• Journal of the Korean Academy of Clinical Electrophysiology
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• v.3 no.1
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• pp.31-47
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• 2005

Fatigue is a common experience in our daily life and in therapeutic exercises. Human muscle fatigue has been studied using a wide variety of exercise models, protocols and assessment methods. This study conducts quantitative evaluation of fatigue of knee extensor with surface electromyography and dynamometer and is to provide basic materials in physical therapy diagnosis and assessment of skeletal muscle. Measurement of two stages was conducted with 88 normal adults between their twenties and seventies, correlations and differences using collected data according to age was compared and correlations among measured items were analyzed and then the following conclusions were obtained. Analysis of sEMG and dynamometry of knee extensor showed that MDF, FI, MVIC, ET had the closest relations with age and MDF, FI, MVIC were significantly increase with aging. In addition, it was found that there were high correlation among items of analysis.

• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.197-205
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• 2007

The purpose of this study is to analyze the muscle activations and Ground Reaction Force(GRF) in university judo players, and provide the guide of training in Judo. Using surface electrode electromyography(EMG), we evaluated muscle activity in 5 university judo players during the Judo Uke Movements. Surface electrodes were used to record the level of muscle activity in the Tibialis Anterior, Rectus Femoris, Elector Spinae, Gluteus Maximus, Gastrocnemius muscles during the Uke. These signals were compared with %RVC(Reference voluntary contraction) which was normalized by IEMG(Integrated EMG). The Uke was divided into four phases : Kuzushi-1, Kuzushi-2, Tsukuri, Kake. The results can be summarized as follows: 1. The effective Uke Movements needs to short time in the Kake Phase 2. The Analysis of Electromyography of Uke Movements in Supporting Leg; TA(Tibialis anterior) had Higher %RVC in the Kuzushi Phase, RF(Rectus Femoris) had Higher %RVC in the Tsukuri Phase, GM(Gluteus Maximus) had Higher %RVC in the Kake Phase 3. The ground reaction force for Z(vertical) direction was showed increase tendency in Kuzushi phase, Tsukuri phase and decrease tendency in Kake phase.

• The Journal of Korean Physical Therapy
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• v.15 no.2
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• pp.196-209
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• 2003

본 연구의 목적은 보통 보행과 장애물 보행 시작시에 accuracy constraints, 즉 발꿈치 닿기(swing limb heel-strike)의 정확도가 힘판(forceplate) 상에서 힘의 조절 (force modulation)과 EMG에 어떠한 영향을 미치는지를 분석하는 것이다. 본 실험의 대상자는 힘판(forceplate)위에서 보통 보행과 장애물 보행을 하되, 대상자 앞에 놓인 표적(target)에 정확히 발꿈치 닫기 (heel-strike)를 하도록 유도되었다. 이 때 힘판 자료와 전경골근(tibialis anterior)및 가자미근 (soleus)의 근전도 (EMG)의 활동을 양쪽 다리에서 측정하였다. 대상자 앞에 놓인 표적 (target)에 정확한 발꿈치 닫기(heel-strike)가 요구되었을 때에는 발끝밀기(swing toe-off) 시간이 증가되었으며 힘판(forceplate)상에서의 peak farce와 slope to peak force 가 감소되는 것으로 나타났다. 전경골근 (tibialis anterior)의 활동역시 큰 차이로 감소하는 것으로 나타났다. 하지만 보통 보행과 장애물 보행시의 근전도 혹은 힘판상의 자료에는 큰 차이점이 없는 것으로 나타났다. 이러한 결과는 기존의 상지(upper extremity)에서 보여준 운동제어 (motor control)의 이론들이 하지(lower extremity)에서도 동일하게 적용될 수 있음을 보여주는 것이다.

• Korean Journal of Applied Biomechanics
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• v.15 no.2
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• pp.139-146
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• 2005

We selected six kinds of stretching exercises that can be easily acquired and put to practical use by back pain patients and arranged the practicing order of the exercising method after measuring the % MlVC of the muscle power when a normal person was exercising with a surface EMG. Among the patients complaining of back pain, 20 case groups were given the selected exercise and physical therapy, and 20 control groups were only given a physical therapy. Before and 2 weeks, 4weeks, 6 weeks and 8 weeks after the exercise therapy, a muscle power was measured with a fitness machine and the effectiveness of the exercise was compared. After six weeks difference of the muscle power between the case group and control group was shown, and after 8weeks the case group manifested the stronger muscle power than that of the control group in both male and female. Exercising therapy clearly seems to be helpful in strengthening the muscle power of the back pain patients.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.5 no.1
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• pp.20-25
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• 2012

