• Journal of The Korean Society of Integrative Medicine
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• v.5 no.2
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• pp.19-23
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• 2017

Purpose: The purpose of this study was to determine the muscle activity ratio according to the shoulder abduction angle by identifying the mean muscle activities and calculating the muscle ratios for use in developing strengthening methods. Methods: The participants were healthy adults in their 20s (n=19). The activity of the deltoid middle, upper trapezius, middle trapezius, and lower trapezius muscles was measured by 8-channel surface electromyography. Muscle activity was measured during 4 conditions of angle of shoulder abduction: $30^{\circ}$, $60^{\circ}$, $90^{\circ}$, and $120^{\circ}$. The data used in the analysis were the root mean square and % total muscle activity values. Results: The root mean square values for the deltoid middle, upper trapezius, middle trapezius, and lower trapezius muscles showed significant differences. No significant differences were detected in the % total muscle activity of the deltoid middle, upper trapezius, middle trapezius, or lower trapezius muscles. Conclusion: Future studies aimed at developing selective shoulder abductor muscle strengthening methods are likely to provide more effective results by using muscle activity ratios.

• Journal of Korean Physical Therapy Science
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• v.3 no.4
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• pp.139-145
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• 1996

This study was carried out to investigate the scapular rhythm of normal persons. 16 persons was no disease, injury and after-effect in period for July 1, 1996 to July 14, 1996. The statistical measures were performed by SPSS/PC t-test for classification. The result of this study were as follow : 1. There was a significant difference between the body median line and scapular superior angle from the mean distance in 83.4 mm of male and 86.0 mm of female to shoulder neutral position(p<0.05). 2. The mean distance of body median line between scapular inferior angle was 97.9 mm of male and 92.0 mm of female to shoulder neutral position. 3. There was a significant difference between the body median line and scapular inferior angle from the mean distance with male and female to shoulder abduction $90^{\circ}$ position(p<0.05). 4. The mean angle of body median line between scapular angle was $6.4^{\circ}$ of male and $4.4^{\circ}$ of female with shoulder neutral position. 5. The mean ratio of scapular rhythm was 5.6 : 1 in shoulder abduction of $90^{\circ}$ and 5.1 : 1 in shoulder abduction of 180.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.1
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• pp.125-132
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• 2014

PURPOSE: This study aims to determine the optimal knee joint angle and hip joint angle for minimizing the cervical muscle tension and maximizing the muscle activity of the trunk during the bridging exercise for trunk stabilization. METHODS: The bridging exercise in this study included seven forms of exercise: having a knee joint flexion angle of $120^{\circ}$, $90^{\circ}$, $60^{\circ}$, $45^{\circ}$ and hip joint abduction angle of $15^{\circ}$, $10^{\circ}$, $5^{\circ}$. The posture of the bridging exercise was as follows. To prevent the increase of hyper lumbar lordosis during the bridging exercise, the exercise was practiced after maintaining the lumbar neutral position through the pelvic posterior tilting exercise. RESULTS: The abduction angles did not result in statistically significant effects on the cervical erector, external oblique, rectus abdominis and erector spinae muscles. However, in relation to the knee joint angles, during the bridging exercise, statistically significant results were exhibited. CONCLUSION: The knee joint angle affected the muscle activity of the neck muscle. The greater the knee joint angle, the lower the load placed on the neck muscle. In contrast, the load increased as the knee joint angle decreased. In addition, the muscle activity of the neck muscle and trunk muscle increased as the knee joint angle decreased.

• Physical Therapy Korea
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• v.17 no.1
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• pp.1-8
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• 2010

The purpose of this study was to compare EMG activity for pectoralis major muscle during shoulder movement with various abduction angle and rotation position in supine position. Fifteen healthy subjects were recruited for this study. All subjects performed shoulder horizontal adduction holding a 2 kg dumbbell in shoulder abduction $40^{\circ}C$, $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $160^{\circ}C$ with shoulder neutral, internal rotation (IR), and external rotation (ER). Surface EMG activity was recorded from pectoralis major clavicle part and pectoralis major sternum part for 5 seconds and EMG activity was normalized to the value of maximal voluntary isometric contraction (%MVIC). Dependent variables were examined with 3 (Neutral, IR, ER) ${\times}$ 5 ($40^{\circ}C$, $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $160^{\circ}C$) analysis of variance with repeated measures. The EMG activity of pectoralis major muscle was significantly different between shoulder abduction angles and between shoulder rotation positions (p<.05). The highest value of EMG activity of pectoralis major clavicle part among shoulder abduction angles was in $70^{\circ}C$ and, $90^{\circ}C$ in that order. The highest value of EMG activity of pectoralis major sternum part among shoulder abduction angles was in $130^{\circ}C$ and, $90^{\circ}C$ in that order. According to the rotation degree, shoulder ER showed the highest value and IR showed the lowest value in both muscle parts. These results suggest that shoulder abduction $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$ will be effective during manual muscle testing (MMT) and strengthening exercise for pectoralis major muscle. It is also supposed that shoulder ER is the efficient posture for strengthening of pectoralis major muscle.

