• Physical Therapy Korea
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• v.26 no.2
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• pp.61-68
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• 2019

Background: Forward head posture (FHP) is a postural alignment of the cervical vertebrae that leads to increased gravitational load on cervical segmental motions. The overhead arm lift test assesses the ability to actively dissociate and control low cervical flexion and move the shoulders through overhead flexion. Objects: The purpose of this study was to explore muscle activities in the upper trapezius (UT), serratus anterior (SA), sternocleidomastoid (SCM), and lower trapezius (LT) alongside changes in head position during the overhead arm lift test in individuals with FHP. Methods: Fifteen subjects with forward head posture and fifteen subjects with normal subjcects were enrolled in this study. The patients performed the overhead arm lift test, and muscle activities of the UT, SCM, SA, and LT were measured using surface electromyography and by evaluating changes in head position. Independent t-tests were used to detect significant differences between the two groups and Cohen's d was calculated to measure the size of the mean difference between the groups. Results: The FHP group demonstrated significantly increased muscle activity of the UT ($32.46{\pm}7.64$), SCM ($12.79{\pm}4.01$), and LT ($45.65{\pm}10.52$) and significantly decreased activity in the SA ($26.65{\pm}6.15$) than the normal group. The change in head position was significantly higher in the FHP group ($6.66{\pm}2.08$) than the normal group. Effect sizes for all parameters assessed were large between the two groups. Conclusion: The subjects with excessive FHP displayed were unable to fix their heads in position during the overhead arm lift test. The overhead arm lift test can thus be used in clinical settings to confirm control of the neck in these subjects.

• The Journal of Korean Physical Therapy
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• v.22 no.5
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• pp.1-8
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• 2010

Purpose: This study aimed to provide a scientific basis for effects of the push-up plus exercise program on scapular position and on muscle activity in individuals with rounded shoulder posture (RSP). Methods: The supine method was applied to 46 potential subjects, of which 30 with RSP were selected. Subjects with RSP were divided into two groups: a gender push-up plus group as the experimental group a pectoralis minor self.stretch group as the control group. RSP data after 4 weeks of each intervention were obtained and analyzed to measure the activities of the 3 muscles. Results: The two groups differed significantly with regard to EMG changes in the serratus anterior (p<0.05). The EMG results indicated a significant reduction in the activity of the upper trapezius in the experimental group (p<0.05). EMG results indicated a significant increase in the activity of the serratus anterior after the intervention (p<0.05). EMG results of the subjects in the control group indicated that the activity of the upper trapezius significantly decreased (p<0.05). The RSP values of the subjects in both groups were significantly decreased (p<0.00). Conclusion: An improvement in the strength of the serratus anterior, and in the stretch effectiveness of the pectoralis minor, as well as changes in the scapular position were observed after 4 weeks of push-up plus exercise by the subjects.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.3
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• pp.75-80
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• 2018

PURPOSE: Scapular stability is very important to arm function during activities of daily living. The push-up plus exercise is commonly used to stabilize the shoulder muscles. In the present study, we designed an elastic shoulder band (ESB) that could be used with the push-up plus exercise and studied muscle activities of the serratus anterior (SA) and the lower and the upper trapezius (LT and UT) on stable and unstable support. METHODS: Fifteen healthy people participated in this study. Three muscles were investigated using surface EMG with and without the ESB on stable and unstable support. All subjects performed each trial three times for 7 seconds per set and rested for 30 seconds. Repeated one-way ANOVA was used for statistical analyses. RESULTS: The EMG activity of the SA was significantly different during the push-up plus exercise on stable support with the ESB compared with that on unstable support without the ESB (p<.05). However, there were no differences in the activities of UT and LT on stable and unstable support (p>.05). CONCLUSION: The ESB was effective for the activity of SA during the push-up plus exercise on stable support; therefore, it has the potential for use by people during push-up plus exercises. However, further studies are required to investigate the rehabilitation tools for patients with shoulder instability.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.1
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• pp.41-48
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• 2013

