• Journal of International Academy of Physical Therapy Research
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• v.11 no.4
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• pp.2173-2177
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• 2020

Background: Shoulder horizontal abduction in the prone position (SHAP) has been reported as an effective exercise to strengthen the lower trapezius. However, the effects of pre-emptive scapular posterior tilt on scapular muscle activity and scapulohumeral movements during SHAP have not been examined. Objectives: To examine the effect of the addition of scapular posterior tilt on muscle activity of the trapezius and posterior deltoid, and scapular posterior tilt and shoulder horizontal abduction, during SHAP. Design: Cross-sectional study. Methods: Fifteen healthy male subjects performed two types of SHAP: general and modified SHAP (SHAP combined with pre-emptive scapular posterior tilt). To perform modified SHAP, pre-emptive scapular posterior tilt training was performed prior to the modified SHAP. Muscle activity of the middle and lower trapezius and posterior deltoid, and the amount of scapular posterior tilt and shoulder horizontal abduction, were measured during two types of SHAP. Results: Muscle activity of the lower trapezius and scapular posterior tilt was significantly increased during the modified SHAP, while muscle activity of the posterior deltoid and the amount of shoulder horizontal abduction were significantly decreased. However, the middle trapezius muscle activity did not change during the modified SHAP. Conclusion: The SHAP with pre-emptive scapular posterior tilt can be useful to strengthen the lower trapezius.

• Journal of The Korean Society of Integrative Medicine
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• v.3 no.3
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• pp.1-8
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• 2015

Purpose : The purpose of this study was to find out the effect of shoulder exercise program for improving forward head posture. Method : Subjects were divided into two groups. The experimental group(15 people) participated in strength exercise and stretching exercise, three times every week, during 4 weeks. And the control group(the other 15 people) didn't participate in exercises. Exercise program was composed of strength exercise of middle and lower trapezius and stretching exercise of levator scapulae and upper trapezius. And then we measured cervical alignment with GPS and muscular activity by EMG. Result : The results of this study were as follows; 1. After the intervention, experimental group was significantly decreased in cervical alignment than control group(p<.05). 2. After the intervention, experimental group was significantly increased in middle lower trapezius musclar activity than control group(p<.05). Conclusion : Strength exercise of middle and lower trapezius and stretching exercise of levator scapulae and upper trapezius were considered a efficient for improving forward head posture.

• Journal of The Korean Society of Integrative Medicine
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• v.1 no.4
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• pp.85-92
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• 2013

PURPOSE : The purpose of this study was to determine the effects of the length of the pectoralis minor on muscle activity of trapezius and pectoralis major in subjects in subjects with shortened pectoralis minor muscle. METHOD : The subjects was participated in 36 with shortened pectoralis minor muscle. All subjects was examined the length test of pectoralis minor muscle. we divided by 3 groups. group I(n=12) was for 4~5cm of length of pectoralis minor muscle, group II(n=12) was for 5~6cm, group III(n=12) was for above 6cm. The EMG activity of upper trapezius, middle trapezius, lower trapezius and pectoralis major muscle activity was measured by surface EMG while elevationg the right arm in sitting postion with head to the neutral, shoulder elevation $135^{\circ}$ with scaption. Data were analyed using one-way ANOVA with a Tukey post hoc test. RESULT : The EMG activity differed significantly among the three groups(p<.05). The group III had significantly greater EMG activity of upper trapezius and pectoralis major muscles than group I and II(p<.05). Also, The group III had significantly smaller EMG activity of lower trapezius muscle than group I and II(p<.05). But, these was no significant difference in the EMG activity of the middle trapezius muscle among the groups (p.05). CONCLUSION : Therefore, the result of this study should be suggested that the shortened pectoralis minor muscle was affected the EMG activity of the upper trapezius, lower trapezius and pectoralis major. Ultimately the length of the pectoralis minor muscle leads to the muscle imbalance in shoulder girdle.

• 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.

