• 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.

• Physical Therapy Korea
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• v.23 no.1
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• pp.80-86
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• 2016

Background: Prone hip extension (PHE) can be performed to measure the lumbopelvic motor patterns and motions. Imbalances in lumbopelvic muscle activity and muscle weakness can result in instability including pain in lumbopelvic region. The posterior oblique sling (POS) muscles contribute to dynamic lumbopelvic stability. In addition, POS are anatomically aligned with the trapezius muscle group according to shoulder positions. Objects: This study compared the electromyography (EMG) activity of POS and pelvic compensations during PHE with and without pre-activation of lower trapezius muscle (lowT). Methods: Sixteen healthy males were recruited. PHE was performed in randomized order: PHE with and without lowT pre-activation. Surface EMG signals were recorded for biceps femoris (BF), gluteus maximus (GM) (ipsilateral), lumbar multifidus (MF) (bilateral), and the lowT (contralateral). An electromagnetic tracking motion analysis was used to measure the angle of pelvic rotation and anterior tilting. Results: The ipsilateral GM and bilateral MF EMG amplitudes were greater during PHE with lowT pre-activation compared to PHE without lowT pre-activation (p<.05). The BF amplitude during PHE without lowT pre-activation was significantly greater than that during PHE with lowT pre-activation (p<.05). The angles of pelvic rotation and anterior tilting during PHE with lowT pre-activation were significantly smaller compared to PHE without lowT pre-activation (p<.05). Conclusion: PHE with lowT pre-activation, which is aligned with the POS, showed more increased MF and GM muscular activity with smaller lumbopelvic compensations in rotation and anterior tilting compared to PHE without lowT pre-activation.

• Korean Journal of Applied Biomechanics
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• v.25 no.2
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• pp.219-229
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• 2015

Objective : The purpose of this study was to analyze EMG according to surface type and elastic band usage during the pilates Superman movement. Method : The subjects were 10 female university students with a mean age of 27. The independent variables were surface type (yoga mat, air filled equipment, elastic mat) and elastic band usage. In order to measure muscle activity, the Noraxon(USA) was used. Eight muscles (upper trapezius, lower trapezius, thoracic spine, lumbar spine, gluteus maximus, gluteus medius, biceps femoris, semitendinosus) activation were analyzed. For the statistical analysis, MANOVA, independent t-test and Scheffe test for the post-hoc via SPSS 20.0 was used. Results : The left and right upper trapezius muscle activities were significantly reduced when using the elastic bands. In addition gluteus medius muscle activities significantly increased with the elastic band as well. Conclusion : According to the usage of the elastic band and the different types of surfaces, different muscle groups were recruited. Elastic bands were found to have more activation on the gluteus medius muscle meanwhile there was less activation on the upper trapezius during the pilates Superman movement.

• Physical Therapy Korea
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• v.28 no.3
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• pp.194-199
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• 2021

Background: The scapulo-thoracic musculatures including serratus anterior (SA), upper trapezius and lower trapezius can provide shoulder stability and functional shoulder movement. Objects: The muscle activities of upper and lower SA were compared during three different scapular protraction exercises in healthy individuals in sitting position. Methods: Twenty-five healthy subjects were participated. Electromyography device was used to measure muscle activity of upper and lower SA and trapezius muscles. Each subject was asked to perform three different scapular protraction exercises (scapular protraction [SP], SP with self-resistance [SPSR], SPSR with hand-exerciser [SPSRH]) in random order. One-way repeated measures analysis of the variance and a Bonferroni post hoc test were used. Results: The muscle activity of lower SA muscle was significantly different among three conditions (SP vs. SPSR vs. SPSRH) (p < 0.01). The lower SA muscle activity was significantly greater during SPSRH compared to SP and SPSR, which required joint stability more than SP and SPSR (p < 0.01). Conclusion: SPSRH exercise can be recommended to facilitate the muscle activity of lower SA. In addition, the intramuscular variation in the upper and lower SA during scapular protraction exercise is required to consider the effective rehabilitation.

• Journal of Oral Medicine and Pain
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• v.22 no.2
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• pp.327-339
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• 1997

This study aimed at evaluating tile relationship between pressure pain threshold(PPT) and electromyographic(EMG) activity in 30 healthy volunteers and 30 patients with temporomandibular disorders. PPTs were determined with electric pressure algometry over masseter, temporalis anterior, sternocleidomastoid, and trapezius muscle during resting and clenching. To obtain more reliable result, two examiners measured PPTs two times on each muscles, randomly. Resting and clenching EMG activity and tenderness of all muscles were measured to evaluate the relationship with PPTs. The collected data were processed by SAS/STAT program. The obtained results were as follows : 1. Pressure pain thresholds in tendered muscles were lower than those in non-tendered muscles. This tendency was more prominant in masticatory muscles than in cervical muscles and in clenching than in resting. 2. There ware a tendency of higher PPTs in unaffected side than in affected side, but there were no significant difference statistically. 3. There wert no difference of PPTs between in preferred side and in ipsilateral side, significantly. 4. There was a significantly positive correlation between resting and clenching PPTs, but there were no correlation between PPTs and EMG activities. 5. Comparison of EMG activity between in higher group and in lower group by resting PPTs didn't show any significant difference. But resting EMG activity in the higher group of clenching PPTs were lower, on the contrary, clenching activity were higher than those in lower groups of clenching PPTs. From this results, the author concluded that the clenching PPTs was more important than resting PPTs in diagnosis of muscle dysfunction. And the author recommanded that all of three following test were performed for the proper diagnosis and treatment of orofacial Pain : muscle tenderness, EMG activity, and PPT.

