Effects of muscle kinematics on surface EMG amplitude and frequency during fatiguing dynamic contractions

1997 ◽  
Vol 82 (1) ◽  
pp. 144-151 ◽  
Author(s):  
J. R. Potvin
Keyword(s):  
Biceps Brachii ◽  
Elbow Flexion ◽  
Surface Emg ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Emg Amplitude ◽  
Flexion Extension ◽  
Dynamic Contractions ◽  
Power Frequency ◽  
Voluntary Contractions

Potvin, J. R. Effects of muscle kinematics on surface EMG amplitude and frequency during fatiguing dynamic contractions. J. Appl. Physiol. 82(1): 144–151, 1997.—Fifteen male subjects performed a repetitive elbow flexion/extension task with a 7-kg mass until exhaustion. Average joint angle, angular velocity, and biceps brachii surface electromyographic (EMG) amplitude (aEMG) and mean power frequency (MPF) were calculated with each consecutive 250-ms segment of data during the entire trial. Data were separated into concentric or eccentric phases and into seven 20°-ranges from 0 to 140° of elbow flexion. A regression analysis was used to estimate the rested and fatigued aEMG and MPF values. aEMG values were expressed as a percentage of amplitudes from maximum voluntary contractions (MVC). Under rested dynamic conditions, the average concentric aEMG amplitude was 10% MVC higher than average eccentric values. Rested MPF values were similar for concentric and eccentric phases, although values increased ∼20 Hz from the most extended to flexed joint angles. Fatigue resulted in an average increase in concentric and eccentric aEMG of 35 and 10% MVC, respectively. The largest concentric aEMG increases (up to 58% MVC) were observed at higher joint velocities, whereas eccentric increases appeared to be related to decreases in velocity. Fatigue had a similar effect on MPF during both concentric and eccentric phases. Larger MPF decreases were observed at shorter muscle lengths such that values within each angle range were very similar by the end of the trial. It was hypothesized that this finding may reflect a biological minimum in conduction velocity before propagation failure occurs.

The Effects Of Parallel Versus Perpendicular Electrode Orientations On EMG Amplitude And Mean Power Frequency From The Biceps Brachii

2009 ◽  
Vol 41 ◽  
pp. 199 ◽  
Author(s):  
Jorge Zuniga M. Zuniga ◽  
Terry J. Housh ◽  
Clayton L. Camic ◽  
Michelle Mielke ◽  
C. Russell Hendrix ◽  
...  
Keyword(s):  
Biceps Brachii ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Emg Amplitude ◽  
Power Frequency

Basic reporting and interpretation of surface EMG amplitude and mean power frequency: a reply to Vitgotsky, Ogborn, and Phillips

2015 ◽  
Vol 116 (3) ◽  
pp. 659-661 ◽  
Author(s):  
Nathaniel D. M. Jenkins ◽  
Terry J. Housh ◽  
Haley C. Bergstrom ◽  
Kristen C. Cochrane ◽  
Ethan C. Hill ◽  
...  
Keyword(s):  
Surface Emg ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Emg Amplitude ◽  
Power Frequency

Intramuscular and surface electromyogram changes during muscle fatigue

1986 ◽  
Vol 60 (4) ◽  
pp. 1179-1185 ◽  
Author(s):  
T. Moritani ◽  
M. Muro ◽  
A. Nagata
Keyword(s):  
Muscle Fatigue ◽  
Biceps Brachii ◽  
Surface Emg ◽  
Firing Frequency ◽  
Voluntary Contraction ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Surface Electromyogram ◽  
Spike Amplitude ◽  
Frequency Power

Twelve male subjects were tested to determine the effects of motor unit (MU) recruitment and firing frequency on the surface electromyogram (EMG) frequency power spectra during sustained maximal voluntary contraction (MVC) and 50% MVC of the biceps brachii muscle. Both the intramuscular MU spikes and surface EMG were recorded simultaneously and analyzed by means of a computer-aided intramuscular spike amplitude-frequency histogram and frequency power spectral analysis, respectively. Results indicated that both mean power frequency (MPF) and amplitude (rmsEMG) of the surface EMG fell significantly (P less than 0.001) together with a progressive reduction in MU spike amplitude and firing frequency during sustained MVC. During 50% MVC there was a significant decline in MPF (P less than 0.001), but this decline was accompanied by a significant increase in rmsEMG (P less than 0.001) and a progressive MU recruitment as evidenced by an increased number of MUs with relatively large spike amplitude. Our data suggest that the surface EMG amplitude could better represent the underlying MU activity during muscle fatigue and the frequency powers spectral shift may or may not reflect changes in MU recruitment and rate-coding patterns.

