• The Journal of Korean Physical Therapy
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• v.30 no.2
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• pp.47-53
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• 2018

Purpose: To find the effect of visual feedback of head angle with using a mobile posture-aware system on craniocervical angle and neck and shoulder muscles fatigue for preventing or decreasing the forward head posture. Methods: Twenty-four healthy young adults in Chungbuk to participate in this study. The subjects started to watch a movie clip for 10 minutes with visual feedback in $0^{\circ}$, $30^{\circ}$, and $60^{\circ}$ of head angles. During the task, surface electromyography (EMG) was used to collect data from the upper trapezius (UT), sternocleidomasetoid muscle (SCM), cervical erecter spinae (CES) during watching the smartphone. Craniocervical angles were measured using a sagittal-view photograph of the subject in a sitting posture. A one-way repeated analysis of variance with a significant level of 0.05 used for statistical analysis. Results: Craniocervical angle with $0^{\circ}$ visual feedback was significantly greater than $30^{\circ}$ and $60^{\circ}$. Craniocervical angle with $30^{\circ}$ visual feedback was significantly greater than $60^{\circ}$. In addition, MDF of UT muscles in $0^{\circ}$ and $30^{\circ}$ of visual feedback was significantly greater than $60^{\circ}$. Conclusion: We concluded that $0^{\circ}$ visual feedback of head angle with using a mobile posture-aware system would be beneficial to prevent or decrease forward head posture during watching a smartphone. We also could recommend using of $30^{\circ}$ visual feedback in case of caring UT muscle fatigue primarily.

• The Journal of Korean Physical Therapy
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• v.11 no.3
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• pp.1-12
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• 1999

The aim of this study is to examine the sensitivity and characteristics of electromyography abnormalities detected by using various paramenters in patients with lumbosacral radiculopathies. EMG is widely used for disgnosing and localizing the level of radiculopathy. The results of the study were as follow : 1. In electromyography, L5 radiculopathy usa 95 cases(51.690). S1 radiculopathy was $45m(24.5\%)$ L4 radiculopathy was 18cases $(9.8\%)$, and L2, 3 radiculopathy was 8cases$(4.3\%)$. Remains 18cases$(9.8\%)$ had no definite radiculopathy. 2. Peroneal and tibial motor nerve conduction velocity studies were not significant as compared to the side to side. 3. Latency of H-reflex in L5 radiculopathy was $30.55\pm2.47$ in affected side, $29.47\pm2.29$ in unaffected side, in S1 radiculopathy was $33.00\pm2.03$ in affected side, R30.18\pm2.21$ in unaffected side. It was statistically significant(p<0.01). H-reflex mean difference of S1 radiculopathy group was significantly prolonged as compared to the L5 and S1 radiculopathies(p<0.001). 4. In L2, 3 radiculopathy, abnormal spontaneous activities and motor unit action potentials were showed high sensitivity in upper lumber paraspinal, hip adductors, quadriceps and iliopsoas muscles. 5. In L4 radiculopathy, lower lumbar paraspinal, tibialis anterior, quadriceps muscles were showed high sensitivity. 6. In L5 radiculopathy, lower lumbar paraspinal, extensor hallucis longus, extensor digitorum longus, peroneus longus, extensor digitorum brevis, gluteus maximus, tensor fasciae latae muscles were showed high sensitivity. 7. In S1 radiculopathy, lower lumbar paraspinal, gluteus maximus, peroneus longus, soleus, abductor hallucis, hamstrings, extensor digitorum brevis, extensor hallucis lognus, gastrocnemius muscles were showed high sensitivity.

