• Physical Therapy Korea
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• v.10 no.1
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• pp.109-128
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• 2003

This study tested whether repeated measurement of median frequency (MDF)-related variables could express the muscle power changes during a 12-week DeLome strengthening program, by using consecutive overlapping FFT (Fast Fourier transformation) and integrated EMG (IEMG) from surface EMG data for isometric and isotonic exercise. To evaluate the effect of training, the following were recorded every 3 weeks for the elbow flexors and knee extensors of 5 healthy male volunteers: MVC, lRM, limb circumference, and surface EMG during isometric MVC or isotonic contraction at 10RM load. From the EMG data, IEMG and variables from a regression analysis between MDF and time were obtained. MVC, lRM, IEMG, and initial MDF increased linearly over the training period. The fatigue index and slope of the regression line increased temporarily until the 6th week and decreased thereafter. From these results, there appeared to be enhanced neural recruitment of fast twitch fibers in the first 6 weeks and continued enhancement in the recruitment and hypertrophy of fast twitch fibers, which led to increased fatigue resistance, over the last 6 weeks. Accordingly, the MDF and IEMG analysis technique could demonstrate the effect of the program detected significant changes in both isometric and isotonic contractions. EMG analysis methods can be used to estimate the electrophysiological and histological changes in skeletal muscles during a strengthening program.

• Transactions on Electrical and Electronic Materials
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• v.18 no.5
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• pp.298-302
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• 2017

With an increasing aging population and improved standards of living, more attention has been paid to health. Although walking exercise is known as an aerobic exercise, it imposes repeated and continuous impacts on the joints of the lower extremities. Therefore, when overweight gives a burden to the lower extremity or there is a joint disease, exercise limit occurs. The articular cartilage, weakened with age, also makes it difficult for the elderly to perform walking exercises. Accordingly, this study conducted a comparative analysis between regular walking using only the lower extremity and Nordic walking, which has been known as stable. For analysis, electromyography (EMG) was performed and the ground reaction force of the upper and lower extremities were measured in the same exercise. Integrated EMG (iEMG) revealed that the upper extremity muscles were more active in Nordic walking than in regular walking, where lower extremity muscles were relatively more inactive. In addition, when EMG measurements were performed at each measurement point during walking exercise, the pattern was different. Nevertheless, the result was the same as in iEMG. The load that occurs in each exercise was measured using the ground reaction force system. As a result, Nordic walking had a lower load than regular walking. Therefore, it was found that Nordic walking minimized the load on the lower extremities owing to the effect of whole-body exercise and was a safer and more efficient exercise method.

• The Journal of Korean Physical Therapy
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• v.25 no.1
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• pp.16-22
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• 2013

Purpose: This study evaluated the validity of measuring paravertebral muscle function with 3D-NEWTON (Hanmed, Korea) by assessing the correlation between Biodex (Biodex, USA) and surface electromyography (EMG). Methods: Nineteen healthy adults participated. The function of their paravertebral muscle was measured in three ways. Maximum endurance time was measured in seconds when 3D-NEWTON was inclined forward for assessing extensor function, and inclined backward for assessing flexor function. Using surface EMG, maximum muscle activity was obtained from the eractor spinae and rectus abdominis during the 3D-NEWTON measurement. Maximum muscle activity was the mean activity from 10 seconds when the root mean squared firing data was highest. Through Biodex the peak torques of the extensor and flexor were measured during isometric exercises. The Spearman correlation coefficiencts from 3D-NEWTON, surface EMG, and Biodex were calculated. Results: The data from surface EMG and Biodex were statistically correlated when measured for flexor function, but less so for extensor function. In the case of 3D-NEWTON, the correlation coefficient with Biodex was 0.50 (p=0.05), while the coefficient with surface EMG was 0.53 (p=0.02) when measured for extensor function. Similarly, the correlation coefficienct with Biodex was 0.60 (p=0.01), while the surface EMG was 0.51 (p=0.03) for flexor function. Conclusion: 3D-NEWTON was a useful method for measuring paravertebral muscle function and can give helpful information for treating people with diseases associated with the lumbar spine.

• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.157-165
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• 2007

The Work-Related Musculoskeletal Disorders (WMSDs) can be occurred by various factors such as repetition, forceful exertions and awkward postures. Especially, occurrences of the WMSDs on the waist and lower limb are reported in workplaces, demanded standing postures for a long time, in service and manufacturing industry. The static and standing postures without movement for a long time increase work loads to the lower limb and the waist. Accordingly, anti-fatigue mat or anti-fatigue insole is used as a preventing device of the WMSDs. However anti-fatigue mats are limited in space and movement. In this study, multi-elastic insoles are designed and shown the effects of the workload reduction for a long time under the standing work. The foot pressures and EMG (Electromyography) are measured at 0 hour and after 2 hours by 6 health students in their twenties. The 6 prototype insoles are designed with three elastic (Low, Medium and High). These insoles are compared with no insole (insole type 7) as control group. The EMG measurement was conducted to waist (erector spinae muscle), thigh (vastus lateralis muscle) and calf (gastrocnemius muscle). The foot pressure is analyzed by mean pressure value and the EMG analysis is investigated through MF (Median Frequency), MPF (Mean Power Frequency) and ZCR (Zero Crossing Rate). The results of the foot pressure show that the multi-elastic insoles had smaller foot pressure value than that of no-insole. Moreover, Insole 2 and Insole 3 have the smallest increasing rate in foot pressure. The EMG results show that the multi-elastic insoles had smaller EMG shift value than that of no-insole in 2 hour, and then shift value shows the smallest value in Insole 2. Therefore, this study presents that the multi-elastic insoles have reducing effects of the work load for a long time standing work in both side of foot pressure and EMG.

• Journal of Biomedical Engineering Research
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• v.40 no.6
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• pp.223-229
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• 2019

The number of knee-related disease patients and knee joint surgeries is steadily increasing every year, and for knee rehabilitation training for these knee joint patients, it is necessary to strengthen the muscle of vastus medialis and quadriceps femoris. However, because of the cost and time-consuming difficulties of receiving regular hospital treatment in the course of knee rehabilitation, we developed knee exoskeleton using rapid prototype for knee rehabilitation with feedback from the electromyogram (EMG) and inertia motion unit (IMU) sensor. The modules was built on the basis of EMG and an IMU sensor applied complementary filter, measuring muscle activity in the vastus medialis and the range of joint operation of the knee, and then performing the game based on this measurement. The IMU sensor performed up to 97.2% accuracy in experiments with ten subjects. The functional game contents consisted of an exergaming platform based on EMG and IMU for the real-time monitoring and performance assessment of personalized isometric and isotonic exercises. This study combined EMG and IMU-based functional game with knee rehabilitation training to enable voluntary rehabilitation training by providing immediate feedback to patients through biometric information, thereby enhancing muscle strength efficiency of rehabilitation.

• Fashion & Textile Research Journal
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• v.25 no.2
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• pp.210-220
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• 2023

Recently, smart wearable products, including electromyography (EMG) measurement devices and clothing, have been developed to monitor users' exercise levels, muscle activation, and muscle balance more effectively during fitness activities. However, technical and socioeconomic barriers, such as flexibility and durability, still pose challenges in terms of comfort, ease of wear, and wearability of smart clothing, which includes devices and circuits. To address these issues, this study developed a wearable EMG device integrated with clothing to collect valid EMG signals from desired muscles while maintaining comfort, functionality, and ease of wear. After deriving a combined structure that could stably position the wearable device within the clothing, a prototype was manufactured and evaluated for fit, compression, comfort, and exercise comfort test by ten participants (height = 176.2 cm, weight = 76.4 kg, chest circumference = 101.2 cm). The study found that the prototype had smaller circumferences around the chest, waist, and abdomen compared to commercial products, resulting in lower ratings for wearing comfort and ease of wear. However, the prototype received high ratings for fitting, pressure, and the exercise comfort test. Valid signals were obtained when the EMG device was combined to the prototype for the rectus femoris muscle, indicating stable positioning of the device during exercise.

