• The Journal of Korean Physical Therapy
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• v.31 no.4
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• pp.199-203
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• 2019

Purpose: This study investigated the effects of shoulder protraction exercise according to weight by examining the surface electromyography (EMG) amplitude in the serratus anterior (SA), upper trapezius (UT), and pectoralis major (PM) as well as the activity ratio of each muscle. Methods: Twenty three winging scapula subjects participated in the study. The subjects performed scapula protraction at shoulder $90^{\circ}$ flexion and $60^{\circ}$ horizontal abduction with up to four (none, 1kg, 1.5kg, and 2kg) dumbbells in the supine position. The EMG data were collected from the dominant side muscles during a shoulder protraction exercise according to weight in the supine position. One way repeated measures analysis of variance (ANOVA) was used to compare the normalized activities of the SA, UT, and PM and the ratios of PM/SA and UT/SA. Results: The results showed that the activities of both the SA and UT were highest for the shoulder protraction exercise at 2kg in the supine position. The UT/SA ratio also was the lowest for exercise at 2kg. On the other hand, the activities of both the UT and PM/SA ratio were similar under all conditions. Conclusion: These results show that there is a need to selectively strengthen the SA muscle in the case of patients with the shoulder dysfunction. In particular, it is necessary to weigh 2kg when performing shoulder protraction exercises in the supine position to activate the SA muscle in patients with a winging scapula.

• Physical Therapy Korea
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• v.26 no.1
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• pp.1-7
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• 2019

Background: The Microsoft Kinect which is a low-cost gaming device has been studied as a promise clinical gait analysis tool having satisfactory reliability and validity. However, its accuracy is only guaranteed when it is properly positioned in front of a subject. Objects: The purpose of this study was to identify the error when the Kinect was positioned at a $45^{\circ}$ angle to the longitudinal walking plane compare with those when the Kinect was positioned in front of a subject. Methods: Sixteen healthy adults performed two testing sessions consisting of walking toward and $45^{\circ}$ obliquely the Kinect. Spatiotemporal outcome measures related to stride length, stride time, step length, step time and walking speed were examined. To assess the error between Kinect and 3D motion analysis systems, mean absolute errors (MAE) were determined and compared. Results: MAE of stride length, stride time, step time and walking speed when the Kinect set in front of subjects were investigated as .36, .04, .20 and .32 respectively. MAE of those when the Kinect placed obliquely were investigated as .67, .09, .37, and .58 respectively. There were significant differences in spatiotemporal outcomes between the two conditions. Conclusion: Based on our study experience, positioning the Kinect directly in front of the person walking towards it provides the optimal spatiotemporal data. Therefore, we concluded that the Kinect should be placed carefully and adequately in clinical settings.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.1
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• pp.101-110
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• 2019

PURPOSE: This study was conducted to analyze the effects of virtual reality inspiratory muscle training and conventional inspiratory muscle training on diaphragm movement and pulmonary function in patients with thoracic restriction. METHODS: This study measured diaphragm movement, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow (PEF), and thoracic mobility (upper, middle, and lower trunk) under two different conditions. Forty young women between 19 and 24 years of age who had no history of orthopedic symptoms for the last 6 months were divided into experimental and control groups. The experimental group performed virtual reality inspiratory muscle training and diaphragm breathing, and the control group performed conventional inspiratory muscle training and diaphragm breathing. RESULTS: The control group showed a significant increase in all dependent variables except for lower trunk mobility and PEF. The experimental group showed a significant increase in all dependent variables except for lower trunk mobility. Particularly, the experimental group showed significant increases in diaphragm movement (p<.05), FVC (p<.05), FEV1 (p<.05), and PEF (p<.05) relative to the control group. CONCLUSION: We recommend inspiratory muscle training with a virtual reality program over conventional training to improve diaphragm movement and pulmonary function in patients with thoracic restriction.

• Physical Therapy Rehabilitation Science
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• v.8 no.3
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• pp.158-161
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• 2019

Objective: Attentional focus is one of the critical factors that has consistently been demonstrated to enhance motor performance and motor skill. Focusing attention on the inside of the body while engaging in a particular exercise is called internal focus (IF) and focus on the external environment is called external focus (EF). The purpose of this study was to identify effects of IF and EF of attention on postural balance in healthy school-aged children. Design: Cross-sectional study. Methods: Twenty-four healthy school-aged children participated in this study. School-aged children was defined as children ages 8-12 years old. They performed the one-legged standing with EF (focusing on the marker at the level of participants' chest and 150 cm away), IF (focusing the supporting feet), and control (no instruction) respectively. The order of the focus condition was randomly selected. The center of pressure (COP) range, distance, and velocity was measured to compare the effects of applying different attentional focuses in the three conditions. Results: The results of our study show that differences in COP range, distance, and velocity among groups were not significant between the different attentional focuses, although all variables of EF were smaller than IF. It is postulated that the reason for this may be that school school-aged children between 8-12 years old go through a transitional phase from IF to EF in effective motor learning. Conclusions: These findings reveal that the type of attentional focus did not have any effect on postural balance in healthy school-aged children.

