• The Journal of Korean Physical Therapy
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• 제35권5호
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• pp.151-155
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• 2023

Purpose: This study examined the effect of the degree of neck flexion on the muscle activity of the upper trapezius and sternocleidomastoid muscles in the sitting position. Methods: Twenty-five healthy young adults participated in this study. The study was designed to compare the muscle activity of the upper trapezius and sternocleidomastoid muscles according to the neck flexion angle under the three conditions (neutral position, 15° neck flexion, and 45° neck flexion) in the sitting position. During the neck position of three conditions in sitting, the electromyography (EMG) data (% maximum voluntary isometric contraction) of the muscles were recorded using a wireless surface EMG system. Results: The muscle activity of the upper trapezius muscle and the sternocleidomastoid muscles showed a significant difference according to the three-neck position conditions (p<0.05), and in the post-hoc test results, both muscles showed significant differences between the neutral position and 15° flexion, the neutral position and 45° flexion, and the 15° flexion and 45° flexion, respectively. Conclusion: The load on the muscles around the neck and shoulders increased as the neck flexion angle increased. This suggests that performing various daily activities and tasks with the neck as neutral as possible can prevent muscle fatigue or musculoskeletal disorders.

• 한국전문물리치료학회지
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• 제28권2호
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• pp.108-116
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• 2021

Background: Whole-body vibration (WBV) has been used to alleviate proprioceptive damage by musculoskeletal and neurological conditions. However, no study has determined whether wearing shoes while applying WBV can affect proprioception precision of the knee joint. Objects: This study aimed to determine the differences in the proprioceptive precision of the knee joint before and after WBV and to compare the proprioceptive precision of the knee joint between barefoot and shoe-wearing conditions. Methods: This study recruited 33 healthy participants. A passive-to-active angle reproduction test was used to measure the proprioception precision of the knee joint using an electrogoniometer, and the target angle was set to a knee flexion of 30°. Proprioception precision was calculated using the error angle (angular difference from 30°). Proprioceptive precision was measured in weight-bearing and non-weight-bearing positions before and after applying WBV for 20 minutes at 12 Hz in barefoot and shoe-wearing conditions. Mixed repeated analysis of variance was used to determine the differences in changes in the proprioceptive precision of the knee joint according to foot conditions. Results: There were significant improvements in the weight-bearing (p = 0.002) and non-weight-bearing (p < 0.001) proprioceptive precision of the knee joint after applying WBV. However, there was no significant difference in the change in proprioceptive precision of the knee joint after applying WBV between the barefoot and shoe-wearing conditions. Conclusion: WBV stimulation had an immediate effect on improving the proprioceptive precision of the knee joint. However, foot conditions (barefoot or shoe-wearing) during WBV application did not influence the proprioceptive precision of the knee joint.

• PNF and Movement
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• 제19권3호
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• pp.375-382
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• 2021

Purpose: The objectives of the present study were to investigate the disadvantages of tire pressure asymmetry of a wheelchair tire and recommend the criterion for appropriate tire pressure without generating negative changes in the musculoskeletal system in asymptomatic participants. Methods: Fourteen asymptomatic participants were asked to sit in pressure-controlled wheelchairs and perform desk work for 20 minutes in each tire condition. The asymmetry of the tire conditions was set as 0% difference, 25% difference, and 50% difference from the recommended pressure. The pelvic alignment and muscular recruitment represented as a flexion-relaxation ratio (FRR) were measured at pre-test, and after each condition of desk work. The displacement of the center of pressure (COP) was measured during the desk work. Results: The tire air pressure condition significantly affected the FRR and COP (P < 0.05). Both sides of the FRR values were significantly higher under the symmetrical tire conditions (0% difference) and pre-test, compared with the asymmetrical tire condition of 50% difference (P < 0.05). The mediolateral COP displacement of the asymmetrical tire conditions (25% and 50% difference) was significantly higher than that of the symmetrical tire conditions (0%) (P < 0.05). Conclusion: Asymmetrical tire conditions could cause changes in the muscle recruitment pattern of the erector spine and mediolateral COP displacement. Tire pressure asymmetry higher than 50% could be a risk factor for prevalence of back pain, so this level of asymmetry in tire pressures should be cautioned against for wheelchair users.