• PNF and Movement
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• v.14 no.1
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• pp.1-6
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• 2016

Purpose: The purpose of this study was to analyze the effects of proprioceptive neuromuscular facilitation (PNF) patterns on electromyography (EMG) activity in the rectus abdominis, internal abdominal oblique, external abdominal oblique, and erector spinae according to position changes. Methods: Ten healthy adults volunteered to participate in the study. The subjects were required to complete exercises that followed two PNF extremity patterns, namely, an upper extremity extension-adduction-internal rotation pattern and a lower extremity flexion-adduction-external rotation pattern. The exercises were applied in the supine, side-lying, and sitting positions. Repeated measure one-way ANOVA and post-hoc Bonferroni correction were used to determine the influence of the patterns on muscle activity for each muscle, and descriptive statistics were then used to determine the local/global muscle ratios. Results: The upper extremity pattern had a significant effect on the rectus abdominis and erector spinae in the supine position, and on the internal oblique and external oblique in the sitting position (p<0.05). The median value for the internal oblique/rectus abdominis showed a high ratio of 2.05, and a high ratio of 1.01 was shown for the internal oblique/external oblique in the sitting position. The lower extremity pattern had a significant effect on the rectus abdominis in the side-lying position and on the internal oblique, external oblique, and erector spinae in the sitting position (p<0.05). The median value for the internal oblique/rectus abdominis showed a high ratio of 2.83 in the sitting position and a high ratio of 1.30 for the internal oblique/external oblique in the side-lying position. Conclusion: The PNF pattern increases local muscle activation in an unstable position. Therefore, when the pattern is used for intervention purposes, trunk stability and varied position changes should be taken into account.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.8 no.2
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• pp.7-12
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• 2010

Purpose : The purpose of this study was to determine the effects of hip adduction using a ball on the activation of the vastus medialis oblique (VMO) and the vastus lateralis (VL) during dynamic semisquat exercises. Methods : Twenty seven participants performed three repetitions of a double-leg semisquat and squeeze semisquat (semisquat with hip adduction using a ball) at $60^{\circ}$ knee flexion. The activation of the VMO and the VL was recorded at dominant leg during both semisquat exercises using surface electromyography (MP 100). EMG data were normalized to the maximal voluntary isometric contraction (MVIC) of the quadriceps produced during seated, isometric knee extension. Results : Results of paired t-test analyses revealed that there were no differences between activity of the VMO and the VL in both double-leg semisquat and squeeze semisquat. The activity of the VMO was significantly increased in squeeze semisquat whereas there was no difference in activity of the VL between double-leg semisquat and squeeze semisquat. Conclusion : Combining hip adduction using a ball with semisquat at $60^{\circ}$ knee flexion preferentially increases the activity of the VMO. We can conclude that semisquat at $60^{\circ}$ knee flexion with hip adduction using a ball selectively recruits the VMO. Rehabilitation for quadricep imbalance should consider these findings when selecting exercises which could preferentially activate the VMO.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.8 no.2
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• pp.33-37
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• 2010

Purpose : We investigated the effects of the insole types on lower leg muscle activation during treadmill walking. The three insole types investigated for this study were normal insole, medial wedge insole, and viscoheel. Methods : Participants were assigned into three groups. People with foot transformation were excluded from this study. Each participant walked for ten minutes. The first day we applied a normal insole. On the second day, a medial wedge insole was applied. Finally, on the last day a viscoheel was applied. After walking on a treadmill for ten minutes, we measured muscle activation in lower leg muscles (gastrocnemius and tibialis anterior). Surface electromyography (EMG) was used to measure muscle activity. The data were analyzed using one-way analysis of variance (ANOVA) with repeated measures to determine the statistical significance. Results : The results of this study were summarized as follows. While walking on the treadmill, root mean square (RMS) values of the gastrocnemius when the viscoheel was applied were significantly lower than the other insole types. There was no significant difference for the RMS values for the tibialis anterior using viscoheel. The normal insole and viscoheel insole were significantly different in a post hoc analysis. However, there was no significant difference for normal insole and medial wedge insole. Conclusion : Using a viscoheel insole decreases muscle activity of the lower leg. Therefore, in conclusion, the viscoheel insole type reduces the load on the lower leg during walking.