• Physical Therapy Korea
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• v.18 no.1
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• pp.47-56
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• 2011

The purpose of this study was to compare electromyography (EMG) activity for the middle and lower trapezius muscle according to various shoulder abduction angles. Thirty healthy male subjects were recruited for this study. Each subject performed three repetitions of horizontal abduction at $75^{\circ}$, $90^{\circ}$, $125^{\circ}$, $160^{\circ}$, and $180^{\circ}$ of shoulder abduction angle in a prone position. Surface EMG activity was recorded from the middle and lower trapezius while the subjects held for five seconds at a predetermined position. The EMG activity was normalized using the maximal voluntary isometric contraction (MVIC) elicited using a manual muscle testing technique. A repeatedly measured ANOVA was performed by Bonferroni's post hoc test. The EMG activity of the middle and lower trapezius was significantly different among shoulder abduction angles (p<.05). The greatest level of muscle activity for the middle and lower trapezius were demonstrated at $90^{\circ}$ and $160^{\circ}$ of shoulder abduction angle, respectively. These results suggest that middle and lower trapezius strengthening exercise and manual muscle testing should be performed at different shoulder abduction angles.

• Physical Therapy Korea
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• v.20 no.4
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• pp.16-21
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• 2013

The purpose of this study was to determine the effect of contralateral hip adduction (CHA) on the muscle activity of lumbar stabilizers and the angle of pelvic lateral tilting during hip abduction in side lying. Twenty healthy male subjects with no medical history of lower extremity or lumbar spine disorders were recruited for the study. Subjects randomly performed preferred hip abduction (PHA) and hip abduction with contralateral hip adduction in side lying. The muscle activities of the dominant side rectus abdominis, external oblique, internal oblique, quadratus lumborum, gluteus medius, and non-dominant side hip adductor longus were measured during PHA and CHA by using a surface electromyography (EMG) system. Pelvic lateral tilting motion was measured by using a three-dimensional motion analysis system. Data on EMG and pelvic motion were collected at the same time during PHA and CHA. A paired t-test was used to compare EMG activity and the angle of pelvic lateral tilting in the two exercises. The study found that the EMG activities of all muscles were more increased significantly in CHA than PHA condition. The angle of pelvic lateral tilting was more decreased significantly in CHA than PHA condition. These findings suggest that CHA could be recommended as a hip abduction exercise for activating lumbar stabilizers and decreasing compensatory pelvic lateral tilting motion.

• Journal of the Korean Society of Radiology
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• v.6 no.5
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• pp.427-433
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• 2012

This study aimed at identifying changes in the acromiohumeral distance (AHD) and arm when the caudal gliding gradeII and III of Kaltenborn-Evjenth Concept$^{(R)}$ are applied to the right glenohumeral joint. The humeral head moved down about 5mm from the initial position when the gliding gradeII was applied, and about 8mm from the initial position when the gliding gradeIII was applied. Although men showed a higher acromiohumeral distance per grade than women in comparisons by gender for the acromiohumeral distance, there was no significant difference in statistics. The Abduction angle improved about $10^{\circ}$ from the initial angle when the gliding gradeII was applied, and about $12^{\circ}$ from the initial angle when the gliding gradeIII was applied. Although women showed the abduction angle greater than men for every grade in comparisons by gender for the abduction angle, there was no significant difference in statistics. Based on the aforesaid findings, the extent of kinematic changes in the humeral head could be identified when the gliding grades were applied. Accordingly, it is considered that more scientific evidence based treatments could be expected if influences on the surrounding structures by these changes could be learned through more studies in the future.