• PNF and Movement
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• v.16 no.1
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• pp.33-42
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• 2018

Purpose: The aim of this study was to investigate the effects of trapezius and serratus anterior strengthening exercise on the shoulder pain and muscle activation of patients with spinal cord injury and functional shoulder impingement syndrome. Methods: The study consisted of 10 patients with spinal cord injury who were hospitalized in Rehabilitation Hospital U, Uijeongbu, South Korea. The exercise was implemented three times a week for 10 weeks. In each session, the subjects performed one of a total of five types of exercise at mid-level intensity. The shoulder pain and disability index (SPADI) was used to evaluate the patients before and after the intervention. The muscle activation of the upper trapezius, middle trapezius, lower trapezius, and anterior serratus muscle was assessed by surface electromyography (EMG) at the beginning of the experiment and 10 weeks later. Wilcoxon's singed-rank test was conducted to determine differences in the pain index and muscle activation before and after the exercise. The level of statistical significance was set at ${\alpha}=0.05$. Results: SPADI scores significantly decreased after the exercise (p<0.05). In comparisons of muscle activation, there was a significant improvement in the upper trapezius at $60^{\circ}$ shoulder joint flexion (p<0.05). There was no significant improvement at $90^{\circ}$ shoulder joint flexion. The middle trapezius showed a significant improvement at $120^{\circ}$ shoulder joint flexion (p<0.05). Conclusion: Trapezius and serratus anterior strengthening exercise reduced pain in spinal cord injury patients with functional shoulder impingement syndrome. The decreased muscle activation of upper trapezius and increased muscle activation of the anterior serratus muscle at $60^{\circ}$ shoulder joint flexion point to positive effects of the exercise on supraduction of the scapula.

• Physical Therapy Korea
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• v.19 no.2
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• pp.12-19
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• 2012

The purpose of this study was to assess the influence of scapular alignment on the electromyographic (EMG) activity of the trapezius in people with a short pectoralis minor muscle. For the study, we recruited 15 volunteers who had positive results for short on a pectoralis minor muscle length test. We measured the EMG activity of the upper, middle and lower trapezius muscles. The participants lifted their dominant arm to ear level with the thumb up toward the ceiling in the prone position on a table with the shoulder at a flexion angle of 180 degrees and a horizontal abduction angle of 120 degrees. Scapula was manually aligned by an experienced physical therapist prior to arm lift for the scapular alignment condition. A paired t-test was used to compare the effects of scapular alignment on the EMG activity of the trapezius muscles. The EMG activity of the lower trapezius muscle was significantly increased during the test with the scapular alignment compared to that without scapular alignment (p<.05), while the upper trapezius and middle trapezius exhibited no significant difference between the two conditions (p>.05). The findings of this study suggest that a scapular alignment may alter the recruitment of the lower trapezius muscle during arm lifting in the prone position in people with a short pectoralis minor muscle.

• Physical Therapy Korea
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• v.13 no.4
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• pp.39-46
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• 2006

The purpose of this study was to determine the effects of slump sitting postures on the masticatory, neck, shoulder, and trunk muscles associated with work-related musculoskeletal disorders (WRMD). Eleven healthy adults (age, $23.3{\pm}2.7$ yrs; height, $174.0{\pm}4.1$ cm; weight, $61.4{\pm}6.6$ kg) participated in this study. The participants were free of injury history and neurologic deficits in the masticatory, neck muscles and upper extremities at the time of participation. The subjects were asked to perform erect and slump sitting postures under the guidance of physical therapists. The surface electromyography (EMG) was recorded from the anterior temporalis, masseter, upper trapezius, serratus anterior, middle trapezius, L3 paraspinal, external abdominal oblique, gluteus maximus muscles of 11 adults as they performed visual terminal display work, which are known as the weakened and tightened muscles owing to WRMD. The recorded signals were averaged and normalized to the mean amplitude of the EMG signal obtained during submaximal reference voluntary contractions. The results of study were as follows: The masseter, upper trapezius, serratus anterior, middle trapezius, L3 paraspinal, external abdominal oblique muscles significantly differed in the slump sitting posture (p<.05). The muscle activities of the serratus anterior, middle trapezius muscle, and external abdominal oblique were significantly lower and that of the masseter, upper trapezius, L3 paraspinal muscles were significantly higher. Further research is needed to assess the motor control problems and the function of the deep muscles in posture stability of patients with WRMD.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.4
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• pp.199-207
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• 2022

