• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.1015-1016
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• 2010

• The Korean Journal of Physiology
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• v.3 no.1
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• pp.33-44
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• 1969

Electoromyographic studies were performed on the action of the muscles of the temporomandibular joints following exfoliation of the deciduous teeth. The subjects examined, being 50 children. between the age of 6 and 13 years, divided into 5 groups. They were; 1) Deciduous dentition were complete in the first group. 2) Deciduous incisors were missing in either upper or lower jaw in the second group. 3) Deciduous canine and molars were missing in the left side of either upper or lower jaw in the third group. 4) Deciduous canine and molars were missing in the right side of either upper or lower jaw in the fourth group. 5) Permanent dentition completed in the fifth group(except third molars). Electromyogram was recorded with 4 channel polygraph (Grass model VII modified for 7P3). Electrodes which were the cup-typed gold discs, 9 millimeters in the diameter, were located on the anterior, middle and posterior lobes of the temporal muscles, and also on the superficial and deep layers of the masseter muscles. Paired electrodes were held by electrode cream so that they were pressed on the skin surface at right angle, adhesive tape being used to anchor them. The distance of the pair electrodes was about 5 millimeters. The results obtained were as follow: 1) In rest position of mandible; All groups showed slight, electrical activities in the muscles involved, but in the middle lobe of temporal muscle they were slightly higher. 2) In molar occlusion of mandible; High activity-anterior lobe of temporal muscle and superficial layer of masseter muscle. Moderate activity-deep layer of masseter muscle. Low activity-middle and posterior lobes of masseter muscle. There were no differences among the first, the second and the fifth groups. In the third group the muscle activity was weaker than that of the right, and in the fourth group opposite characteristics was revealed. 3) In incisal bite of mandreble; Hight activity-superficial layer of masseter muscle. Modertae activity-deep layer of masseter muscle. Low activity-anterior, middle and posterior lobes of temporal muscle. The first, the third, the fourth and the fifth groups showed no differences but the second group showed less activity than those of others. 4) In protrusion of mandible; High activity-deep layer of masseter muscle Moderate activity-superficial layer of masseter muscle. Low activity-anterior, middle and posterior lobes of temporal muscle. In the first, the fourth and the fifth groups, there were no differences in the activities, but the second group showed less activity than the others. 5) In retrusion of mandible; High activity-deep layer of masseter muscle. Moderate activity-superficial layer of masseter muscle. Low activity-anterior, middle and posterior lobes of temporal muscle. In the first, the third, the fourth and the fifth groups, there were no differences but the second group showed less activity than the others. 6) In lateral excursion of the mandible (either direction); High activity-posterior lobe of temporal muscle. Moderate activity-anterior and middle lobes of temporal muscle. Low activity-superficial and deep layers of masseter muscle. The muscle action potentials were weaker than those of the right side in the third group and vice ver'sa in the fourth group. 7) In chewing movement; Temporal muscle activities were higher than those of masseter, especially in the middle lobe of temporal muscle the activity was highest. Right side muscle activities were higher than those of the left in the third group and, on the contrary, the left side was dominant over the right in the fourth group.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1867-1872
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• 1991

A method of estimating mechanical parameters of the intact human muscle is proposed; force responses to ramp length perturbation of the muscle both at the resting and constant contracting states are compared with those of the model. The response during the short period (50ms) after the onset of the perturbation is used for the estimation. Time course of the length perturbation which could lead to the accurate estimation is determined by model analysis. Availability of this method is showed by applying it to the human thumb flexor muscle.

• Proceedings of the ESK Conference
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• 1994.04a
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• pp.124-135
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• 1994

A biomechanical model of lower extremity in seated postures was developed to assess muscular activities of lower extremity involved in a variety of foot pedal operations. It is found that nonlinear optimization method which has been used for modeling the articulated body segments does not predict the forces generated from biarticular muscles reasonably, so the revised nonlinear optimization scheme was employed to consider the synergistic effects of biarticular muscles in the model, assuming that the muscle forces are distributed proportionally based on their physiological cross sectional area and moment arm. The model incorporated four rigid body segments with the nine muscles to represent lower extreimity. For the model valida- tion, three male subjects performed the experiments in which EMG activities of the nine lower extremity muscles were measured. Predicted muscle forces were compared with the corresponding EMG amplitudes and it showed no statistical difference. The developed model can be used to design and to assess the pedals and foot-related equipments design.

