• Physical Therapy Korea
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• v.11 no.1
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• pp.19-25
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• 2004

The purpose of this study was to investigate the effects of backrests of varying degrees ($90^{\circ}$, $100^{\circ}$, $110^{\circ}$) on three abdominal muscles (upper rectus abdominis, external oblique, internal oblique) and back extensor activation during lower extremity exercise. The three different conditions during bilateral knee extention exercise were: (1) leaning on a chair with a $90^{\circ}$ backrest, (2) leaning on a chair with a $100^{\circ}$ backrest, (3) leaning on a chair with a $110^{\circ}$ backrest. Fifteen healthy muscle subjects (mean age=24.2 years [SD=2.96], mean height=175.6 cm [SD=7.46], mean weight=69.1 kg [SD=7.36]) with no history of neuromusculoskeletal disease voluntarily participated in this study. Electromyography was used to collect muscle activation, and the muscle activation was expressed as a percentage of maximal voluntary isometric contraction (%MVIC). Repeated one-way analysis of variance (ANOVA) was used to determine the statistical significance. The results were as follows: (1) upper rectus abdominis, external oblique, internal oblique activation measured significantly lower. (2) measured significantly lower when lower degree.

• Journal of the Ergonomics Society of Korea
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• v.33 no.1
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• pp.15-25
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• 2014

Objective: This study aims to analyze the factors that affect the ability to maintain dynamic sitting balance (DSB), biomechanical characteristics, and physical characteristics in spinal cord injuries (SCI) patients. Background: Virtual ski training systems, ski equipment, and training protocols for disabled skiers are being studied to spread awareness. However, few studies have been reported on the sitting balance ability associated with chair mono skiing. Method: A dynamic sitting balance border system was built to investigate the ability to maintain dynamic sitting balance in SCI patients. Trunk muscle activity was evaluated by electromyogram while conducting dynamic sitting balance tests. The trunk muscle strength was tested with a portable handheld dynamometer. Physical activity scores were measured with the physical activity recall assessment. Results: There were high levels of correlation between the ability to maintain DSB and trunk flexor strength, extensor strength, rotator strength, and physical activity score. However, height, weight, and injury level in SCI patients were not correlated with the ability to maintain DSB. Additionally, strong negative correlations were found between muscle activities of the external oblique and lumbar erector spinae muscles and the ability to perform the backward tilt test. Trunk extensor muscle activity during the ball lifting test was significantly higher than in other tests. Conclusion: The results indicate that improving trunk muscle strength and physical activity can increase the ability to maintain DSB. Application: The findings of a close relationship between trunk strength, physical activity, and the ability to maintain DSB need to be reflected in the chair mono ski training program.

• The Journal of Korean Academic Society of Nursing Education
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• v.22 no.4
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• pp.485-494
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• 2016

Purpose: The present research is a descriptive study aimed at understanding clinical nurses' Video display terminal (VDT) syndrome and identifying the factors that affect their VDT syndrome. Methods: Data were collected from 239 clinical nurses working in two metropolitan cities. Research tools included subject's VDT syndrome assessing musculoskeletal, ophthalmic, dermal, psychiatric, and whole body syndromes. The data were analyzed using frequency analysis, average and standard deviation, t-test, One-way ANOVA, and multiple regression analysis with the SPSS/WIN 20.0 program. Results: The subjects' VDT syndrome score was 1.34 out of 5. There were significant differences in participating subjects' VDT syndrome, hospital's size, working unit, health status, diagnosis of illness, having an Order Communication System (OCS), having an Electronic Medical Record (EMR) System, continuous VDT working for more than one hour, break time during VDT use, VDT use time, comfort of the chair, adjustability of the height of the chair, size of the VDT's desk, distance between the monitor and the user's eyes, resolution of the monitor, and frequency of eye exercise during VDT use. According to the research, influencing factors on VDT syndrome in clinical nurses included size of the VDT's desk, frequency of eye exercise during VDT use, having an EMR system, break time during VDT use, diagnosis illness, and having an OCS' system. Conclusion: The findings from this study can be used as a basis for future VDT syndrome prevention education and programs for clinical nurses.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.3
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• pp.89-100
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• 2019

