• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.723-728
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• 2003

The physical restoration technology for lower limb amputees is being advanced as the biomechatronics is being applied to the area of rehabilitation. As the advanced prosthetics for lower limb amputees are introduced, a suitable prescription of biomechanical rehabilitation training becomes important to utilize the advanced full features of the devices. Since lower limb amputation significantly affects biomechanical balance of mosculoskeletal system for gait, an appropriate and optimal biomechanical training and exercise should be provided to rebalance the system before wearing the prostheses. Particularly, biomechanical muscular training for hip movements in the both affected and sound lower limbs is important to achieve a normal-like ambulation. However, there is no study to understand the effect of hip muscle strength on the gait performance of lower limb amputees. To understand the hip muscle strength characteristics for normal and amputated subjects, the isokinetic exercises for various ratios of concentric contraction to eccentric contraction were performed for hip flexion-extension and adduction-abduction. As a results. biomechanical isokinetic training protocols and performance measurement methodologies for lower limb amputees were developed in this study. Using the protocols and measurement methods, it has been understood that the appropriate and optimal biomechanical prescription for the rehabilitation process for lower limb amputees is important for restoring their gait ability

• Yonsei Medical Journal
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• v.59 no.9
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• pp.1115-1122
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• 2018

Purpose: To investigate biomechanical properties of the cornea using a dynamic Scheimpflug analyzer according to age. Materials and Methods: In this prospective, cross-sectional, observational study, participants underwent ophthalmic investigations including corneal biomechanical properties, keratometric values, intraocular pressure (IOP), and manifest refraction spherical equivalent (MRSE). We determined the relationship of biomechanical parameters and ocular/systemic variables (participant's age, MRSE, IOP, and mean keratometric values) by piecewise regression analysis, association of biomechanical parameters with variables by Spearman's correlation and stepwise multiple regression analyses, and reference intervals (RI) by the bootstrap method. Results: This study included 217 eyes of 118 participants (20-81 years of age). Piecewise regression analysis between Corvis-central corneal thickness (CCT) and participant's age revealed that the optimal cut-off value of age was 45 years. No clear breakpoints were detected between the corneal biomechanical parameters and MRSE, IOP, and mean keratometric values. Corneal velocity, deformation amplitude, radius, maximal concave power, Corvis-CCT, and Corvis-IOP exhibited correlations with IOP, regardless of age (all ages, 20-44 years, and over 44 years). With smaller deformation amplitude and corneal velocity as well as increased CorvisIOP and Corvis-CCT, IOP became significantly increased. We provided the results of determination of confidence interval from RI data using bootstrap method in three separate age groups (all ages, 20-44 years, and over 44 years). Conclusion: We demonstrated multiple corneal biomechanical parameters according to age, and reported that the corneal biomechanical parameters are influenced by IOP.

• Journal of the Ergonomics Society of Korea
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• v.29 no.4
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• pp.445-453
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• 2010

It is necessary to quantitatively evaluate the workload of workers in order to improve the level of safety and efficiency as well as to prevent workers from musculoskeletal disorders. The purpose of this study is to introduce biomechanical methods that are largely used to quantitatively evaluate workload. The biomechanical methods use kinematics and kinetics to analyze the movement and force of biomechanical body. Motion analysis, joint angle measurement, ground reaction force, mathematical model, and electromyography (EMG) were introduced as a tool or device for biomechanical evaluation. In this study, the special feature of each method was emphasized and important tips for field measurement were summarized. The information and technique disclosed in this summary can be used to evaluate and design the workplace better by effectively control the workload of field workers.

• The Journal of Korean Physical Therapy
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• v.35 no.5
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• pp.132-138
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• 2023

Purpose: This study compared the effects of the elastic resistance and general training for college Taekwondo athletes, and investigated the biomechanical ability and lower extremity function according to the movement speed of the knee joint. Methods: Twenty university student Taekwondo athletes participated voluntarily in this study. The subjects performed general resistance training for four weeks, followed by elastic resistance training for another four weeks. The biomechanical parameters during the fast and slow isokinetic conditions, Y-balance ability, and vertical jump ability were measured three times: before training, after general resistance training, and after elastic resistance training. Statistical analysis was performed under isokinetic conditions and the intervention effect. Results: The biomechanical ability differed significantly between fast and slow isokinetic conditions (p<0.05). An analysis of the training method revealed a significant difference in the maximum knee extension speed and the posterior-lateral direction of the Y-balance test (p<0.05). Conclusion: Elastic resistance training had a more positive effect on the functional task performance than biomechanical factors related to muscular strength compared to general resistance training. In addition, speed-related knee biomechanical information of subjects with strong physical abilities could be utilized in sports physiotherapy.

• Journal of KSNVE
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• v.10 no.2
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• pp.269-279
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• 2000

This paper deals with the development of biomechanical model on a seat with backrest support in the vertical direction. Four kinds of biomechanical models are discussed to depict human motion. One DOF model mainly describes z-axis motion of hip, two and three DOF models describe z-axis of hip and head, and while nine DOF model suggested in this study represents more motion than the otehr model. Three kinds of experiments were executed to validate these models. The first one was to measure the acceleration of the floor and hip surface in z-axis, the back surface in x-axis, and the head in z-axis under exciter. From this measurement, the transmissiblities of each subject were obtained. The second one was the measurement of the joint position by the device having pointer and the measurement of contact position between the human body and the seat by body pressure distribution. The third one was the measurement of the seat and back cushion by dummy. The biomechanical model parameters were obtained by matching the simulated to the experimental transmissiblities at the hip, back, and head.