• Journal of the Ergonomics Society of Korea
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• v.1 no.2
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• pp.3-9
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• 1982

This study demonstrates that certain personal and task factors can be modelled to predict slip potential as well as back loadings durings dynamic pushing and pulling tasks. Such tasks are com- mon to many manual material handling jobs in industry and the results of this work will hopefully be of use in improved job design. The objective of this research is to formulate and validate a dynamic biomechanical model of pushing and pulling a cart. For pushing and pulling tasks, the model can : (1) estimate foot forces for given hand forces, and (2) estimate tors muscle and vertabral column loadings. In order to formulate and validate the model, experiments involving pushing and pulling of a cart were performed. These experiments produced data of the following type : (1) dynamic forces on the feet, (2) hand forces required to move the cart, (3) body motions as functions of various cart motion and (4) back muscle actions. The model was validated using three different methods; precision was tested using correlation between predicted and measured results, accuracy using standard error between of predicted and measured results, and intuitive comparison of predicted results using sensitivity analyses.

• Journal of International Academy of Physical Therapy Research
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• v.2 no.2
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• pp.274-280
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• 2011

This study was designed to analyze repetitive dorsiflexion and plantarflexion exercises in ankles have effects on the muscle tones of triceps, vastus medialis and gastrocnemius. 25 healthy woman volunteers(ankle dorsiflexion exercise group: 13, ankle plantarflexion exercise group: 12) participated in the two ankle exercise models, which have performed 3 times a week for 3 weeks. Myotonometer was used to measure the muscle tones of the triceps, vastus medialis, gastrocnemius muscles, and measurements were performed before and after the application of the each exercise model. Repeated measured paired t-test and independent t-test was used to determine a statistical significance. The group of repetitive dorsiflexion exercise of the ankle have effects on the muscle tones of triceps, vastus medialis and gastrocnemius (p>.05). The group of repetitive plantarflexion exercise of the ankle have effects on the muscle tones of triceps, vastus medialis and gastrocnemius(p>.05). The groups of repetitive dorsiflexion and plantarflexion exercise of the ankle have effects on the muscle tones of triceps, vastus medialis and gastrocnemius(p>.05).

• The Journal of Korean Physical Therapy
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• v.18 no.3
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• pp.9-21
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• 2006

Purpose: This study was intended to examine the effects of electroacupuncture and therapeutic exercise on muscle atrophy and exercise function in an ischemic stroke model induced by middle cerebral artery occlusion. Methods: This study selected 120 Sprangue-Dawley rats, 8-week of age, divided them into six groups, and assigned 5 rats to each group. Experiments were conducted for 1, 3 days, 1, and 8 weeks, respectively. Group I was a group of electroacupuncture and therapeutic exercise after inducing ischemic stroke; Group II was a group of therapeutic exercise after inducing ischemic stroke; Group III was a group of electroacupuncture after inducing ischemic stroke; Group IV was a sham group of electroacupuncture after inducing ischemic stroke; Group V was a control group and Group VI was a sham group without ischemic stroke. In each group, changes in weight of muscle and relative muscle of TA muscle, neurologic motor behavior test, histologic observations were observed and analyzed. Results: For the changes in muscle weight of unaffected and affected sides of TA muscle, muscle atrophy was seen in an affected side 3 days after ischemic stroke was induced. There was statistically significant difference in Group I 1 week and 8 weeks after ischemic stroke was induced, compared to Group V (p<0.05). For the changes in relative muscle weight of unaffected and affected sides of tibial anterior muscle, there was significant decrease in each group 3 days after ischemic stroke was induced, compared to Group IV, while there was statistically significant increase in Group I 1 week after ischemic stroke was induced, compared to Group V (p<0.05). For neuologic exercise behavior test, Group I generally had the highest score, compared to other groups. Conclusion: electroacupuncture and therapeutic exercise may improve muscle atrophy and change in histologic observations expression of ischemic stroke rats and contribute to the improvement of exercise function.

