• The Journal of Korean Physical Therapy
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• v.26 no.3
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• pp.140-146
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• 2014

Purpose: Differences in scapular kinematics and muscle activity appear in the forward head and rounded shoulder posture (FHRSP). Thus, the aim of this study was to investigate the following effects according to different postures on scapular kinematics and muscle activity around scapular region in individuals with and without FHRSP during overhead reaching task. Methods: Thirty pain-free subjects with/without FHRSP participated in this study. All subjects were positioned into three positions: habitual head posture (HHP), self-perceived ideal head posture (SIHP) and therapist-perceived neutral head posture (TNHP). Muscle activities of upper trapezius (UT), lower trapezius (LT) and serratus anterior (SA) were measured during overhead reaching task. Results: Muscle activity of trapezius muscle (UT and LT) during HHP was significantly higher than SIHP and TNHP in FHRSP group (p<0.05), but there was no difference between SIHP and TNHP. SA also significantly increased muscle activity in HHP more than SIHP and TNHP in FHRSP group (p<0.05), but there was no significant difference between SIHP and TNHP. In Non-FHRSP group, although there was a tendency of different muscle activities among three postures, it was not statistically significant. Conclusion: This result demonstrates that muscle activity associated with overhead reaching task is increased in HHP which affects the scapular kinematics and SIHP contributes changed scapular kinematics and proper recruitment of muscle activity in FHRSP similarly to TNHP.

• Physical Therapy Korea
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• v.24 no.1
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• pp.61-70
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• 2017

Background: Scapular winging is a prominence of the entire scapular medial border, mainly caused by insufficient activity of the serratus anterior (SA) and imbalance of scapulothoracic muscles. Push-up plus (PUP) exercise has been commonly used to increase SA muscle activity. The facilitation of abdominal muscle may affect scapular muscle activity by myofascial connections. Thus, the sequential activation of the turnk muscles is suggested to facilitate the transition of proper force from upper limb and restore force couple of scapular muscles. The abdominal drawing-in maneuver (ADIM) has been effective in improving activation of the deep trunk muscles during movement. Objects: The aim of this study was to determine the effect of ADIM on the activity of the upper trapezius (UT), lower trapezius (LT), and SA during PUP exercises in subjects with scapular winging. Methods: Fourteen men with scapular winging (determined as a of distance between the scapular medial border and thoracic wall over 3 cm) volunteered for our study. The subjects performed the PUP exercise with and without ADIM. Surface electromyography was used to collect the electromyography data of the UT, LT, and SA. A scapulometer was used to measure the amount of scapular winging. Results: SA activity was significantly greater and scapular winging significantly lower during the PUP exercise with ADIM than during those without ADIM. Conclusion: PUP exercise with ADIM can be used as an beneficial method to improve SA activation and to reduce the amount of scapular winging in subjects with scapular winging.

• 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.

• 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.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.3
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• pp.29-41
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• 2020

PURPOSE: The aim of this study was to provide evidence for the treatment of Forward Head and Rounded Shoulder Posture (FHRSP) using posture correction exercises by comparing muscle activity and onset time around the neck and shoulder area during an arm elevation task. METHODS: The subjects were divided into FHRSP (21 persons) and non-FHRSP (19 persons) groups to measure muscle activity and onset time of muscle contraction. Wireless surface electromyography was used to assess the muscle activity and onset time of the right and left sternocleidomastoid (SCM), splenius capitis, anterior deltoid, middle deltoid, serratus anterior, upper trapezius, pectoralis major, and infraspinatus during an arm elevation task. After the pre-measurement, the participants performed the postural correction exercises, and then the post-measurement was conducted. RESULTS: After the posture correction exercises, there were significant differences in the muscle activity and onset time of all muscles in the FHRSP group. The results of the comparison of the muscle onset time during an arm elevation task demonstrated that after the postural correction exercises, the muscle onset time was significantly reduced in the right and left SCM and left splenius capitis, but there were no significant changes in the onset time of other muscles. CONCLUSION: The results of this study help us understand the change in muscle activities and muscle contraction onset time in a person with FHRSP when lifting the arm and suggest the relevant basis to apply the posture correction exercise in clinical settings.

• Journal of the Korean Applied Science and Technology
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• v.37 no.1
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• pp.1-6
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• 2020

The purpose of this study was to investigate the effects of sling and vibrator application of knee push-up plus motion on trunk muscle activities. Ten healthy adult males(age, 23.00±0.45 years; height, 176.60±1.64 cm; body mass, 67.50±1.22 kg; and BMI, 21.65±0.34 kg/㎡) were participated in this study as subjects. Three types' knee push-up plus motions were performed(basic knee push-up plus motion, BKPP; knee push-up plus motion with sling, KPPS; knee push-up plus motion with vibration, KPPV). We measured the right side's trunk muscle activities of the upper trapezius(UT), pectoralis major(PM), serratus anterior(SA), rectus abdominis(RA), and external oblique(EO). The research findings were as follows. UT, PM, SA, RA, and EO muscle activities were greatest during KPPV(p<.001). These results are expected to serve as reference materials for knee push-up plus motion applications in training programs for trunk muscle strengthening.

