• 한국전문물리치료학회지
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• 제10권1호
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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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• 제18권5호
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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.

• 센서학회지
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• 제12권2호
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• pp.88-94
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• 2003

근전도는 근육의 수축을 관장하는 신경다발의 전기적 흥분에 의해 생기는 생체전기신호이다. 따라서 근육운동에 따라 발생하는 근전도 신호를 측정, 분석하면 운동기능의 정상여부를 판단할 수 있을 뿐 아니라 사용자의 동작에 의해 컴퓨터나 전자장치를 작동시키는 인간-기계 인터페이스(man-machine interface)용 입력신호로도 사용할 수 있다. 본 연구에서는 사용자의 일상생활에서의 자연스러운 동작과 관련된 근전도 신호를 측정할 수 있는 소형의 무선 생체신호 측정시스템을 개발하였다. 기존의 근전도 측정 시스템에서 전극과 증폭기 사이에 존재하는 전선은 동적잡음의 원인이 되고 사용자의 동작을 방해할 수 있으므로 소형의 증폭회로를 전극 바로 위에 일체형으로 제작하였고 증폭기와 컴퓨터 사이에 무선 데이터 전송을 사용하여 사용자의 일상적인 원활한 동작을 가능케 하였다. 개발된 측정 시스템의 크기는 $60{\times}40{\times}25mm$이고 무게는 100g이다. 개발된 시스템에 대한 성능 평가결과 컴퓨터를 위한 새로운 인터페이스 장치, 운동선수의 훈련결과 분석, 환자의 재활훈련 성과 측정 그리고 가상현실 입력장비 등의 용도로 사용될 수 있음을 확인하였다.

• 한국의류산업학회지
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• 제25권2호
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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.

• Journal of Oral Medicine and Pain
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• 제24권4호
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• pp.421-437
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• 1999

This study was performed to investigate the electromyographic(EMG) activity, firing time and sequence of the mandibular elevator muscle on gum chewing. For this study, 28 patients with temporomandibular disorders(TMD), especially internal derangement of TM joint, and 16 dental students without any signs and symptoms in the masticatory system were selected as the patients group and as the normal group, respectively. The patients group was composed of 14 right and 14 left side affected patients. For recording of EMG activity(${\mu}V$) of the anterior temporalis(TA) and the masseter muscle(MM), and measuring of firing time(millisecond) from the start of mandibular opening movement to the firing of the muscles, BioEMG, BioEGN, and Combo program integrated in the Biopak system(Bioresearch Inc., Milwaukee, USA) were used. Gum chewing stroke was performed in both right and left side for several times, and the first and the second chewing strokes were analysed and compared with regard to EMG activity, firing time, firing sequence, correlation between EMG activity and firing time. The data obtained were analysed by SPSS windows program and the results of this study were as follows : 1. In the patients group, chewing on the affected side showed higher EMG activities in the masseter of the side than those of the contralateral side, but chewing on the unaffected side showed higher EMG activity in the masseter and in the anterior temporalis of the side than those of the contralateral side. 2. There were no difference of firing time between both sides on chewing on the affected side, but firing time in the chewing side were earlier than that of contralateral side on chewing on the unaffected side in patients group. 3. In the normal group, EMG activities in the masseter and in the anterior temporalis in the chewing side were always higher than those of the contralateral side, and there were no difference of firing time between the two sides. 4. In general, firing sequence of four muscles of both sides were ipsilateral TA, ipsilateral MM, contralateral TA, and contralateral MM in earlier order of time in both groups. Correlation coefficients between EMG activity and firing time were negative value, and more significant correlation were appeared in the normal group than in the patients group.

• 대한의용생체공학회:의공학회지
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• 제35권6호
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• pp.227-233
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• 2014

In this paper, to quantitatively evaluate the degree of rehabilitation for the disabled of unilateral lower extremity, we compared the EMG pattern of normal and simulated abnormal gait. The EMG signal was measured at a rate of 1 kHz on the quadriceps and biceps femoris, the pressure sensor was attached to the sole in order to distinguish the gait cycle. Integrated EMG (IEMG) was obtained by the gait cycle, and classified four patterns that were the normal gait pattern, amplitude decrease pattern, reversed pattern, and irregular pattern. For comparison of the patterns, a curve fitting was performed using the trigonometric functions. The result of curve fitting, the method using a variable A that corresponds to the amplitude of the regression curve was able to distinguish the reverse pattern and remaining pattern. The coefficient of determination ($R^2$) representing coincidence of the pattern of the regression curve and EMG was confirmed the biggest value at the normal gait. Therefore, the degree of normal gait can be confirmed using the coefficient of determination. This results show that it is possible to quantitatively confirm the degree of unilateral lower extremity disabled rehabilitation, and it will be contributed to the study of efficient rehabilitation methods by objective analysis.