• Journal of the Ergonomics Society of Korea
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• v.34 no.1
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• pp.11-18
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• 2015

Objective: The aim of this study was to understand the effects of phone weight on the typing performance and muscle recruitment in the neck and upper extremity while typing a text message with dominant hand. The iPhone4 and iPhone5 were compared due to their 28-gram differences in weight. Background: Too much use of a cellular phone can lead the musculoskeletal disorders in the upper extremity. Phone makers tend to make their new models bigger, lighter, faster and smarter. Method: Fourteen healthy volunteers without any history of neuromuscular disorders or ongoing pain who used their smartphone more than one year were recruited. A 112g phone (iPhone5) and a 142g phone (iPhone4) were used for typing the lyric of the Korean national anthem with their dominant hand. Typing duration, the typing error, the perceived fatigue, and preference was investigated. Muscle recruitment and the resting gap of neck (middle trapezius and levator scapula), shoulder (infraspinatus and mid deltoid), elbow (biceps brachii and brachioradialis), thumb (extensor and abductor policis brevis) were collected using surface electromyography. Typing error was counted and typing speed was calculated in characters per min. The data were analyzed using a paired t-test and chi-square (${\chi}^2$) analysis for the effects of phone weight on the typing performance parameters and muscle recruitment. Results: Typing text message with iPhone5 took longer but had less muscle recruitment in brachioradialis, and extensor policis brevis muscles. Lighter weight of iPhone5 made biceps brachii to rest less without increasing the mean %EMG. Conclusion/Application: Findings of this study can be valuable information for phone designers to develop more productive device and for smartphone users to prevent the musculoskeletal disorders in the upper extremities.

• PNF and Movement
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• v.13 no.2
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• pp.81-88
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• 2015

Purpose: The purpose of this study was to analyze the effect of normal timing according to angular motion in PNF patterns on electromyography (EMG) activity in rectus abdominis, internal oblique abdominal muscle, external oblique abdominal muscle, and erector spinae. Methods: Ten healthy adults volunteered to participate in this study. The participants were required to complete following two PNF extremity patterns; upper extremity extension- adduction-internal rotation pattern with $180^{\circ}$, $90^{\circ}$, $30^{\circ}$ and lower extremity flexion- adduction-external rotation pattern with $0^{\circ}$, $60^{\circ}$, $90^{\circ}$. A paired t-test was used to determine the influence of the two PNF patterns on muscle activity in each muscle. Descriptive statistics were used to determine the ratio of local muscle activity to global muscle activity. Results: In terms of their effect on applied normal timing, the upper and lower extremity pattern significantly affected the rectus abdominis, internal oblique, external oblique, and erector spinae (p < .05). The upper extremity pattern (at an extension angle of $30^{\circ}$) and the lower extremity pattern ((at a flexion angle of $90^{\circ}$) influenced the rectus abdominis, internal oblique, external oblique, and erector spinae (p < .05). Conclusion: The effect of the upper and lower extremity patterns on applied normal timing was significant in that these patterns increased trunk muscle activation. The upper extremity pattern (at an extension angle of $30^{\circ}$) and the lower extremity pattern (at a flexion angle of $90^{\circ}$) increased trunk muscle activation. Normal timing is required to increase trunk muscle strength and extremity movement.

• Physical Therapy Korea
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• v.28 no.2
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• pp.132-137
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• 2021