• PNF and Movement
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• v.12 no.3
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• pp.167-171
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• 2014

Purpose: The purpose of this study was to show the effects of voluntary change of weight bearing on the vastus medialis oblique and the vastus lateralis ratio during squat exercise. Methods: Twenty-four healthy adults were recruited for this study. The subjects performed squat exercise with median weight bearing, lateral weight bearing and non-changed weight bearing. The muscle activities of the vastus medialis oblique and the vastus lateralis were measured during the squat for all three conditions. The measured data were analyzed using one-way ANOVA to investigate the effect of muscle activation on the each condition. The statistical analyses were performed using SPSS ver. 17.0, and a p-value of less than 0.05 was considered significant for all cases. A post-hoc test was performed using Tukey's test. Results: The study showed that the vastus medialis oblique and the vastus lateralis ratio significantly changed according to the voluntary change of weight bearing during a squat. The vastus medialis oblique and the vastus lateralis ratio significantly decreased under the condition of voluntary lateral weight bearing. Conclusion: We suggest squat exercise on median weight bearing to increase the vastus medialis oblique and the vastus lateralis ratio. If your patient has.

• Physical Therapy Korea
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• v.28 no.3
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• pp.194-199
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• 2021

Background: The scapulo-thoracic musculatures including serratus anterior (SA), upper trapezius and lower trapezius can provide shoulder stability and functional shoulder movement. Objects: The muscle activities of upper and lower SA were compared during three different scapular protraction exercises in healthy individuals in sitting position. Methods: Twenty-five healthy subjects were participated. Electromyography device was used to measure muscle activity of upper and lower SA and trapezius muscles. Each subject was asked to perform three different scapular protraction exercises (scapular protraction [SP], SP with self-resistance [SPSR], SPSR with hand-exerciser [SPSRH]) in random order. One-way repeated measures analysis of the variance and a Bonferroni post hoc test were used. Results: The muscle activity of lower SA muscle was significantly different among three conditions (SP vs. SPSR vs. SPSRH) (p < 0.01). The lower SA muscle activity was significantly greater during SPSRH compared to SP and SPSR, which required joint stability more than SP and SPSR (p < 0.01). Conclusion: SPSRH exercise can be recommended to facilitate the muscle activity of lower SA. In addition, the intramuscular variation in the upper and lower SA during scapular protraction exercise is required to consider the effective rehabilitation.

• PNF and Movement
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• v.19 no.2
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• pp.261-267
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• 2021

Purpose: This study aimed to investigate changes in gait variables depending on whether a task was performed using a smartphone while walking on a ramp. Methods: The participants of this study were 41 college students attending U University located in Gyeongju City, Gyeongsangbuk-do. In this study, gait variables were measured during ramp gait while using a smartphone to perform a task and during ramp gait without performing such tasks. In other words, four walking conditions were used: 1) walking up a ramp, 2) walking up a ramp while using a smartphone to perform a task, 3) walking down a ramp, and 4) walking down a ramp while using a smart phone to perform a task. Gait variables were measured using a gait analysis tool (Legsys; BioSensics, USA), and stride time, stride length, stride velocity, cadence, and double support were analyzed. The order of measurements was randomized to control for order effects due to repeated measurements. Results: The comparative analysis of gait variables according to the presence or absence of smartphone use during ramp gait showed that there were significant differences in stride time, stride length, and stride velocity during both ramp ascent and ramp descent (p < 0.05). In both ramp ascent and ramp descent, stride time increased when walking using a smartphone, compared to when walking without using a smartphone (p < 0.05). However, in both ramp ascent and ramp descent, stride length and stride velocity were decreased when walking using a smartphone compared to when walking without using a smartphone (p < 0.05). Conclusion: The study results showed that the use of a smartphone during walking can affect safety. Therefore, it is necessary to improve the awareness of risks associated with walking while using a smartphone, and further research needs to be conducted in various environments and with different ramps.

