• Physical Therapy Korea
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• v.4 no.1
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• pp.78-86
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• 1997

Back muscles play an important role in protecting the spine. Epidemiological studies have shown that loads imposed on the human spine during daily living play a significant role in the onset of low back pain. No previous study has attempted to correlate the response of the trunk musculature with the type of external load. The purpose of this study was to use surface electromyography (EMG) to quantify the relative demands placed on the back muscles while lifting loads in one hand. Forty asymptomatic, twenty year-old subjects stood while lifting loads of 10% of body weight(BW) unilaterally. All EMG data were normalized to a percentage of the EMG voltage produced during no-load standing(%EMG). Our major analysis involved a paired t-test for repeated measures. Of particular note was the fact that the ipsilateral 10% of BW condition produced statistically less % EMG change than did the contralateral 10% of the condition.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.5
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• pp.380-388
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• 2004

This study proposed an improved spike detection algorithm which automatically detects suitable spike threshold on the amplitude of surface electromyography(SEMG) signal during isometric contraction. The EMG data from the low back muscles was obtained in six channels and the proposed signal processing algorithm is compared with the median frequency and Gabriel's spike parameter. As a result, the reliability of spike parameter was inferior to the median frequency. This fact indicates that a spike parameter is inadequate for analysis of multi-channel EMG signal. Because of uncertainty of fixed spike threshold, the improved spike detection algorithm was proposed. It automatically detects suitable spike threshold depending on the amplitude of the EMG signal, and the proposed algorithm was able to detect optimal threshold based on mCFAR(modified Constant False Alarm Rate) in the every EMG channel. In conclusion, from the reliability points of view, neither median frequency nor existing spike detection algorithm was superior to the proposed method.

• Physical Therapy Rehabilitation Science
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• v.6 no.3
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• pp.127-133
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• 2017

Objective: The purpose of this study was to explore the effect of repetitive wrist extension task training with electromyography (EMG)-triggered neuromuscular electrical stimulation (NMES) for wrist extensor muscle recovery in patients with stroke. Design: Randomized controlled trial. Methods: Fifteen subjects who had suffered a stroke were randomly assigned to an EMG-triggered NMES group (n=8) or control group (n=7); subjects in both groups received conventional therapy as usual. Subjects in the experimental group received application of EMG-triggered NMES to the wrist extensor muscles for 20 minutes, twice per day, five days per week, for a period of four weeks, and were given a task to make a touch alarm go off by activity involving extension of their wrist. In the control group, subjects performed wrist self-exercises for the same duration and frequency as those in the experimental group. Outcome measures included muscle reaction time and spectrum analysis. Assessments were performed during the pre- and post-treatment periods. Results: In the EMG-triggered NMES group, faster muscle reaction time was observed, and median frequency also showed improvement, from 68.2 to 75.3 Hz, after training (p<0.05). Muscle reaction time was significantly faster, and median frequency was significantly higher in the experimental group than in the experimental group after training. Conclusions: EMG-triggered NMES is beneficial for patients with hemiparetic stroke in recovery of upper extremity function.

• Journal of Acupuncture Research
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• v.34 no.2
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• pp.75-82
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• 2017

Objectives : The purpose of this study was to determine the electrical properties of the buccal area using facial surface electromyography (sEMG). Methods : This research was conducted on 44 healthy participants irrespective of their sex. Surface electrodes were attached to the midpoints of three imaginary lines connecting ST4 (Dicang) to ST6 (Jiache), ST4 to SI18 (Quanliao), and ST4 to the center point of SI18 and ST6. Then, the participants were trained in the movement that included a comprehensive action of buccal area. While the participants were performing the motion, sEMG values ($E_1$, $E_2$, $E_3$) and the distance change of the three imaginary lines ($D_1$, $D_2$, $D_3$) were measured. The data were statistically analyzed using SPSS ver. 22.0. Results : Significant differences were observed in the distance changes ($D_1$>$D_3$, $D_2$>$D_3$) and sEMG values ($E_1$<$E_2$<$E_3$). Moreover, there were positive correlations between $D_1$ and $E_1$, $D_2$ and $E_2$. Conclusion : We suggest that the measurement at ST4 to the center point of ST6 and SI18 with this motion would be adequate to check the electrical characteristics of the buccal area.

• Journal of the Ergonomics Society of Korea
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• v.30 no.6
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• pp.689-694
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• 2011

Objective: The aim of this study is to evaluate the fluctuation of signal amplitude during repetitive dynamic contraction based on surface electromyography(EMG). Background: The most previous studies were considered isometric muscle contraction and they were difference to smoothing window length by moving average filter. In practical, the human movement is dynamic state. Dynamic EMG signal which indicated as the nonstationary pattern should be analyzed differently compared with the static EMG signal. Method: Ten male subjects participated in this experiment, and EMG signal was recorded by biceps brachii, anterior/posterior deltoid, and upper/lower trapezius muscles. The subject was performed to repetitive right horizontal lifting task during ten cycles. This study was considered three independent variables(muscle, amplitude processing technique, and smoothing window length) as the within-subject experimental design. This study was estimated muscular activation by means of the linear envelope technique(LE). The dependent variable was set coefficient of variation(CV) of LE for each cycle. Results: The ANOVA results showed that the main and interaction effects between the amplitude processing technique and smoothing window length were significant difference. The CV value of peak LE was higher than mean LE. According to increase the smoothing window length, this study shows that the CV trend of peak LE was decreased. However, the CV of mean LE was analyzed constant fluctuation trend regardless of the smoothing window length. Conclusion: Based on these results, we expected that using the mean LE and 300ms window length increased reproducibility and signal noise ratio during repetitive dynamic muscle contraction. Application: These results can be used to provide fundamental information for repetitive dynamic EMG signal processing.