Purpose : The purpose of this study is to investigate the effect of shoulder stabilization exercise accompanied by application of a pelvic compression belt on the muscle activity, pain and function of the muscles around the shoulder in subjects with round shoulders. Methods : For the study method, 28 students who were enrolled in K University with a distance of 1 cm or more between the clavicle of the peak and the outer ear path were selected through GPS 400 global postural analysis system measurement. The subjects were randomly assigned to 14 participants in the group wearing a pelvic compression belt and 14 patients in the group not wearing a pelvic compression belt. In all subjects, the muscle activities of the middle trapezius, lower trapezius, and serratus anterior muscles and the shoulder pain disorder index (SPADI) were measured. The intervention was performed 3 times a week for 4 weeks, and the applied intervention was push-up plus and modified prone cobra exercise. The muscle activities of the middle trapezius, lower trapezius, and serratus anterior muscles and SPADI score were compared using dependent t test before and after intervention. Results : In this study, both groups showed that the muscle activity of the middle trapezius, lower trapezius, and serratus anterior significantly increased after the intervention compared to before the intervention. On the other hand, SPADI showed no significant difference. Conclusion : The results of this study showed that muscle activity in the peri-shoulder joint was increased after push-up plus and modified prone cobra exercise in both groups, regardless of whether pelvic compression was applied or not. Therefore, it was found that shoulder stabilization exercise using the pelvic compression belt also contributed to the enhancement of muscle activity in the joints around the shoulder.

• The Journal of Korean Physical Therapy
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• v.24 no.6
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• pp.388-392
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• 2012

Purpose: Muscle imbalance between upper trapezius (UT) and serratus anterior (SA) during arm elevation is a factor causing shoulder dysfunction. However, there is no study to compare the muscle activities of the UT and middle deltoid (MD). The purpose of this study was to compare the muscle activities of the UT and MD between with and without elevation of shoulder girdle (ESG) during shoulder abduction. Methods: The subjects without (control group=9) or with (ESG group=8) participated in this study. The muscle activities of the UT and MD were measured using a electromyography during $90^{\circ}$ shoulder abducted position in both group. The data in middle of 3-second of the 5-second periods were used. The mean value of three trials was used in the data analysis. For each muscle, independent t-tests were performed to compare for group differences. Results: The muscle activity of UT was significantly greater in ESG group, compared to that of the control group (p<0.05). The muscle activity of MD was significantly smaller in ESG group, compared to that of the control group (p<0.05). Conclusion: These findings showed that low muscle activation of MD as well as SA may contribute to hyperactivity of UT during arm elevation.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.1
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• pp.1975-1980
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• 2020

Background: It has been argued that changes in muscle activity in the upper trapezius and serratus anterior may or may not cause shoulder joint pain and dysfunction. Objective: To investigate the effects of active vibration exercise on muscle activity regarding scapular stabilization using a flexi-bar. Design: A randomized controlled trial. Methods: A total of 24 subjects were randomly assigned to a flexi-bar group with active vibration and general stick group with non-active vibration. Both groups performed the same four action programs for 6 weeks, three times a week for 30 minutes at a time. The upper trapezius muscle, middle trapezius muscle, lower trapezius muscle and serratus anterior muscle of the dominant side was measured by electromyography before and after the 6 weeks of exercise. The independent t-test and paired t-test were used to analyze data. Results: There was a significant difference between groups in upper trapezius muscle and serratus anterior muscle activity after exercise (P<.05). Also, there was a significant difference in upper trapezius muscle and serratus anterior muscle activity before and after exercise in the flexi-bar group (P<.05). Conclusion: This study demonstrates that active vibration exercise using a flexi-Bar contribute to reduce the activity of the upper trapezius muscle and promote the activity of the serratus anterior muscle.