• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.16 no.1
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• pp.26-36
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• 2010

Purpose: The study compared the muscle activity and ratio of upper trapezius (UT) to lower trapezius (LT) activity between acute and chronic whiplash-associated disorder (WAD) patients. Methods: Twelve healthy (male: 7), 14 acute WAD (male: 7), and 11 chronic WAD (male: 3) volunteers participated in this study. Electromyography using a surface EMG recorded the activity of the upper trapezius and lower trapezius of both shoulders (dominant and non-dominant) during $120^{\circ}$ elevation when standing and shoulder depression when sitting. The testing order was selected randomly. Subjects were asked to maintain each experimental position for 5 seconds at end range. EMG activity was normalized using the maximal voluntary isometric contraction (MVIC) elicited using a manual muscle-testing technique. One-way repeated measures analysis of variance (ANOVA) was used to compare the average root mean square (RMS) value of EMG activity for each condition. Results: The EMG activity of the dominant UT for chronic WAD subjects was significantly higher than for acute WAD subjects during $120^{\circ}$ elevation (p<.05). The EMG activity of the dominant LT for acute WAD subjects was significantly lower than for the control group (p<.05) during $120^{\circ}$ elevation. The EMG activity of the dominant LT for WAD patients was significantly lower than for the control group during shoulder depression (p<.05), and the chronic WAD patients scored significantly the lowest (p<.01). The dominant UT/LT for chronic WAD patients was significantly higher than the ratio for acute WAD subjects during shoulder depression (p<.05); this result was higher than for the control group (p<.01). The non-dominant UT/LT (ratio) for chronic WAD patients was significantly higher than the ratio for acute WAD subjects during shoulder depression (p<.05). Conclusion: The UT for chronic WAD subjects was hyperactive when compared to the acute WAD subjects, and the was hypoactive for both acute and chronic patients, therefore intra-trapezius imbalance was more prevalent during shoulder depression.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.3
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• pp.81-86
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• 2015

PURPOSE: Bridge exercises are broadly used to develop trunk co-activation patterns that promote spine stability. This study was to analyze the trunk muscle activity during bridge exercise with various shoulder support surface(stable, sling, Swiss ball). METHODS: The subjects were 20 healthy subjects in their twenties. Subjects were performed bridge exercise on 4 different shoulder support surfaces using stable and labile instruments. 1) Bridge exercise on a stable surface. 2) Bridge exercise with their shoulder on a stable bench. 3) Bridge exercise with their shoulder on a sling. 4) Bridge exercise with their shoulder on a Swiss ball. Rectus abdominis, erector spinae, internal oblique, external oblique muscle activities were measured using electromyography. RESULTS: There were significant differences in RA, EO muscles between performing each of the 4 exercises(p<.05). RA and EO was recorded the highest activity during the bridge exercise with their shoulder on a sling. The lowest activity was recorded during conventional supine bridge on a stable surface. There were no differences found for the EO/RA and IO/RA ratio. The EO/RA and IO/RA ratio was the highest in the bridge exercise with their shoulders resting on a stable bench. CONCLUSION: These findings suggest that change of shoulder support surface during bridge exercise may be useful for enhancing the trunk stability.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.2
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• pp.13-21
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• 2021

Purpose : Instrument-assisted soft tissue mobilization (IASTM) has been widely used to improve pain and range of motion. However, research on IASTM using vibration stimulation is lacking. Therefore, this study investigates how IASTM using vibration stimulation affects chronic pain on muscle activity and flexibility of the shoulders. Methods : A total of 20 patients with chronic shoulder pain were divided into the experimental group and the control group. The experimental group (n=10) used vibration stimulus for IASTM, while the control group (n=10) used general IASTM. For six weeks, this training lasted for 30 min a day, twice a week. Muscle activity was evaluated using the surface electromyograph. The back and reach test was used to assess flexibility, the visual analogue scale to measure pain, and the paired t-test to compare the groups before and after the experiment. An independent ANCOVA was conducted to assess differences in the degree of transition between the two groups before and after the experiment. Results : Significant differences in muscle activity, flexibility, and pain in both groups before and after the experiment (p<0.05) were observed, as well as in the muscle activity of the pectoralis major and associated pain (p<0.05). however, muscle activity and flexibility of the upper trapezius and infraspinatus were not significantly different between groups (p>0.05). Conclusion : This study confirms the importance of IASTM using vibration. Design and manufacture of IASTM using vibration based on our results would be useful in the management of shoulder pain, Further clinical evidence are needed.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.4
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• pp.65-70
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• 2016

