• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.10 no.1
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• pp.24-29
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• 1999

Extrinsic laryngeal muscles are well known to be important for the classical singers. We tried to elucidate any differences in the function of above muscles between trained and untrained singers by non-invasive surface electromyography(EMG). Four trained sopranos and four untrained singers sang vowel /i/ at different pitch(E3, G3, C4, E4, G4, C5, E5, G5, C6). The EMG activities of the suprahyoid, infrahyoid and omohyoid muscles were measured using surface electrodes. In trained singers, infrahyoid muscle activities increased more than those of suprahyoid in most of pitch. To the contrary, in untrained singers, the pattern of EMG activities were variable among each subjects and the EMG activities of suprahyoid muscles were relatively greater than those of infrahyoid.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.2
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• pp.103-110
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• 2004

This paper proposes a new method on the EMG AR(autoregressive) modeling in pattern recognition for various head motions. The proper electrode placement in applying AR or cepstral coefficients for EMG signature discrimination is investigated. EMG signals are measured for different 10 motions with two electrode arrangements simultaneously. Electrode pairs are located separately on dominant muscles(S-type arrangement), because the bandwidth of signals obtained from S-type placement is wider than that from C-type(closely in the region between muscles). From the result of EMG pattern recognition test, the proposed mIAR(modified integrated mean autoregressive model) technique improves the recognitions rate around 17-21％ compared with other the AR and cepstral methods.

• Physical Therapy Korea
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• v.20 no.1
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• pp.55-63
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• 2013

This study investigated the effects of axillary crutch length on trunk muscle activity and lumbo-pelvic-hip complex movements during crutch gait. Eleven healthy men participated in this study. The participants performed a three-point gait with optimal, shorter, and longer crutch lengths. Weight-bearing (WB) side was determined as the dominant leg side. The electromyography (EMG) activity of the bilateral rectus abdominis (RA) and erector spinae (ES) muscles and lumbo-pelvic-hip complex movements were monitored using a three-dimensional motion system with wireless surface EMG. Differences in the EMG activity of RA and ES muscles and range of motion (ROM) of lumbar spine, pelvis, and hip among conditions were analyzed using one-way repeated-measures analysis of variance, and a Bonferroni correction was conducted. There was less RA muscle activity on the WB side under the optimal crutch length condition compared with shorter and longer crutch length conditions (p<.05). The EMG activity of the RA muscle on the non-WB side and ES muscle on the WB side were significantly decreased under the optimal crutch length condition compared with shorter crutch length condition (p<.05). No significant differences in the EMG activity of the ES muscle on the non-WB side and ROM of lumbo-pelvic-hip complex were found among conditions (p>.05). These findings indicate that the optimal crutch length improves the trunk muscle efficiency during crutch gait.

• Physical Therapy Korea
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• v.13 no.3
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• pp.102-110
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• 2006

To improve trunk stability, various exercise protocols were introduced into the clinical field. Trunk and lumbar stability exercises on unstable surfaces are especially recommended to improve lumbar stability. The purpose of this study was to compare abdominal oblique muscle activity during leg raising in hook-lying position among 3 different type of surface conditions (on floor (F), vestibular board (VB), and foam roll (FR)). Sixteen able-bodied volunteers, who had no medical history of lower extremity or lumbar spine disease, were recruited for this study. Surface electromyography (EMG) activity was recorded from the internal and external oblique muscles of both sides. The normalized EMG activity was compared using a one-way repeated ANOVA. The results showed that the EMG activities of the internal oblique and external oblique of the lifted leg side during straight leg raising significantly increased under the FR condition when compared to the F condition. There was no significant difference of the EMG activity in abdominal oblique muscles between the VB and the FR conditions. The EMG activity of the internal oblique of supported leg side during the straight leg raising was significantly greater under the FR condition than the VB and F conditions (p<.05). The composition ratio of EMG activity of internal oblique muscles during straight leg raising was significantly increased under the FR condition. Therefore, straight leg raising exercise on foam roll in hook lying position could be beneficial to improve trunk and lumbar stability.

• Journal of Korean Physical Therapy Science
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• v.10 no.2
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• pp.96-103
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• 2003

The purpose of this study was to assess the effect of applied pressure to abdomen on lumbar and abdominal muscle activation during upper limb exercise. The experimental group consisted of twenty-seven healthy male subjects (mean age=$22.40{\pm}2.19years$, mean height=$175.30{\pm}2.19cm$, mean weight= $67.67{\pm}7.44kg$, RM=$8.43{\pm}2.76kg$). In each different pressure condition (OmmHg, 30mmHg, 70mmHg, 100mmHg), upper limb exercise was performed in total of 10 trials with 10 RM dumb-bell exercise. Lumbar and abdominal muscle activity was measured using surface bipolar electrode electromyography(EMG). EMG activity was measured from upper rectus abdominis, external oblique abdominis, internal oblique abdominis, and elector spinae. The raw EMG signal was processed into the root mean square(RMS). All RMS EMG data were normalized and express as a percentage of the EMG(%EMG). Collected data were statistically analyzed by SPSS/PC Ver 10.0 using two-way analysis of variance for repeated measures($4{\pm}3$) and Bonferroni post hoc, test. Lumbar and abdominal muscle activation was significantly increased when 100 mmHg was applied(p<.05). Upper rectus abdominis activation was significantly increased compared as other muscles activation(p<.05). However, there were no interaction between pressure and muscles(p>.05). The findings of this study can be used as a fundamental data when lumbar orthosis is applied and external pressure can be used as a therapeutic tool.

