• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.745-746
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• 2012

• Physical Therapy Korea
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• v.13 no.4
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• pp.30-38
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• 2006

This study was to investigate the influence of cooling on muscle force and viscoelastic properties of tendon structures in themedial gastrocnemius (MG) muscle. The subject was instructed to gradually increase force (10% MVC step) from a relaxed state to MVC within 3 s. At this time, it was measured by an ultrasonographic probe was attached and that an electrode was attached to monitor EMG. The F values at 50 100% of MVC were significantly greater under the cold condition than under the non-cold condition (p<.05). The ${\Delta}F/{\Delta}L$ values at 80~100% of MVC were significantly higher under the cold condition than under the non-cold condition (p<.05). The elongation under the non-cold condition had a tendency to be greater than that under the cold condition. The results suggest that cooling results in an increase in the stiffness of tendon structures with a reduction of muscle force and elongation.

• Journal of the Ergonomics Society of Korea
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• v.28 no.3
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• pp.1-6
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• 2009

Recently, importance of the rehabilitation of hand pathologies as well as the development of high-technology hand robot has been increased. The biomechanical model of hand is indispensable due to the difficulty of direct measurement of muscle forces and joint forces in hands. In this study, a three-dimensional biomechanical model of four fingers including three joints and ten muscles in each finger was developed and a mathematical relationship between neural commands and finger forces which represents the enslaving effect and the force deficit effect was proposed. When pressing a plate under the flexed posture, the muscle forces and the joint forces were predicted by the optimization technique. The results showed that the major activated muscles were flexion muscles (flexor digitorum profundus, radial interosseous, and ulnar interosseous). In addition, it was found that the antagonistic muscles were also activated rather than the previous models, which is more realistic phenomenon. The present model has considered the interaction among fingers, thus can be more powerful while developing a robot hand that can totally control the multiple fingers like human.

• PNF and Movement
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• v.19 no.1
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• pp.1-8
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• 2021

Purpose: The purpose of this study was to determine how the position of tibial rotation affects peak force and hamstring muscle activation during isometric knee flexion in healthy women. Methods: Seventeen healthy women performed maximum isometric knee flexion at 30˚ with three tibial rotation positions (tibial internal rotation, neutral position, and tibial external rotation). Surface electromyographic (EMG) activity was recorded from the medial hamstring (MH) and lateral hamstring (LH) muscles. The strength of the knee flexor was measured with a load-cell-type strength-measurement sensor. Data were analyzed using one-way repeated analysis of variance. Results: The results showed that MH and LH activities and peak force were significantly different among the three tibial rotation conditions (p < 0.01). The post-hoc comparison revealed that the MH EMG activity in tibial neutral and internal rotation positions were significantly greater than tibial external rotation (p < 0.01). The LH activity in tibial external rotation was significantly greater than the tibial neutral position and internal rotation (p < 0.01). The peak force of the knee flexor was also greater in the external tibial rotation position compared with the tibial neutral and internal rotation positions (p < 0.01). Conclusion: Our findings suggest that hamstring muscle activation could be changed by tibial rotation.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.399-417
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• 2008

The aim of this study was to investigate the relationships between bite force, masseter muscle and craniofacial morphology. 141 individuals were included. Bite forces were measured with a bite force transducer(SKT 2004). The facial morphology of the samples was evaluated on the Lateral and PA cephalometric radiographs(Asahi CX-90 SP). Ultrasonographic images were obtained for 36 individuals(Logiq 500). General status of the subjects were also measured for investigating possible relationships. Their relationships were analyzed by means of t-test, Pearson's correlation coefficients and simple regression analysis. In conclusion, bite force of molar was significantly correlated with craniofacial morphology for males and females, but not to masseter muscles. The masseter muscle for males had a significant correlation with craniofacial morphology. The unexpected negative correlations between size of masseter muscle and maxillary width was revealed for males. One possible way to arrive at a plausible explanation for the correlation between masster muscle, bite force and craniofacial morphology of males were the deep layer of masseter muscle had a great influence on males and the superficial layer of masseter muscle had a great influence on females.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1179-1182
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• 2005

To facilitate the cell based robot research, we presented a micro-mechanical force measurement system for the biological muscle actuators, which utilize glucose as a power source for potential application in a human body or blood vessels. The system is composed of a micro-manipulator, a force transducer with a glass probe, a signal processor, an inverted microscope and video recoding system. Using this measurement system, the contractile force and frequency of the cardiac myocytes were measured in real time and the magnitude of the contractile force of each cardiac myocyte on a different condition was compared. From the quantitative experimental results, we estimated that the force of cardiac myocytes is about $20{\sim}40\;{\mu}$N, and showed that there is difference between the control cells and the micro-patterned cells.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.1
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• pp.173-181
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• 2021