• 대한인간공학회지
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• 제23권3호
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• pp.121-134
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• 2004

A research project was conducted to study work-related musculoskeletal disorders （MSDs） at subway train repair plant in Korea. The project was consisted of 4 main parts; education on the topics of MSDs for all workers, symptom survey, medical check-up, investigation of MSD risk factors. The result of symptom survey showed that 95.2％ of the respondents complained pains on at least one part of the body. After cross-sectional analysis of various information and risk factors, 86.8％ of respondents were considered as active health surveillance level 1 that require continuous monitoring on their symptoms and working conditions. And 57.1％ of the respondents were considered as active health surveillance level 2 that needed medical check-ups for proper medical treatment. The analysis of occupational risk factors revealed that handling of heavy object (46.15％) and repeated awkward postures (46.15％) were two most contributing risk factors for the on-set of MSD at this work site followed by static strain (7.7％), and vibration and impact (3.8％). Medical examination was performed by an industrial medicine MD on 156 workers those considered as active health surveillance level 2. The result showed that 35 workers (20.7％) were considered as MSD patient group at severe level, and 68.6 workers (68.6％) were considered as moderate group and 18 workers (10.6％) were considered minor or normal group those have no symptom.

• Clinical Pain
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• 제19권1호
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• pp.16-22
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• 2020

Objective: Recent studies have shown that repetitive peripheral magnetic stimulation (rPMS) reduces pain in various conditions. This pilot study aimed to investigate the effects of rPMS depending on the pain characteristics. Method: Adult patients aged 19~85 years evaluated at our institution between September 1, 2017 and February 28, 2018 for subacute to chronic musculoskeletal pain equivalent to a numeric rating scale of 3 or higher for at least one month were enrolled. Pain scores as determined using a numeric rating scale at baseline and at the end of treatment were set as the primary outcome. Additionally, we classified the pain into nociceptive, intermediate, or neuropathic pain using the PainDETECT questionnaire and compared the responsiveness to rPMS according to the type of pain. Results: The average pain scores significantly decreased after the 2-week rPMS treatment in all enrolled subjects (p<0.001). There was no statistically significant difference in pain reduction between groups divided by PainDETECT questionnaire. Conclusion: This study suggests that rPMS could safely relieve various types of pain.

• 한국전문물리치료학회지
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• 제30권3호
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• pp.221-229
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• 2023

Background: In modern society, the use of computers accounts for a large proportion of our daily lives. Although substantial research is being actively conducted on musculoskeletal diseases resulting from computer use, there has been a recent surge in interest in improving the working environment for prevention. Objects: This study aimed to examine the effects of posture correction feedback (PCF) on changes in neck posture and muscle activation during computer typing. Methods: The participants performed a computer typing task in two sessions, each lasting 16 minutes. The participant's dominant side was photographed and analyzed using ImageJ software to verify neck posture. Surface electromyography (EMG) was used to confirm the participant's cervical erector spinae (CES) and upper trapezius muscle activities. The EMG signal was analyzed using the percentage of reference voluntary contraction and amplitude probability distribution function (APDF). In the second session, visual and auditory feedback for posture correction was provided if the neck was flexed by more than 15° in the initial position during computer typing. A 20-minute rest period was provided between the two sessions. Results: The neck angle (p = 0.014), CES muscle activity (p = 0.008), and APDF (p = 0.015) showed significant differences depending on the presence of the PCF. Furthermore, significant differences were observed regarding the CES muscle activity (p = 0.001) and APDF (p = 0.002) over time. Conclusion: Our study showed that the feedback system can correct poor posture and reduces unnecessary muscle activation during computer work. The improved neck posture and reduced CES muscle activity observed in this study suggest that neck pain can be prevented. Based on these results, we suggest that the PCF system can be used to prevent neck pain.

