• Journal of the Korean Society of Physical Medicine
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• v.11 no.3
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• pp.97-104
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• 2016

PURPOSE: Bridge exercise is widely used in rehabilitation exercise for trunk stabilization through various applications in clinical practice. However, there is a lack of studies changing the base of support for the shoulders. The purpose of this study is to investigate the changes in the base of support for the shoulders of trunk muscle activation during bridge exercise. METHODS: 20 healthy subjects (10 men, 10 women) in their twenties were participated in this study. They performed 5 bridge exercises (bridge exercise with their shoulders on a stable table (1/2 knee height, knee height), and on a sling (1/2 knee height, knee height), conventional bridge exercise. The surface electromyography were used for rectus abdominis (RA), internal oblique (IO), external oblique (EO), and erector spinae (ES). RESULTS: During bridge exercise that their shoulders on the sling of 1/2 knee height, the RA, EO, IO muscle activities were significant increased. And during bridge exercise that their shoulders on the stable surface of knee height, the IO/RA ratio were higher than other positions but there were no significant difference between positions for EO/RA, IO/RA ratio. CONCLUSION: Based on this result, using various bases of support and changing the height of bridging exercise may be used to provide effective trunk stabilization exercises.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.4
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• pp.497-503
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• 2013

PURPOSE: The purpose of this study was to investigate the change of triceps surae activation during heel raise test in standing among knee flexion angles($0^{\circ}C$, $30^{\circ}C$, $45^{\circ}C$, $60^{\circ}C$). METHODS: Twenty healthy individuals performed unilateral plantarflexion in standing with $0^{\circ}C$, $30^{\circ}C$, $45^{\circ}C$, $60^{\circ}C$ knee flexion. Activity of medial gastrocnemius(MG), lateral gastrocnemius(LG), soleus(Sol) was recorded with surface electromyography(EMG). RESULT: The muscle activations induced the four different positions were compared and results showed that was significant difference MG and LG while the angle increase from $0^{\circ}C$ to $30^{\circ}C$, $45^{\circ}C$, $60^{\circ}C$ but Sol did not show significant differences in every angle. CONCLUSION: This study suggest that $30^{\circ}C$ knee flexion is required to induce a significant mechanical disadvantage of gastrocnemius.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.523-529
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• 2020

Foot drop is a common symptom in stroke patients due to central nervous system (CNS) damage, which causes walking disturbances. Functional electrical stimulation (FES) is an effective rehabilitation method for stroke patients with CNS damage. Aim of this study was to determine the effectiveness of 6 weeks FES walking training based lower limb muscle synergy of stroke patients. Lower limb muscle synergies were extracted from electromyography (EMG) using a non-negative matrix factorization algorithm (NMF) method. Cosine similarity and cross correlation were calculated for similarity comparison with healthy subjects. In both stroke patients, the similarity of leg muscle synergy during walking changed to similar to that of healthy subjects due to a decrease in foot drop during. FES walking intervention influenced the similarity of muscle synergies during walking of stroke patients. This intervention has an effective method on foot drop and improving the gait performance of stroke patients.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.841-847
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• 2007