scholarly journals The Excitability of Ipsilateral Motor Evoked Potentials Is Not Task-specific and Spatially Distinct From the Contralateral Motor Hotspot

2022 ◽  
Author(s):  
Nelly Seusing ◽  
Sebastian Strauss ◽  
Robert Fleischmann ◽  
Christina Nafz ◽  
Sergiu Groppa ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Evoked Potentials ◽  
Primary Motor Cortex ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Elbow Flexion ◽  
Motor Pathways ◽  
Task Dependence ◽  
Flexion Extension ◽  
Voluntary Contractions

Abstract ObjectiveThe role of ipsilateral descending motor pathways in voluntary movement of humans is still a matter of debate. Few studies have examined the task dependent modulation of ipsilateral motor evoked potentials (iMEPs). Here, we determined the location of upper limb biceps brachii (BB) representation within the ipsilateral primary motor cortex. MethodsMR-navigated transcranial magnetic stimulation mapping of the dominant hemisphere was undertaken with twenty healthy participants who made tonic unilateral, bilateral homologous or bilateral antagonistic elbow flexion-extension voluntary contractions. Map center of gravity (CoG) and area for each BB were obtained. ResultsThe map CoG of the ipsilateral BB was located more anterior-laterally than those of the contralateral BB within the primary motor cortex. However different tasks had no effect on either the iMEP CoG location or the size. ConclusionOur data suggests that ipsilateral and contralateral MEP might originate in distinct adjacent neural populations in the primary motor cortex, independent of task dependence.

Features for muscle fatigue computed from electromyogram and mechanomyogram: A new one

2016 ◽  
Vol 230 (12) ◽  
pp. 1096-1105 ◽  
Author(s):  
Şükrü Okkesim ◽  
Kezban Coşkun
Keyword(s):  
Muscle Fatigue ◽  
Frequency Ratio ◽  
Biceps Brachii ◽  
Median Frequency ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Power Frequency ◽  
Ratio Change ◽  
The Mean ◽  
New Feature

Muscle fatigue produces negative effects in the performance and it may lead to a muscle failure. This problem makes the quantitative grading of muscle fatigue a necessity in ergonomic and physiological research. Moreover, the quantitative grading of muscle fatigue is needed to increase work and sport productivity and prevent several accidents that result from muscle fatigue. Even though there are many studies for this aim, there is no quantitative criterion for the evaluation of muscle fatigue. The main reason is that muscle fatigue is a complex physiological situation that is dependent on several parameters. Our aim in this study is to present a new feature to evaluate muscle fatigue and prove the reliability of the new feature by making correlation analyses between this with other features. For this aim, electromyography and mechanomyography signals were simultaneously recorded from the biceps brachii and triceps brachii muscles during the isometric and isotonic contractions of 60 healthy volunteers (30 females, 30 males). The mean power frequency and median frequency, which are used in the literature, were compared to the frequency ratio change, the new measure; correlations between the frequency ratio change and the mean power frequency and median frequency were analysed. There was a high correlation between the features, and frequency ratio change can be used to quantitatively evaluate muscle fatigue.

scholarly journals PENGEMBANGAN SISTEM DETEKSI KELELAHAN PADA PENGEMUDI MOBIL BERBASIS SINYAL ELECTROMYOGRAPHY (EMG)

2016 ◽  
Vol 3 (1) ◽  
pp. 18
Author(s):  
Sukma Firdaus ◽  
Marlia Adriana
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Surface Emg ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Power Frequency ◽  
High Pass

