• Journal of the Ergonomics Society of Korea
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• v.31 no.3
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• pp.445-453
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• 2012

The aim of this paper was to prove that if the risk level in combined tasks was improved through evaluation of postural load of liquid weight measurement process, the workload level and ratio of exposure time would be changed, and the time of process would be seen concurrently. Background: According to results of epidemiological studies conducted by Korea Occupational Safety & Health Agency, 122 musculoskeletal disorders occurred during 1992 to 2008, in which manufacturing industry covers 96(78.7%) of total. However, this is an insufficient level and only occupies 39% based on the South Korea's manufacturing standard industrial classification(246 industries). Method: Firstly, the number of batches weighed on one day(460min) was investigated based on the work performed and Weight measured weekly. VCR recording was taken based on the level of liquid ingredients prescribed for 1batch using the Camcorder. After dividing a 356 sec video into 1 sec using the screen capture function in Gom player, the job classification was performed by analyzing the change of working postures, which revealed 148 working postures. Time measurement was decided by time of the postures was being maintained. Then, the REBA analysis was performed for the working postures. The ratio of Exposure time was calculated based on the measurement time and REBA Score. In addition, the recommendations were designed and implementation was carried out for the working postures with REBA Score higher than 3. Finally, after the intervention, REBA measurement, time measurement, and ratio of exposure time were calculated for the comparison of works before and after improvement. Results: The number of work elements was decreased by 30.4% from 148 to 103 after improvement. The results of time measurement showed that the time was reduced by 46.3% from 356 sec to 191 sec. And the ratio of exposure time was also improved by 52.1% from 0% to 52.1% after improvement. Conclusion: The reduction of time was found to improve the productivity of management. Furthermore, because the reduction of ratio of exposure time and the improvement of workload level are the improvement of discomfort, it would contribute to the improvement of the worker's psychological working posture. Application: These results would contribute to musculoskeletal disease prevention and management performance. Further studies for other industries would be needed based on this case study.

• Journal of the HCI Society of Korea
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• v.10 no.2
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• pp.13-19
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• 2015

Display technology has recently made enormous progress. In particular, display companies are competing each other to develop flexible display. Curved display, as a precursor of flexible display, are now used for smart phones and TVs. Curved monitors have been just introduced in the market, and are used for office work or entertainment. The aim of the current study was to investigate whether the curvature of a 42" multi-monitor affects postural control when it is used for entertainment purpose. The current study used two curvature levels (flat and 600mm). Ten college students [mean(SD) age = 20.9 (1.5)] with at least 20/25 visual acuity, and without color blindness and musculoskeletal disorders participated in this study. In a typical VDT environment, each participant played a car racing video game using a steering wheel and pedals for 30 minutes at each curvature level. During the video game, a pressure mat on the seat pan measured the participant's COP (Center of Pressure), and from which four measures (Mean Velocity, Median Power Frequency, Root-Mean-Square Distance, and 95% Confidence Ellipse Area) were derived. A larger AP (Anterior-Posterior) RMS distance was observed in the flat condition, indicating more forward-backward upper body movements. It can be partly due to more variability in visual distance across display, and hence longer ocular accommodation time in the case of the flat display. In addition, a different level of presence or attention between two curvature conditions can lead to such a difference. Any potential effect of such a behavioral change by display curvature on musculoskeletal disorders should be further investigated.

• The Journal of Korean Physical Therapy
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• v.21 no.3
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• pp.69-74
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• 2009

Purpose: This study examined that effect of a change in balance index on ankle Kinesio taping, muscle strength exercises and taping after muscle strength exercises in 30 healthy adult subjects. Methods: The Sway Index of the left, right, front and back on stable, toes up and linear were compared using a Balance System, a balance experimental instrument. Results: The pre and post experimental balance index regarding stable, toes up, and linear were taken for the Kinesio taping group, lower extremities muscle strengthening group, and muscle strengthening with the Kinesio taping group. Statistically significant decreases were observed in all variables except for the left and right pre and post experiment results under stable conditions. Conclusion: The balance index of exercise with taping was lower than that of exercise only. There is a need for objective research on the long-term applications and post-exercise. The body balance appears to be influenced by ankle stabilization using taping.

• The Journal of Korean Physical Therapy
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• v.25 no.4
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• pp.217-223
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• 2013

Purpose: This study was to investigate whether the two different head postures, natural and ideal head posture, affect head/shoulder posture and muscle activity. Methods: Thirty healthy subjects with the forward head and round shoulder posture were participated in this study. This study utilized a within-subjects design with subjects being positioned into two sitting positions: natural head posture (NHP) and ideal head posture (IHP). Forward head angle (FHA) and forward shoulder angle (FSA) of each subject were measured for assessing the head/shoulder posture and muscle activities of upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA) during the forward overhead reaching. Results: There were significant increases in both FHA and FSA after taking IHP, which showed greater angles than in taking NHP. In change of muscle activities, there were significant decreases in both LT and SA after taking IHP, which showed lower activities than in taking a NHP, whereas there was no significant change in UT. Conclusion: These findings demonstrate that postural alterations associated with forward head and rounded shoulder postures could alter scapular kinetics and muscle activity during the forward overhead reaching.