• 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.

• Physical Therapy Rehabilitation Science
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• v.4 no.1
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• pp.22-27
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• 2015

Objective: Jump training helps increase the muscle power by improving the muscle strength and reaction time of the muscle in operation. The purpose of this study was to identify the effects of strengthening, stretching exercise and meditation on electromyographic (EMG) onset timing of rectus femoris and gastrocnemius muscle during vertical jump performance. Design: Cross-sectional study. Methods: Ten healthy adults (5 male and 5 female) who were familiar with the vertical jumping task and had no lower extremity injuries or any bone or joint disorders, were recruited for this study. Muscle onset timing was measured by surface EMG. After EMG onset timing were measured during performing three baseline vertical jump trials, strengthening and stretching exercises of the rectus femoris and gastrocnemius, and meditation were performed in random order. EMG onset timing was measured during vertical jump after intervention, respectively. EMG value was averaged for the three trials and analyzed using one-way repeated ANOVA. Results: During vertical jump, EMG onset timing of gastrocnemius was a significant difference after intervention (p<0.05), and then there was significantly faster in strengthening exercise than meditation (p<0.05). Conclusions: These results indicate the potential positive effect of performing strengthening exercise of the gastrocnemius before a jumping event. Future research is required to identify the effects of intervention over a long period.

• Physical Therapy Korea
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• v.18 no.1
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• pp.37-46
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• 2011

The purpose of this study was to investigate intra-rater reliability and determine the validity of electromyography (EMG) measurements to represent muscle activity and ultrasonography (US) to represent muscle thickness during manual muscle testing (MMT) to external abdominal oblique (EO) and lumbar multifidus (MF). Twenty healthy subjects were recruited for this study and asked to perform MMT at differing levels. The subjects' muscle activity using EMG was measured by a ratio to maximum voluntary contraction (MVC) and root mean square (RMS) methods. The subjects' muscle thickness using US was measured by raw muscle thickness and change ratio of thickness to maximum (MVC) or resting condition. In three trials, measurements were performed on each subject by one examiner. The intra-rater reliability of measurements of EMG and US to EO and MF was calculated using intra-class coefficients. The intra-rater reliability of all measurements was excellent (ICC=.75~.98) in EMG and US. The conduct validity was calculated by one-way ANOVA with repeated measurements to compare whether the EMG and US measurements were different between MMT at different levels. There was only a significant difference between all grades at %MVC thickness measurement of US. These results suggest that a %MVC thickness measurement of US was a more sensitive and discriminate in all manual muscle testing grades. This information will be useful for the selection of US measurement and analysis methods in clinics.

• Journal of the Korea Society of Computer and Information
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• v.29 no.5
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• pp.111-121
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• 2024

With strength training comes the risk of injury and the benefits of exercise. Lack of knowledge and experience or repetitions at excessive intensity can lead to injury. Adequate feedback on an exercise's progress can increase the exercise's effectiveness and reduce injuries by providing scientific data and psychological motivation. This study aimed to validate EMG equipment and examine the effects of 8 weeks of biofeedback training with wireless electromyography. A correlation analysis between the Noraxon device and Fitsig^®(EMG Prototype), a well-known instrument in the field of research, showed a moderate correlation. Statistically significant differences in humeral circumference, humeral muscle mass, and biceps and triceps strength were found between the left and right sides of the body over time, with no differences in the type of exercise. Feedback training with real-time EMG was found to be favorable for hypertrophic growth and strength improvement. Future studies should be conducted to investigate its application in sports activities further.

• The Journal of Korea Robotics Society
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• v.12 no.2
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• pp.206-216
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• 2017

This paper proposes a method to simultaneously estimate two degrees of freedom in wrist forces (extension - flexion, adduction - abduction) and one degree of freedom in grasping forces using Electromyography (EMG) signals of the forearms. To correlate the EMG signals with the forces, we applied a multi - layer perceptron(MLP), which is a machine learning method, and used the characteristics of the muscles constituting the forearm to generate learning data. Through the experiments, the similarity between the MLP target value and the estimated value was investigated by applying the coefficient of determination ($R^2$) and root mean square error (RMSE) to evaluate the performance of the proposed method. As a result, the $R^2$ values with respect to the wrist flexion-extension, adduction - abduction and grasping forces were 0.79, 0.73 and 0.78 and RMSE were 0.12, 0.17, 0.13 respectively.