최근 삶의 수준의 향상과 의학 기술의 발전으로 노인 인구가 증가하고 있다. 하지만 늘어나는 노인 인구에 비례하여 신체적 노화로 거동이 어려운 노인의 수 또한 증가하는 추세이다. 실제로 많은 노인 인구가 거동이 불편해 정상적인 생활을 하지 못하고 있기 때문에 보행 시 적절한 힘을 보조해 줄 수 있는 보행 보조 장치의 개발이 필요하다. 이 같은 보행 보조 장치를 개발함에 있어 보행자의 보행 패턴이 고려된다면 보행자의 걸음걸이에 맞춰 자연스럽게 힘을 보조해 줄 수 있기 때문에 보행자의 보행 단계 분류에 관한 연구가 선행되어야 한다. 그래서 본 논문에서는 하지 근전도 신호를 이용해 보행 단계를 구분하는 방법을 제안하고자 한다. 근전도 신호는 근육이 움직일 때 발생하는 아주 작은 전기적인 신호이다. 근전도 신호는 작은 잡음에도 민감하며, 전극을 부착하는 근육의 위치에 따라서도 값의 차이가 크기 때문에 근전도 신호의 획득 및 처리 방법이 중요하다. 위를 위해 피실험자 별 근육의 위치와 보행 속도를 달리하여 근전도 신호를 획득하고 획득한 신호로부터 여러 특징 값을 추출한다. 그리고 새로운 데이터에 대해 적응성이 강하고 시간에 따라 변하는 근전도 신호의 특성을 잘 반영할 수 있으며 각 집합(class)의 비선형 분리가 가능한 퍼지 최대-최소 신경망(Fuzzy Min-Max Neural Network: FMMNN)을 이용해 보행 단계를 분류해 본다. 실험 결과를 통해 제안한 방법의 타당성을 검증해 보고 보행자, 보행속도, 근전도 측정을 위한 근육의 위치가 보행 패턴 분류에 미치는 영향을 알아본다.

• The Journal of Korean Physical Therapy
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• v.30 no.1
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• pp.23-28
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• 2018

Purpose: This study examined the effectiveness of iliopsoas self-stretching on the hip extension angle, gluteus maximus (GM) activity, and pelvic compensated angle during prone hip extension (PHE) in subjects with iliopsoas shortness. Methods: Twenty-healthy subjects with iliopsoas shortness were recruited. Electromyography (EMG) was used to examine erector spinae (ES), multifidus (MF), GM, and biceps femoris (BF) while performing PHE. An electromagnetic tracking motion analysis device was used to measure the pelvic compensations. The pelvic compensations while performing PHE were considered to be anterior tilting and rotation. A modified Thomas test was used to monitor the hip extension angle before and after iliopsoas self-stretching. A paired t-test was used to investigate the significant difference after iliopsoas self-stretching during PHE. The level of statistical significance was set to ${\alpha}=0.05$. Results: Muscle activity of GM and hip extension angle were significantly greater after iliopsoas self-stretching compared to that before iliopsoas self-stretching during PHE (p<0.05). BF and pelvic rotation angle were significantly lower after iliopsoas self-stretching compared to that before iliopsoas self-stretching during PHE (p<0.05). The muscle activity of ES was not significantly different between PHE before and after iliopsoas self-stretching (p>0.05). Conclusion: Iliopsoas self-stretching can be effective in selectively strengthening the GM muscles with minimized pelvic compensation in subjects with iliopsoas shortness.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.1
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• pp.103-108
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• 2011

Purpose : The purposes of this study were to compare the muscle activity ratio of tibialis anterior (TA) / extensor digitorum longus (EDL) during the active ankle dorsiflexion in subjects with the normal toe (NT) and the hammer toe (HT). Methods : Nineteen subjects with the NT group and nineteen subjects with the HT group were recruited for this study. The muscle activities of TA and EDL were measured by using surface electromyography (EMG) and the angles of ankle dorsiflexion and eversion of the subtalar joint were measured by using 3-dementional motion analysis during the active ankle dorsiflexion in prone position. Results : The muscle activity ratio of TA / EDL was significantly lower in the HT group compared to the NT group (p<.05). The angle of ankle dorsiflexion was significantly lower in the HT group compared to the NT group (p<.05). Conclusions : These results suggest that muscle imbalance between TA and EDL muscle and decreased ankle dorsiflexion range of motion may contribute to hammer toe deformity. Further studies are needed to confirm that the correcting of this imbalance and the increasing ankle dorsiflexion could improve toe alignment in the subjects with HT.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.3
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• pp.333-338
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• 2014