Uniform and integrated college desks and chairs have low efficiency of loading for transportation and delivery and low efficiency of storage for warehousing due to their simple uniform physical properties, thus increasing logistics costs for companies and decreasing their competitiveness. In an effort to overcome the limitations of previous studies, this study analyzed the stages of logistics for desks and chairs in college lecture rooms via the transportation route including the factory warehouses and local warehouses and via the delivery route from local warehouses by the region to the orderers including college lecture rooms. The study developed a model for the rationalization of corporate logistics by making a variable folding desk and chair capable of distance adjustment according to height to replace the uniform and integrated college desks and chairs in lecture rooms. A model was developed between the old uniform and integrated college desks and chairs and the new variable folding desks and chairs for three scenarios of cost development including product storage costs, transportation costs from the specialized factory warehouses to the local warehouses by the region, and delivery costs from the local warehouses to college lecture rooms as the orderer. For the generalization of the model, it was applied to each of the 90%, 95%, and 99% service levels.

• Journal of the Ergonomics Society of Korea
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• v.30 no.5
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• pp.605-611
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• 2011

Objective: The aim of this study was to investigate the influence of seat heights for optimizing the ingress/egress performance in the elderly people. Background: Recently elderly users have been increasing in number and the ease of ingress/egress of the vehicle becomes an important issue. Method: Seven elderly subjects participated in this study(age: 71.7${\pm}$3.6yr, height: 167.7${\pm}$5.4cm, weight: 68.1${\pm}$11.5kg). Each subject performed the sitting and rising task from comfortable seated position on the chair under the following conditions: (1) with a lumbar support and (2) without a lumbar support. We measured EMG activities of seven muscles(tibialis anterior, soleus, gastrocnemius, vastus lateralis, rectus femoris, biceps femoris and erector supinae) and ranges of motion in lower limb during sitting and standing from three different heights (400mm, 500mm and 600mm from ground) of slide-up seat. Results: Muscle activities and angular movements of hip and knee joints during standing-up and sitting-down with a high seat height(600mm) were reduced mean 30.4% in extensor muscles, 57.11% in flexor muscle, 18.74% in erector muscle and 31.0% in joints compared with a low seat height(400mm). Conclusion: Muscle activities and joint movements in hip and knee were reduced when rising/sitting from a high seat height(600mm) compared with a low seat height(400mm). Application: This study can be used to design vehicle that are easy to get in and out of by older peoples with or without impairments.

• Journal of the Korean Society of School Health
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• v.8 no.2
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• pp.219-232
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• 1995

