• International journal of advanced smart convergence
• /
• v.12 no.3
• /
• pp.211-220
• /
• 2023

Surface electromyography (sEMG) is a noninvasive method used to capture electrically muscle activity, which can be easily measured even during exercise. The basic unit of muscle activity is the motor unit, and because an sEMG signal is a superposition of motor unit action potentials, analysis of muscle activity using sEMG should ideally be done from the perspective of motor unit activity. However, conventional techniques can only evaluate sEMG signals based on abstract signal features, such as root-mean-square (RMS) and mean-power-frequency (MPF), and cannot detect individual motor unit activities from an sEMG signal. On the other hand, needle EMG can only capture the activity of a few local motor units, making it extremely difficult to grasp the activity of the entire muscle. Therefore, in this study, a method to visualize the activities of motor units in a single-channel sEMG signal by relocating wavelet coefficients obtained by redundant discrete wavelet analysis is proposed. The information obtained through this method resides in between the information obtained through needle EMG and the information obtained through sEMG using conventional techniques.

• Physical Therapy Rehabilitation Science
• /
• v.8 no.1
• /
• pp.1-7
• /
• 2019

Objective: The aim of this study was to evaluate the validity and reliability of using static surface electromyography (sEMG) on persons with neck pain and in healthy adults. Design: Cross-sectional study. Methods: Twenty-two female participants with neck pain and thirty healthy adults in the age group of 20-65 years were recruited in this study. To evaluate the validity and reliability of sEMG in subjects with neck pain, the subjects'characteristics were recorded and the Visual Analog Scale (VAS) and Neck Disability Index (NDI) were examined in addition to sEMG and algometer tests being carried out on the subjects. The site for using the sEMG and algometer was the upper trapezius. sEMG test-retest reliability was measured by intraclass correlation coefficients (ICCs). Independent t-tests were used to analyze the differences in the dependent variables between subjects with neck pain and healthy adults. The Pearson correlation coefficient was used to examine the linear relationship between measured variables. Results: sEMG and algometer tests were reliable according to the test-retest reliability results in subjects with neck pain and healthy adults (ICC=0.815-0.979). The results of this study showed that there were significant differences in respect to age, VAS, sEMG and algometer tests between persons with neck pain and healthy adults (p<0.05). The VAS and NDI were statistically correlated with sEMG and algometer results (p<0.05). Conclusions: In this study, we investigated the clinical usefulness of the static sEMG test in evaluating the pain scale of persons with neck pain with high reliability and validity.

• Journal of Korea Multimedia Society
• /
• v.24 no.8
• /
• pp.1035-1043
• /
• 2021

The shoulder is less stable than other joints, making it easier to onset of various shoulder disorders. In addition, limited range of motion and pain in the shoulder due to shoulder disorders restricts daily life and social activities. The problem with exercise therapy can be reduced in exercise effect by causing boredom through simple repetition of motion, thus reducing the patient's willingness to participate. Therefore, this paper aims to provide a treatment method that can induce active participation of patients by developing devices capable of passive, active, and resistance exercise and serious game contents using them. Furthermore, sEMG was used to verify whether the rotational exercise in the horizontal and vertical using serious game contents helps the shoulder movement actually. The measured sEMG signal was classified as 5 phases according to the angle of rotation and calculated the mean integrated EMG. The mean integrated EMG for the experimental results was higher in all phases when rotational was performed compared to those when both horizontal and vertical rotational exercise remained initial posture, indicating an increase in muscle activity.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.7 no.2
• /
• pp.19-26
• /
• 2013

This paper propose a surface EMG signal based gait phase recognition method that selects features and channels adaptively. The proposed method can be used to control powered artificial prosthetic for lower limb amputees and can reduce overhead in real-time pattern recognition by selecting adaptive channels and features in an embedded device. The method can enhance the classification accuracy by adaptively selecting channels and features based on sensitivity and specificity of each subject because EMG signal patterns may vary according to subject's locomotion convention. In the experiments, we found that the muscles with highest recognition rate are different between human subjects. The results also show that the average accuracy of the proposed method is about 91% whereas those of existing methods using all channels and/or features is about 50%. Therefore we assure that sEMG signal based gait phase recognition using small number of adaptive muscles and corresponding features can be applied to control powered artificial prosthetic for lower limb amputees.

• Journal of Pharmacopuncture
• /
• v.21 no.4
• /
• pp.258-267
• /
• 2018

Objectives: The purpose of this study was to find out validity of Surface Electromyography(sEMG) compared with Nerve Conduction Study and clinical assessment scale as assessment factors for facial palsy. Methods: We investigated 50 cases of patients with peripheral facial palsy who had records of sEMG and NCS to check. Then we analyzed the correlation between sEMG and NCS that carried out around 1 week after onset. And we analyzed the correlation between sEMG and clinical assessment scales that were measured three times around 1 week, 3-4 weeks and 5-6 weeks after onset. Clinical assessment scales used in this study were House-brackmann grade, Yanagihara unweighted grading scale and Sunnybrook facial grading system. We used Pearson's correlation for statistical analysis. Results: sEMG and NCS, measured at similar times, were statistically correlated. Especially, the correlation with the forehead region was high. And sEMG and clinical assessment scale, measured at same time, were statistically correlated, especially after 5 weeks from onset. Conclusion: According to this study, sEMG is expected to be useful to assessment facial palsy.