• Physical Therapy Korea
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• v.29 no.1
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• pp.11-18
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• 2022

Background: Muscle activities of gluteus maximus (GM) and hamstring (HAM) have important roles in the stability and mobility of the hip joint during various functional activities including bridge and prone hip extension exercises. Objects: The purpose of this study is to investigate muscle activities of GM, multifidus (MF) and HAM during three different bridge exercises in healthy individuals. Methods: Twenty healthy subjects were participated. Electromyography device was used to measure muscle activities of GM, MF and HAM. Each subject was asked to perform three different bridge exercises with hip abduction (0°, 15°, 30°) in random order. One-way repeated measures analysis of the variance and a Bonferroni post hoc test were used. Statistical significance was set at α = 0.01. Results: The muscle activity of GM was significantly different among three conditions (hip abduction 0°, 15°, 30°) (adjusted p-value [Padj] < 0.01). The muscle activity of GM was significantly greater during bridge exercise with hip abduction 30° compared to 0° and 15° (Padj < 0.01). There was no significant difference in the muscle activity of MF and HAM muscle (Padj > 0.01). The ratio of muscle activity (ratio = GM/HAM) during bridge exercise with hip abduction 30° was significant greater compared to the hip abduction angles 0° and 15° (Padj < 0.01). Conclusion: Bridge exercise with hip abduction 30° can be recommended to selectively facilitate the muscle activity of GM and improve the ratio of muscle activity between GM and HAM.

• Geomechanics and Engineering
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• v.25 no.3
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• pp.179-194
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• 2021

In this paper, to study the stability of surrounding rock during roadway excavation in different rock mass structures, the physical model test for roadway excavation process in three types of intact rock mass, layered rock mass and massive rock mass were carried out by using the self-developed two-dimensional simulation testing system of complex underground engineering. Firstly, based on the engineering background of a deep mine in eastern China, the similar materials of the most appropriate ratio in line with the similarity theory were tested, compared and determined. Then, the physical models of four different schemes with 1000 mm (height) × 1000 mm (length) × 250 mm (width) were constructed. Finally, the roadway excavation was carried out after applying boundary conditions to the physical model by the simulation testing system. The results indicate that the supporting effect of rockbolts has a great influence on the shallow surrounding rock, and the rock mass structure can affect the overall stability of the surrounding rock. Furthermore, the failure mechanism and bearing capacity of surrounding rock were further discussed from the comparison of stress evolution characteristics, distribution of stress arch, and failure modes in different schemes.

• Physical Therapy Korea
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• v.29 no.3
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• pp.215-224
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• 2022

Background: The presence of the lumbopelvic-hip neuromuscular chain is essential for dynamic spinal stabilization; its therapeutic effects on dynamic movements of the distal extremity segment and underpinning motor mechanism remain unknown and warrant further study on participants with low back pain (LBP). Objects: We aim to compare the effects of the broken chain exercise (BCE) and connected chain exercise (CCE) on electromyography (EMG) amplitude and onset time in participants with and without LBP. Methods: Randomized controlled clinical trial. A convenience sample of 40 nonathletic participants (mean age: 24.78 ± 1.70) with and without LBP participated in this study. All participants underwent CCE for 30 minutes, 30-minute daily. We measured EMG amplitude and onset times on bilateral erector spinae (ES), gluteus maximus (GM), hamstring (HAM), transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) during the prone hip extension (PHE) test before and after the BCE and CCE. We used multivariate analysis of variance (MANOVA) to analyze the amplitude and onset time difference between exercises (BCE and CCE) and Pearson's correlations to determine any synergistic relationship among the HAM, GM, bilateral TrA/IO, and ES muscles. The statistical analyses were used at p < 0.05. Results: MANOVA showed that CCE was more decreased on EMG amplitude in HAM and bilateral ES, while increased GM and contralateral TrA/IO than BCE (p < 0.05). MANOVA EMG onset time data analyses revealed that the main effect of the conditions was significant for all HAM, GM, and bilateral ES muscles, whereas the main effect for the group was significant only for GM and contralateral ES in healthy and LBP groups. Pearson's correlation coefficient was computed to assess the relationship between BCE and CCE on dependent variables. In most of the muscles, there was a strong, positive correlation between the two variables, and there was a significant relationship (p < 0.001). Conclusion: CCE produced more effective and coordinated core stabilization and motor control mechanism in the lumbopelvic-hip muscles in participants with and without LBP during PHE than BCE.