• Diabetes and Metabolism Journal
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• v.42 no.6
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• pp.488-495
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• 2018

Background: Skeletal muscle plays a major role in glucose metabolism. We investigated the association between thigh muscle mass, insulin resistance, and incident type 2 diabetes mellitus (T2DM) risk. In addition, we examined the role of body mass index (BMI) as a potential effect modifier in this association. Methods: This prospective study included 399 Japanese Americans without diabetes (mean age 51.6 years) who at baseline had an estimation of thigh muscle mass by computed tomography and at baseline and after 10 years of follow-up a 75-g oral glucose tolerance test and determination of homeostasis model assessment of insulin resistance (HOMA-IR). We fit regression models to examine the association between thigh muscle area and incidence of T2DM and change in HOMA-IR, both measured over 10 years. Results: Thigh muscle area was inversely associated with future HOMA-IR after adjustment for age, sex, BMI, HOMA-IR, fasting plasma glucose, total abdominal fat area, and thigh subcutaneous fat area at baseline (P=0.033). The 10-year cumulative incidence of T2DM was 22.1%. A statistically significant interaction between thigh muscle area and BMI was observed, i.e., greater thigh muscle area was associated with lower risk of incident T2DM for subjects at lower levels of BMI, but this association diminished at higher BMI levels. Conclusion: Thigh muscle mass area was inversely associated with future insulin resistance. Greater thigh muscle area predicts a lower risk of incident T2DM for leaner Japanese Americans.

• Journal of Korean Neurosurgical Society
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• v.59 no.5
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• pp.430-436
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• 2016

Objective : The objective of this study is to establish an animal model of chronic paraspinal muscle injury in rat. Methods : Fifty four Sprague-Dawley male rats were divided into experimental group (n=30), sham (n=15), and normal group (n=9). Incision was done from T7 to L2 and paraspinal muscles were detached from spine and tied at each level. The paraspinal muscles were exposed and untied at 2 weeks after surgery. Sham operation was done by paraspinal muscles dissection at the same levels and wound closure was done without tying. Kyphotic index and thoracolumbar Cobb's angle were measured at preoperative, 2, 4, 8, and 12 weeks after the first surgery for all groups. The rats were sacrificed at 4, 8, and 12 weeks after the first surgery, and performed histological examinations. Results : At 4 weeks after surgery, the kyphotic index decreased, but, Cobb's angle increased significantly in the experimental group (p<0.05), and then that were maintained until the end of the experiment. However, there were no significant differences of the kyphotic index and Cobb's angle between sham and normal groups. In histological examinations, necrosis and fibrosis were observed definitely and persisted until 12 weeks after surgery. There were also presences of regenerated muscle cells which nucleus is at the center of cytoplasm, centronucleated myofibers. Conclusion : Our chronic injury model of paraspinal muscles in rats shows necrosis and fibrosis in the muscles for 12 weeks after surgery, which might be useful to study the pathophysiology of the degenerative thoracolumbar kyphosis or degeneration of paraspinal muscles.

• Journal of Korean Academy of Nursing
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• v.37 no.1
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• pp.81-90
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• 2007

Purpose: The purpose of this study was to examine the effects of daily exercise before steroid treatment on mass, the type I and II fiber cross-sectional area, and myofibrillar protein content of hindlimb muscles in a rat model. Method: Adult male Sprague-Dawley rats were randomly assigned to one of three groups: a control group(n=10) that had a normal saline injection for 7days, a steroid group(n=10) that had a steroid injection for 7days, and an exercise-steroid group(n=10) that ran on the treadmill for 7days before a steroid treatment. Body weight and food intake were measured every day. At 15 days all rats were anesthetized and the soleus, plantaris and gastrocnemius muscles were dissected. Result: The exercise-steroid group showed significant increases as compared with the steroid group in body weight, muscle weight of the soleus and gastrocnemius, type II muscle fiber cross-sectional area of plantaris, and myofibrillar protein content of the soleus, plantaris, and gastrocnemius. As compared with the control group, the steroid group showed significant decreases in body weight and diet intake, muscle weight, the type II fiber cross-sectional area and myofibrillar protein content of the soleus, plantaris, and gastrocnemius muscles. Conclusion: Daily exercise before steroid treatment attenuates hindlimb muscle atrophy, with type II muscle changes more apparent than type I muscle changes.