• Journal of the Korean Society of Physical Medicine
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• v.14 no.2
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• pp.9-19
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• 2019

PURPOSE: This study compared the effects of three different clamshell exercises (CLAM) on the gluteus medius (GMED), quadratus lumborum (QL), anterior hip flexor (AHF), gluteus medius/quadratus lumborum ratio, and gluteus medius/anterior hip flexor ratio by studying the activities of participants with GMED weakness. METHODS: Eleven subjects with weak GMED participated in this study. Subjects performed CLAM under three different conditions (standard, and modified 1 and 2). Surface electromyography was then used to measure the muscle activity and one-way repeated-measures analysis of variance was used to assess the statistical significance of the measured variables. RESULTS: GMED and the QL muscle activities did not differ significantly between the standard CLAM and the modified CLAM with the 2 different foot positions (F=4.74, P=.02; F=4.57, P=.02, respectively). AHF activity was significantly different in the two different foot positions when compared to the standard CLAM (F=11.17, P=.00). However, there was no significant difference between the AHF activities for the two different foot positions (P=.09). Finally, GMED/QL and GMED/AHF ratios were not significantly different between the three different CLAM exercises (F=.63, P=.55; F=.82, P=.45, respectively). CONCLUSION: Modified CLAM can be recommended as a good method to minimize AHF activity while maintaining GMED activity in subjects with weak GMED.

• Journal of the Korean Society of Physical Medicine
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• v.17 no.3
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• pp.23-30
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• 2022

PURPOSE: This study was designed to investigate the effects of keeping contraction of abdominal and pelvic floor muscles on 3D pelvic stability in individuals with nonspecific chronic low back pain (CLBP) during normal speed walking. METHODS: The subjects were 20 adults with CLBP deformity and had moderate pain intensity of the visual analog scale. A three-dimensional camera capture system was used to collect kinematic pelvic motion data with and without contraction of the abdominal and pelvic floor muscles during gait. The subjects were asked to walk on a walkway in the lab room and they were attached 40 reflective markers to their pelvic segment and lower extremities. A Visual3D Professional V6 program and Vicon Nexus software were used to analyze 3D pelvic kinematic data. RESULTS: There were significant differences between with and without contraction of the abdominal and pelvic floor muscles of the pelvic depression and the total pelvic motion in coronal plane during gait (p < .05). However, there were no significant differences in any of the maximal motion of the pelvic segment in sagittal and transverse motion plane according to the different muscle contraction conditions (p > .05). CONCLUSION: The results of this study suggest that maintaining co-contraction of the abdominal and pelvic floor muscles in individuals with CLBP increased pelvic stability and contributed to preventing excessive pelvic movements during gait.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.46.3-47
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• 2021

Recently a multilayer spectral inversion (MLSI) model has been proposed to infer the physical parameters of plasmas in the solar chromosphere. The inversion solves a three-layer radiative transfer model using the strong absorption line profiles, H alpha and Ca II 8542 Å, taken by the Fast Imaging Solar Spectrograph (FISS). The model successfully provides the physical plasma parameters, such as source functions, Doppler velocities, and Doppler widths in the layers of the photosphere to the chromosphere. However, it is quite expensive to apply the MLSI to a huge number of line profiles. For example, the calculating time is an hour to several hours depending on the size of the scan raster. We apply deep neural network (DNN) to the inversion code to reduce the cost of calculating the physical parameters. We train the models using pairs of absorption line profiles from FISS and their 13 physical parameters (source functions, Doppler velocities, Doppler widths in the chromosphere, and the pre-determined parameters for the photosphere) calculated from the spectral inversion code for 49 scan rasters (~2,000,000 dataset) including quiet and active regions. We use fully connected dense layers for training the model. In addition, we utilize a skip connection to avoid a problem of vanishing gradients. We evaluate the model by comparing the pairs of absorption line profiles and their inverted physical parameters from other quiet and active regions. Our result shows that the deep learning model successfully reproduces physical parameter maps of a scan raster observation per second within 15% of mean absolute percentage error and the mean squared error of 0.3 to 0.003 depending on the parameters. Taking this advantage of high performance of the deep learning model, we plan to provide the physical parameter maps from the FISS observations to understand the chromospheric plasma conditions in various solar features.

