• Physical Therapy Korea
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• v.19 no.4
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• pp.32-37
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• 2012

The purpose of this study was to investigate the quantitative data of downward pulling tension in subjects with scapular downward rotation syndrome (SDRS) before and after 6-week self scapular upward rotation exercise (SURE) program. Eleven subjects with bilateral SDRS. The downward pulling tension(DPT) was measured digital tension-meter. The tension force data were collected using a surface electromyography before and after a 6-week self-scapular SURE program. The significance of difference between pre- and post-program was assessed using a paired t-test, with the level of significance set at ${\alpha}$=.05. The results showed that significant differences between pre- and post-SURE program were found for DPT (p<.05). These findings suggest that 6-week self SURE program is effective for reducing DPT in subjects with SDRS. Additionally, our DPT measurement can be useful for maintaining shoulder position and providing quantitative data between pre- and post-SURE program during passive correction of scapular position test.

• Physical Therapy Korea
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• v.22 no.4
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• pp.17-26
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• 2015

The purpose of this study was to investigate the effects of visual electromyography (EMG) biofeedback on the EMG activity of the lower trapezius (LT), serratus anterior (SA), and upper trapezius (UT) muscles, the LT/UT and SA/UT EMG activity ratios, and the scapular upward rotation angle during scapular posterior tilting exercise (SPTE). Twenty-four subjects with round-shoulder posture participated in this study. The EMG activities of the LT, SA, and UT were collected during SPTE both without and with visual EMG biofeedback. The scapular upward rotation angle was measured at the baseline, after SPTE without visual EMG biofeedback, and after SPTE with visual EMG biofeedback. The LT, SA, and UT EMG activities, and the LT/UT and SA/UT EMG activity ratios were analyzed by paired t-test. The scapular upward rotation angle was statistically analyzed using one-way repeated analysis of variance. If a significant difference was found, a Bonferroni correction was performed (p=.05/3=.017). The EMG activities of LT and SA significantly increased, and the EMG activity of UT significantly decreased during SPTE with visual EMG biofeedback compared to SPTE without visual EMG biofeedback (p<.05). In addition, the LT/UT and SA/UT EMG activity ratios significantly increased during SPTE with visual EMG biofeedback compared to SPTE without visual EMG biofeedback (p<.05). Significant increases were found in the scapular upward rotation angle after SPTE without and with visual EMG biofeedback compared to baseline (p<.017), and no significant differences were observed in the scapular upward rotation angle between SPTE without and with visual EMG biofeedback. In conclusion, SPTE using visual EMG biofeedback may be an effective method for increasing LT and SA activities while reducing UT activity.

• Physical Therapy Korea
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• v.24 no.4
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• pp.60-67
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• 2017

Background: Scapular downward rotation syndrome (SDRS) is a common scapular alignment impairment that causes insufficient upward rotation and muscle imbalance, shortened levator scapulae (LS) and rhomboid, and lengthened serratus anterior (SA) and trapezius. A modified shrug exercise (MSE), performing a shrug exercise with the shoulders at $150^{\circ}$ abduction, is known as an effective exercise to increase scapular stabilizer muscle activation. Previous studies revealed that scapular exercise are more effective when combined with trunk stabilization exercises in decreasing scapular winging and increasing scapular stabilizer muscle activation. Objects: The purpose of our study was to clarify the effect of MSE with or without trunk stabilization exercises in subjects with SDRS. Methods: Eighteen volunteer subjects (male=10, female=8) with SDRS were recruited for this experiment. All subjects performed MSE under 3 different conditions: (1) MSE, (2) MSE with an abdominal draw-in maneuver (ADIM), and (3) MSE with an abdominal expansion maneuver (AEM). The muscle thickness of the lower trapezius (LT) and the SA were measured using an ultrasonography in each condition. Electromyography (EMG) data were collected from the LT, LS, SA, and upper trapezius (UT) muscle activities. Data were statistically analysed using one-way repeated analysis of variance at a significance level of .05. Results: The muscle thickness of the LT and the SA were the significant different in the MSE, MSE with ADIM (MSE+ADIM) and MSE with AEM (MSE+AEM) conditions (p<.05) In both LT and SA, the order of thick muscle thickness was MSE+AEM, MSE+ADIM, and MSE alone. No significant differences were found in the EMG activities of the SA, UT, LS, and LT in all condition. Conclusion: In conclusion, MSE is more beneficial to people with SDRS when combined with trunk stabilization exercises by increased thickness of scapular stabilizer muscles.

• Physical Therapy Korea
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• v.24 no.4
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• pp.29-37
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• 2017

Background: The serratus anterior (SA) muscle is one of the important muscles in the upward rotation of the scapula when the arm is raised. Insufficient muscle activity of the SA can cause deformation of the shoulder rhythm resulting in shoulder pathology. Objects: This study intends to compare SA and upper trapezius (UT) activity during the conventional wall-slide and push-up plus exercises for SA muscle strengthening and the scapular upward rotation (SUR) exercise. Methods: A total of 30 subjects participated in this study, and we measured the muscle activity of the SA and UT muscles during the wall-slide, push-up plus and SUR exercises. The one-way repeated ANOVA was used to compare SA and UT muscle activities during the 3 exercises. Results: During the SUR exercise, SA muscle activity was 79.88% maximum voluntary isometric contraction (MVIC), which was significantly higher than its activity during the other 2 exercises. The UT muscle activity was 47.53 %MVIC during the SUR exercise, indicating a significantly higher UT muscle activity than during the other 2 exercises. Conclusion: These findings suggest that the SUR exercise can maximize SA muscle activity to strengthen the SA while keeping UT muscle activity at an appropriate level.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.10 no.2
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• pp.23-29
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• 2012

