• Journal of the Ergonomics Society of Korea
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• v.18 no.1
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• pp.91-108
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• 1999

In our previous work using a motion analyzer and 3-dimensional sonic digitizer, the arm shapes for 23 women in their early twenties were classified into three characteristic types. In order to design sleeves, suitable for arm movements for the three characteristic arm shapes, a relationship between arm length variation and shoulder/elbow angles has been investigated for four cases of arm movements (flexion, extension, adduction and abduction). Each arm movement can be characterized by the changes in shoulder angle and the changes in elbow angle at the maximal shoulder angle. In all the four cases of arm movements, the changes of shoulder length and cap height are largest at the maximal shoulder angle. These changes were little affected by changes in elbow angle. The changes in the lower arm length and the difference between cap height and upper arm length are the largest at the maximal elbow angle of the maximal shoulder angle. There is a linear relationship between cap height and shoulder angle during arm movements; thus, in designing sleeves the cap height can be determined from the regression of cap height vs. shoulder angle.

• Journal of the Ergonomics Society of Korea
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• v.24 no.2
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• pp.9-15
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• 2005

The purpose of this study is to quantitatively investigate perceived discomfort of complex shoulder postures with external loads and to propose a preliminary evaluation scheme of shoulder postures. Twelve healthy male adults participated in an experiment to rate their perceived discomfort of shoulder postures. The independent variables were shoulder flexion angle(45, 90 and 150$^{\circ}$), adduction/abduction angle(-30, -10, 0, 30 and 60$^{\circ}$), and external load(0, 1.5 and 3.0kg). The results revealed that the flexion angle, external load and their interaction significantly affected the perceived discomfort(p$<$0.05) but the effect of adduction/abduction angle on the discomfort was not significant(p$>$0.05). The effect of external load was much larger than that of any other factor with explaining about 81% of the total variation of discomfort scores. Based on the experimental results a preliminary scheme was presented to evaluate the stress of shoulder postures with external loads.

• Physical Therapy Korea
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• v.24 no.2
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• pp.1-8
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• 2017

Background: Individuals with spinal cord injury (SCI) rely on their upper limbs for body-lifting activity (BLA). While studies have examined the electromyography (EMG) and kinematics of the shoulder joints during BLA, no studies have considered foot position during BLA. Objects: This study compared the effects of different foot positions during BLA on the shoulder muscle activities, peak plantar pressure, knee flexion angle, and rating perceived exertion in individuals with SCI. Methods: The study enrolled 13 mens with motor-complete paraplegic SCI, ASIA (American Spinal Injury Association) A or B. All subjects performed BLA with the feet positioned on the wheelchair footrest and on the floor independently. Surface EMG was used to collect data from the latissimus dorsi, pectoralis major, serratus anterior, and triceps brachii. The peak plantar pressure was measured using pedar-X and the knee flexion angle with Image J. Borg's rating perceived exertion scale was used to measure the physical activity intensity level. The paired t-test was used to compare the shoulder muscle activities, peak plantar pressure, knee flexion angle, and rating perceived exertion between the two feet positions during BLA. Results: The activity of the latissimus dorsi, pectoralis major, serratus anterior, and triceps brachii and rating perceived exertion decreased significantly and the peak plantar pressure and knee flexion angle increased significantly when performing BLA with the feet positioned on the wheelchair footrest compared with on the floor (p<.05). Conclusion: These findings suggest that individuals with SCI may perform BLA with the feet positioned on the wheelchair footrest for weight-relief lifting to decrease the shoulder muscle activities and the rating perceived exertion and to increase the peak plantar pressure and the knee flexion angle.

• Physical Therapy Korea
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• v.7 no.2
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• pp.88-95
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• 2000

Thirty normal adults were tested to measure the electrical activity of the anterior (AD), middle (MD), and posterior portion (PD) of the deltoid muscle and sternal portion of the pectoralis major muscle (PM) during the performance of four upper extremity PNF diagonal patterns with elbow flexion angle in $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$. The PNF patterns in which these muscles function optimally have been theoretically advanced by Kabat and further described by Knott and Voss. They theorize that the MD should be most active with shoulder flexion, abduction, and external rotation (D2F); the PD with shoulder extension, abduction, and internal rotation (D1E); the AD with shoulder flexion, adduction, and external rotation (D1F); and the PM with shoulder extension, adduction and internal rotation (D2E). The patterns were performed through range of motion, with an isometric contraction performed in the shortened range. When the EMG activity of AD, MD, PD and PM in its optimal patterns was measured, it does not have significant difference among fixed elbow flexion angle $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$ (p>.05). In addition, suggestions were made for study of patients who exhibit imbalance of muscle strength and have muscle weakness.

• Journal of the Ergonomics Society of Korea
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• v.25 no.4
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• pp.145-151
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• 2006

The objective of this study is to investigate the perceived discomfort for postures combined with shoulder flexion/extension and elbow flexion, and external load. 12 healthy male undergraduate and graduate students participated in this experiment. Experimental variables were the shoulder flexion/extension angle(-20°, 0°, 45°, 90°, 135°), the elbow flexion angle (0°, 45°, 120°), and the external load(0, 1.5Kg, 3Kg) as independent variables and a whole body perceived discomfort using Borg's CR10 as a dependent variable. The subjects maintained the given posture for 60 seconds and then rated the perceived discomfort. The ANOVA results showed that all main factors and two-way interactions were statistically significant at α=0.05. As a result of regression analysis to examine the effect of external load on the perceived discomfort, the perceived discomfort linearly increased as the level of external load increased. Then, the effect of external load on the perceived discomfort was quantitatively classified into three levels based on the result of regression analysis.