• Physical Therapy Korea
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• v.24 no.3
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• pp.30-39
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• 2017

Background: Scapular posterior tilt (SPT) is important in the prevention of abnormal scapular movement and pain during elevation of the arm. However, previous studies have overlooked increased upper trapezius (UT) muscle activity interrupting the normal force couple of scapular motion and compensation of levator scapulae (LS) muscle activated simultaneously with UT during SPT exercise. Objects: The purpose of this study was to compare the effects of modified SPT with depression exercise versus SPT exercise on serratus anterior (SA), lower trapezius (LT), UT, and LS muscle activities and the clavicular tilt angle, in subjects with rounded shoulder posture (RSP) and myofascial pain in the UT muscle region. Methods: Eighteen subjects with RSP were recruited and randomly allocated to 2 groups; 9 in the SPT group and 9 in the SPT with depression group. All subjects met the specific RSP criteria and had myofascial pain of UT region. Depending on the allocated group, subjects performed the assigned SPT exercise and EMG data were recorded during the each exercise. Clavicular tilt angle was defined as the angle between the line joining the medial and lateral end of the clavicle and a horizontal line. Results: The SA muscle activity was significantly greater in SPT with depression than with SPT exercise (p<.05). The UT, LS muscle activity and the clavicular tilt angle was significantly lower in SPT with depression than with SPT exercise (p<.05). Conclusion: These findings were insightful because the potential risk of pain from overactivation of the UT and LS was considered, in contrast with SPT exercise. SPT with depression exercise can be implemented as an effective method to facilitate scapular muscle activity for stability and to prevent myofascial pain in the neck and shoulder.

• Physical Therapy Korea
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• v.29 no.2
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• pp.165-170
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• 2022

Background: The serratus anterior (SA) muscle prevents scapular winging (SW) by stabilizing the medial border of the scapula during arm movement. The upper trapezius (UT) and lower trapezius (LT) muscles may compensate for the weak SA muscle in individuals with SW during shoulder flexion. However, there is no study to examine whether compensation by UT and LT occurs in individuals with SW. Objects: This study compared the muscle activities of UT, LT, and SA as well as the SA/UT activity ratio between individuals with and without SW during shoulder flexion with load. Methods: This study recruited 27 participants with SW (n = 14) and without SW (n = 13). Electromyography data of the SA, UT, and LT muscles and SA/UT activity ratio were recorded and analyzed during shoulder flexion with 25% load of the maximal shoulder flexion force. Independent t-test was used to compare the UT, LT, and SA muscle activities and SA/UT ratio between the groups with and without SW; statistical significance was set at α of 0.05. Results: SA activity was significantly lesser in the group with SW than in the group without SW. However, there were no significant differences in the UT and LT activities and SA/UT activity ratio between the two groups. Conclusion: The SA activity was lesser in the group with SW than in the group without SW with 25% load of the maximal shoulder flexion force, but there was no compensatory muscle activity of the UT and LT observed. Therefore, further studies are warranted to clarify the compensatory strategy of scapular stabilization in individuals with SW during shoulder flexion under other heavy load conditions.

• 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.

• PNF and Movement
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• v.22 no.2
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• pp.315-324
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• 2024

Purpose: The aim of this study was to compare the activation of shoulder stabilizer muscles to variations of manual resistance during three-dimensional shoulder rehabilitation exercises. Methods: A total of 13 participants were included in this study. To normalize each muscle's activity, a maximal isometric voluntary contraction was performed by all participants. After receiving 30 minutes of training in three-dimensional shoulder rehabilitation exercises, participants randomly performed PNF arm and scapular patterns according to the intensities of manual resistance. The activities of the upper trapezius, lower trapezius, and serratus anterior were measured during these patterns. All exercises were performed for five seconds, and the average of three seconds, excluding the first and last seconds, was used for data analysis. Results: Lower trapezius activity was significant among manual resistance intensities. In both the PNF arm and scapular patterns, using 80% manual resistance of maximum resistance showed higher activity of the lower trapezius muscle compared to 20% of the maximum resistance. Conclusion: It is expected that PNF arm and scapular patterns, with varying intensities of manual resistance, can be used for early rehabilitation of patients with shoulder impingement syndrome.