• Korean Journal of Human Ecology
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• v.18 no.2
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• pp.451-463
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• 2009

Although they generally undergo less change in somatotype than other age groups, women in their early twenties have postural changes incurred with their inappropriate postures during the growth period. Since such somatotype changes reduce their satisfaction in the fitting of ready-made clothing, the study intends to examine the inadequate postures and life habits of women in their twenties and to analyze their self-recognition and actual conditions of the bad fit of ready-made clothes. A survey questionnaire was conducted on 225 customers and 29 sellers of ready-made clothes. According to the result, it was found that their inappropriate postures had made their back and shoulders undesirably bent and led to their low satisfaction in the fitting of ready-made clothes. Therefore, it is necessary to perform researches for developing renovated design in consideration of their somatotype changes.

• The Journal of Korean Physical Therapy
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• v.26 no.4
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• pp.257-261
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• 2014

Purpose: The purpose of this study was to compare plantar foot pressure distribution in adults and elderly according to obstacle height. Methods: Nine healthy adults and nine older adults were recruited and the subjects provided written informed consent consent prior to participation. Both groups walked and crossed obstacles with heights of 0%, 10%, 20%, and 30% of their height. Foot pressure was measured by peak pressure using the Pedar System (Novel Gmbh, Germany) during obstacle walking with barefeet in shoes. Three trails were calculated on eight areas and then averaged for data analysis. Results: A significant difference in great toe, little toes, and lateral metatarsal area was observed between adults and elderly groups, but other areas did not show significant differences. Foot pressure was increased in groups according to obstacle height. Conclusion: These findings showed that change in foot pressure distribution is more lateral in elderly in order to maintain postural control during obstacle crossing.

• Physical Therapy Korea
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• v.5 no.3
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• pp.48-55
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• 1998

The purpose of this study was to identify vital capacity (VC) in relation to the changing position of 19 patients with spinal cord injury (SCI) and 20 normal controls. Among the 19 SCI patients, there were 9 quadriplegics and 10 paraplegics. The vital capacity was measured in each subject during sitting, standing, lying, and head down position of 30 degrees. The data were analysed by the Kruskal-Wallis test, Mann-Whitney test, and Wilcoxon signed rank test. For the SCI, significant difference of VC accoring to the 4 positions between quadriplegics and paraplegics. In the control group, significant difference of VC according to the 4 positions. In 4 positions the VC of men were significantly larger than that of women between two groups. No statistical significant difference was shown in VC by the postural change between quadriplegics and paraplegics.

• The Journal of Korean Physical Therapy
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• v.12 no.1
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• pp.57-63
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• 2000

The purpose of this study was to evaluate of balance performance and to examine the relationship between balance performance and feet position, platform speed. Twenty two subjects(men 8, women 14, mean age 24.45years) performed nine balance test with eyes closed for 25seconds:3 feet position(feet together, feet 12cm in apart, feet 24cm in apart) and 3 platform speed$(100\%,\;70\%,\;40\%)$. The results were as fellows: 1. There are significant difference between center of balance and feet position(p<0.05). 2. There are no significant difference between center of balance and plaform speed(p<0.05). 3. There are significant difference between sway index and feet position(p<0.05). 4. There are significant difference between away index and plaform speed(p<0.05).

• PNF and Movement
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• v.18 no.3
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• pp.415-424
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• 2020

Purpose: This study aimed to compare changes in abdominal muscle thickness in different standing postures with a handheld load between subjects with and without chronic low back pain (CLBP). Methods: Twenty subjects with CLBP and 20 controls participated in this study. Ultrasound imaging was used to assess the changes in the thickness of the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles. Muscle thickness in three different standing postures (standing at rest, standing with loads, standing with lifting loads) was compared with the muscle thickness at rest in the supine position and was expressed as a percentage of change in the thickness of the muscle. Results: While standing with loads, the change in IO muscle thickness in the CLBP patients increased more significantly than in the pain-free controls (p < 0.05). The standing with lifting loads posture showed a significant increase in the change in thickness of the TrA compared with the standing with loads posture (p < 0.05). In addition, the standing with lifting loads posture showed a significant decrease in the change in the thickness of the EO when compared with the standing with loads posture (p < 0.05). Conclusion: The automatic activity of the IO muscle in subjects with CLBP increased more than that of the pain-free controls in the standing with loads posture. These findings suggest that IO muscle function may be altered in those with CLBP while standing with loads. Additionally, TrA the activation level was found to be associated with increased postural demand caused by an elevated center of mass.

• Physical Therapy Korea
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• v.22 no.1
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• pp.93-102
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• 2015

Prolonged sitting can contribute to low back pain. The lumbar taping can be applied to correct the sitting posture. This study aimed to investigate the effect of lumbar taping on lumbar kinematics and the muscle activities of multifidus (MF) and internal oblique in the individuals with nonspecific chronic low back pain (NSCLBP) as they type for 30 minutes. Nineteen subjects with NSCLBP (9 people in non taping group and 10 people in taping group) were recruited. Lumbar taping was applied to the taping group before typing. Both groups started typing in a neutral sitting position with their feet on the floor. The change of posture and S2 posterior tilting (S2P) were measured to investigate kinematic data. Three sensors were attached on T12, L3, and S2 to identify the change of posture. Surface electromyography was used to measure the muscle activities. Palpation meter was used to standardize the angle of pelvic tilt in sagittal plane before typing. All instruments were used to measure each data before and after typing. Independent t-test was used to compare the changing values of lumbar kinematics and muscle activities before and after typing between both groups. The changing values of S2P and change of posture of L3 and S2 were significantly smaller in the taping group compared to the non taping group (p<.05). The changing value of muscle activities of MF between before and after typing was significantly smaller in the taping group compared to the non taping group (p<.05). In conclusion, the lumbar taping during the 30-minute typing task can be applied to maintain correct sitting posture in the lumbar and pelvis and to maintain activation of MF.