• Journal of Oral Medicine and Pain
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• 제21권2호
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• pp.293-304
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• 1996

The purpose of this study was to investigate the peak electromyographic activity(EMG) and time intervals in firing sequence of Anterior temporalis(TA) and Masseter(MM) on clenching, the number of tender points in the head and neck muscles, the occlusal contact state on clenching, and their relationship. 78 patients with Temporomandibular Disorders(TMDs) participated and were classified into articular or muscular group by clinical signs and symptoms. BioEMG$\textregistered$ of integrated masticatory function analyzer, Biopak$\textregistered$ system(Bioresearch Inc., USA), was used to measure EMG and related items, and T- Scan$\textregistered$(Tekscan, USA), computerized occlusal analyser, was used to record occlusal contact state on maximum voluntary clenching. EMG and occlusal contact were synchronously recorded and analysed with SAS Statistical program. The results of this study were as follows : 1. In total subjects, EMG of TA was lower than that of MM in articular group but in muscular group, vice versa, As a result, the ratio TA to MM was significantly different between the two groups. no significant differece. 3. The number and force of occlusal contact were more in articular group, but there was no significant difference in Total Left-Right statistics(TLR) between the two groups. 4. In unilaterally affected subjects for muscle function, no significant difference was observed between the affected side and the contralateral side in articular group, but in muscular group, the item of the number of tender points showed significant difference. However, for occlusal contact items, contact force in articular group shows significant difference between the two sides. 5. Rate of coincidence of the first firing side of TA with affected side or preferred chewing side was higher and not different between the two groups, but no significant correlation was showed between the first firing side and the first occlusal contact side.

• 한국지능시스템학회논문지
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• 제22권5호
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• pp.533-539
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• 2012

본 연구는 사람 팔의 움직임에 따른 신체 발생 신호인 근육의 근전도 데이터를 실시간으로 추출하여 신호 발생에 따른 외골격 로봇 팔의 동작을 통해 제어신호의 유효성을 평가하는데 그 목적이 있다. 지능형 알고리즘에 의해 인간의 인지와 판단의 결과가 팔의 근육을 통해서 제어 가능한 지를 실제 시스템을 구성하여 확인해 보는 것이다. 근육의 수축과 이완에 따른 근전도 센서 데이터는 외골격 로봇 팔을 구동하는 원신호로 사용되며 로봇 구동을 위한 힘을 전달하는 엑츄에이터가 인간의 팔의 동작을 모사한다. 이를 위해 아날로그 필터회로와 관련 회로를 설계하여 신호를 추출하였고 시스템의 동작을 위해 DSP컨트롤러를 통한 신호처리과정을 거친 후 지능 알고리즘을 통한 부하의 정확한 예측을 위한 퍼지 논리 알고리즘의 동작을 표현할 수 있는 외골격 로봇 팔을 제작하였다.

• 한국산업정보학회논문지
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• 제5권2호
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• pp.1-8
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• 2000

인력물자취급(MMH)작업은 작업현장에서 육체적 상해와 요통(LBP)을 발생시키는 주요 원인 중에 하나이며 이러한 산업재해는 점점 증가하고 있는 실정이다. 특히 좋지 않은 작업환경 즉, 비탈진 경사면에 위치한 농장이나 과수원, 항만부두의 하역작업, 경사진 벌목장 작업, 광산의 막장에서의 작업은 많은 재해의 위험성을 초래하며, 신체균형의 상실은 근골격계(musculoskeletal System)의 부상을 초래하게 된다. 본 연구는 경사면에서의 들기작업시 작업자의 근육의 force information과 근피로도를 측정하기 위해 EMG 시스템을 이용하였다. 측정결과 AEMG의 경우 모든 조건에서 일반적으로 multifidus 근육에 걸리는 부하가 다른 근육에서보다 많은 것으로 나타났고, 15$^{\circ}$, 20$^{\circ}$인 경우 neck extensors의 사용이 많은 것으로 나타났다. MPF천이 결과 공통적으로 multifidus부위 근육의 천이정도가 가장 많은 것으로 나타났다. 근육별 부하(%)에 대한 결과는 deep spinal 근육인 multifidus, erectorspinae부위가 상대적으로 많은 것으로 나타났고 neck extensor부위는 근육분담이 적은 것으로 나타났다.

• 한국운동역학회지
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• 제31권2호
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• pp.140-147
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• 2021

Objective: The purpose of this study is to identify the mechanism of changes in maximum voluntary torque with the magnitude and duration of pre-activation torque during voluntary isometric knee extension. Method: 11 male subjects (age: 25.91±2.43 yrs., height: 173.12±3.51 cm, weight: 76.45±7.74 kg) participated in this study. The subjects were required to produce maximal voluntary isometric torque with a particular pre-activation torque condition. The properties of pre-activation torque consisted of the combinations of 1) three levels of magnitude, e.g., 32 Nm, 64 Nm, 96 Nm, and 2) two levels of duration, e.g., 1 sec, and 3 sec; thus, a total of six conditions were given to the subjects. The force and EMG data were measured using the force transducers and wireless EMG sensor, respectively. Results: The results showed that the maximum voluntary torque increased the most with relatively large and fast (96 Nm, 1 sec) pre-activation condition. Similarly, with relatively large and fast (96 Nm, 1 sec) preactivation, it was found that the integrated EMG (iEMG) of the agonist muscles increased, while no significant changes in the co-contraction of the antagonist muscles for the knee extension. Also, the effect of pre-activation conditions on the rate of torque development was not statistically significant. Conclusion: The current findings suggest that relatively larger in magnitude and shorter in duration as the properties of pre-activation lead to a larger magnitude of maximal voluntary torque, possibly due to the increased activity of the agonist muscles during knee extension.