PURPOSE: This study was to determine the effect of the plane of movement (sagittal plane vs. scapular plane) and shoulder flexion angle ($90^{\circ}$ vs. $130^{circ}$) during scapular protraction exercises in healthy subjects by investigating the elecromyographic (EMG) activities of the serratus anterior (SA), upper trapezius (UT), and pectoralis major (PM). METHODS: Twenty-one healthy subjects participated in this study. Subjects performed maximal scapular protraction at the $90^{\circ}$ or $130^{\circ}$ shoulder flexion angles in the sagittal or scapular planes. Surface EMG was recorded from the SA and UT, and PM muscles. Dependent variables were examined by 2 (plane) ${\times}$ 2 (angle) repeated measures of analysis of variance (ANOVA). RESULTS: Significantly increased EMG activities in the SA and UT were found during scapular protraction exercise at the $130^{\circ}$ shoulder flexion angle in the sagittal and scapular plane. Also, EMG activity of the PM significantly decreased at the $130^{\circ}$ shoulder flexion angle in the sagittal plane and the $90^{\circ}$ and $130^{\circ}$ shoulder flexion in the scapular plane. CONCLUSION: we recommend scapular protraction exercise at the $90^{\circ}$ shoulder flexion in the sagittal plane to selectively strengthen the SA muscle with limitation of upper trapezius activity and at the $130^{\circ}$ shoulder flexion in the scapular plane to selectively strengthen the SA muscle with limitation of pectoralis major activity.

• PNF and Movement
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• v.14 no.2
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• pp.113-120
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• 2016

Purpose: The purpose of this study was to compare the intramuscular activation of the scapular stabilizing muscles and the upper trapezius/middle serratus anterior (UT/MSA) ratios during shrug exercise and proprioceptive neuromuscular facilitation (PNF) scapular pattern exercise. Methods: The participants of this study were 13 young adult men who voluntarily consented to participate in this experiment after listening to its purpose and methods. All participants were instructed on maximal voluntary isometric contraction and scapular exercises. The intramuscular activation of the upper trapezius (UT), lower trapezius (LT), middle serratus anterior (MSA), and lower serratus anterior (LSA) muscles while performing scapular exercises in a side-lying position were measured using surface electromyography. To analyze the muscle activation and UT/MSA ratio between the two exercises, a one-way repeated ANOVA was performed. Post-hoc analyses were conducted using Tukey's multiple comparison and analysis. Hamstring flexibility for each group was measured by a passive straight leg raising test. Results: The shrug exercise showed significantly higher UT activation compared to PNF anterior elevation and posterior elevation scapular patterns. The PNF scapular anterior elevation pattern showed significantly higher serratus anterior activation than the shrug exercise. Additionally, the UT/MSA ratios were significantly lower in the PNF scapular anterior elevation pattern than in the two exercises. Conclusion: Although shrug exercise was effective for strengthening UT, the PNF scapular anterior elevation pattern may be effective for strengthening MSA and improving the UT/MSA ratio.

• Physical Therapy Korea
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• v.29 no.2
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• pp.117-123
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• 2022

Background: Push-up are effective exercises for shoulder stability. Previous studies have documented the effects of support plane and hand position and width on muscle activities during a push-up. Objects: This study aimed to investigate the changes in muscle activities in the upper extremity when performing the standard and the knee-flexed push-up with different hand shapes. Methods: A total of twenty-six healthy males participated in this study. Three different hand shapes (finger abduction, finger adduction, and fists) and two types of push-up posture (standard and knee-flexed push-up) were set as the independent variables. Electrograms were used to measure the muscle activity of the upper trapezius (UT), triceps brachii (TB), pectoralis major (PM), and serratus anterior (SA). Each participant performed the randomly assigned push-up to the sound of the metronome. The mixed-effect linear regression model was used to detect the changes in muscle activities after changing the hand shape and push-up posture. Statistical significance was set at α = 0.05. Results: The UT muscle activity was statistically significantly higher when performing push-up with fists than finger abduction (p = 0.035) or finger adduction (p = 0.044). During the standard push-up, the muscle activity in all muscles was that the push-up with fists showed the highest muscle activity compared to the finger abduction (p < 0.01) and finger adduction (p < 0.01). Regardless of the shape of the hand, UT had the lowest muscle activity compared to other muscles (p < 0.001). In contrast, the SA muscle had the highest muscle activity among four muscles during the standard push-up. Conclusion: Based on the results of this study, we suggest hand shape is related to the difficulty level of push-up either in the standard or the knee-flexed push-up, especially in the push-up with fists. In addition, knee push-up can be recommended as shoulder muscle-strengthening exercises for individuals with low shoulder muscle strength.