PURPOSE: This study aimed to compare the electromyography (EMG) activity for the middle deltoid (MD) and upper trapezius (UT) muscles in various shoulder abduction angles in patients with adhesive capsulitis (AC). METHODS: A total of 15 subjects participated in the study: 6 without AC (control group) and 9 with AC (AC group). The muscle activities of the UT and MD were measured using EMG during maximal static shoulder abductions in both groups. Each subject performed three repetitions of horizontal abduction at $0^{\circ}$, $30^{\circ}$, $60^{\circ}$, and $90^{\circ}$ of the shoulder abduction angle in a sitting position. The measurement data from the middle 3-seconds of the 5-second periods were used. The mean value of three separate sets of measurements was used in the data analysis. For each muscle, independent t-tests were performed to determine group differences. A measured repeated-measures ANOVA was performed using Bonferroni's post-hoc test. RESULTS: The muscle activity of the UT was significantly greater in the AC group; than in the control group (p<.05). The muscle activity of the MD was significantly lower in the AC group; than in the control group (p<.05). The greatest level of muscle activity for both the MD and UT was demonstrated at the $0-60^{\circ}$ and $0-90^{\circ}$ of shoulder abduction angles in the AC group. CONCLUSION: These findings showed that low muscle activation of the MD may contribute to hyperactivity of the UT during shoulder abduction in AC patients.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.4
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• pp.41-50
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• 2023

Purpose : The aim of study was to determine the effect of lower trapezius muscle strengthening exercises on the height of rounded shoulder posture and muscle activity in patients with rounded shoulder posture. Methods : Thirty-one subjects with rounded shoulders were selected and assigned, with the use of a random number table, to an experimental group (EG, n=16) that received resistance exercises of the trapezius (lower) muscles or a control group (CG, n=15) that received isometric exercises of the lower trapezius muscles. In the EG, with the subject in a prone position, both arms were abducted at the angles suggested for each posture (145 °, 45 ° abduction), with the hands holding dumbbells to assume a functional posture. The CG performed only isometric exercises without dumbbells in the same conditions. At the start signal, with the thumb raised, the arm was raised to the level of the ear. Both groups were assessed by the height of the rounded shoulder posture (RSP) and muscle activity (EMG). The intervention was performed three times a week. Results : The RSP significantly decreased during the intervention period in both the EG and CG (p<.05), and a significant difference was determined between the RSP of the two groups (p<.05). In the EG, the EMG significantly increased during the intervention period (p<.05), but the CG did not show any significant increase (p>.05). The final EMG was significantly higher in the EG than in the CG (p<.05). Conclusion : Both the EG and CG showed positive improvement in rounded shoulder posture during the intervention period. In particular, lower trapezius resistance exercise appears to reduce shoulder height and positively affects the activity of muscles around the shoulder.

• Journal of Korean Physical Therapy Science
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• v.15 no.3
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• pp.31-41
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• 2008

Purpose : The purpose of this study is to examine the muscle activity of shoulder stabilization according to change of supporting base interval between push-up bend and push-up plus position and is to prevent or treat a shoulder injury by the most effective exercise for rehabilitation. Methods : This study analyzed the muscle activity according to change of supporting base interval between push-up bend and push-up plus movement. The participants without neuromuscular disease were 25 students - 12 males and 13 females - all twenty or over and the surface electrode of EMG attached on pectoralis major, triceps long head, middle trapezius, lower trapezius, serratus anterior and latissimus dorsi. The process has practiced 3 sessions of supporting base interval - narrowing interval, two shoulder interval, broad interval - by push-up bend and push-up plus movement. Result : 1. The muscle activity of pectoralis major was significantly increased according to narrow interval of supporting base on push-up plus movement and was significant difference(p<.05). 2. The muscle activity of biceps was significantly increased according to narrow interval of supporting base on push-up bend movement(p<.05). 3. The muscle activity of middle or lower trapezius was a difference according to change of supporting base on push-up bend and push-up plus movement but was not significant difference. 4. The muscle activity of serratus anterior was significantly increased according to broad interval of supporting base on push-up bend movement(p<.05). 5. The muscle activity of latissimus dorsi was significantly increased according to broad interval of supporting base on push-up bend movement(p<.05). Conclusion : These results lead us to the conclusion that push-up bend exercise have the effect of muscle strength of biceps on narrowing interval, of serratus anterior or latissimus dorsi on broad interval and push-up plus exercise have the effect of muscle strength of pectoralis major on narrowing interval of support base.

• 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.

