• The Journal of Korean Physical Therapy
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• v.32 no.5
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• pp.319-324
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• 2020

Purpose: This study was to investigate the effect of dorsal neck muscle fatigue on the cervical range of motion (CROM) and proprioception in adults with the forward head posture (FHP). Methods: Thirty pain-free subjects were enrolled in this study. All subjects were measured the forward head angle by taking the capture of the sagittal plane of their upper body to determine the FHP. Subjects were distributed into two groups: the FHP group (n=14) and Control group (n=16). All subjects were measured the CROM and the Head repositioning accuracy (HRA) for joint proprioception before and after inducing muscle fatigue of the dorsal neck. The CROM and HRA were measured in neck flexion, extension, right-left lateral flexion, and right-left rotation. Sorenson's test was used to induce muscle fatigue of the dorsal neck. Results: Total CROMs were significantly decreased after dorsal neck muscle fatigue in both groups (p<0.05). Total HRAs were significantly increased after dorsal neck muscle fatigue in the FHP group (p<0.05), but there were no significant differences in the control group (p>0.05). Total CROM changes were not significant differences between groups (p>0.05), but total HRA changes were significant differences between groups (p<0.05) except for right and left lateral flexion (p>0.05). Conclusion: Immediate CROM and proprioception reduction after the dorsal neck muscle fatigue were observed in adults with the FHP. Therefore, FHP can significantly affect the CROM and positioning consistency of cervical proprioception.

• Earthquakes and Structures
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• v.10 no.5
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• pp.1143-1179
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• 2016

Offshore wind turbines are considered as a fundamental part to develop substantial, alternative energy sources. In this highly flexible structures, monopiles are usually used as support foundations. Since the monopiles are large diameter (3.5 to 7 m) deep foundations, they result in extremely stiff short monopiles where the slenderness (length to diameter) may range between 5 and 10. Consequently, their elastic deformation patterns under lateral loading differ from those of small diameter monopiles usually employed for supporting structures in offshore oil and gas industry. For this reason, design recommendations (API and DNV) are not appropriate for designing foundations for offshore wind turbine structures as they have been established on the basis of full-scale load tests on long, slender and flexible piles. Furthermore, as these facilities are very sensitive to rotations and dynamic changes in the soil-pile system, the accurate prediction of monopile head displacement and rotation constitutes a design criterion of paramount importance. In this paper, the Fourier Series Aided Finite Element Method (FSAFEM) is employed for the determination of static impedance functions of monopiles for OWT subjected to horizontal force and/or to an overturning moment, where a non-homogeneous soil profile has been considered. On the basis of an extensive parametric study, and in order to address the problem of head stiffness of short monopiles, approximate analytical formulae are obtained for lateral stiffness $K_L$, rotational stiffness $K_R$ and cross coupling stiffness $K_{LR}$ for both rough and smooth interfaces. Theses expressions which depend only on the values of the monopile slenderness $L/D_p$ rather than the relative soil/monopile rigidity $E_p/E_s$ usually found in the offshore platforms designing codes (DNV code for example) have been incorporated in the expressions of the OWT natural frequency of four wind farm sites. Excellent agreement has been found between the computed and the measured natural frequencies.

• Physical Therapy Korea
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• v.21 no.3
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• pp.28-37
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• 2014

The purpose of this study was to investigate the effects of smartphone use on muscle fatigue and tenderness in the cervical erector spinae (CES) and the upper trapezius (UT) and on the cervical range of motion among subjects with and without neck muscle pain. The subjects were 30 smartphone users in their 20 s who -were assigned to either an experimental group with neck muscle pain or a control group without neck muscle pain. Muscle fatigue and tenderness in the CES and the UT as well as the subjects' cervical range of motion were measured before and after 20-min smartphone sessions in a sitting position. In a between-group comparison of muscle fatigue, the experimental group showed a significantly greater decrease in median frequency in the CES and the right UT after smartphone use (p<.05). Regarding the assessment of muscle tenderness after smartphone use, the experimental group showed a statistically significant decrease in the pressure-pain threshold (PPT) in all muscles (p<.05), whereas the control group showed a significantly decreased PPT in the right CES and the UT (p<.05). The assessment of the cervical range of motion revealed a statistically significant reduction in the cervical flexion-extension and left lateral flexion in the experimental group (p<.05) after smartphone use. However, there was no significant change in the cervical range of motion in the control group (p>.05) after smartphone use. When compared with the control group, the experimental group demonstrated greater changes in cervical extension, lateral flexion, and rotation, except for cervical flexion (p<.05). In conclusion, when smartphone users have pre-existing neck muscle pain, the use of a smartphone further increased muscle fatigue and tenderness in the neck and reduced PPT and the cervical range of motion.