Gender differences have been studied by using spectral features such as median frequency (MDF) respectively. MDF is the most commonly used as a feature to describe muscle conduction velocity. The aim of this paper is to detect gender differences from surface EMG signals during isotonic contractions of the bicep Brachii. Eight volunteers participated in surface EMG recordings placed on the biceps brachii and each recording experiment continued until their exhaustion. We used feature values and regressive slopes and compared the feature changes from the onset to the endurance time to find gender differences. The result of experiments shows that the regressive slope of these features is valid to measure gender differences.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.398-401
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• 1997

The EMG signal of spinal cord injured patient is very feeble because that the information from central nervous system is not sufficiently transmitted to molter neuron or muscle fiber. Therefore the observer can not observe contraction and relaxation movement of muscle from the raw EMG signal. In this paper, we propose the muscle contraction and relaxation pattern analysis method of spinal cord injured patient whose EMG signal is composed of the sum of motor unit action potential train with additive white Gaussian noise and impulsive noise. From the EMG model, we denoise impulsive noise using median filter which is a kind of nonlinear filter and the output of median filter is transformed to wavelet transform domain for denoising additive white Gaussian noise using threshold level removal technique. As a result, we can obtain the clear contraction and relaxation pattern.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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• pp.30-36
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• 2012

This study is aimed to show that an asymmetric load in the frontal plane leads to an increase in low back loading and fatigue in comparison with a symmetric load when workers lift an external weight by investigating previous studies and verifying the phenomenon with an experiment. Ten male subjects are required to lift and hold an given external load at 70cm height during 50sec, then the EMG amplitude and median frequency on bilateral low back muscle groups (Longissimus, Iliocostalis, and Multifidus) are recorded and analyzed. Independent variables are two-level load weight (13kg, 20kg) and three-level LCG (Center, 6.5cm to the right, and 13cm to the right), and dependent variables are EMG amplitude average, difference, and Fatigue Index (FI). Results show that load weight increases significantly amplitude average and FI, but LCG does significantly amplitude difference and FI significantly (P-value < 0.05). Also the correlation coefficient between amplitude difference and FI is over 0.99. These implies that trunk loading should be explained by not EMG amplitude but muscle fatigue aspect since the association between an external load and amplitude is linear, but the relationship between an external load and median frequency as muscle fatigue index is almost exponential.

• Journal of Korean Physical Therapy Science
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• v.19 no.4
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• pp.1-6
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• 2012

Purpose : The current research examines the muscle activity that happens during scaling practice subject to 20 dental hygienic students with musculoskeletal pain and then propose a basic data according to the working attitude of the Dental Hygienist. Method : The Nordic-style questionnaire is used to define experimental group with musculoskeletal pain and control group. During the scaling the surface EMG device is used to measure the muscle activity of experimental and control group. Study design : The surface EMG is measure RMS(root mean square) of suboccipital muscle, biceps brachii, upper trapezius, and brachioradialis muscle activity. Results : In the experimental group, the RMS of upper trapezius and brachioradialis is increased during scaling practice(p<0.05), but the control group's RMS is not changed(p>0.05). Conclusion : Musculoskeletal pain may contribute to increase muscle activity of neck & arm during scaling practice. In the future we think there is a need to raise the office efficiency by subjecting to dental hyginiest that are in the clinics and performing experiments.

• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.37-44
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• 2006

The purposes of this study were to analyze and compare EMG activities of the pectoralis major, biceps brachii, triceps brachii, and brachioradialis muscles during biceps curls using a VRT device and an elastic tubing. Fifteen male college students were recruited as subjects and they performed 10-RM and 20-RM biceps curls. For each load and device condition, the mean and peak normalized EMG levels during different phases of a biceps curl were computed. For each load and phase, paired t-test (p.05) was used to find the significant difference between two devices. ANOVA with repeated measures was also used to find the significant difference among phases in terms of EMG values for each muscle. For each load and device condition, the peak and mean EMG levels during different phases of a biceps curl were computed The significant differences between devices were found in biceps brachii for EA, MD, LD phases, and triceps brachii muscles for all phases, respectively. However, no differences were found among phases for any muscle. This indicated that elastic band could have a similar characteristics of VRT. High antagonistic muscle activity as a function of injury prevention which found particularly in VRT device may suggest that elastic tubing can be a safer training device than VRT. This also imply that elastic tubing could be very effective as a home exercise tool for rehabilitation patients and elderly people.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.5 no.3
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• pp.152-157
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• 2012

In this paper, we develop a muscle exercise prescription system and present a prescription method by analyzing bioelectric signal of human muscles. This system is designed to give right exercise prescriptions include strength, duration, frequency of exercise after diagnosing personal body condition using EMG(Electromyography). With the help of these prescriptions all users can keep there optimum exercise status and avoid excess exercise symptom and, we van utilize in all the measurements like abnormal posture, muscle power, muscle regidity, muscle fatigue, muscle balance. Also easily accessable system can offer variable utilizations such as in health care center, sports center, social welfare center, social medical center, school, and kinder garden.