• Safety and Health at Work
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• v.11 no.1
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• pp.80-87
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• 2020

Background: Residential and commercial cleaning is a part of our daily routine to maintain sanitation around the environment. Health care of professionals involved in such cleaning activities has become a major concern all over the world. The present study investigates the risk of musculoskeletal disorders in professional cleaners involved in floor mopping tasks. Methods: A cross-sectional study was performed on 132 mopping professionals using a modified Nordic questionnaire. The Pearson correlation test was implemented to study the association of perceived pain with work experience. The muscle strain and postural risk were evaluated by means of three-channel electromyography and real-time motion capture respectively of 15 professionals during floor mopping. Results: Regarding musculoskeletal injuries, risk was reported majorly in the right hand, lower back, left wrist, right shoulder, left biceps, and right wrist of the workers. Work experience had a low negative association with MSDs in the left wrist, right wrist, right elbow, lower back, and right lower arm (p < 0.01). Surface EMG showed occurrence of higher muscle activity in upper trapezius and biceps brachii (BB) muscles of the dominant hand and flexor carpi radialis and BB muscles of the nondominant hand positioned at the upper and lower portion of the mop rod, respectively. Conclusion: Ergonomic mediations should be executed to lessen the observed risk of musculoskeletal injuries in this professional group of workers.

• Physical Therapy Korea
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• v.9 no.4
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• pp.69-76
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• 2002

본 연구에서는 상부 승모근의 근막통증(myofascial pain syndrome; MPS)를 대상으로 이완상태에서 근 활성도를 측정해보고, 통증을 감소시키는 데 주로 이용되는 경피신경자극 치료 후 근 활성도에 어떠한 영향을 미치는지 알아보기 위해 실시하였다. 본 연구의 대상자는 근막 통증으로 진단을 받은 총 10명을 대상으로 실시하였다. 주관적 시각 척도(visual analogue scale; VAS)와 압통 역치 측정계(pressure threshold meter)를 이용하여 경피신경자극 전, 후 통증의 정도를 평가하였고, 표면 근전도를 이용하여 이완시 근 활성도를 측정하였다. 치료 기구는 경피신경자극기(TENS: HAT-2000)를 이용하였다. 치료 전과 비교하여 VAS는 통증이 심한 쪽과 약한 쪽 모두에서 유의하게 감소하였으며(p<.05), 압통 역치는 통증이 심한 쪽과 약한 쪽 모두에서 유의한 차이가 없었고(p>.05), 근 활성도는 통증이 심한 쪽에서 유의하게 감소하였다(p<.05).

• Journal of the Korea Convergence Society
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• v.10 no.3
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• pp.67-72
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• 2019

The purpose of this study was to analyze the effects of computer game usage time on trunk muscle thickness and pressure pain threshold. The 33 study participants were divided into Group A, which spent less than 10 hours per week playing computer games; Group B, which spent between 10 and 20 hours per week playing computer games; and Group C, which spent more than 20 hours per a week playing computer games. The thickness of the participants' upper trapezius (UT), pectoralis minor (PM), anterior scalene (AS), and middle scalene (MS) muscles as well as the pressure pain threshold of their UT, PM, AS, MS, and levator scapular (LS) were measured. The study found that the PM, AS, and MS muscle thickness in group C was significantly greater than in the other groups (p<.05), and the UT, AS, PM, and LS pressure pain threshold in group C was significantly lower than in other groups (p<.05). Therefore, those who use computers for a long period of time during the week should recognize that their computer usage may cause musculoskeletal disorders.

• Journal of Oral Medicine and Pain
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• v.21 no.2
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• pp.393-405
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• 1996