• Journal of KSNVE
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• v.10 no.5
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• pp.811-818
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• 2000

This paper deals with the design of a car seat for enhancing dynamic ride quality using a Biomechanical Model that was developed from the measured whole-body vibration characteristic. For evaluation of seat ride quality, the z-axis acceleration of floor as an input of biomechanical model was measured on a driving passenger car at highway and national road. Form the floor signal and the estimated biomechanical model, overall ride value evaluated by parameter study of seat stiffness and damping. The result shows that overall ride value decreases as the seat damping increases and the sear stiffness decreases. A lot of polyurethane foams were manufactured and tried to evaluate dynamic ride quality of a seat. It is found that stiffness and damping of a seat show a linear relationship, which means the stiffness and damping are not independent each other, So the optimal seat parameters within practically achievable space are determined.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.3
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• pp.121-132
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• 2018

PURPOSE: This study was conducted to investigate the effects of type of exercise on neck disability, pain, and postural changes in subjects with forward head posture. METHODS: Two independent researchers conducted a search using KISS, RISS, DBpia (domestic), PubMed, OVID, and Science Direct (overseas) databases. We selected randomized controlled clinical trials by searching using the terms "forward head posture", "exercise therapy", and "therapeutic exercise". Studies published from 2007 to December 2017 were included. PEDro Scale was used to evaluate the quality of the selected studies, and meta-analysis was conducted using the CMA program. This review was registered at PROSPERO (CRD42018068633). RESULTS: Of the total 13768 studies searched, 17 were selected. Positive effects on neck disability were achieved with the base and biomechanical elements (ES=1.63, 95% confidence interval [CI] .49 to 2.75) as well as base, modulator, and biomechanical elements (ES=1.50, 95% [CI] .69 to 2.30). Neck pain improved with the base, modulator, and biomechanical elements (ES=1.96, 95% [CI] 1.08 to 2.82), while postural changes improved with biomechanical elements (ES=1.45, 95% [CI] .64 to 2.25). Additionally, type of exercise had a positive effect. CONCLUSION: The most effective exercises for neck disability are of the base and biomechanical elements, while the most effective types for neck pain are of the base, modulator, and biomechanical elements and the most effective exercise for posture is of biomechanical elements. Combined exercises targeting biomechanical elements were effective at treating disability, pain, and postural changes.

• Korean Journal of Computational Design and Engineering
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• v.21 no.4
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• pp.426-432
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• 2016

Designing a morphologically well-fitted hip implant to a patient anatomy is desirable to improve surgical outcomes since a commercial ready-made hip implant may not well conform to the patient joint. In this study, biomechanical stability of patient-specific hip implants with two different stem lengths was compared and discussed using a 3D finite element analysis (FEA). The FEA results in this study showed that an increase in stem length brings about more the peaked von-Mises stress (PVMS) in the prosthesis and less in the femur. However the decrease in von-Mises stress in the femur causes stress shielding phenomenon that usually leads to considerable bone resorption. Although, in biomechanical stability point of view, this work recommends the use of smaller stems, the length of stem must be determined by considering both the von-Mises stress and the stress-shielding phenomenon.

• Journal of the Korean Society of Safety
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• v.10 no.4
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• pp.103-108
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• 1995

This study was performed to investigate a relationship between a biomechanical analysis of compressive force at L5/S1 and electromyographic analysis of erector spinae muscle during lifting task. In the experiment, isometric contractions at 25, 50, 75, 100%MVC for short duration and sustained isometric contractions at 50%MVC were performed. For muscle recruitment patten and compressive force analysis, rectified EMG amplitudes analysis and computerized biomechanical analysis were used. To achieve data, angles of neck, shoulder, elbow, wrist, hip, knee, ankle and length of body segments were measured. Results shows that trends of initial EMG rectified amplitude were similar to those of biomechanical calculation value and for sustained isometric contraction at 50%MVC EMG rectified amplitude of erector spinae muscle after 40seconds was increased up to level of 75%MVC. Based on the results of this study, biomechanical analysis should be supplemented considering muscle fatigue, and it is also suggested that work-rest cycle critera and the evaluation of back-pain injuries should include muscle fatigue.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1990.04a
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• pp.140-150
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• 1990

Further developments on a dynamic biomechanical model are presented to assess musculoskeletal stresses and human responses. The model being developed is an extension of the Articulated Total Body (ATB) Model, originally developed by Calsapan Corp. for the study of human dynamics during automobile crashes, later adopted to the U.S.Air Force to simulate the reactions of aircrew personnel to such forces typically encountered in various phases of flight operations. Further refinements were introduced by Freivalds and Kaleps(1984) to account for a human neuromusculature. In this study, modelling of active neuromusculature was described and simulations of whole-body human motion were performed using the ATB Model. It indicated the potential of using a muscularized biomechanical model coupled with CAD capabilities to simulate human responses in a variety of industrial settings as well. This will serve as a basis of incorporating computer aided design methods into a muscularized biomechanical models.