• 한국안전학회지
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• 제31권4호
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• pp.111-119
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• 2016

This study aimed to analyze postures that were frequently conducted in manufacturing industry. To find grip strength and muscle activities of each posture, Maximum Voluntary Contraction (MVC) and ElectroMyoGraphy (EMG) were measured. Based on the results of this study, the most appropriate posture could be suggested and used as a basic information for preventing musculoskeletal disorders. Most work-related musculoskeletal disorders have been occurred in the fields of manufacturing industry. According to previous studies, it was reported that the rate of musculoskeletal diseases of upper extremity was higher than that of other body parts. Accordingly, there were many studies about discomfort and grip strength of upper extremity. However, these studies dealt with single selection of wrist, elbow and shoulder. So, it was insufficient for comprehensive studies about upper extremity. And in order to improve the work posture, the physiological changes being generated by the combination of wrist, elbow and shoulder postures should be observed and analyzed. In order to conduct this study, thirty university students who had no records of MSDs involved were recruited. Independent variables were postures of wrist(pronation, neutral, supination), postures of elbow(flexion $45^{\circ}$, $90^{\circ}$) and postures of shoulder(flexion $0^{\circ}$, $90^{\circ}$). And dependent variables were MVC values and EMG values. Jamar dynamometer and TeleMyo 2400T G2 was used to measure MVC and EMG. MVC and EMG for 12 postures were measured for three second and for three times. Experiment was performed randomly. A 10 minutes rest period was provided after each t. To measure muscle load, the EMG signals of eight muscles (Biceps, Medial triceps, Lateral triceps, Brachioradialis, Extensor carpi ulnaris, Extensor carpi radialis, Flexor carpi ulnaris and Flexor carpi radialis) were evaluated. MVC values and EMG values were analyzed using Minitab ver. 14. The results showed that MVC value was the highest at shoulder $0^{\circ}$, elbow $45^{\circ}$ and wrist supination. In case of wrist postures, MVC of supination is the highest. In case of elbow and shoulder postures, MVC of flexion $45^{\circ}$ and $0^{\circ}$ was the highest. It was found that there were interaction between wrist and elbow posture under shoulder flexion and between shoulder and wrist under elbow flexion $45^{\circ}$. In case of the angle of shoulder $0^{\circ}$, elbow $45^{\circ}$ and wrist supination, the EMG values of four muscles(Medial Triceps, Extensor carpi ulnaris, Extensor carpi radialis, Flexor carpi ulnaris) were the highest. Based on this study, it is worth to note that the combination postures of upper extremity have a large impact on the MVC and EMG. The optimal condition upper extremity was shoulder flexion $0^{\circ}$, elbow flexion $45^{\circ}$ and wrist supination for preventing work-related musculoskeletal disease.

• PNF and Movement
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• 제13권1호
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• pp.1-7
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• 2015

Purpose: This study aimed to examine the activity of the shoulder flexor and extensor when hold-relax and contraction-relax techniques were applied with shoulder joint flexion. Methods: The subjects of this study were 15 healthy women. With the shoulder joint flexion at $0^{\circ}$ and $90^{\circ}$, hold-relax and contraction-relax techniques were applied for the same submaximal resistance to measure the activities of the deltoid muscle anterior fiber, deltoid muscle posterior fiber, pectoralis major fiber, and latissimus dorsi muscle with surface electromyography. An independent t-test was conducted in order to compare activities of each muscle according to the two techniques. Results: When the hold-relax and contraction-relax techniques were applied with the shoulder joint flexion at $0^{\circ}$, the activities of the shoulder flexor and extensor were not significantly different, but the activity of the flexor was higher when the contraction-relax technique was applied than when the hold-relax technique was applied. When the hold-relax and contraction-relax techniques were applied with the shoulder joint flexed at $90^{\circ}$, the activities of the shoulder flexor and extensor were not significantly different, but the activity of the extensor was relatively higher than when the flexor was at $0^{\circ}$ Conclusion: When the hold-relax and contraction-relax techniques were applied with the shoulder joint flexion at $0^{\circ}$, the activities of the shoulder flexor and extensor were not significantly different, but the activity of the flexor was higher when the contraction-relax technique was applied than when the hold-relax technique was applied. When the hold-relax and contraction-relax techniques were applied with the shoulder joint flexed at $90^{\circ}$, the activities of the shoulder flexor and extensor were not significantly different, but the activity of the extensor was relatively higher than when the flexor was at $0^{\circ}$.