This study was performed to investigate the effects of changes of head posture and cervical spine shape on the mandibular resting or clenching electromyographic(EMG) activity in anterior temporalis(TA), masseter(MM), sternocleidomastoid muscle(SCM) and trapezius insertion(TI). 30 patients with Temporomandibular Disorders(TMDs) participated in this study. EMG activity($\mu$V) at rest and clenching was observed in four head postures, namely natural head posture(NHP), forward head posture(FHP), upward head posture(UHP), and downward head posture(DHP). For taking in upward or downward head posture head was inclined 10$^{\circ}$ upward or downward and CROM$^\textregistered$(cervical-range-of motion, Performance attainment Inc., USA) was used to maintain same posture during the procedure, and BioEMG$^\textregistered$ (Bioelectromyograph, Bioresearch Inc., USA) was used to record EMG activity in the above four muscles at eight locations on both sides. The recorded EMG activity($\mu\textrm{V}$) were compared and analyzed by cervical spine shape such as the head position from plum line, cervical curvature, and cervical inclination. Head position from plum line was measured in vertical plate calibrated with cm scale, comical curvature by radius was measured with adjustable curved ruler, and cervical inclination by cervical vertebrae tangent(CVT)was measured in lateral cephalograph. The results obtained were as follows : 1. Mean value of head position from plum line, cervical curvature, and cervical inclination were 4.8cm, 26.7cm, and 86.6$^{\circ}$, respectively, And There were no correlationship among these items. 2. For resting EMG activity by head posture, the value in anterior temporalis was higher at FHP than at DHP, the value in masseter was higher at FHP than at NHP, and DHP, the value in sternocleidomastoid muscle was higher at UHP than at NHP, and the value in trapezius insertion was higher at FHP and DHP than, NHP and UHP. The clenching EMG activity, however, did not show any difference by head posture. 3. Comparison of resting and clenching EMG activity between higher and lower groups by head position from plum line, cervical curvature, and cervical inclination did not show any significant difference. From this result, the author concluded that the cervical spine shape had not significantly affected to EMG activity in usual patients with TMDs.

• Journal of the Ergonomics Society of Korea
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• v.34 no.1
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• pp.11-18
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• 2015

Objective: The aim of this study was to understand the effects of phone weight on the typing performance and muscle recruitment in the neck and upper extremity while typing a text message with dominant hand. The iPhone4 and iPhone5 were compared due to their 28-gram differences in weight. Background: Too much use of a cellular phone can lead the musculoskeletal disorders in the upper extremity. Phone makers tend to make their new models bigger, lighter, faster and smarter. Method: Fourteen healthy volunteers without any history of neuromuscular disorders or ongoing pain who used their smartphone more than one year were recruited. A 112g phone (iPhone5) and a 142g phone (iPhone4) were used for typing the lyric of the Korean national anthem with their dominant hand. Typing duration, the typing error, the perceived fatigue, and preference was investigated. Muscle recruitment and the resting gap of neck (middle trapezius and levator scapula), shoulder (infraspinatus and mid deltoid), elbow (biceps brachii and brachioradialis), thumb (extensor and abductor policis brevis) were collected using surface electromyography. Typing error was counted and typing speed was calculated in characters per min. The data were analyzed using a paired t-test and chi-square (${\chi}^2$) analysis for the effects of phone weight on the typing performance parameters and muscle recruitment. Results: Typing text message with iPhone5 took longer but had less muscle recruitment in brachioradialis, and extensor policis brevis muscles. Lighter weight of iPhone5 made biceps brachii to rest less without increasing the mean %EMG. Conclusion/Application: Findings of this study can be valuable information for phone designers to develop more productive device and for smartphone users to prevent the musculoskeletal disorders in the upper extremities.

• Journal of Yeungnam Medical Science
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• v.26 no.1
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• pp.74-77
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• 2009

There are debates about whether peripherally induced movement disorders exist. We report a case of upper limb tremor induced by peripheral nerve injury. A 20-year-old male patient presented with pain and tremor of the left upper extremity, 2 days after a car accident. Magnetic resonance images of the brain and cervical spine were normal. His past medical history was unremarkable and there were no family members with symptoms of movement disorders. He suffered from an aggravating tremor for about 10 minutes, four to six times a day. We treated the patient with medication, epidural infusion, cervical nerve root block and trigger point injection of the trapezius muscle. The pain subsided 50% and the incidence of tremor attacks was reduced to once or twice a day. The role of peripheral trauma in the genesis of movement disorders has not been generally accepted. It is unclear whether peripheral trauma can induce dystonia and other movement disorders. It has been proposed that peripheral trauma can alter sensory input and induce cortical and subcortical reorganization that generates a movement disorder. Some studies provide evidence for central reorganization following peripheral injury.