• Physical Therapy Korea
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• v.19 no.1
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• pp.46-55
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• 2012

The purpose of this study was to investigate the effect of the two different types of chairs on trapezius muscle activation during dictation tasks. Seventeen university students, each of whom were within ${\pm}1$ standard deviation of the mean Korean standard body size, voluntarily participated in this study. Surface electromyography was used to collect electrical signals from both the upper and lower trapezius muscles. Amplitude Probability Distribution Function (APDF) was performed to analyze the muscle activity. The findings of this study were 1) The backrest-point height of the auditorium chair and the height, length and width of the connected desk were shorter than what was suggested by the KS. Another difference was that the auditorium chair had a bigger angle of the backrest compared to the classroom chair. 2) Regarding within-subject effect the sole statistically significant difference was found between activation of the upper trapezius muscle. The upper trapezius muscle's %RVC in the APDF 10th-50th-90th percentile was statistically higher for participants sitting in the auditorium chair than for participants sitting in the classroom chair (p<.05). 3) There was an interaction effect between the 'two chair-types' and the 'two muscle-sides' in the APDF 10th-50th percentile (p<.05). 4) There was an interaction effect between the 'two chair-types' and the 'three gaze-direction' in the APDF 90th percentile (p<.05). The findings of this study indicated that maintaining a writing posture for a prolonged period of time in an auditorium chair significantly increased the left upper trapezius muscle activation compared to a classroom chair.

• The Journal of Korean Physical Therapy
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• v.25 no.5
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• pp.316-321
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• 2013

Purpose: The aimed of this study was to investigate muscle activation related to postural stability according to different frequency of whole body vibration during quiet standing, to identify the most effective training conditions that cause the highest neuromuscular responses, and to evaluate the difference of EMG activation according to the anatomical position of the muscle - proximal or distal from the vibration platform. Methods: Eighteen healthy subjects voluntarily participated in this single-group, repeated-measures study in which EMG data from upper trapezius, rectus abdominalis, external oblique abdominalis, elector spinae, gluteus maximus, rectus femoris, semitendinosus, and gastrocnemius were collected over different frequencies (0-5-10-15-20-25Hz) for each subject during quiet standing. Results: We observed a statistically significant difference in the mean values of %RVC of muscular activation according to different frequencies of whole body vibration during quiet standing in all muscles (p<0.05). Conclusion: Our results indicate that lower frequencies of vibration result in low muscular activation, and higher frequencies elicit high muscular activation. However, the most effective training condition that caused the highest activation was 20 Hz. In addition, the proximally located lower extremity muscles (GCM, RF, ST, GM) showed higher activation than the distally located trunk and neck muscles (ES, EO, RA, UT) together with increasing frequency.

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.3
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• pp.21-28
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• 2017

Purpose: The purpose of this study was to investigate the effects of three exercise programs on forward head posture. Methods: Ninety-five individuals were recruited to assess the of the pectoralis minor muscle. Of these, 36 individuals with pectoralis minor muscles were selected and randomly divided into three groups: a functional massage group, a stretching group, and a stretching and muscle strengthening group. The exercise program consisted of sessions four times per week for two weeks. The length of pectoralis minor and the activity of the trapezius muscles were measured using electromyography. Forward head posture was assessed using the craniovertebral angle (CVA) and the cranial rotation angle (CRA) pre-, during and post-treatment. Result: Significant improvements were observed in pectoralis minor length, CRA, and CVA post-treatment in all groups (p<0.05, p<0.01, p<0.001). However, only the activity of the lower trapezius demonstrated a statistically significant difference post-treatment. There were no significant differences between the groups. Conclusion: The findings of this study suggest that all three exercise programs were effective in improving forward head posture and the length of pectoralis minor post-treatment.

• PNF and Movement
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• v.21 no.1
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• pp.87-94
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• 2023

Purpose: The present study aims to investigate the effects of a diagonal exercise pattern on selective activation of the upper extremity muscles using both normalization and isolation methods. Methods: In total, 17 asymptomatic subjects participated in this study. During the two diagonal patterns of exercise (diagonals 1 and 2), muscular activities of the upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), anterior deltoid (AD), and infraspinatus (IS) were measured. The collected data were analyzed in two ways, according to the dominance of muscle activities (%Isolation) and according to normalized activities (%MVIC). Results: There were significant differences in LT, SA, AD, and IS between %MVIC and %Isolation (p<0.05), and the diagonal 1 pattern of exercise showed significantly more LT activities compared with the diagonal 2 pattern (p<0.05). Further, except for LT, there were no significant differences in muscle activities between the diagonal 1 and 2 exercises. Conclusion: The present study suggests that a diagonal pattern of exercise is advantageous for strengthening shoulder muscles, but caution is needed when applying to patients requiring selective strengthening. Regarding both the concentric and eccentric phases of exercise, there was no significant difference in muscular activation, except in LT, between the two diagonal patterns of exercises.

• Journal of the Korean Society of Safety
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• v.27 no.1
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• pp.111-116
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• 2012

Workers who work with his neck bent backward in the standing posture have often complained of their musculoskeletal stress. The objective of this study was to find how much stress there was for workers who worked with their neck bent backward. The subjective evaluation and electromyography(EMG) were used to check the level of the stress. It was found that all subjects felt extreme pain after working with the neck bent backward and alternating 1 minute work and 0.5 minute rest for 30 minutes. The EMG level(amplitude) of neck muscles increased 80 percent on the average and the center frequency of EMG shifted to the lower frequency level which indicated fatigue of neck muscles. Thus, the intervention of this musculoskeletal stress is strongly recommended.