• The korean journal of orthodontics
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• v.50 no.3
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• pp.170-180
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• 2020

Objective: To compare short- and long-term dentoalveolar, skeletal, and rotational changes evaluated by Björk's structural method of superimposition between children with Class II malocclusion treated by functional appliances and untreated matched controls. Methods: Seventy-nine prepubertal or pubertal children (mean age, 11.57 ± 1.40 years) with Class II malocclusion were included. Thirty-four children were treated using an activator with a high-pull headgear (Z-activator), while 28 were treated using an activator without a headgear (E-activator). Seventeen untreated children were included as controls. Lateral cephalograms were obtained before treatment (T1), after functional appliance treatment (T2), and after retention in the postpubertal phase (T3). Changes from T1 to T2 and T1 to T3 were compared between the treated groups and control group using multiple linear regression analysis. Results: Relative to the findings in the control group at T2, the sagittal jaw relationship (subspinale-nasion-pogonion, p < 0.001), maxillary prognathism (sella-nasion-subspinale, p < 0.05), and condylar growth (p < 0.001) exhibited significant improvements in the Z- and E-activator groups, which also showed a significantly increased maxillary incisor retraction (p < 0.001) and decreased overjet (p < 0.001). Only the E-activator group exhibited significant backward rotation of the maxilla at T2 (p < 0.01). The improvements in the sagittal jaw relationship (p < 0.01) and dental relationship (p < 0.001) remained significant at T3. Condylar growth and jaw rotations were not significant at T3. Conclusions: Functional appliance treatment in children with Class II malocclusion can significantly improve the sagittal jaw relationship and dental relationships in the long term.

• Journal of International Academy of Physical Therapy Research
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• v.7 no.2
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• pp.989-993
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• 2016

The purpose of this study was to investigate the effects of occipital bone stimulation by cervical stabilizing exercise on the muscle tone, stiffness, ROM, and cervical lordosis in patient with forward head posture(FHP). This study was a case study of a single patient with forward head posture. This study used a ABA' design, A and A' were the baseline phases and B was the intervention phase. The intervention was occipital bone stimulation by cervical stabilization exercise. It was administered once daily for 7 days. The therapist kept hands together, and placed the two index fingers under the subject's occipital bone. The subject performed the chin-in exercise with a maximum isometric contraction for 20 sec.The exercise was implemented by performing the movements 10 times as a set and repeating the set three times. The muscle tone was not significantly changed after intervention. However, the stiffness was decreased and lasted the effect lasted without intervention. The cervical flexion angle was increased, but the cervical extension angle was not significantly changed after the intervention. The left and right lateral flexion angles were increased and the effect lasted without any intervention. However, the left and right rotation angles were significantly changed after the intervention. Cervical lordosis increased not from $37^{\circ}$ to $41^{\circ}$ after the intervention. These results suggest that occipital bone stimulation by cervical stabilizing exercise had a positive effect on cervical stiffness, flexion and lateral flexion ROM, and lordosis in a patient with forward head posture.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.891-898
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• 1992

When catilever beams rotate about axes perpendicular to the underformed beam's longitudinal axis, their bending stiffnesses change due to the stretching caused by centrifugal inertia forces. Such phenomena result in variations of natural frequencies and mode shapes associated with constant speed rotational motions of the beams. These variations are important in many practical applications such as helicopter blades, turbomachines, and space structures. This paper presents the formulation of a set of linear equations governing the lateral motion of rotating cantilever beams. These equations can be used to provide accurate predictions of the variations of natural frequencies and mode shapes associated with constant speed rotational motions of the beams. These variations are important in many practical applications such as helicopter blades, turbomachines, and space structures. This paper presents the formulation of a set of linear equations governing the lateral motion of rotating cantilever beams. These equations can be used to provide accurate predictions of the variations of natural frequencies and mode shapes due to rotation. This technique is simpler and more consistent than other conventional techniques which are commonly used in the literature.

• Journal of Korean Neurosurgical Society
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• v.53 no.6
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• pp.331-336
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• 2013

Objective : The offset connector can allow medial and lateral variability and facilitate intralaminar screw incorporation into the construct. The aim of this study was to compare the biomechanical characteristics of C7 intralaminar screw constructs with and without offset connector using a three dimensional finite element model of a C6-7 cervical spine segment. Methods : Finite element models representing C7 intralaminar screw constructs with and without the offset connector were developed. Range of motion (ROM) and maximum von Mises stresses in the vertebra for the two techniques were compared under pure moments in flexion, extension, lateral bending and axial rotation. Results : ROM for intralaminar screw construct with offset connector was less than the construct without the offset connector in the three principal directions. The maximum von Misses stress was observed in the C7 vertebra around the pedicle in both constructs. Maximum von Mises stress in the construct without offset connector was found to be 12-30% higher than the corresponding stresses in the construct with offset connector in the three principal directions. Conclusion : This study demonstrated that the intralaminar screw fixation with offset connector is better than the construct without offset connector in terms of biomechanical stability. Construct with the offset connector reduces the ROM of C6-7 segment more significantly compared to the construct without the offset connector and causes lower stresses around the C7 pedicle-vertebral body complex.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.1
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• pp.125-138
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• 2024