• Journal of Biomedical Engineering Research
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• v.40 no.6
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• pp.242-249
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• 2019

Forearm electromyography (EMG) generated by wrist movements has been widely used to develop an electrical prosthetic hand, but EMG generated by finger movements has been rarely used even though 20% of amputees lose fingers. The goal of this study is to improve the classification performance of different finger movements using a deep learning algorithm, and thereby contributing to the development of a high-performance finger-based prosthetic hand. Ten participants took part in this study, and they performed seven different finger movements forty times each (thumb, index, middle, ring, little, fist and rest) during which EMG was measured from the back of the right hand using four bipolar electrodes. We extracted mean absolute value (MAV), root mean square (RMS), and mean (MEAN) from the measured EMGs for each trial as features, and a 5x5-fold cross-validation was performed to estimate the classification performance of seven different finger movements. A long short-term memory (LSTM) model was used as a classifier, and linear discriminant analysis (LDA) that is a widely used classifier in previous studies was also used for comparison. The best performance of the LSTM model (sensitivity: 91.46 ± 6.72%; specificity: 91.27 ± 4.18%; accuracy: 91.26 ± 4.09%) significantly outperformed that of LDA (sensitivity: 84.55 ± 9.61%; specificity: 84.02 ± 6.00%; accuracy: 84.00 ± 5.87%). Our result demonstrates the feasibility of a deep learning algorithm (LSTM) to improve the performance of classifying different finger movements using EMG.

• Science of Emotion and Sensibility
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• v.26 no.4
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• pp.41-50
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• 2023

This study aims to develop electromyography (EMG) textile electrodes and assess their performance and signal stability by examining variations in layer count and fabric types. We fabricated the electrodes through layering and pressing techniques, focusing on configurations with different layer counts (Layer-0, Layer-1, and Layer-2). Our findings indicate that layer presence significantly influences muscle activation measurements, with enhanced performance correlated with increased layer numbers. Subsequently, we created electrodes from five distinct fabrics (neoprene, spandex cushion, 100% polyester, nylon spandex, and cotton canvas), each maintaining a Layer-2 structure. In performance tests, nylon spandex fabric, particularly heavier variants, outperformed others, while the spandex cushion electrodes showed superior stability in muscle activation signal acquisition. This research elucidates the connection between electrode performance and factors like layer number and electrode-skin contact area. It suggests a novel approach to electrode design, focusing on layer properties and targeted pressure application on specific sensor areas, rather than uniformly increasing sleeve pressure.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.1
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• pp.55-64
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• 2004

Conventional bipolar surface electromyography(EMG) technique detects only the superimposed electromyographic activity of a large number of motor units due to its low spatial resolution. For the diagnosis of neuromuscular disorder, the information of single MU is required. In this paper, 9 channel array surface electrode system was as designed and MLoG filter was proposed. Also the MCPT(modified convolution processing technique)method was proposed for the improvement of MUAP resolution. For performance evaluation, power spectrum analysis of random data and raw EMG signal comparison of MUAP shape and quantitative estimation of SNR were executed. As a result, the MUAP resolution improvement of 32％ was obtained from the standpoint of the signal-to-noise ratio(SNR).

• Journal of the Korean Society of Physical Medicine
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• v.5 no.4
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• pp.605-613
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• 2010

Purpose : The purpose of this study was to investigate the VMO/VL ratio and onset timing using EMG biofeedback training over a 5-day period. Methods : Twenty-one healthy female college students with no known right knee musculoskeletal dysfunction were recruited this study. Muscle activity was measured by surface electromyography(Myosystem 1400A, Noraxon Inc., U.S.A). Statistical analysis was used two-way repeated ANOVA to know difference between the vastus lateralis and vastus medialis oblique onset timing differences, VMO/VL ratio. Results : Biofeedback training group significantly improved VMO/VL ratio and EMG activity of the vastus medialis oblique after intervention. Conclusion : These result indicate that biofeedback training on the vastus medialis oblique has effect on the VMO/VL ratio. EMG biofeedback can be recommended for the facilitation of VMO muscular recruitment.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1173-1178
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• 2005

This paper proposes an IPMC actuating system with a bio-mimetic function. EMG signals generated by an intended contraction of muscles in forearm are used for the actuation of the IPMC. To obtain higher actuation force of the IPMC, the single layered as thick as 800 [${\mu}$m] or multi-layered IPMC (Nafion) of which each layer can be as thick as 178 [${\mu}$m] are prepared. The experimental results using an implemented IPMC control system show a possibility and a usability of the bio-mimetic artificial muscle.