• 대한산업공학회지
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• 제41권1호
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• pp.74-78
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• 2015

A bus seat is required to be ergonomically designed in terms of its shape and physical properties to increase seating comfort. The present study is intended to develop a systematic bus seat evaluation protocol based on seating comfort. A total of 48 participants evaluated 12 parts (seat belt, recliner, armrest, headrest, upper-back support, lumbar support, seatback bolster, seatback overall, hip support, thigh support, seatpan bolster, and seatpan overall) of 12 bus seats with 17 subjective comfort measures (e.g., convenience of control, suitability of size, and overall comfort). Lastly, ergonomic features of shape and physical properties of each seat part were identified based on the subject evaluation analysis results. The developed bus seat evaluation protocol can be applied to evaluate various types of seats.

• 한국전문물리치료학회지
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• 제19권1호
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• pp.19-27
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• 2012

The purpose of this study was to determine the effect of contralateral hip adduction (CHA) on thickness of lumbar stabilizers during hip abduction in side-lying. Twenty healthy subjects without back pain were recruited for this study. The thickness of transverse abdominis (TrA), internal oblique (IO) and quadratus lumborum (QL) were measured by ultrasonography. Pelvic lateral tilting motion was measured using a three-dimensional motion analysis system. Measurements were performed at rest position (RP), $35^{\circ}$preferred hip abduction (PHA) and $35^{\circ}$abduction with $10^{\circ}$contralateral hip adduction (CHA) in side-lying at the end of expiration. During the measurements, subjects were asked to maintain steady trunk alignment without hand support. Thickness of TrA and IO was significantly greater in CHA than in PHA and RP conditions. There was no significant difference in thickness of TrA and IO between PHA and RP conditions. Medio-lateral (M-L) thickness of QL was not significant between PHA and CHA conditions. Anterio-posterior (A-P) thickness of QL in PHA and CHA significantly decreased compared to RP condition. Angle of pelvic lateral tilting was significantly decreased in CHA compared to PHA condition. In conclusion, CHA can be recommended for increasing trunk stability without compensatory pelvic motion during hip abduction exercise in side-lying.

• Journal of Korean Neurosurgical Society
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• 제63권6호
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• pp.723-729
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• 2020

Objective : The use of oblique lateral interbody fusion at the L5-S1 level (OLIF51) is increasing, but no study has directly compared OLIF51 and transforaminal lumbar interbody fusion (TLIF) at the L5-S1 level. We evaluated the usefulness of OLIF51 by comparing clinical and radiologic outcomes with those of TLIF at the same L5-S1 level. Methods : We retrospectively reviewed and compared 74 patients who underwent OLIF51 (OLIF51 group) and 74 who underwent TLIF at the L5-S1 level (TLIF51 group). Clinical outcomes were assessed with the visual analogue scale for back pain and leg pain and the Oswestry Disability Index. Mean disc height (MDH), foraminal height (FH), disc angle (DA), fusion rate, and subsidence rate were measured for radiologic outcomes. Results : The OLIF51 group used significantly higher, wider, and larger-angled cages than the TLIF51 group (p<0.001). The postoperative MDH and FH were significantly greater in the OLIF51 group than in the TLIF51 group (p<0.001). The postoperative DA was significantly larger in the OLIF51 group than in the TLIF51 group by more than 10º (p<0.001). The fusion rate was 81.1% and 87.8% at postoperative 6 months in the OLIF51 and TLIF51 groups, respectively, and the TLIF51 group showed a higher fusion rate (p<0.05). The subsidence rate was 16.2% and 25.3% in the OLIF51 and TLIF51 groups, respectively, and the OLIF51 group showed a lower subsidence rate (p<0.05). Conclusion : OLIF51 was more effective for the indirect decompression of foraminal stenosis, providing strong mechanical support with a larger cage, and making a greater lordotic angle with a high-angle cage than with TLIF.

• 대한인간공학회지
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• 제30권5호
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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.

• 대한의용생체공학회:의공학회지
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• 제45권2호
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• pp.75-80
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• 2024

This research investigates the influence of chair tilt functionality on biometric signals and user comfort, addressing the ergonomic challenges posed by modern sedentary lifestyles. Through an experimental study involving eight male participants, the impact of chair tilt on electromyography (EMG), heart rate, metabolic rate, pressure distribution, and distance between the lumbar spine and the lumbar support part of the chair was measured across different seating postures. The study utilized chairs with both synchronous and non-synchronous tilt mechanisms to explore how adjustments in chair design affect user comfort and physiological responses during prolonged sitting. Key findings suggest that chair tilt functionality can significantly reduce muscle activity and energy expenditure, enhancing user comfort and potentially mitigating health risks associated with prolonged sedentary behavior. Notably, the study revealed a preference among participants for chairs that aligned the rotational center of the tilt with the hip joint, highlighting the importance of this ergonomic feature in enhancing user comfort. Additionally, the research proposes a novel methodology for assessing seating comfort through the analysis of both biometric and physical signals, providing valuable insights for the development of ergonomic chair designs focused on user health and comfort.