PURPOSE: The purpose of this study was to investigate any changes in abdominal muscle activity after curl-up and jack-knife exercisse using a sling and swiss-ball. METHODS: Sixteen asymptomatic subjects were randomly assigned into either a sling exercise group (SG) or swiss-ball exercise group (SBG). Subjects performed curl-up and jack-knife exercise using sling and swiss ball. Activity of abdominal muscles (rectus abdominis and external oblique) was assessed using surface electromyography (EMG) and normalized maximal voluntary isometric contraction (MVIC) before and after exercises. The significance of differences between the SG and the SBG was evaluated by analysis of covariance (ANCOVA). RESULTS: There was an increase in activity of all abdominal muscles after the curl-up and jack-knife exercises for 6 weeks. However, there was not a significant difference between the SG and the SBG after curl-up exercise (p>.05). There was also not a significant difference between the SG and the SBG after Jack-knife exercise (p>.05) except for the right external oblique muscle (p<.05). CONCLUSION: Exercises on an unstable surface using a sling and swiss ball are effective ways of abdominal muscle exercise.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.301-309
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• 2015

Objective : The purpose of this study was to describe the correlation between the activity of the muscles of upper and lower limbs of a golf driver swing according to shoulder injury. Method : The subjects were 18 professional golfers (7 male in KPGA and 11 female in KLPGA). Using surface electromyography, we evaluated muscle activities during the golf drive swing. Surface electrodes were used to record the level of muscle activity in the left Deltoid(MD), Triceps Brachii(TB), Pectoralis(PM), Trapezius(UT), Rectus Femoris(RF), Vastus Medialis Obilique(VMO), Biceps Femoris(BF), Gastrocnemius(GCM) muscles during the golfer's swing. The golf swing was divided into five phases: take away, forward swing, acceleration, early follow through, late follow through. Results : The results can be summarized as follows: MD, VMO had statistically significant difference in take away phases, GCM had statistically significant difference in acceleration phases, MD, PM, VMO had statistically significant difference in early follow through phases, PM had statistically significant difference in late follow through phases, Conclusion : Muscle activity of the 8 muscles(Deltoid, Triceps Brachii, Pectoralis, Trapezius, Rectus Femoris, Vastus Medialis Obilique, Biceps Femoris, Gastrocnemius) along the shoulder damage or absence of has shown that they are organically connected to each of the phases.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1603-1608
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• 2008

Powered robotic exoskeletons are currently under development for assisting or supporting human muscle power. Many applications using this system for the purpose of national defense system, medical support, and construction industry are now frequently introduced. In this paper, we proposed the exoskeletal wearable robotics for construction workers. First, we analyzed general work conditions at the construction site and set up target tasks through the datum. Then dominant muscles’ activity which is related with the defined target tasks was checked up. Herein, wearers’ intent signal generation methodology was introduced in order to effectively activate the proposed system. In the final part of this paper, we evaluated the capability and feasibility of the exoskeletal robotics by the electromyography (EMG) signal variance; demonstrated that robotic exoskeletons controlled by muscle activity could be useful way of assisting with construction workers.

• The Journal of Korean Physical Therapy
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• v.31 no.6
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• pp.363-367
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• 2019

Purpose: This study was to investigate the effect of instability on the activation of lower limb muscles during lunge exercise. Methods: The study subjects were healthy twenties and were selected to have no orthopedic or neurological diseases. 1) Flat lunge exercise (Lunge 1, 2) Lunge exercise on TOGU (Lunge 2, 3) Holding the olympic bar and moving the lunge on TOGU (Lunge 3, 4) Holding the Surge and moving the lunge on TOGU (Lunge 4). Through the above four actions, we can see how the top-down instability influences the lower limb unlike the Bottom-up instability. EMG attachment sites were gluteus medius, vastus medialis, gastrocnemius, tibialis anterior. Results: These result suggest that exercise using Lunge 4 activity was the highest in muscle activity compared to other exercises, but vastus medialis showed the highest muscle activity in Lunge 2 exercise(p<0.05). Conclusion: This study showed the muscular activity of the lower extremities according to the lunge exercise using the instability tools.