• The Journal of Korean Physical Therapy
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• 제10권2호
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• pp.77-86
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• 1998

The shoulder joint permit ate greatest mobility of any joint area carries out the importment function of stabilization for hand use. So handgrip activity is important to evaluate while assessing shoulder load in manual work. There was an association between static handgrip and shoulder muscle activity. The purpose of this study was to find out the changes of the hand grip strength according to shouter an81e. One hundred (50 female, 50 male) college adult volunteers with no known shoulder dysfunction participated subject in three positions with elbow extension: (1) shoulder $0^{\circ}$ flexion (2) shoulder $90^{\circ}C$ flexion (3)shoulder $180^{\circ}C$ flexion. The paired t-test was used to determine the different in grip strength between right and left hand at shouter position change. All, there was significiant for all three position by right and left shoulder (p<0.001). In mon, the ANOVA results revealed not a significiant F-ratio fer all three position by right and left hand. In woman, revealed significiant (p<0.05).

• 한국의류학회지
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• 제26권12호
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• pp.1739-1748
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• 2002

본 연구의 목적은 소방용 coverall의 디자인이 소방수들의 동작기능성에 어떤 영 향을 주는지에 관하여 고찰하여, 보다 기능적 인 coverall을 개발, 궁극적으로 작업자의 노동력을 향상시키고, 보다 안락한 환경 속에서 작업할 수 있도록 도와주는데에 있다. 미국 캔사스 지역의 전문 소방수를 대상으로, interview 및 video analysis를 통하여, 그들이 현재 사용하고 있는 current coverall의 동작기능면에서의 문제점을 조사, 분석한 후, 이를 바탕으로 prototype coverall을 개발하였다 prototype coverall의 동작기능성을 객관적으로 측정하기 위하여 10가지 실험동작(shoulder adduction/ abduction, shoulder flexion/extension, trunk flexion/extension(standing), hip flexion/extension(knee), hip flexion/extension(trunk), upper leg flexion, trunk lateral flexion, hip adduction, trunk flexion/ extension(sitting), upper leg flexion)을 선택하여 이의 관절각도(range-of-motion)를 Leighton flexometer, goniometer, computer-aided method를 이용하여 측정하였으며, 착용자의 주관적 평가를 위하여서는 23 항목의 wearer acceptability scale를 사용하였다. ANOVA(Analysis of Variance)와 LSD(Least Significant Difference)를 이용한 통계처리 결과, prototype coverall이 current coverall에 비해 동작기능성 (특히 crotch, torso, hip movement)에 있어서 우수함을 보이고 있다.

• 한국전문물리치료학회지
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• 제24권4호
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• pp.11-19
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• 2017

Background: Methods for exercising serratus anterior (SA) and upper trapezius (UT) muscles are important for the recovery of patients with various shoulder disorders, yet the efficacy of closed or open kinetic chain exercises have not yet been evaluated. Objects: The purpose of this study was to compare the activation of the SA and UT muscles during scapular protraction considering both closed and open kinetic chain exercises. Methods: Thirty subjects were randomly divided into experimental groups (closed kinetic chain exercise) and control groups (open kinetic chain exercise) in which scapular protraction was performed at $90^{\circ}$ or $125^{\circ}$ shoulder flexion. Electromyographic activity data were collected from the SA and UT muscles per position and exercise method. Results: Separate mixed 2-way analysis of variance showed significant differences in the activation of the SA (F1,28=6.447, p=.017) and the UT (F1,28=35.450, p=.001) muscles between the groups at $90^{\circ}$ and $125^{\circ}$ shoulder flexion. Also, the SA/UT ratio measures at $90^{\circ}$ and $125^{\circ}$ shoulder flexion significantly differed between the groups (F1,28=15.457, p=.001). That is, the closed chain exercise was more effective than open chain exercise for strengthening the SA muscle and controlling the UT muscle, $125^{\circ}$ of shoulder joint was more effective than $90^{\circ}$. Conclusion: The findings suggest that scapular protraction with shoulder $125^{\circ}$ flexion at the closed kinetic chain exercise may be more effective in increasing SA muscle activation and decreasing UT muscle activation as well as increasing the SA/UT ratio than open kinetic chain exercise.

• PNF and Movement
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• 제16권1호
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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.

