Spectral analysis of root-mean-square processed surface electromyography data as a measure of repetitive muscular exertion

2012 ◽  
Author(s):  
Lauren Christine Gant
Keyword(s):  
Spectral Analysis ◽  
Root Mean Square ◽  
Surface Electromyography ◽  
Mean Square ◽  
Muscular Exertion

Some further studies about generalised spectral norms

2021 ◽  
Vol 63 (6) ◽  
pp. 362-369
Author(s):  
K Karioja ◽  
E Juuso ◽  
J Nissilä
Keyword(s):  
Spectral Analysis ◽  
Root Mean Square ◽  
Automatic Monitoring ◽  
Vibration Monitoring ◽  
Spectral Information ◽  
Measured Signal ◽  
Mean Square ◽  
Automatic Monitoring System ◽  
Special Cases ◽  
Peak Value

Spectral analysis is a very common tool in vibration monitoring. While useful in machine diagnostics, spectral analysis can be rather time consuming. Tasks that require an extensive amount of time are often considered too expensive, especially in modern industry. To achieve an automatic monitoring system of some kind, different features, such as the root mean square (RMS) or the peak value of signals, are often monitored. These are special cases of generalised norms, which can be effective tools to determine whether a signal has shown some kind of change and how notable the change is when compared to a previously measured signal, for example. However, no spectral information is obtained in this way and the question regarding the frequency in the signal at which the change has occurred remains unanswered. Generalised spectral norms are a frequency-domain application of these norms and, as presented in this paper, provide a suitable way to perform automatic monitoring regarding the spectral information, for example.

A STUDY OF MODELS FOR HANDGRIP FORCE PREDICTION FROM SURFACE ELECTROMYOGRAPHY OF EXTENSOR MUSCLE

2009 ◽  
Vol 21 (02) ◽  
pp. 81-88 ◽  
Author(s):  
Wensheng Hou ◽  
Xiaolin Zheng ◽  
Yingtao Jiang ◽  
Jun Zheng ◽  
Chenglin Peng ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Surface Electromyography ◽  
Random Sequence ◽  
Maximum Voluntary Contraction ◽  
Force Production ◽  
Voluntary Contraction ◽  
Mean Square ◽  
Force Level ◽  
Force Output ◽  
Mean Square Errors

Force production involves the coordination of multiple muscles, and the produced force levels can be attributed to the electrophysiology activities of those related muscles. This study is designed to explore the activity modes of extensor carpi radialis longus (ECRL) using surface electromyography (sEMG) at the presence of different handgrip force levels. We attempt to compare the performance of both the linear and nonlinear models for estimating handgrip forces. To achieve this goal, a pseudo-random sequence of handgrip tasks with well controlled force ranges is defined for calibration. Eight subjects (all university students, five males, and three females) have been recruited to conduct both calibration and voluntary trials. In each trial, sEMG signals have been acquired and preprocessed with Root–Mean–Square (RMS) method. The preprocessed signals are then normalized with amplitude value of Maximum Voluntary Contraction (MVC)-related sEMG. With the sEMG data from calibration trials, three models, Linear, Power, and Logarithmic, are developed to correlate the handgrip force output with the sEMG activities of ECRL. These three models are subsequently employed to estimate the handgrip force production of voluntary trials. For different models, the Root–Mean–Square–Errors (RMSEs) of the estimated force output for all the voluntary trials are statistically compared in different force ranges. The results show that the three models have different performance in different force ranges. Linear model is suitable for moderate force level (30%–50% MVC), whereas a nonlinear model is more accurate in the weak force level (Power model, 10%–30% MVC) or the strong force level (Logarithmic model, 50%–80% MVC).

Involuntary ankle oscillations from normal subjects

1977 ◽  
Vol 233 (1) ◽  
pp. R8-R14
Author(s):  
R. N. Stiles ◽  
R. R. Rietz
Keyword(s):  
Spectral Analysis ◽  
Root Mean Square ◽  
Power Function ◽  
Normal Subjects ◽  
Displacement Amplitude ◽  
Mean Square ◽  
Hand Tremor ◽  
Negative Relation ◽  
Tremor Frequency

Spectral analysis of ankle tremor records obtained from normal seated subjects during continuous elevation of the heel for 10-45 min revealed that the root-mean-square (rms) displacement amplitude of the tremor increased from minimum values of about 4 micronm to values as large as 4,000 micronm. Associated with this increase in the displacement amplitude was a systematic decrease in the tremor frequency from values of 7-8 Hz to values of 5-6 Hz. Spectral analysis of demodulated soleus EMG records indicated that the rms value of this EMG (calculated at the tremor frequency) and the rms displacement of the tremor are related by a power function, with the rms value of the EMG increasing over a range of about 4-40 micronV as the tremor displacement increased from about 4 to 4,000 micronm. The negative relation between frequency and rms displacement amplitude values for postural ankle tremor was similar to that found previously for postural hand tremor.