• Clinics in Shoulder and Elbow
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• v.2 no.1
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• pp.8-13
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• 1999

The results of the operative treatment of the Grade III acromioclavicular joint injury is defined by the durability of the reduced joint and free of exertional pain. Several surgical techniques have been applied to reduce and stabilize the joints effectively. Resection of clavicular lateral end and subacromial decompression also could be applied to prevent post-operative arthritic change. Biomechanical studies reveals the role of clavicular elevation and rotation to achieve more than 90 degrees of elevation. It also serves as a attachment site of deltoid and trapezius muscle. The stability and mobility of the both acromioclavicular and coracoclavicular joint are important to get full functional recovery. We modified the methods of coracoacromial ligament transfer described by Weaver-Dunn and by Shoji et a!. to pre­vent pullout of the transferred ligament and to get more improved functional results. Main technical point was harvesting full thickness bone block and fix it through the key-hole to reduce pull out angle.

• Archives of Plastic Surgery
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• v.34 no.6
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• pp.792-795
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• 2007

Purpose: Scoliosis is a multifactorial disorder caused by genetic, biochemical, developmental, neuromuscular factors and causes complex deformities which include skeletal deformity, pain, cardiovascular dysfunction, motor function disorder. Until now, the treatment of scoliosis have been focused on orthopedic correction, preservation of cardiopulmonary and neurologic function. But recently, as aesthetic demands increases, the needs for the correction or improvement of the trunk and extremity contour does. So, the correction of soft tissue contour deformity can be a new concept for the treatment of scoliosis. Methods: We corrected a deformed contour with prefabricated silicone implant in a scoliosis patient who had been operated for orthopedic correction previously. Submuscular pocket was made under trapezius and latissimus dorsi muscle. Silicone implant was placed in the pocket and fixed to thoracolumbar fascia with sutures. Results: We had a satisfactory results for the correction of contour deformity. There was no significant complication. Conclusion: Silicone implant is a new trial for the correction of scoliosis contour deformity. This method is simple, safe and brings on satisfactory results.

• Journal of Digital Convergence
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• v.12 no.6
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• pp.425-432
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• 2014

The purpose of this study was to examine the effect of myofascical release (MR) on the degree of pain and nerve conduction velocity (NCV) in middle-aged women. Participants were 28 middle-aged women and MR carried out three times (1, 3, 5 day) at intervals of two times. We did survey about changes of pain before the MR and how they changed after the MR. Also measured pressure pain threshold (PPT) and visual analogue scale (VAS) by using the algometer at trapezius muscle. In median nerve, we did motor nerve conduction velocity (MNCV) test and sensory nerve conduction velocity (SNCV) test for measuring incubation period, amplitude and nerve conduction. The most painful time was 18~21 and the most painful part was shoulder. The pain scale, PPT and VAS after the MR had significantly decreased than before the MR. The latency was significantly decreased and the amplitude was significantly increased in the MNCV and the latency was significantly decreased in the SNCV after the MR. Also it was effective in ameliorating pain scale and latency of NCV. Consequently, the MR can be effective in prevent pain scale caused by fatigue in middle-aged women as replacement therapy.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.209-216
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• 2018

This study aimed to investigate the association of the muscle activity around the neck of the operator(dental hygienists') according to the change in the patient's neck angle during a direct visual inspection on the maxillary right-side molar palatal surface. The operators were $4^{th}$ year dental hygiene students, who are future dentalhy gienists, having accurate understanding on and awareness of the location of the operation site, hand fixation, and how to use the tools. Data on the change in the muscle activity around the neck were collected by using surface electromyography and neck goniometer. SPSS statistics 20 was used for statistical analyses including Shapiro-wilk test and one-way ANOVA. As a result, the activities of the operator upper trapezius, cervical erector spinae, and levator scapulae muscles significantly decreased when the patient's head was angled compared to when it was not. For the angle of the operator head, the head bend significantly decreased when the patient's head was angled than when it was not. Based on the study results, it is expected that angling the patient's head when treating his or her teeth will decrease the excessive muscle activity around the neck of the operator, and will reduce muscle fatigue. Therefore, angling the head of the patient while treating his or her teeth is recommended. This suggests that muscle pain caused by repetitive actions in the wrong posture can be reduced.