• Physical Therapy Korea
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• v.30 no.3
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• pp.221-229
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• 2023

Background: In modern society, the use of computers accounts for a large proportion of our daily lives. Although substantial research is being actively conducted on musculoskeletal diseases resulting from computer use, there has been a recent surge in interest in improving the working environment for prevention. Objects: This study aimed to examine the effects of posture correction feedback (PCF) on changes in neck posture and muscle activation during computer typing. Methods: The participants performed a computer typing task in two sessions, each lasting 16 minutes. The participant's dominant side was photographed and analyzed using ImageJ software to verify neck posture. Surface electromyography (EMG) was used to confirm the participant's cervical erector spinae (CES) and upper trapezius muscle activities. The EMG signal was analyzed using the percentage of reference voluntary contraction and amplitude probability distribution function (APDF). In the second session, visual and auditory feedback for posture correction was provided if the neck was flexed by more than 15° in the initial position during computer typing. A 20-minute rest period was provided between the two sessions. Results: The neck angle (p = 0.014), CES muscle activity (p = 0.008), and APDF (p = 0.015) showed significant differences depending on the presence of the PCF. Furthermore, significant differences were observed regarding the CES muscle activity (p = 0.001) and APDF (p = 0.002) over time. Conclusion: Our study showed that the feedback system can correct poor posture and reduces unnecessary muscle activation during computer work. The improved neck posture and reduced CES muscle activity observed in this study suggest that neck pain can be prevented. Based on these results, we suggest that the PCF system can be used to prevent neck pain.

• Physical Therapy Rehabilitation Science
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• v.13 no.2
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• pp.187-195
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• 2024

Objective: Physical activity can promote physical and mental well-being. University students are more sedentary recently due to the increased use of computers and other technology. The aim of this study was to investigate differences between immersive 360-degree virtual cycling (IVC) and virtual cycling with head-mounted display (VCHMD) on aerobic capacity and usability in young adults. Design: A crossover study. Methods: Twenty-five university students (13 male, 12 female) participated in this study and completed 2 separate 30 min cycling sessions, such as IVC and VCHMD. In the IVC, participants rode on a stationary cycle while watching curved TV where recorded video was played. To enhance the sense of realism, auditory stimulation was given to the headset, and the gyroscope sensor was used to track the screen as the head moved. In the VCHMD, participants rode on the stationary cycle with head-mounted display, and other conditions were the same as IVC. Participants were assessed the aerobic capacity which included gas analyzer and portable near-infrared spectroscopy, and usability which included simulator sickness questionnaire and system usability scale. Results: Aerobic capacity was significantly difference in the IVC compared with the VCHMD except for the total hemoglobin of right and left rectus femoris and muslce oxygen saturation of left rectus femoris (p<0.05). Cybersickness was less in the IVC than VCHMD and usability was high in the IVC than VCHMD (p<0.05). Conclusions: The findings suggested that IVC might be beneficial exericse to improve aerobic capacity and has lower cybersickness and higher usability than VCHMD.

• Journal of the Korean Institute of Educational Facilities
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• v.14 no.4
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• pp.75-85
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• 2007

The purpose of this study is to find out the characteristics of physical planning elements in the pedestrian malls when cultural events for young ages proved; the planning strategies for the regeneration of the block of Kyungchun-railroad track, which is removing planned in campus surroundings. Local Government' initiation makes possible to make improvement and give administrative and financial support which is sensitive to the existing conditions of railroad for the better living environment. Thus, this research suggests how the block of Kyungchun-railroad track, which is removing planned, as a newly organized pedestrian mall design system can cope with collaborating a board and community, which has in campus surroundings related. This study consists of following four parts; 1. six-case pedestrian mall in campus surroundings in Seoul were analyzed in terms of physical and cultural factors for young ages between university and community. 2. we focused on the analysis of correlation between the physical planning factors and the spatial requirements for cultural event when the pedestrian mall in campus surroundings is designed. The paper's significance lies in that it shows a new direction in urban renewal planning and design which has been made into a pedestrian mall plan through in support of the application to the pilot project compared with previous physical environment.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.3
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• pp.302-314
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• 2015

There is an adsorption method using activated carbon as a typical method for removing elemental mercury. Physical characteristics of activated carbon such as specific surface area and volume of pore (micro and meso) have positive effect for mercury adsorption. Activated carbon is carbon-based material with a high specific surface area. This activated carbon can be manufactured through carbonization and activation process. In this process, physical characteristics of specific surface area and pore distribution are changed by controlling operating parameters like temperature, time and reagent of activation. In this study, we evaluated characteristics of activated carbons manufactured from pinewood and coal with the operating parameters. We evaluated mercury adsorption capacities of the activated carbons having excellent physical characteristics and compared those to the commercial activated carbon.