Purpose : The purpose of this study is to compare muscle activity after applying two muscle energy techniques (MET) to subjects with forward head posture to see if the post isometric relaxation (PIR) technique is more effective than the reciprocal inhibition (RI) technique. Methods : The muscle activity was measured using EMG after applying the PIR and RI techniques to 30 adults at K College. Subjects were selected for forward head posture whose ear center was 2.5 ㎝ front of the center of the shoulder. EMG equipment was used to measure muscle activity, and the measurement sites were measured in cervical flexor and extensor muscles. The experiment period was performed once a week for a total of two weeks, and after the pre-measurement was performed for 5 minutes PIR and RI exercise. In the PIR technique, the head is tilted back in a sitting position, and the experimenter applies resistance with the same force for 7~10 seconds and repeats 3-5 times after rest. In the RI technique, in a sitting position, the subject gives the force to bend the head forward, and the experimenter applies resistance with the same force for 7 to 10 seconds, and repeats 3 to 5 times after rest. Results : The result is same as the following. In the comparison of muscle activity, there was a significant decrease in both PIR and RI at 1 and 2 weeks. And there was a greater decrease in muscle activity in PIR. There was no difference in the comparison of decrease in muscle activity at 1 week and 2 week. Conclusion : Both PRI and RI can be said to be effective in improving the function of the forward head posture in the neck muscles. Therefore, the selection of the two techniques in clinical practice should be appropriately performed under the judgment of experts according to the patient's situation.

• Journal of Life Science
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• v.11 no.1
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• pp.62-69
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• 2001

This study was aimed to investigate the effect Chukdamtanggamibang on the vascular systems including changes in blood pressure and regional cerebral blood flow(rCBF) of male Sprague-Dawely rats, contractile force of guinea pig`s tracheal smooth muscle and abdominal aorta and femoral artery in rabbits. Blood pressure was not affected by Chukdamtanggamibang in rats. rCBF was significantly increased by Chukdamtanggamibang in a dose-dependent manner. Contractile force of isolated guinea pig`s tracheal smooth muscle evoked by His ({TEX}$ED_{50}${/TEX}) were inhibited significantly by Chukdamtanggamibang. Propranolol, indomethacin and methylene blue did not significantly alter the inhibitory effect of Chukdamtanggamibang. Contractile force of isolated rabbit`s abdominal aorta and femoral artery evoked by NE ({TEX}$ED_{50}${/TEX}) were inhibited significantly by Chukdamtanggamibang. ODQ and L-NNA significantly attenuated the inhibitory effects of Chukdamtanggamibang in abdominal aorta, whereas propranolol did not significantly alter the inhibitory effect of Chukdamtanggamibang. These results indicate that Chukdamtanggamibang can relax hitamine-induced contraction of guinea pig`s tracheal smooth muscle and that this inhibition involves, in part, the relation to the soluble guanylyl cyclase synthesis and nitric oxide (NO) synthesis.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.459-465
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• 2012

This study has investigated the effect of isometric contractile force and muscle activity applying ice and hot according to the time from the biceps brachii muscle. In this study, 20 university students participants without musculoskeletal and neurological disorders. By applying a hot pack 5 min, 10 min, 20 min and 30 min respectively and ice pack for 5 min, 10 min, and 20 min respectively. After that measurement are skin temperature, contractile force and muscle activity. Skin temperature of the hot and cold 5 min applied that rapidly changing. Increasing the time it takes to apply a variance has been reduced(p<.001). Isometric contractile force was not statistically significant but highest when applying the hot pack 5 minutes and lowest when applying the hot pack 30 minutes(p<.001). Muscle activity and median frequency was highest when applying the hot pack 5 minutes. To analyze the above results, it was found that isometric contractile force and muscle activity changed according to the applying time. These result lead us to the conclusion that this study will be more evidence for changes in muscle contraction to apply hot pack and ice pack on clinic.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1345-1350
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• 2010

Sit-to-stand movement is a basic movement in daily activities. On the basis of this movement, the biomechanical functions of a person can be evaluated. The study of the joint kinematics, moment, and muscle coordination is necessary to understand the characteristics of the sit-to-stand movement. We have developed a motion-based program for inverse dynamics analysis and the electromyogram-based program for muscle force prediction. The joint kinematics and the kinetic results estimated on the basis of obtained motion data, ground reaction force, and electromyogram signals were compared with those reported in previous studies, and the muscle forces determined by the two methods were compared with each other. The methods and programs developed in this study can be used to understand biomechanics and muscle coordination involved in basic movements in daily activities.