Purpose : Purpose of this study was to investigate whether cervicothoracic posture was associated with scapula orientation and muscle activity during shoulder abduction. Methods : Cervicothoracic junction angle and thoracic kyphosis angle were measured in health twenty subjects. Then, scapular resting orientation and range of motion (upward/downward rotation, internal/external rotation) and muscle activity (upper trapezius, lower trapezius, serratus anterior) was determined using motion capture system and surface electromyography while subjects performed shoulder abduction. Results : Cervicothoracic junction angle was significantly associated with range of motion of scapular internal/external rotation during shoulder abduction. Thoracic kyphosis angle was significantly associated with scapular resting orientation of upward/downward rotation and average IEMG of lower trapezius. Conclusion : The result of this study shows that poor cervicothoracic posture is relationship with altered scapular kinematics cause of shoulder dysfunction. These findings suggested that cervicothoracic posture may be considered in occupation and exercise including arm elevation over head as well as used as predict factor to estimate shoulder dysfunction.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.4
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• pp.113-121
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• 2015

PURPOSE: The purpose of this study was to determine the effect of shoulder external rotation on muscle activities of the scapular upward rotators during arm elevation. METHODS: Nineteen healthy subjects with no medical history of shoulder pain or upper extremity disorders were recruited for this study. Electromyography (EMG) was used to measure the muscle activities of the serratus anterior (SA), upper trapezius (UP), lower trapezius (LT) and infraspinatus (IS) muscles during arm elevation. The EMG activities were recorded while the subjects performed $90^{\circ}$ arm elevation with three different arm positions; palm down (PD), neutral position (NP), and palm up (PU). While seated in a chair, the subject was asked to raise the upper extremity in the sagittal plane in random order. Subjects performed $90^{\circ}$ arm elevations in three trials at each arm position. The mean EMG activity normalized by the maximal voluntary isometric contraction was analyzed across three arm positions. Repeated measures one-way ANOVA and the post hoc Bonferroni tests were used to determine the differences in muscle activities among the three arm positions. RESULTS: The EMG activities of the SA and IS were significantly greater in the PU condition than in the other conditions during arm elevation. No significant difference was noted between the NP and PD conditions during arm elevation. CONCLUSION: These results suggest that shoulder external rotation (palm up position) can be used to activate the SA. Therefore, we recommend a scapular protraction exercise in the palm up position for strengthening the SA.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.11 no.2
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• pp.71-82
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• 2005

The couple force of the scapular stabilizers for upward rotation that include the upper and lower trapezius, serratus anterior muscles is essential to maintain the stability of shoulder joint. But if there is an imbalance of these muscles, it would occur many problems of shoulder joint. A push-up plus exercise with an unstable support is used in order to increase the muscle activity and stimulate the proprioception of shoulder joint. The purpose of this study was to compare the muscle activity of upper and lower trapezius, serratus anterior muscles and to determine which exercise is more effective when subjects perform push-up plus exercise in the stable support and unstable support. 15 healthy subjects and 15 painful subjects with injury of shoulder joint participated in this study. Surface electromyography data were collected during plus phase of push-up plus exercise. The types of push-up plus exercise were composed of three conditions. Stable type is subjects performed the push-up plus exercise on the fixed support and unstable type 1 is on the sling without shaking and unstable type 2 is on the sling with shaking by tester's manual. The upper and lower trapezius activities of injured group were higher than uninjured group at three measure conditions, but serratus anterior activities were not. The UT/SA ratio of injured group was higher than uninjured group at three measure conditions. The serratus anterior activities were most high at unstable 2 measure in both groups. The UT/SA ratio was most low at unstable 2 measure condition in injured group only. The present result revealed that push-up plus exercise in the unstable support with shaking which took most high serratus anterior activities and most low of UT/SA ratio is optimal cure method that can improve the imbalance of the scapular stabilizer.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.3
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• pp.369-378
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• 2013

PURPOSE: The purpose of present study was to ascertain how the activity of the serratus anterior muscle, the upper trapezius muscle and the pectoral major muscle was affected while the upper arm was being flexed at 70, 90 and 110 degrees respectively in a closed kinetic chain exercise (wall push up plus) and an open kinetic chain exercise (static hug). METHODS: Sixteen healthy young men subjects participated in the study. Surface electromyography (EMG) data were collected from the dominant-side muscles during a closed kinetic chain exercise and an open kinetic chain exercise. The activity of each muscle was measured quantitatively, and by the use of the two-way repeated ANOVA, the data were compared with each other according to exercises and shoulder flexion angles. RESULTS: Results indicated that the closed kinetic chain exercise did not interact with the open kinetic chain exercise (p>.05). In both the closed kinetic chain exercise and the open kinetic chain exercise, the activity of the serratus anterior muscle became different significantly according to angles (p<.05). Its activity increased in order of 70, 90 and 110 degrees (p<.05). In both exercises and all angles, muscle activity was significantly higher in the serratus anterior muscle than in the upper trapezius muscle and the pectoral major muscle (p<.05). CONCLUSION: The above results show that there is a need to selectively control the exercise stress of the serratus anterior muscle in the case of the patients with the shoulder impingement syndrome characterized by the winged scapula, insufficient scapular protraction and upward rotation.