Background: Flat feet can be identified by assessing the collapse of the medial longitudinal arch (MLA) and these conditions can trigger epidemiological changes in the feet. Many of previous studies compared the muscle activity of lower body in terms of intervention and dynamics to treat the structural defect of flat feet. However, few studies have investigated or analyzed the muscle activity of gastrocnemius muscle in the subjects with flat feet. Objects: This study investigated the differences in changes of medial and lateral plantar flexors in subjects with flat feet during bipedal heel-rise (BHR) task and analyzed the differences in muscle activity between two groups by measuring the electromyography (EMG) of abductor hallucis (AH), tibialis anterior (TA), medial gastrocnemius (MG), lateral gastrocnemius (LG). Methods: A total of Twenty one adult females participated in this experiment. Subjects were assigned to groups according to the navicular drop test. The task was applied to the leg, where the heel lifting action prevailed. The muscle activity of the medial and lateral feet plantar flexors was evaluated, and the % maximum voluntary isometric contractions (%MVIC) of these were compared. Results: For the difference between groups the muscle activity (%MVIC) of LG muscle was statistically significantly low in flat feet group compared to healthy feet group (flat feet: 64.57, healthy feet: 90.17; p < 0.05). Conclusion: The results of this study will contribute to identifying the muscle activities of medial and lateral feet plantar flexors among subjects with flat feet, which can cause abnormal epidemiological changes in the feet.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.2
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• pp.125-135
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• 2019

PURPOSE: This study examined the effects of low frequency neuromuscular electrical stimulation (NMES) training on abdominal obesity in middle-aged women through electromyography and ultrasound. METHODS: Twenty-two middle aged women with abdominal obesity participated in the study. A low-frequency NMES device was used on the abdomen and waist of each subject for 20 minutes each (a total of 40 minutes) three times a week for eight weeks. The waist-hip ratio (WHR), weight and BMI (Body Mass Index) were measured. Electromyography (EMG) and ultrasound measurements were performed three times in total (pre-intervention, four weeks into the intervention, and eight weeks post-intervention) to examine the effects of low-frequency NMES on the abdominal muscle activity, muscle thickness, and subcutaneous fat. RESULTS: The results indicated a difference in the WHR and waist circumference before and after intervention (p<.05). The external oblique muscle (EO) showed a significant increase in muscle activity during all measurements taken post-intervention (p<.05). The abdominal subcutaneous fat thickness also showed a significant decrease between each measurement (p<.05). The test results showed that the abdominal subcutaneous fat thickness values taken eight weeks post-intervention were significantly lower than those taken pre-intervention and four weeks into the intervention (p<.05). CONCLUSION: These findings show that low-frequency NMES device training can be applied to middle-aged women with abdominal obesity to improve their body shape and exercise performance.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.2
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• pp.177-186
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• 2024

Purpose : The purpose of this study was to use oral instruction and taping to induce abdominal draw-in in the previous study, but there is a lack of research on the comparison of effects. Therefore, in this study, we would like to study how the effect of oral instruction, taping, and no feedback can affect muscle activity when performing abdominal draw-in pier exercises. Methods : Before the experiment, group A trained piers and applied only draw-in piers, group B applied taping feedback, and group C were divided into three groups per week for six weeks, and three sets of contractions for five seconds per group were performed five times, and a minute break was provided between each exercise. As a measurement tool, a wireless surface electromyography (EMG) was used to measure surface electromyography (Telemyo-DTS, NORAXON, USA) that derives a synthetic unit of muscle using a surface electrode. For statistical processing of data, the analysis is performed using the SPSS/PC Version 25.0 statistical program for Windows, and the statistical significance level is a=.05 Results : First, the duration was somewhat shorter in order to more accurately compare the muscle activity of the core muscles. Therefore, future research needs to be research that can be exercises with precise biofeedback and taping applied over a longer period of time. Secondly, it is believed that there is no significant difference, since the subjects were studied in healthy young adult men and women, not patients. Thirdly, they could not control the daily life of the subjects. Through future research, it is necessary to analyze the correlation between muscle activity and abdominal muscle thickness by adding ultrasound in addition to muscle activity in various age groups. Conclusion : During draw-in bridge exercise according to feedback, the muscle activity of the back muscle increased, and there was no significant difference in the muscle activity of the back muscle according to each feedback. Therefore, both the feedback applied during the draw-in pier exercise and the control group are effective in changing the thickness of the abdominal muscles.