• 한국환경보건학회지
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• 제4권1호
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• pp.13-22
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• 1977

In an attempt to evaluate working conditions and hazardous environmental factors, a survey on health problems was conducted for 721 employees from 18 industrial plants in Young Dung Po and Sung Dong districts of Seoul in the period from May 1975 to Feb, 1976. The questionnaire and survey was inclusive of all illnesses known as most common to industrial workers (according to the report by Korea Industrial Health Association) of this country and envi ronmental factors pointed out by the workers. The results were as following. 1. The over whelming majority of complaints were psychiatric, ear,eye, and digestive disorders. 2. Those whose work time is the longest have a propotionately higer incidence of complaints especially in eye,ear, neuromusculoskeletal, and neurosensory systems. 3. In females whose occupational history is relatively short, a higher incidence of digestive and skin section disorders was noted and this is especially true among those working in night shift. 4. Among machinery industry workers, most complaints were of eye, ear, and neuro musculoskeletal disturbances, and this fact seems to be closely related to physical over works. 5. Dust and noise were pointed out by the largest number of workers as undisirable conditions in work environment. 6. Distribution of complaints are closely related to the type of industry, and in comparison with the result reported by Korea Industrial Health Association in 1972, the prevalence rates of occupational disorder were similar in our study,

• 한국안전학회지
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• 제23권2호
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• pp.30-36
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• 2008

This paper suggests the best work conditions, including short break time and number of mouse clicks on a computer, to prevent MSDs(Musculoskeletal Disorders) on VDT(Visual Display Terminal) work. Discomfort measures are calculated according to the Borg's CR-10 Scale. The short break time conditions are grouped into 7, 15, and 30 seconds after every 10-minute work period and the number of mouse clicks are divided into 10 clicks/min, 20clicks/min, and 30clicks/min. The result of the ANOVA on the shift value of subjective discomfort shows the following: 1) Regarding the break time and the number of mouse clicks, there are statistical differences between the measured values for the neck and the wrist(p<0.05). 2) Regarding the number of mouse clicks, there are statistical differences between the measured values for the shoulder and the forearm(p<0.1). 3) Regarding the break time and the number of mouse clicks, there are no statistical differences between the measures values for the eyes, upper arms and back(p<0.1).

• 대한골관절종양학회지
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• 제9권2호
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• pp.206-211
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• 2003

수장족저 농포증은 특별한 골, 관절계 질환과 관련이 있을 수 있다. 초기 전흉벽에 국한되었던 이러한 질환은 이후 말초 골, 관절계를 침범하는 것으로 밝혀졌다. 무균성 가감염성 골, 관절 질환 역시 심한 여드름과 관련이 있는 것으로 밝혀졌다. 1987년 Kahn 등은 과거 25년간 발표된 특별한 골, 관절 그리고 피부병변에 관한 수많은 보고들을 기술하기 위하여 약성어를 제시하였다. SAPHO 증후군은 Synovitis, Acne, Pustulosis, Hyperostosis and Osteitis syndrome을 뜻한다. 저자들은 SAPHO 증후군으로 의심되는 과골증을 동반한 좌측 쇄골 및 우측 천장 관절 동통과 수장 농포증이 있는 27세 여자 환자 1예를 경험하였기에 보고하고자 한다.

• 대한물리의학회지
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• 제6권2호
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• pp.135-143
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• 2011

Purpose: The purpose of this study was to investigate onset timing of vastus medialis oblique(VMO) relative to vastus lateralis(VL) the VMO/VL electromyographic(EMG) ratio according to heel height Methods: A repeated measures design was used. Fifteen healthy female college students with no known knee musculoskeletal dysfunction were recruited this study. They carried out a standardised stair acent activity under 4 conditions; barefoot, and with heel height of 1, 3, 7 cm. Muscle activity was measured by surface EMG (Myosystem 1400A, Noraxon Inc., U.S.A). Data were analysed using $1{\times}4$ repeated measures ANOVA. Results: Onset timing differed with heel height(p<.05). However, the VMO/VL EMG ratio was not significantly difference between conditions. Conclusion: We found that 7 cm heel height delayed in VMO onset compared with 3 cm heel height during stair ascent, but no change in the relative EMG intensity of VMO and VL as measured by th VMO/VL ratio. The findings indicate that high-heeled shoes may have disadvantages in knee stability because of delayed onset of VMO. Due to a lack of knee joint stability, wearing of high heeled shoes should be avoided.