Peningkatan alat trasportasi khususnya kendaraan roda empat (mobil) mengakibatkan peningkatan volume kendaraan di jalan. Hal ini berdampak pada meningkatnya kemacetan. Selain kemacetan, peningkatan volume kendaraan berdampak juga pada peningkatan kecelakan lalu lintas. Salah satu penyebab kecelakan lalu lintas adalah faktor pengendaranya, yaitu kelelahan. Penelitian ini, merancang sistem pendeteksi kelelahan pengemudi, berdasarkan sinyal biologis pengemudi yaitu sinyal biologis kondisi otot lengan. Sinyal tersebut direkam dengan menggunakan metode surface EMG. Elektroda yang ditempelkan disebelah kanan lengan dihubungkan dengan penguat instrumentasi dan digitalisasi melalui unit pemproses sinyal untuk dapat disimpan kedalam komputer. Kegiatan pengambilan data dilakukan sebanyak 8 kali dengan jarak tempuh pengemudi sebesar 80 km dari Kota Banjarmasin menuju Kota Pelaihari. Akuisisi data menggunakan frekuensi sampling sebesar 4 KHz dan diproses secara filter analog untuk High Pass Filter sebesar 2 KHz dan Low Pass Filter sebesar 500 Hz. Setelah data direkam, sinyal dilakukan proses downsampling menjadi 1 KHz. Pada proess digital, dilakukan lagi proses pemfilteran secara Low Pass Filter sebesar 500 Hz. Proses digital selanjutnya adalah melakukan analisis pada domain frekuensi menggunakan transformasi fourier dengan memakai algoritma fast fourier transform (fft). Hasil dari transformasi fourier diidentifikasi berdasarkan nilai Mean Power Frequency (MPF). Berdasarkan hasil perhitungan MPF yang telah dilakukan, diperoleh saat awal berkendara nilai rata-rata MPF nya adalah sebesar 25,2 Hz sedangkan pada akhir berkendara bernilai sebesar 33,3 Hz. Dengan hasil ini dapat tergambarkan kondisi pengemudi pada awal mengemudi dan tidak terjadi kelelahan maka nilai frekuensi yang dominan cenderung lebih rendah jika dibandingkan dengan setelah berkendara atau saat kelelahan.

Gender Comparisons of Mechanomyographic Amplitude and Mean Power Frequency versus Isometric Torque Relationships

2005 ◽  
Vol 21 (1) ◽  
pp. 96-109 ◽  
Author(s):  
Travis W. Beck ◽  
Terry J. Housh ◽  
Glen O. Johnson ◽  
Joseph P. Weir ◽  
Joel T. Cramer ◽  
...  
Keyword(s):  
Biceps Brachii ◽  
Maximum Voluntary Contraction ◽  
Fluid Pressure ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Power Frequency ◽  
Isometric Torque ◽  
Muscle Actions ◽  
Best Fit ◽  
Isometric Muscle

This study compared the patterns of mechanomyographic (MMG) amplitude and mean power frequency vs. torque relationships in men and women during isometric muscle actions of the biceps brachii. Seven men (mean age 23.9 ± 3.5 yrs) and 8 women (mean 21.0 ± 1.3 yrs) performed submaximal to maximal isometric muscle actions of the dominant forearm flexors. Following determination of the isometric maximum voluntary contraction (MVC), they randomly performed submaximal step muscle actions in 10% increments from 10% to 90% MVC. Polynomial regression analyses indicated that the MMG amplitude vs. isometric torque relationship for the men was best fit with a cubic model (R2= 0.983), where MMG amplitude increased slightly from 10% to 20% MVC, increased rapidly from 20% to 80% MVC, and plateaued from 80% to 100% MVC. For the women, MMG amplitude increased linearly (r2= 0.949) from 10% to 100% MVC. Linear models also provided the best fit for the MMG mean power frequency vs. isometric torque relationship in both the men (r2= 0.813) and women (r2= 0.578). The results demonstrated gender differences in the MMG amplitude vs. isometric torque relationship, but similar torque-related patterns for MMG mean power frequency. These findings suggested that the plateau in MMG amplitude at high levels of isometric torque production for the biceps brachii in the men, but not the women, may have been due to greater isometric torque, muscle stiffness, and/or intramuscular fluid pressure in the men, rather than to differences in motor unit activation strategies for modulating isometric torque production.

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