• Transactions on Control, Automation and Systems Engineering
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• v.4 no.1
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• pp.43-48
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• 2002

We show that humans execute the postural control ingeniously by regulating the impedance properties of the musculo-skeletal system as the motor command against the alteration of the environment. Adjusting muscle activity can control the impedance properties of the musculo-skeletal system. To quantify the changes in human arm viscoelasticity on the vertical plane during interaction with the environment, we asked our subject to hold an object. By utilizing surface electromyographic(EMG) studies, we determined a relationship between the perturbation and a time-varying muscle co-activation. Our study showed when the subject lifts the object by himself the muscle stiffness increases while the torque remains the same just before the lift-off. These results suggest that the central nervous system(CNS) simultaneously controls not only the equilibrium point(EP) and the torque, but also the muscle stiffness as themotor command in posture control during the contact task.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.261-267
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• 2000

A mathematical model was developed to calculate the muscle force of lower extremity during the gait. We constructed a model of human locomotion, which includes a muscle-skeletal system with 7 segments and 16 lower limb muscles. Using a optimization technique, muscle forces variation of the lower extremity during the gait were generated and its result was verified by comparing a experimental results of EMG analysis. Moreover. the walking movement of the model could be compared quantitatively with those of experimental studies in human by inverse dynamics.

• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.270-278
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• 2017

The electrical muscle stimulator (EMS) based human machine interface (HMI) free to mechanical constraint and muscle fatigue problems are proposed for force feedback in a virtual reality. The device was designed to provide force feedback up to 4.8 N and 2.6 N each to the thumb and forefingers. The main objective of the HMI is to make unnecessary mechanical structures to attach on the hand or fingers. It employs custom EMSs and an interface arranged in the forearm. In this work, major muscle groups such as extensor pollicis brevis (EPB), extensor indicis proprius (EIP), flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) are selected for efficient force feedback and controlled individually. For this, a human muscular-skeletal analysis was performed and verified. The validity of the proposed multi-channel EMS based HMI was evaluated thorough various experiments with ten human subjects, interacting with a virtual environment.

• Archives of Plastic Surgery
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• v.32 no.4
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• pp.421-427
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• 2005

Although the incidence of mediastinal wound infection in patient undergoing median sternotomy for cardiovascular surgery is relatively low(less than 1%), it is not only a devastating and potentially life-threatening complication but also associated morbidity, mortality and cost are unacceptably high. During the past few decades various methods had been applied for the treatment of postoperative mediastinitis. Currently, chest wall reconstruction by using muscle flaps-especially pectoralis major muscle and rectus abdominis muscle are commonly selected for the reconstruction after wide debridement has become widely accepted. We performed bilateral pectoralis major-rectus abdominis muscles in-continuity bipedicle flap to overcome the limit of each flap for reconstruction of sternal defects in 17 patients. We analyzed the results of the surgery. Recurrent infection developed in 17.6% of cases and abdominal herniation was observed in one patient. There was no postoperative hematoma or death. We conclude that this flap is very valuable in reconstruction of the anterior chest wall defect caused by post-sternotomy infection because it provides sufficient volume to fill the entire mediastinum, and the complication rate compares favorably to that of other methods.

• Archives of Plastic Surgery
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• v.33 no.4
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• pp.510-513
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• 2006

Purpose: The Rectus abdominis muscle free flap is utilized in various reconstruction surgeries due to easiness in harvesting, consistency of vascular pedicle and reduced donor site morbidity. But rarely, femoral nerve injury during rectus abdominis harvesting can be resulted. We report a case of femoral nerve injury after rectus muscle harvesting and discuss the injury mechanism with the follow-up process of this injury. Methods: To reconstruct the defect of middle cranial base after wide excision of cystic adenocarcinoma of the external ear, rectus muscle free flap was havested in usual manner. To achieve a long vessel, inferior epigastric artery was dissected to the dividing portion of femoral artery and cut. Results: One week after the surgery, the patient noted sensory decrease in the lower leg, weakness in muscle strength, and disabilities in extension of the knee joint resulting in immobilization. EMG and NCV results showed no response on stimulation of the femoral nerve of the left leg, due to the defects in femoral nerve superior to the inguinal ligament. With routine neurologic evaluations and physical therapy, on the 75th day after the operation, the patient showed improvement in pain, sensation and muscle strength, and was able to move with walking frame. In 6 months after the operation, recovery of the muscle strength of the knee joint was observed with normal flexion and extension movements. Conclusion: Rarely, during dissection of the inferior epigastric artery, injuries to the femoral nerve can be resulted, probably due to excessive traction or pressure from the blade of the traction device. Therefore, femoral nerve injury can be prevented by avoiding excessive traction during surgery.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.4 no.2
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• pp.143-152
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• 2000

As muscular contraction is sustained, the Fourier spectrum of the myoelectric signal is shifted toward the lower frequency. This spectral density is associated with muscle fatigue. This paper describes a quantitative measurement method that performs the measurement of localized muscle fatigue by tracking changes of median frequency based on stationary wavelet transform. Applying to the human masseter muscle, the proposed method offers the much information for muscle fatigue, comparing with the conventional FFT-based method for muscle fatigue measurement.

