nem sua relação com a sensação de esforço e fadiga percebida pelo sujeito.Objetivo: Analisar a relação entre o comportamento da FM e raiz media quadrática (RMS) de diafragma (DPH) e esternocleidomastóideo (ECOM) e a SSF durante uma sessão de treino de musculatura inspiratória com válvula umbral em pacientes com LMCC.Métodos: Foi registrada a atividade eletromiográfica do diafragma e o esternocleidomastoideo durante quinze minutos de treino com válvula umbral a 30% de PIM. Foi calculada a frequência média e a raiz quadrada média do DPH e ECOM. Foi registrada a SSF a cada minuto. Foi determinada a correlação entre as variáveis mediante rho de Spearman.Resultados: A correlação entre SSF e FM de DPH foi 0.22. A correlação entre SSF e FM de ECOM foi 0.36. A correlação entre SSF e RMS_INDEX foi -0.09.Conclusão: Não existe correlação entre as variáveis estudadas. O RMS_INDEX é apresentado como uma ferramenta útil para descrever o comportamento muscular durante um treino com a válvula umbral.

Joint analysis of spectrum and amplitude (JASA) of electromyograms applied for the indication of muscular fatigue in carpet weaving

2019 ◽  
Author(s):  
Narges Mortazavi ◽  
Teimour Allahyari ◽  
Hamid Reza Khalkhali ◽  
Mohammad Ali Sanjari
Keyword(s):  
Muscle Fatigue ◽  
Joint Analysis ◽  
Separate Analysis ◽  
Median Frequency ◽  
Mean Square ◽  
Spectral Parameters ◽  
Upper Trapezius ◽  
Emg Signal ◽  
Repetitive Tasks ◽  
High Prevalence

Abstract Background Hand carpet weaving requires prolonged static and repetitive tasks in a stationary and constrained postures, thus there is a high prevalence of muscle pain and fatigue and musculoskeletal disorders among carpet weavers.Methods This study aimed to determining the muscle fatigue in carpet weaving tasks by Joint Analysis of Spectral and amplitude (JASA (method. Two typical carpet weaving workstations were simulated in laboratory, and 12 female carpet weavers participated in this study. Electromyography (EMG) signals were recorded during work in bilateral upper trapezius and bilateral middle deltoid. The root mean square (RMS) and median frequency (MF) values were extracted from the raw EMG signal and used to estimate muscle load and fatigue. Joint analysis of spectral and amplitude (JASA (was performed for estimating the muscle fatigue.Results Result showed that in three out of four tested muscles, muscle fatigue and force decrease in workstation B were higher than those in workstation A.Conclusion In comparison to the simultaneous analysis of amplitude and spectral parameters in JASA method, it seems that the results are more reliable than the separate analysis of spectral and amplitude parameters. However further studies on other involved muscles in carpet weaving tasks were recommended.

scholarly journals Muscle Fatigue in the Three Heads of the Triceps Brachii During a Controlled Forceful Hand Grip Task with Full Elbow Extension Using Surface Electromyography

2015 ◽  
Vol 46 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Md. Asraf Ali ◽  
Kenneth Sundaraj ◽  
R. Badlishah Ahmad ◽  
Nizam Uddin Ahamed ◽  
Md. Anamul Islam ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Root Mean Square ◽  
Isometric Contraction ◽  
Surface Electromyography ◽  
Fiber Type ◽  
Mean Square ◽  
Elbow Extension ◽  
Triceps Brachii ◽  
Hand Grip ◽  
Triceps Brachii Muscle

AbstractThe objective of the present study was to investigate the time to fatigue and compare the fatiguing condition among the three heads of the triceps brachii muscle using surface electromyography during an isometric contraction of a controlled forceful hand grip task with full elbow extension. Eighteen healthy subjects concurrently performed a single 90 s isometric contraction of a controlled forceful hand grip task and full elbow extension. Surface electromyographic signals from the lateral, long and medial heads of the triceps brachii muscle were recorded during the task for each subject. The changes in muscle activity among the three heads of triceps brachii were measured by the root mean square values for every 5 s period throughout the total contraction period. The root mean square values were then analysed to determine the fatiguing condition for the heads of triceps brachii muscle. Muscle fatigue in the long, lateral, and medial heads of the triceps brachii started at 40 s, 50 s, and 65 s during the prolonged contraction, respectively. The highest fatiguing rate was observed in the long head (slope = −2.863), followed by the medial head (slope = −2.412) and the lateral head (slope = −1.877) of the triceps brachii muscle. The results of the present study concurs with previous findings that the three heads of the triceps brachii muscle do not work as a single unit, and the fiber type/composition is different among the three heads.

scholarly journals Enhancement of muscle’s activity by woven compression bandage

2021 ◽  
Vol 72 (04) ◽  
pp. 408-417
Author(s):  
ABDELHAMID R.R. ABOALASAAD ◽  
BRIGITA K. SIRKOVÁ ◽  
GOZDE GONCU-BERK
Keyword(s):  
Electrical Activity ◽  
Root Mean Square ◽  
Main Tool ◽  
Medial Gastrocnemius ◽  
Median Frequency ◽  
Compression Bandage ◽  
Mean Square ◽  
Electrical Voltage ◽  
Flexion Extension ◽  
Calf Muscles

Electromyography (EMG) test, the recording of electrical activity in muscle, is a main tool usually used to evaluate themuscle’s activation. This study aims to discuss and analyse the effect of woven compression bandage (WCB) onmuscles’ activation. Flexor Carpi (FC), Soleus (SO), and Medial Gastrocnemius (MG) muscles were selected torepresent the wrist, ankle, and mid-calf muscles respectively, which were then evaluated by EMG electrical voltage testwith and without wearing WCB. The standardized activities used to test the FC muscle were flexion-extension andsqueezing a soft roll. While the protocol activities for MG and SO muscles were flexion-extension and walking actions.Wearing WCB significantly decreased the muscle’s activation and was associated with higher median frequency for bothSO and MG muscles during the tested activities. The EMG signals were analysed and filtered using MegaWin andMATLAB software. Root mean square (RMS) values confirmed that wearing WCB could improve the performance of FC,SO, and MG muscles and might reduce the muscle’s fatigue during the selected activities.

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