• The Journal of Korean Physical Therapy
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• v.29 no.4
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• pp.218-222
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• 2017

Purpose: Driving is an important activity that is affected by various motor and cognitive deficits after stroke. On the other hand, there is no standard screening tool to evaluate the sitting asymmetry during driving, which is the stereotyped postural characteristic observed in patients with stroke. Therefore, this study compared the buttock pressure during simulated driving between healthy adults and patients with stroke. Methods: Ten post-stroke patients and ten healthy subjects participated in the experiment. The participants experienced simulated driving of 6.1 km during approximately 5 minutes for adaptation. The driving scenario consisted of 3.5 km urban traffic conditions, 10 km straight highway, and 7 km curved or hilly rural roads. Force sensitive application (FSA) was used to analyze the distribution of the buttock pressure on the driver's seat. The symmetry index (SI) was determined using the average buttock pressure of each side of the buttock. The closer SI is to zero, the higher the symmetry of buttock pressure. Results: These studies showed that the SI of healthy subjects was significantly closer to zero than that of the stroke patients. Conclusion: The buttock pressure of the stroke patients showed more asymmetry than that of the healthy subjects during simulated driving. Therefore, a therapeutic approach is needed for symmetrical sitting to improve the driving performance.

• The Journal of Korean Physical Therapy
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• v.27 no.5
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• pp.292-298
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• 2015

Purpose: The purpose of this study was to examine the effects of dual tasks on balance and postural control during standing in patients with cerebellar ataxia (CA). It was hypothesized that CA patients would exhibit different sway characteristics of the center of mass (COM) depending on the complexity of the secondary cognitive tasks compared with normal control subjects. Methods: A total of 8 patients with CA and age-matched healthy control subjects participated in this study. They were instructed to perform two balance tasks (non-dual and dual movement) with 3 different complexity of dual tasks. Range, variability, and velocity of COMs were measured. Results: According to the results CA patients showed deficits in balance and postural control with increased dual-task complexity during the static balance task in saggital sway movements. However, there was no significant difference in static balance in frontal sway. With higher difficulty in the cognitive task, CA patients took longer to stabilize their body center, while normal control subjects showed no change between conditions. In addition, CA patients had a greater COM resultant velocity during recovery in the dual-task condition compared with the single-task condition. These findings indicate that CA patients had defendable compensatory strategies in performing dual tasks. Conclusion: In conclusion, CA patients appeared to manage the priority to balance and postural control. Particularly in a situation with a postural threat such as when potential consequences of the loss of stability increase, they appeared to prioritize the control of balance and posture over the performance of the secondary task.

• The Journal of Korean Physical Therapy
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• v.27 no.5
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• pp.304-310
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• 2015

Purpose: The purpose of this study was to examine the change in the kinematics and kinetics of the knee joint depending on high-heeled shoes during sit-to-stand (SitTS) task. Methods: Nineteen healthy females participated in this study. The subjects performed the SitTS task wearing high-heeled shoes and barefoot. The experiment was repeated three times for each task with foot conditions. The kinematics and kinetics of the knee joint were measured and analyzed using a 3D motion analysis system. Results: The result of this study showed kinematic and kinetics differences in knee joints during the SitTS task based on high-heeled shoes. Significant differences in knee flexion angle were observed during SitTS. The knee extensor force showed statistically significant differences during SitTS tasks. At the initial of SitTS, the knee flexor and extensor moment showed significant differences. The knee extensor moment showed statistically significant differences at the terminal of SitTS. At the maximum of SitTS, the knee extensor moment showed statistically significant differences. Conclusion: Therefore, wearing high-heeled shoes during SitTS movements in daily life is considered to influence knee joint kinematics and kinetics due to the HH, suggesting the possibility of increased risk of patellofemoral pain, and knee osteoarthritis caused by changes in loading of the knee joint.