• Journal of Korean Medicine Rehabilitation
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• v.18 no.3
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• pp.81-90
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• 2008

Objectives : The purpose of this study was to identify the effect of electro-acupuncture stimulation regarding restoration of range of motion on patients with frozen shoulder. Methods : Experimental group measured with shoulder flexion and abduction angle at pre and post electro-acupuncture stimulation. Results : There were statistically significant difference regarding change of flexion angle of electro-acupuncture stimulation(p<0.01) and the testing value of all levels had a significant difference with the value of final post-test(p<0.01). There were statistically significant difference regarding change of abduction angle of electro-acupuncture stimulation(p<0.01). Conclusions : Electro-acupuncture stimulation of distal part increased range of motion of frozen shoulder. Therefore, application of electro-acupuncture should be developed as a therapeutic method in treatment of frozen shoulder. Also, it can contribute as one of good therapeutic methods offered to patients through approach of oriental rehabilitation medicine.

• Korean Journal of Applied Biomechanics
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• v.22 no.2
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• pp.193-199
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• 2012

The purpose of this study was to investigate the activities of the serratus anterior (SA) and upper trapezius (UT) muscles during scapular protraction exercise with a dumbbell. Twenty-one healthy subjects with no medial history of shoulder pain or upper extremity disorders were recruited for this study. Subjects performed scapular protraction at $90^{\circ}$ and $130^{\circ}$ shoulder flexion with a dumbbell in supine and standing positions. The activities of the SA and UT were measured via surface electromyography (EMG) during 4 scapular protraction exercises. A 2 (angle) ${\times}$ 2 (position) repeated-measures analysis of variance (ANOVA) was used to compare the normalized activities of the SA and UT and the UT/SA ratio. The results showed that activities of both the SA and UT were the highest for the scapular protraction exercise at $130^{\circ}$ shoulder flexion in the standing position. However, the UT/SA ratio was the lowest for the exercise at $90^{\circ}$ shoulder flexion in supine position. Therefore, for selective activation of the SA muscle, we recommend performing the scapular protraction exercise with a dumbbell in the supine position at $90^{\circ}$ shoulder flexion.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.21 no.2
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• pp.33-37
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• 2015

Background: The purpose of this study on the effects of deep cervical flexors strengthening exercise to forward head posture and pain of neck in patients with chronic neck pain. Method: We selected 30 subjects among neck pain patients and carried out measurements. The subjects' forward head posture was measured including head tilt angle (HTA), neck flexion angle (NFA) and forward shoulder angle (FSA), neck disability index (NDI), numeric rating scale (NRS). The subjects underwent deep cervical flexors muscle strengthening with pressure bio-feedback device for 4 weeks. Then, after intervention, the subjects' forward head posture was measured again. It was performed Wilcoxon signed-ranks test for confirming the effect of deep cervical flexor muscles strengthening exercise. Results: As a result of comparison of measurements before and after intervention, we found that there were statistically significant improvement in the subjects' NDI, NRS and forward head posture including head tilt angle, neck flexion angle and forward shoulder angle. Conclusion: We concluded that deep cervical flexors strengthening exercise has the effect of alleviation of neck pain patients and is effective for forward head posture.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.81-86
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• 2020

The Purpose of this study is analysis characteristic of grasping power with each different shoulder horizontal angle. Twenty female university students with no shoulder dysfuction participated subject in three different positions of shoulder horizontal flexion with standing posture, shoulder 0° flexion, elbow 90° flexion, forearm 90° pronation, different positions is followed : shoulder 0° horizontal adduction shoulder 40° horizontal adduction, shoulder 40° horizontal abduction. The One-way repeated ANOVA test was used to determine the different in grip strength on three shoulder horizontal positions. On the average, in the hand grip strength, the horizontal neutral position is higher than horizontal adduction position with significant value. In particular, shoulder horizontal aduction was measured lowest grip strength between three positions.

• The Journal of Korean Physical Therapy
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• v.10 no.2
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• pp.77-86
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• 1998

The shoulder joint permit ate greatest mobility of any joint area carries out the importment function of stabilization for hand use. So handgrip activity is important to evaluate while assessing shoulder load in manual work. There was an association between static handgrip and shoulder muscle activity. The purpose of this study was to find out the changes of the hand grip strength according to shouter an81e. One hundred (50 female, 50 male) college adult volunteers with no known shoulder dysfunction participated subject in three positions with elbow extension: (1) shoulder $0^{\circ}$ flexion (2) shoulder $90^{\circ}C$ flexion (3)shoulder $180^{\circ}C$ flexion. The paired t-test was used to determine the different in grip strength between right and left hand at shouter position change. All, there was significiant for all three position by right and left shoulder (p<0.001). In mon, the ANOVA results revealed not a significiant F-ratio fer all three position by right and left hand. In woman, revealed significiant (p<0.05).