• Physical Therapy Rehabilitation Science
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• v.13 no.2
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• pp.152-162
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• 2024

Objective: This study was conducted to analyze the effect of wearable Electromyography-controlled functional electrical stimulation (EMG-controlled FES) System on Gait Function and cardiopulmonary metabolic efficiency during walking in older adults. Design: Cross-section study Methods: Total 22 older adult participants suitable to selection criteria of this study participated in this study. The EMG-controlled FES System, which functions as a wearable physical activity assist FES system was used. All participations performed randomly assigned two conditions (Non-FES assist [NFA], FES assist [FA]) of walking. In all conditions, spatio-temporal parameters and kinematics and kinetics parameters during walking was collected via 3D motion capture system and 6 minutes walking test (6MWT) and metabolic cost during walking and stairs climbing was collected via a portable metabolic device (COSMED K5, COSMED Srl, Roma, Italy). Results: In Spatio-temporal parameters aspects, The EMG-controlled FES system significantly improved gait functions measurements of older adults with sarcopenia at walking in comparison to the NFA condition (P<0.05). Hip, knee and ankle joint range of motion increased at walking in FA condition compared to the NFA condition (P<0.05). In the FA condition, moment and ground reaction force was changed like normal gait during walking of older adults in comparison to the NFA condition (P<0.05). The EMG-controlled FES system significantly reduced net cardiopulmonary metabolic energy cost, net energy expenditure measurement at stairs climbing (P<0.05). Conclusions: This study demonstrated that EMG-controlled FES is a potentially useful gait-assist system for improving gait function by making joint range of motion and moment properly.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.31-41
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• 2006

The primary purpose of a TKA is to restore normal knee function Therefore, ideally, a TKA should: (a) maintain the natural leverage of the knee joint muscles to ensure generating adequate knee muscle moments to accomplish daily tasks such as rising from climbing stairs; (b) provide adequate knee joint stability. A 16-channel MyoResearch XP EMG system was used to collect the differential input surface electromyography signals VM, VL, RF, BF, ST during climbing/descending stair tests. A Peak Motion Measurement System was used to collect the kinematic and kinetic data. AKIN-COM Ill isokinetic dynamometer was used for EMG of VM, VL, RF, BF and ST during maximal voluntary contraction. I Quadriceps EMG results for the VM of the passed 1year group limb demonstrated significant less RMS EMG than that of the passed 3year group limb $60^{\circ}-15^{\circ}$ of knee flexion(p<0.05). The VL of the passed 1year group limb also demonstrated significants less RMS EMG than that of the passed 3year group limb from $60^{\circ}-45^{\circ}$ of knee flexion(p<0.05). Similar to the VM and VL, the RF of the passed 1year group limb showed less RMS EMG than that of the passed 3year group limb from $60^{\circ}-30^{\circ}$ do knee flexion(p<0.05). Hamstring EMG results for the BF of the passed 1year group limb demonstrated less RMS EMG than that of the passed 3year group limb from $75^{\circ}-15^{\circ}$ of knee flexion(p<0.05). The passed 1year group limb tended to have less ADD displacement(p<0.071) than that of the passed 3year group limb. There was no significant difference of the ABD displacement between the passed 1year group and the passed 3year group limbs(p<0.73). The passed 3year group used compensatory adaptation movement strategies to compensate for the strength deficit of passed 3year group limbs. The passed 3year group limb also increased the quadriceps muscle activation level to produce more knee extension moment to compensate for the short quadriceps moment arm. The passe 3year group limb might have an unstable knee joint in the medio-Iateral direction during the climbing/descending by showing a tendency of more ADD displacement and greater hamming co-activation EMG than the passed 1year group limbs. The TKA design was not able to help the knee joint to produce adequate knee extension moment with less quadriceps muscle effort. I think that old man needs continuous exercise for muscle strength.

• 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.

• 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.