Purpose: The aim of this study was to apply suboccipital muscle inhibition combined with neck muscle stabilization exercise to 20~30s IT industry employees who suffer from chronic non-specific neck pain. Methods: This study was designed as single-blind and randomized controlled trial. The study participants were 20~30s IT industry employees with chonic non-specific neck pain (VAS 3/10) who were divided into an experimental group (n= 20) subjected to suboccipital muscle inhibition with neck muscle stabilization exercise, and control group (n= 20); suboccipital muscle inhibition only. The intervention was applied three times per week for eight weeks. The neck pain·pressure pain threshold·range of motion, and disability index were measured at the 1st, 8th, and 10th week at follow up, then analyzed with an analysis of variance(ANOVA) using the SPSS program. Results: The total number of study participants was 37 (experimental group 19, mean age 34.6±5.3, control group 18, mean age 35.7±4.9). The comparison and analysis of change in VAS, the pressure pain threshold, and the range of motion except the extension (p>.05) revealed a statistically significant decrease between groups over eight weeks and follow up measurement (p<.01). Regarding the within the group differences, the right side of the neck pressure pain threshold showed a statistically significant decrease over eight weeks in the control group (p<.01). The right and left lateral flexion, and the right and left rotation were statistically significant for the experimental group over eight weeks and follow up measurement, but only the left lateral flexion (p<.05) for the control group over eight weeks. The neck disability index showed a slight decrease but this was not satistically significant for the between-grop or the within-group differences (p>.05). Conclusion: The intervention of suboccipital muscle inhibition and a neck muscle stabilization exercise are more beneficial for neck pain and the range of motion than the application of suboccipital muscle inhibition alone.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.2
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• pp.33-45
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• 2024

Purpose : This study aimed to compare the effects of spinal manipulation combined with medication on low back pain (LBP), range of motion, and disability in patients with chronic LBP. Methods : Twenty patients with chronic LBP were included in this study. The participants were randomly assigned to the spinal manipulation with medication group (n=10) or the medication only group (n=10). The intervention group received spinal manipulation for 15 minutes, twice a week, and took medication twice a day for eight weeks. The control group received the medication twice daily for eight weeks. Pain intensity assessed using the visual analog scale (VAS), range of motion, and disability due to LBP assessed using the Oswestry disability index were measured before and after the intervention. Results : The intervention group showed a significant improvement in pain intensity compared to the control group (p<.05), and the intervention and control groups significantly improved low back pain after the intervention (p<.05). The intervention group showed a significant improvement in the range of motion in flexion, extension, right lateral flexion, left lateral flexion, and right rotation (p<.05). The intervention group also showed a significant improvement in the change of disability in total score, pain intensity, personal care, lifting and standing compared to the control group (p<.05). Conclusion : This study showed that the combination of spinal manipulation and medication can benefit patients with chronic LBP, as evidenced by significant improvements in pain intensity, ROM, and disability. These findings suggest that utilizing both spinal manipulation and medication can positively affect individuals with chronic LBP. The results of this study should be applied in clinical settings to optimize treatment outcomes in patients with chronic LBP.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.3
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• pp.73-80
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• 2024

PURPOSE: This study examined the immediate effects of thoracic mobility exercises on the thoracic range of motion and chest expansion to provide data on thoracic mobility exercises in adults. METHODS: Adults were assigned randomly to two groups: the group that performed thoracic mobility exercises (TME group; n=10) or the group that performed thoracic mobility exercises using balance tools (TMEB group; n=10). The exercises were performed for 10 min in three different positions. The range of motion and chest expansion were measured before and after the exercise. RESULTS: The within-group comparisons before and after the intervention showed significant differences in the range of motion measurements for lateral flexion and rotation in the TME and TMEB groups (p < .05); difference in measurements of chest expansion was observed only in the TMEB group (p < .05). No significant differences in the range of motion for flexion and extension were observed in either group or during chest expansion in the TME group (p > .05). The between-group comparisons showed a significant difference in left lateral flexion (p < .05), whereas no other measures differed significantly (p > .05). CONCLUSION: The TME and TMEB groups showed significant increases in the thoracic range of motion; the TMEB group showed a significant increase in chest expansion.