• PNF and Movement
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• v.22 no.1
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• pp.151-158
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• 2024

Purpose: The present study investigated how variations in diagonal exercises affect shoulder muscle activity, examining changes in neuromuscular activation during scapular and shoulder diagonal patterns of exercises. Furthermore, we explored whether the exercise phase affects muscle activation. Methods: Sixteen asymptomatic male participants were recruited. Four diagonal pattern exercises (scapular anterior elevation, posterior elevation, flexion-adduction-external rotation, flexion, abduction-external rotation), and two exercise phases (concentric and eccentric) were administered. Surface electromyography data were collected. Results: Upper trapezius activity was significantly higher during the concentric phase of scapular posterior elevation exercises compared with the others (p<0.05). The serratus anterior, anterior deltoid, and infraspinatus activities were significantly higher during shoulder diagonal pattern exercises compared with the scapular diagonal pattern exercises (p<0.05). Except for the lower trapezius, muscular activities during the concentric phase were significantly greater compared with the eccentric phase (p<0.05). Conclusion: The current study suggests that the diagonal pattern of exercise may contribute to selective strengthening of the shoulder complex muscles and that the form of exercise should be tailored to the subject. It also suggests that diagonal exercises with concentric contractions tend to be more beneficial than eccentric contractions for overall muscle recruitment, but the effects vary for specific diagonal patterns.

• Physical Therapy Korea
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• v.30 no.3
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• pp.237-244
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• 2023

Background: The external rotation (ER) exercise in performed at a 90° abduction of the shoulder joint is an effective to strengthen the infraspinatus. However, failure of the humeral head to control axial rotation during exercise can be increased the posterior deltoid over activity. Biofeedback training is an effective method of promoting motor learning and control it could look forward to activate the infraspinatus selectively by controlling the humeral head during exercise. Objects: The aim of this study was investigated that whether biofeedback for axial rotation was effective to activate selectively the infraspinatus during ER exercise. Methods: The 15 healthy males participated, and all subjects performed both ER exercise in a sitting position with shoulder abducted 90° under conditions with and without axial rotation biofeedback. Exercise was performed in a range of 90° ER, divided into three phases: concentric, isometric, and eccentric. The infraspinatus and posterior deltoid muscle activity were observed using surface electromyography. Results: Both infraspinatus activity (p < 0.01) and infraspinatus to posterior deltoid activity ratio (p = 0.01) were significantly higher with biofeedback however, posterior deltoid activity was significantly lower with biofeedback (p = 0.01). The infraspinatus muscle activity and muscle activity ratio were the highest in the isometric contraction type, and there were significant differences for all contraction types (p < 0.05). Whereas, the posterior deltoid activity was the lowest in the isometric contraction type, and showed a significant difference between isometric and other two contraction types (p < 0.05), but no significant different between concentric and eccentric contraction. Conclusion: Our results indicate that the axial rotation biofeedback during sitting ER exercise might be effective method to activating selective infraspinatus muscle and recommended to enhance the dynamic stability of the shoulder joint.

• The Journal of Korean Physical Therapy
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• v.32 no.4
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• pp.228-232
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• 2020

Purpose: This study examined the electromyography (EMG) activity of the abdominal muscles and the ratio of the oblique abdominal muscle activity to the rectus abdominis muscle during a single-leg holding position with isometric shoulder abduction (SLHISA) in the supine position on a foam roller. Methods: Nineteen healthy males were recruited to the study. Each subject was asked to lay on a round foam roller and perform singleleg (nondominant) holding with contralateral shoulder abduction to one of three angles (45°, 90°, or 135°) in random order. The surface EMG signals of the bilateral rectus abdominis (RA), external oblique abdominis (EO), and combined internal oblique abdominis (IO) and transverse abdominis (TrA) muscle were collected during the tasks. The EO/RA and (IO & TrA)/RA ratios were determined using surface EMG. One way repeated measure ANOVA with three SLHISAs was used to assess the significant abdominal muscle EMG activity and the ratio of the oblique abdominal muscles activity to the RA muscle. The statistical significance level was p<0.05. Results: The results were as follows. The SLHISA 135° showed significantly higher EMG activity of both RAs, left EO, and right IO & TrA muscles (p<0.05). The right EO and left IO and TrA muscles/RA were significantly different among the SLHISA angles. The SLHISA 45° showed a significantly greater ratio of right EO/RA and left IO & TrA/RA (p<0.05). Conclusion: SLHISA on a foam roller is useful for lumbopelvic stabilization exercise by increasing the activity and recruiting a specific pattern of the oblique abdominal muscle.