Quantification of Silymarin in Silybi mariani fructus: Challenging the Analytical Performance of Benchtop vs. Handheld NIR Spectrometers on Whole Seeds

Planta Medica ◽  
2021 ◽  
Author(s):  
Sophia Mayr ◽  
Simon Strasser ◽  
Christian G. Kirchler ◽  
Florian Meischl ◽  
Stefan Stuppner ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Infrared Spectroscopy ◽  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Analytical Performance ◽  
Milk Thistle ◽  
Mean Square

AbstractThe content of the flavonolignan mixture silymarin and its individual components (silichristin, silidianin, silibinin A, silibinin B, isosilibinin A, and isosilibinin B) in whole and milled milk thistle seeds (Silybi mariani fructus) was analyzed with near-infrared spectroscopy. The analytical performance of one benchtop and two handheld near-infrared spectrometers was compared. Reference analysis was performed with HPLC following a Soxhlet extraction (European Pharmacopoeia) and a more resource-efficient ultrasonic extraction. The reliability of near-infrared spectral analysis determined through partial least squares regression models constructed independently for the spectral datasets obtained by the three spectrometers was as follows. The benchtop device NIRFlex N-500 performed the best both for milled and whole seeds with a root mean square error of CV between 0.01 and 0.17%. The handheld spectrometer MicroNIR 2200 as well as the microPHAZIR provided a similar performance (root mean square error of CV between 0.01 and 0.18% and between 0.01 and 0.23%, respectively). We carried out quantum chemical simulation of near-infrared spectra of silichristin, silidianin, silibinin, and isosilibinin for interpretation of the results of spectral analysis. This provided understanding of the absorption regions meaningful for the calibration. Further, it helped to better separate how the chemical and physical properties of the samples affect the analysis. While the study demonstrated that milling of samples slightly improves the performance, it was deemed to be critical only for the analysis carried out with the microPHAZIR. This study evidenced that rapid and nondestructive quantification of silymarin and individual flavonolignans is possible with miniaturized near-infrared spectroscopy in whole milk thistle seeds.

scholarly journals Could Ankle Muscle Activation Be Used as a Simple Measure of Balance Exercise Intensity?

2019 ◽  
Vol 70 (1) ◽  
pp. 47-59
Author(s):  
Jerica Licen ◽  
Vojko Strojnik ◽  
Katja Tomazin
Keyword(s):  
Root Mean Square ◽  
Surface Electromyography ◽  
Muscle Activation ◽  
Sagittal Plane ◽  
Angular Distance ◽  
Stability Conditions ◽  
Mean Square ◽  
Relative Measure ◽  
Balance Exercise ◽  
Ankle Muscle

Abstract Few, if any, studies have reported the effects of intensity of balance exercise for balance training and rehabilitation. The aim of the present study was to find a relative measure of intensity of balance exercise. On this basis, we analysed ankle muscle activation in the sagittal plane with increasing difficulty for a one leg stance on a T-board. Ten adults (7 men, 24.1 ± 3.5 years; 3 women, 30.6 ± 5.8 years) performed 3 trials on a T-board within 6 randomly assigned stability levels. T-board swaying velocities in the sagittal plane were manipulated to attain different stability levels (conditions). Concurrently, angular distance of the T-board and active balance time (i.e., percentage of a total time balancing) under each condition were measured. Surface electromyography from the tibialis anterior, gastrocnemius and soleus were monitored during one leg stance. The surface electromyography amplitude in the time domain was quantified using the root-mean-square values. Significant effect of stability levels on angular distance (F5,45 = 3.4; p = 0.01) and velocity of the T-board (F5,45 = 4.6; p = 0.002) were obtained. Active balance time decreased by ∼15% (p = 0.001) from the maximal to the minimal stability conditions. The graded level of balance board stability conditions did not generate significantly higher root-mean-square values in any muscles and hence could not be used as a relative measure of intensity of balance exercise. These findings imply that there could be a plateau in difficulty of balance exercise for enhancement of ankle muscle activity.

scholarly journals Muscle Activity and Gait Analysis of Assistive Device for Rehabilitation Gait Abnormalities Patient

2021 ◽  
Vol 2107 (1) ◽  
pp. 012063
Author(s):  
Ruzy Haryati Hambali ◽  
Suriati Akmal ◽  
Nurul Hamizan Komaruddin
Keyword(s):  
Gait Analysis ◽  
Muscle Contraction ◽  
Root Mean Square ◽  
Muscle Activity ◽  
Surface Electromyography ◽  
Assistive Device ◽  
Mean Square ◽  
Gait Abnormality ◽  
Muscle Disorder ◽  
Gait Abnormalities

Abstract Gait abnormality is a muscle disorder that disabling the patient to walk properly. This is caused by several factors including genetic influence, accident history, health issue, and others. Some suffered from this illness could be cured but some cases only could be helped by rehabilitation. This work is an original initiative in developing an assistive device as part of patient’s recovery and rehabilitation in helping the patient to regain muscle, as well assisting patient in performing their activities. However, the effectiveness on the device’s performance to serve its purpose has not yet been confirmed. Therefore, an electrical tool known as surface Electromyography (EMG) is being used to obtain the information required. This research is analysing the patient’s nerves system with and without the assistive device and demonstrate the effectiveness of the assistive device in reducing the muscle contraction, as well to increase the time-to-fatigue of the muscle. The findings of this research showed that the reduction in percent of average Root Mean Square (RMS) value of patient’s contraction muscle when using the device has increase the time-to-fatigue of the muscle. In conclusion, this assistive device assists the patient, minimise the muscle fatigue, and ease the patient in their daily chores.

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.

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