• Archives of Craniofacial Surgery
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• v.23 no.4
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• pp.178-182
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• 2022

Postoperative temporal hollowing is a common complication of craniotomy. Damage and repositioning of the temporalis muscle can lead to a depression in the temporal side of the skull with inferior bulging, worsening aesthetic outcomes. We report a case of cranioplasty with three-dimensional (3D) printed mesh involving an additional correction using a temporalis muscle sling to help address this problem. A 3D-printed bioabsorbable mesh was prepared based on preoperative facial computed tomography, and was fixed to the hollowed area for tissue augmentation. The temporalis muscle was elevated and fanned out to its original position, and a sling was attached to a screw that was fixed to the mesh. For reinforcement, an additional sling was attached to another screw fixed to the mesh 2-3 cm vertically above the first screw. Aesthetic results were confirmed immediately after surgery and later during outpatient follow-up. Both depression and lateral bulging were resolved, and there was no delayed drooping of the temporalis muscle on 6-month follow-up. There were no complications, and the patient was satisfied with the appearance. This is a simple yet effective technique with a low risk of complications, and should be considered for postoperative temporal hollowing patients, especially those with severe lateral bulging.

• Anatomy and Cell Biology
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• v.57 no.1
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• pp.13-17
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• 2024

Masseter are commonly botulinum neurotoxin targeted muscle for facial contouring in aesthetic field. However, paradoxical masseteric bulging is common adverse effect that has not been discussed with ultrasonographic observations. Retrospective study has been conducted from October, 2021 to January, 2023, out of 324 patients have done blinded botulinum neurotoxin injection in the masseter at the middle and lower portion of the masseter with each side of 25 units (letibotulinum neurotoxin type A), 3 patients demonstrated paradoxical masseteric bulging has been reported and the image observed by ultrasonography by physician. Based on the observations made, we can infer that the function of the moving muscle involves twisting of the muscle fibers during contraction, along with the twisting of the deep inferior tendon, which causes the muscle to be divided into anterior and posterior compartments rather than into superficial and deep compartments of masseter. In ultrasonographic observe the skin surface of a patient with paradoxical masseteric bulging, it is observable that either the anterior or posterior part contracts significantly. The functional units of anterior and posterior compartment are observable as muscular contraction of inward movement of the muscle from either the anterior or posterior functional unit.

• Journal of Biomedical Engineering Research
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• v.26 no.5
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• pp.257-264
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• 2005

This paper proposes an ionic polymer metal composite (IPMC) based artificial muscle to be applicable to the Myoelectric hand prosthesis. The IPMC consists of a thin polymer membrane with metal electrodes plated chemically on both faces, and it is widely applying to the artificial muscle because it is driven by relatively low input voltage. The control commands for the IPMC-based artificial muscle is given by electromyographic (EMG) signals obtained from human forearm. By an intended contraction of the human flexor carpi ulnaris and extensor carpi ulnaris muscles, we investigated the actuation behavior of the IPMC-based artificial muscle. To obtain higher actuation force of the IPMC, the single layered as thick as $800[{\mu}m]$ or multi-layered IPMC of which each layer can be as thick as $178[{\mu}m]$ are prepared. As a result, the bending force was up to the maximum 12[gf] from 1[gf] by actuating the single layered IPMC with $178[{\mu}m]$, but the bending displacement was reduced to 6[mm] from 30[mm]. The experimental results using an implemented IPMC control system show a possibility and a usability of the bio-mimetic artificial muscle.

• Integrative Medicine Research
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• v.5 no.3
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• pp.176-181
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• 2016

Recent studies have focused on evidence-based interventions to prevent mobility decline and enhance physical performance in older adults. Several modalities, in addition to traditional strengthening programs, have been designed to manage age-related functional decline more effectively. In this study, we reviewed the current relevant literatures to assess the therapeutic potential of eccentric exercises for age-related muscle atrophy (sarcopenia). Age-related changes in human skeletal muscle, and their relationship with physical performance, are discussed with reference to in vitro physiologic and human biomechanics studies. An overview of issues relevant to sarcopenia is provided in the context of the recent consensus on the diagnosis and management of the condition. A decline in mobility among the aging population is closely linked with changes in the muscle force-velocity relationship. Interventions based specifically on increasing velocity and eccentric strength can improve function more effectively compared with traditional strengthening programs. Eccentric strengthening programs are introduced as a specific method for improving both muscle force and velocity. To be more effective, exercise interventions for older adults should focus on enhancing the muscle force-velocity relationship. Exercises that can be performed easily, and that utilize eccentric strength (which is relatively spared during the aging process), are needed to improve both muscle force and velocity.