This study was conducted to examine both usage rate of standard sized desks and chairs for the middle and high school students and pain complant of students who use standard-size desk & chair in Taegu, Korea, by means of questionnaires with 1,201 students of both male and female middle and high schools in Taegu area from March 20 to April 19, 1995. The result of this study is summarized as follows. It was mostly shown that the desks and chairs used by those middle and high school students were 1-3 higher than their standard sizes, and that they also preferred a little higher size with respect to their desired sizes. The rate of students who use the standard size showed that the desk accounted for 30.5%, and chair for 21.0%, that the size bigger than the standard accounted for 61.3%, respectively, and 65.2, and that the size smaller than the standard accounted for 8.2%, respectively, and 13.8%. The using rate of the standard sized for the middle school students indicated that their desk accounted for 44.1%, and their chair for 26.0% which were higher than 16.1% and 14.7% for the high school students. Then, the rate of the male students indicated that their desk accounted for 31.5% and their chair for 24.5% which were higher than 29.6% and 17.6% of the female students. In addition, the using rate of the standard size for the public schools showed that the desk accounted for 34.2% and chair for 24.5% which were also higher than 27.1% and 17.5% of the private schools. It was shown, however, that the using rate of the standard size for both groups was lower. The most inconvenient factor in the usage of their desks appeared in such orders as their wear, narrow drawers, too low height and uneven face, while the factor in their chairs did in such orders as too hard chair body the surface and back part, wear, lower and higher height and narrow width. Their physical pains resulting from usage of those desks and chairs showed that the male and female middle school students' complaint rate of pains in their neck and shoulder accounted for 32.1%, respectively, and 36.0% which were highest, while those high school students' complaint rate in their waist accounted for 37.9%, respectively, and 44.1% which were hight. It was also shown that the bigger their height, the higher their complaint rate of pain in the waist, and that their complaint rate in the shoulder and neck was totally higher. When using the standard-sized desks and chairs, their complaint rate of pain in the shoulder and neck accounted for 25.4%, respectively, and 23.8%. As compared with them, when using the desks or chairs bigger than the standard size, their complaint rate accounted for 31.5%, respectively, and 31.8% which were high while it did 26.5% and 28.9% when using them smaller than the standard size which were also high, the usage of those standard-sized desks and chairs indicated lower complaint rate of pain in their waist than used the desks and chairs bigger or smaller than the standard size. The rate of the middle and high school students who use their standard size is very low and the size of their desks and chairs are quite different from those they hope to use and many students appeal their discomfort with their desks and chairs. Therefore, the school should try to provide the desks and chairs of the various students' standard sizes in consideration of their physical condition and it also should try to get extra desks and chairs of various sizes according to the students' standard size and their preference.

• Journal of The Korean Association For Science Education
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• v.4 no.1
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• pp.15-25
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• 1984

The purpose of this study is to develop a practical and ideal model of science laboratory enrolled 48-60 students by studying optimal facilities such as laboratory tables and chairs proper to elementary school settings. The science laboratory model was figured out in terms of the following six procedures; (1) Current status as well as problems of science laboratory and its facilities was identified by means of the questionnaires conducted to 201 elementary schools, using stratified cluster sampling tehnique, under the consideration of the school size and the regional characteristics across the country. (2) Collected were the anthropometric data with respect to sitting height, popliteal height, buttock popliteal length, elbow rest height, and back width from the 747 students, 4th-6th grade, in Seoul area. (3) It was measured the work apace necessary for individual student to perform his experiment. (4) Using the data of the process (2), we determined the optimal sizes of laboratory tables and chairs fitted for Korean elementary school students. (5) The optimal area of science laboratory for 48-60 students is determined in terms of the data obtained in (3) for individual work space in addition to the appropriate table size figured out by (4). (6) A practical and ideal model for a science laboratory in elementary school was designed according to the above procedures. For the optimal model of science laboratory, the results of this study can be summarized as follows: The sizes of chair and table are categorized into three groups such as small, medium, and large depending on students' physical outfit. The small size base on the 12.5th percentile point of students' sitting height is used for students of the 0-25th percentile ranks. The medium size base on the 50th percentile point of students' sitting height is used for students of the 26-75th percentile ranks. The large size base on the 87.5th percentile point of students' sitting height is used for students of the 76-100th percentile ranks. (1) Sizes of chairs: The small size is 28cm in width and 33cm in height. The medium size is 31cm in width and 36cm in height. The large size is 35cm in width and 38cm in height. (2) Sizes of laboratory tables: The small size is 120cm in length, 86cm in width, and 60cm in height. The large size is 120cm in length, 86cm in width, and 60cm in height. The large size is 120cm in length, 86cm in width, and 65cm in height. (3) Size of science laboratory: The optimal science laboratory for 48-60 elementary school students, which can install the 12 laboratory tables, is 12m in length and 10m in width.