• 대한통합의학회지
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• 제7권2호
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• pp.153-163
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• 2019

Purpose : This study was to identify the effects of Mobilization with Movement combined with exercise (EMWM) on acromio-humeral distance (AHD), range of motion (ROM), pain intensity, and functional performance in patients with impingement syndrome of the shoulder. Methods : The subjects were 40 patients diagnosed with impingement syndrome of the shoulder. Twenty subjects are randomly assigned to each 2 different groups; Group 1. (exercise group), Group 2. (EMWM group). Three weekly interventions were given for 4 weeks. The main outcome measures were ultrasound, goniometer, visual analogue scale (VAS), and Korean Constant shoulder score (K-CSS). The ultrasound (AHD), ROM (flexion, abduction), pain intensity (for shoulder flexion) and functional performance (K-CSS) were compared between the groups. Results : The AHD was significantly increased in Group 2 compared to Groups 1. No significant difference was observed between the groups in the range of abduction of the shoulder, but the range of flexion was significantly increased in Group 2 compared to Groups 1. Pain intensity was significantly lower in Group 2 than in Group 1, and functional performance was significantly increased in Group 2 compared to Group 1. Conclusion : An intervention that combined mobilization with movement with exercise was more effective than exercise alone for rapid recovery from shoulder injury and improvement in functional performance.

• The Journal of Korean Physical Therapy
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• 제23권1호
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• pp.29-35
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• 2011

Purpose: The purpose of this study was to identify the effect of neck exercises on neck-shoulder posture and pain of high school students with neck disorders. Methods: Twenty seven subjects were randomly assigned to one of 3 groups a craniocervical flexion training group (CCFT), a neck strengthening exercise group (ST), and a basic stretching exercise group (CG). CCFT and ST exercised five times a week for eight weeks under the researcher's guidance. The control group performed basic stretching exercises. Diagnostic radiologic equipment was used for the measurement of neck-shoulder posture. Neck disability index, and numeric rating scales were used. Results: The CCFT showed a significant pre-post treatment difference on measures of neck flexion angle and forward shoulder angle changes compared to the ST and CG groups (p<0.05). The CCFT group also showed a significantly greater improvement on the neck disability index and numeric rating scales changes than the ST and CG groups (p<0.01). Conclusion: Because CCFT decreases neck flexion angle, forward shoulder angle, neck disability index, and pain in the forward head posture, it is useful for treating patients with neck disorders.

• 한국운동역학회지
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• 제22권2호
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• pp.193-199
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• 2012

The purpose of this study was to investigate the activities of the serratus anterior (SA) and upper trapezius (UT) muscles during scapular protraction exercise with a dumbbell. Twenty-one healthy subjects with no medial history of shoulder pain or upper extremity disorders were recruited for this study. Subjects performed scapular protraction at $90^{\circ}$ and $130^{\circ}$ shoulder flexion with a dumbbell in supine and standing positions. The activities of the SA and UT were measured via surface electromyography (EMG) during 4 scapular protraction exercises. A 2 (angle) ${\times}$ 2 (position) repeated-measures analysis of variance (ANOVA) was used to compare the normalized activities of the SA and UT and the UT/SA ratio. The results showed that activities of both the SA and UT were the highest for the scapular protraction exercise at $130^{\circ}$ shoulder flexion in the standing position. However, the UT/SA ratio was the lowest for the exercise at $90^{\circ}$ shoulder flexion in supine position. Therefore, for selective activation of the SA muscle, we recommend performing the scapular protraction exercise with a dumbbell in the supine position at $90^{\circ}$ shoulder flexion.

• PNF and Movement
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• 제19권1호
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• pp.19-29
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• 2021

Purpose: This study aimed to compare the effects of a four-week scapular stabilization exercise program using the PNF technique on scapular symmetry and range of flexion motion (ROM), pain, function, and quality of life (QOL) in post-mastectomy women with breast cancer. Methods: This study included 20 women divided into an experimental group (n = 10) and a control group (n = 10). All patients performed complex decongestive physiotherapy for 40 min daily, five times per week for four weeks. The experimental group performed the extra scapular stabilizing exercise program using the PNF technique for 50 min daily, five times per week for four weeks. Scapular symmetry, shoulder flexion ROM, pain and function, and QOL were subsequently assessed. For ROM measurement, the range of shoulder flexion was measured using a clinometer smart phone application; the pain of the shoulder was measured using the visual analogue scale (VAS); the scapular position was measured using a lateral scapular slide test (LSST); the level of pain and functional activity was measured using the Shoulder Pain and Disability Index (SPADI); and the QOL was measured using Functional Assessment of Cancer Therapy-Breast. Results: There were significant differences in shoulder flexion ROM, VAS, SPADI, and LSST 0˚ and 45˚ when the experimental group was compared with the control group (p < 0.05). After the intervention, there was an improved within-group change in the ROM, SPADI, LSST, and QOL in both the experimental and control groups. Conclusion: These findings suggest that a scapular stabilization exercise program using the PNF technique may be used as a possible treatment option for post-mastectomy women with breast cancer that aims to improve scapular position, shoulder ROM and function, and QOL.