• Physical Therapy Rehabilitation Science
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• v.5 no.1
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• pp.15-21
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• 2016

Objective: The purpose of this study was to see the changes in muscle activity of the upper limb in persons using a smartphone. Design: Cross-sectional study. Methods: An experiment was conducted to target 15 right-handed university students. Experiments were carried out for students using cell phones for more than a year. In this study, experiments were carried out with one-handed and both handed operation of smartphone use in a sitting position, the same parameters with smartphone use in a standing position. The experiments were carried out by having the subjects write a text message in Korean on the smartphone for 3 minutes repeated 3 times with a rest period of 10 seconds given between each 3 minute period. Electromyography (EMG) was used to record the muscle activity of the upper trapezius (UT), extensor carpi radialis (ECR), and abductor pollicis (AP) during phone operation. Results: The muscle activity of the AP and ECR were significantly higher during single handed compared to double handed in both sitting and standing position (p<0.05). The muscle activity of the ECR was significantly higher in standing position compared to sitting position with double handed use of the smartphone (p<0.05). UT muscle activity of the right has been activated more than twice compared to the left UT in a sitting position (p<0.05). And UT muscle activity on the right has been activated more than five times compared to the left in a standing position (p<0.05). Conclusions: Using smartphone with double hand is useful for the prevention of musculoskeletal disorders.

• 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.

• The Journal of Korean Medicine
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• v.36 no.4
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• pp.69-73
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• 2015

Objectives: This study was carried out to analyse the skin of the Hand lesser yang in human. Methods: The Hand lesser yang meridian was labeled with latex in the body surface of the cadaver, subsequently dissecting a body among superficial fascia and muscular layer in order to observe internal structures. Results: This study has come to the conclusion that a depth of the skin has encompassed a common integument and a immediately below superficial fascia, and this study established the skin boundary with adjacent structures such as relative muscle, tendon as compass. The skin area of the Hand lesser yang in human is as follows: The skin close to the ulnar root angle of 4th finger nail, above between 4th and 5th metacarpal bone, between extensor digit. minimi tendon(t.) and extensor digit. t., extensor digit. m(muscle). at 2, 4, 7 cun above dorsal carpal striation, triceps brachii m. t., deltoid m., trapezius m., just around the ear, upper orbicularis oculi m. Conclusions: The skin area of the Hand lesser yang from anatomical viewpoint seems to be the skin area outside the superficial fascia or the muscle involved in the pathway of the Hand lesser yang meridian, the collateral meridian, the meridian muscle, with the condition that we consider adjacent skins.

• Journal of Biomedical Engineering Research
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• v.44 no.6
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• pp.476-481
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• 2023

The purpose of this study was to investigate the effects on skin temperature, pain, muscle tone, and ROM after applying the massage robot "PIRO-ZERO" to 6 men and 4 women in their 20s who complained of non-specific pain in the shoulder or back for more than 12 weeks. As a result of the study, there was a significant increase in skin temperature not only in the area where the massage was applied, but also on the opposite side and throughout the body due to increased blood flow. Pain in the upper trapezius, rhomboid, and erector spinae muscle was decreased, and muscle tone in the erector spinae muscles was significantly decreased. There was a significant increase in ROM of neck and trunk flexion, which is thought to be because the massage reduced muscle tone around the spine, increasing flexibility. In the future, as the safety and effectiveness of massage robots are further verified and the pressure, speed, and path become more diverse, satisfaction is expected to increase.