• Journal of the Korean Society of School Health
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• v.12 no.2
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• pp.321-337
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• 1999

The purpose of this study was to obtain basic data for the prevention and control of adolescent back pain through analyzing connections between study environments and physical posture. The subjects were 960 male general high school students in the Chonju area and the data were collected by a self-reported questionnaire from Mar. 17 to Mar. 22, 1999. The collected data were analyzed by a frequency, chi-square and t-test using an SPSS program. The results are as follows; 1) The experience rate of back pain perceived by subjects was 67.5% and by each grade: 1st-27.5%, 2nd-35.4%, 3rd-37.1%. The relationship between grades and the experience of back pain didn't show any significant difference. 2) The causes of back pain perceived by subjects such as 'postures are not good' was 56.7%, 'sitting too much time in a chair' was 39.1%, and 'too severe exercise' was 32.4%. 27.8% had back pain first during the 3rd grade of middle school, and 23.9% had it first during the 1st grade of high school. 3) Intensity of subjects' back pain spread from 'moderate' at 49.6%, to 'severe' at 16.4%. Concerning the frequency of back pain, 58.6% said it was 'irregalar'. 4) Among interventions to deal with back pain: 'move by exercising my back or ask friends to beat my back' was 41.0%, 'just bear it' was 23.1%, and at home 'don't have 'any treatment' was ranked first, at 54.9%. 5) The relationship between subjects' general characteristics and back pain experiences: height (t=-1.99, P=.046), sitting/height (t=-2.61, P=.009), self-perceived condition of health (${\chi}^2=23.530$, P=.000), family history (${\chi}^2=43.903$, P=.000) showed significant difference, but the kinds of transportation, sleeping postures, sleeping method and smoking didn't show significant differences. 6) The relationship between subjects' learning environment and back pain experiences, the height of students' desk and chair showed significant difference (${\chi}^2=23.054$, P=.000), but the sitting time didn't show significant difference. 7) The relationship between the characteristics of subjects' physical postures and back pain experiences: standing postures (${\chi}^2=15.105$, P=.001), and sitting postures (${\chi}^2=20.264$X2, P=.001) showed significant difference, but lifting postures didn't show significant difference.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.328-335
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• 2013

The purpose of this study was to evaluate the height of workbench in dental lab for ergonomic body type which dental technicians are suitable and suggest to effective improvement of workspace. For this purpose, we measured the height, weight, body sizes of total 77 junior majoring in dental laboratory science where they study school located in Gyeonggi and Chungcheong area and we research uncomfortable body type when they had a clinical training. For comparative analysis we had visited 15 dental lab and 2 dental lab of general hospital and we had measured the height of workbench and desk including chair and then We had statistical analysis measured value. Especially we analyzed the important factor causing inconvenience for work environment. As a result, we had examined, we found following results The sand table was the most uncomfortable equipment, when they have clinical training. There is no correlation between sexual characteristics of junior in college and selection of uncomfortable equipment. It is reasonable to assume that sand table which is lower than recommended height brings out inconvenience. It is analyzed that the optimum height of sand table in dental lab for junior in college is lower than the recommended height. The optimum height of sand table in dental lab has deviation according to height of junior in college. The height of worktable in dental lab was lower than recommended height. The recommended range could not apply to posture of dental technician with different height uniformly.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.20 no.1
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• pp.15-20
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• 2014

Background: The purpose of this study was to investigate the effect of differing insole height on the electromyographic (EMG) activity and muscle fatique in tibialis anterior and gastrocnemius a lot of repeat college students from the desk during a sit to stand activity. Methods: For the 20 subjects (males), let them wear insole in order. Using EMG equipment measured the difference in muscle activity and muscle fatigue degree. All subjects measured for 3 seconds in standing up from the chair. It's measured total 3 times. Results: The summary of results stated above is as follows: It's sitting to standing activity when there were no significant differences between the muscles. But sitting activity in muscle fatigue-calf muscle during standing activity correlated only. Conclusion: The results of this study, the height of an adult male lead in adequate to maintain a healthy foot function and health elements of effective and aesthetic elements based on a significance in that it presents.