• Journal of Biomedical Engineering Research
• /
• v.29 no.6
• /
• pp.502-511
• /
• 2008

This study was designed to develop a new algorithm to extract the voluntary EMG and the evoked EMG from a mixed EMG generated when the muscle is stimulated both voluntarily and by electrical stimulation in the FES system. The proposed parallel filter algorithm consists of three phases: (1) Fourier transform of the mixed EMG, (2) multiplication of the transformed signal to two frequency functions, and (3) inverse Fourier transform. Four incomplete spinal cord injured patients participated in the experiments to evaluate the algorithm by measuring the knee extensor torque and the EMG signals from the quadriceps. Two functions of the algorithms were evaluated: (1) extraction of the evoked EMG and (2) the voluntary EMG from the mixed EMG. The results showed that the algorithm enabled us to separate the two EMG components in real time from the mixed EMG. The algorithm can and will be used for estimating the voluntary torque and the evoked torque independently through an artificial neural network based on the two EMG components, and also for generating a trigger signal to control the on/off time of the FES system.

• The Research Journal of the Costume Culture
• /
• v.21 no.4
• /
• pp.606-611
• /
• 2013

It has been reported that tight sportswear could have complicated influence on physiological function of human body. The purpose of this present study was to investigate the effect of wearing gradient compression tights (GCT) on muscle strength and EMG activity during repeated isokinetic muscle contractions. Four healthy male undergraduate students performed maximal voluntary isokinetic concentric muscle contractions on biomechanical test and training systems with GCT and loose pants as control (Cont) respectively. During each test, the peak torque of extensor and flexor contractions and the surface electromyography (sEMG) of the rectus femoris and medial gastrocnemius was recorded simultaneously, the peak torque was recorded as an indicator of muscle strength, and the average amplitude and mean power frequency of sEMG were calculated as indicators of EMG activity. The results showed that: the peak torque decreased gradually during continuous muscle contractions both when the Cont and GCT were worn, average sEMG and mean power frequency declined along with the repetitions of muscle contractions for both wearing conditions, and the change tendency was consistence with that of peak torque. There was no obvious difference between the peak torque recorded wearing the Cont or wearing GCT, but when GCT were worn, average sEMG was lower and mean power frequency was higher than the Cont condition. In 24 samples obtained from four subjects, 80% of results showed the same trend. So we could make a conclusion that wearing GCT had no obvious effect on the improvement of muscle strength, but it would affect the EMG activity positivly.

• The Journal of Korea Robotics Society
• /
• v.14 no.3
• /
• pp.211-220
• /
• 2019

Surface electromyogram (sEMG), which is a bio-electrical signal originated from action potentials of nerves and muscle fibers activated by motor neurons, has been widely used for recognizing motion intention of robotic prosthesis for amputees because it enables a device to be operated intuitively by users without any artificial and additional work. In this paper, we propose a training-free unsupervised sEMG pattern recognition algorithm. It is useful for the gesture recognition for the amputees from whom we cannot achieve motion labels for the previous supervised pattern recognition algorithms. Using the proposed algorithm, we can classify the sEMG signals for gesture recognition and the calculated threshold probability value can be used as a sensitivity parameter for pattern registration. The proposed algorithm was verified by a case study of a patient with partial-hand amputation.

• Journal of The Korean Society of Integrative Medicine
• /
• v.6 no.2
• /
• pp.37-44
• /
• 2018

Purpose : The aim of this study is to compare the trunk muscle activities in trunk stabilization on the stable and unstable supporting surfaces using by sEMG. Methods : The subjects of this study include seventeen male. We measured sEMG activities of rectus abdominis and erector spine in subjects during trunk stabilization such as plank exercise, quadruped position, quadruped position with rising hand and foot on the stable and unstable surface. Results : sEMG activities in plank exercise was significantly higher in left rectus abdominis and left erector spine on unstable surface then stable surface (p<.05). sEMG activities of left rectus abdominis and left erector spine in quadruped position was significantly higher in unstable surface than stable surface (p<.05). In comparison with posture, Plank exercise showed a significant difference increase other postures (p<.05). Conclusion : sEMG activities of muscle in trunk stabilization was significantly higher in unstable surface than stable surface and plank exercise. So, we suggest that trunk stabilization on the unstable supporting surface and plank exercise were more effective method than stable surface to improve trunk muscles activities.

• Korean Journal of Applied Biomechanics
• /
• v.22 no.3
• /
• pp.333-339
• /
• 2012

Freezing of gait is a severely problem in people with Parkinson's disease. The purpose of this study was to investigate the muscle activities of adductor longus, gluteus medius, gluteus maximus, biceps femoris, rectus femoris, gastrocnemius, and tibialis anterior using Noraxon 8 channels EMG system during stop task in patients with Parkinson's disease. Seven parkinson's patients and age matched normal participants were recruited in the study. Filtered EMG signals were rectified, smoothed and integrated. To control for the altered timing and magnitude of activity, iEMG was normalized for time and peak value. The results indicated that the patients with Parkinson showed decreased gait cycle, stance phase, swing phase time, swing phase time ratio and increased stance phase time ratio than normal participants. The patients with Parkinson showed decreased gastrocnemius muscle activity time ratio, while increased tibialis anterior muscle activity time ratio than normal participants. During stance phase before stop, the patients with Parkinson showed relatively lower average and peak iEMG in anterior tibialis and gastrocnemius muscle than normal participants. During swing phase before stop, the patients with Parkinson showed relatively higher average iEMG in gastrocnemius muscle than normal participants. During stop phase, the patients with Parkinson showed relatively lower average and peak iEMG in anterior tibialis and gastrocnemius muscle than normal participants.