• Physical Therapy Korea
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• v.26 no.3
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• pp.1-10
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• 2019

Background: Winged scapular (WS) causes muscle imbalance with abnormal patterns when moving the arm. In particular, the over-activation of the upper trapezius (UT) and decrease in activity of the lower trapezius (LT) and serratus anterior (SA) produce abnormal scapulohumeral rhythm. Therefore, the SA requires special attention in all shoulder rehabilitation programs. In fact, many previous studies have been devoted to the SA muscle strength training needed for WS correction. Objects: The purpose of this study was to investigate the effect of shoulder girdle muscle and ratio according to the angle of shoulder abduction and external weight in supine position. Methods: Twenty three WS patients participated in this experiment. They performed scapular protraction exercise in supine position with the weights of 0 kg, 1 kg, 1.5 kg, and 2 kg at shoulder abduction angles of $0^{\circ}$, $30^{\circ}$, $60^{\circ}$, and $90^{\circ}$. The angle and weight applications were randomized. Surface electromyography (EMG) was used to collect the EMG data of the SA, pectoralis major (PM), and UT during the exercise. The ratio of PM/SA and UT/SA was confirmed. Two-way repeated analyses of variance were used to determine the statistical significance of SA, PM, and UT and the ratios of PM/SA and UT/SA. Results: There was a significant difference in SA according to angle (p<.05). Significant differences were also identified depending on the angle and weight (p<.05). The angle of abduction at $0^{\circ}$, $30^{\circ}$ and weight of 2 kg showed the highest SA activity. However, there was no significant difference between PM and UT (p>.05). There was a significant difference between PM/SA and UT/SA in ratio of muscle activity according to angle (p<.05). Significant differences were found at PM/SA angles of $30^{\circ}$, $60^{\circ}$ and $90^{\circ}$ (p<.05). For UT/SA, significant difference was only observed at $90^{\circ}$ (p<.05). Conclusion: Based on the results of this study, in order to strengthen the SA, it was found to be most effective to use 1 and 1.5 kg weights with abduction angles of $0^{\circ}$ and $30^{\circ}$ at shoulder protraction in supine position.

• Journal of the Ergonomics Society of Korea
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• v.15 no.1
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• pp.39-52
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• 1996

This paper measured the range of arm joint motion for Korean 54 males in twenties. The range of the arm joint motion of the subjects was measured directly using Goniometer and protractor. The number of the static and the dynamic anthropometric variables are seven and thirteen, respectively. The anthropometric data are analyzed by basic statistical analysis (four group), correlation analysis and regression analysis using commercial SAS program. The results of analysis are compared with American students anthropometric data by Laubach(1978). Thin subjects have larger movement angle as wrist flexion, wrist abduction, elbow flexion, and elbow wupination and have smaller as wrist adduction and shoulder flexion. Fat subjects have larger movement angle as shoulder flexion and are smaller wrist abduction, elbow flexion, pronation, shoulder extension, shoulder adduction, shoulder abduction, and shoulder medial rotation Korean are more flexible than American in wrist and ranges of elbow flexion and elbow rotation. The shoulder movement is similar to that of American, but shoulder flexion is less flexible.

• Physical Therapy Korea
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• v.11 no.1
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• pp.45-52
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• 2004

Altered scapular kinematics in the scapular joint is commonly believed to be a factor contributing to trunk posture. The purpose of this study was to analyze the muscle activity with several changes of the shoulder angle. Tests were performed on 10 male subjects by repeated measures. Each subject was measured while sitting in both erect and slouched trunk positions. In each sitting posture, a three-dimensional motion analysis measurement was used to measure thoracic angle and shoulder abduction angle. Measurements were taken with the shoulder abdcution angle at $0^{\circ}$, $30^{\circ}$, $60^{\circ}$, $90^{\circ}$, $120^{\circ}$, and $150^{\circ}$. By using surface Electromyography (EMG) electrodes, we recorded the activity of the upper trapezius, middle trapezius, lower trapezius, middle deltoid, and serratus anterior muscle while the subject held a 4 kg weight at each angle. The mean of root mean square (RMS) of EMG activity was calculated. The middle trapezius, lower trapezius, and middle deltoid muscle activity showed significantly higher results but serratus anterior muscle activity showed significantly lower results (p<.05). With the shoulder angle increased, the muscle activity was also significantly increased (p<.05). In conclusion, the thoracic spine posture significantly affects the scapular muscle during scapular plane abduction, and the slouched posture is associated with increased trapezius muscle activity and with decreased serratus anterior muscle activity.