• 대한정형도수물리치료학회지
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• 제23권1호
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• pp.23-30
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• 2017

Purpose: The purpose of this study was to investigate the effect of transverse abdominis ratio and balance ability during bridge exercises on different support surface. Methods: The subjects were 20 students at G University. Ultrasound equipment was used to measure the transverse abdominisratio and the computerized balance measurement equipment was used to measure the balance ability before and after bridge exercises on different support surface. Results: Transverse abdominis ratio change between the groups was a significant difference only in the unstable support surface training group (p<.05). Normal standing eye close balance ability change between the groups was significantly different only in the unstable support surface training group (p<.05). The changes in the transverse abdominis ratio after 7 days of exercise and 14 days after exercise were significantly different between the groups (p<.05). Normal standing eye close balance ability showed a significant difference at 7 days after exercise and 14 days after exercise (p<.05). Conclusions: It is more effective to balance ability and ratio of the transverse abdominis when bridge exercises on an unstable support surface than to perform bridge exercises on a stable support surface. Therefore, we propose an effective program for patients with instability of the lumbar in clinical practice. bridge exercises on different support surface.

• 대한물리치료과학회지
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• 제29권1호
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• pp.55-63
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• 2022

Background: This study investigated the effect of erector spinae and quadratus lumbar kinesio taping and support surface conditions on abdominal muscle activity during plank exercise. Design: Within-Group design. Methods: A total of twenty-three healthy men and women participated in this study. Abdominal muscle (both external obliques and internal oblique muscle) contraction was analyzed through EMG measurement with the presence or absence of kinesio taping applied to the erector spinae muscle and quadratus lumborum muscle during plank exercise and the difference between the support surfaces (stable surface and unstable surface) as variables. Abdominal EMG was attached to the right external oblique, left external oblique, right internal oblique, and left internal oblique. Results: The results showed that Abdominal left and right external obliques and internal obliques showed significant increases in activity when kinesio taping was applied to the erector spinae and quadratus lumborum muscles and unstable ground (p<0.05). Conclusion: In this study, we confirmed that the activity of the abdominal muscles was significantly increased during the plank operation in the state where the kinesio tape was attached. In addition, it was confirmed that the activity of the abdominal muscles was significantly increased during the plank operation on the unstable surface. These results suggest that in the state of kinesio tape attached and instability, plank motion has a positive effect on abdominal muscle activity.

• The Journal of Korean Physical Therapy
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• 제24권5호
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• pp.300-305
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• 2012

Purpose: This study examined the muscle activity of the trunk muscles during weight shifting exercises on a stable and unstable surface. Methods: Ten healthy young subjects (4 males, 6 females) with no medical history of lower-extremity or lumbar spine disease were enrolled in this study. The muscle activity was recorded using surface electromyography (EMG) electrodes from the both sides of the external obliques and erector spinae muscles. Results: The EMG activities of the both rectus abdominalis, both external obliques and erector spinae muscles were significantly higher when the weight shifting exercise was performed on a firm surface than when a balance pad with a balance ball was used. In weight shifting exercises, the EMG activity of the contralateral external obliques and erector spinae muscles was significantly higher than that of the ipsilateral external obliques and erector spinae muscles under all three support surface conditions. Conclusion: Performing weight shifting exercise using an unstable surface is a useful method for facilitating the trunk-muscle strength and trunk stability.

• 한국산학기술학회논문지
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• 제11권9호
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• pp.3168-3175
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• 2010

럼버 서포트는 허리에 가해지는 압력을 지지하여 장시간 운전시 피로감을 해소하는 자동차 시트의 부품이다. 본 연구에서는 자동차 시트의 럼버 서포트를 모델링 하였으며, 해석은 럼버 서포트의 베드부분에 여러 가지의 비드를 보강하여 사람이 자동차 시트에 앉아 있을 때 작용하는 하중에 따른 변형에 대해 구조해석을 하여 안락성면에서 적합한 모델을 찾는 것이 주된 목적이다. 5줄 보강타입과 풀타입이 5mm안쪽의 변형과 500 N의 접촉력이 나타나 승객의 안락감에 있어 가장 적합하고 내구성도 양호한 것으로 사료된다.

• 국제물리치료학회지
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• 제3권2호
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• pp.464-468
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• 2012

The objective of this study is to provide basic information on coupled motions in thoracic spine during lateral bending from a neutral position for football and baseball players as well as for general university students. In the experiment, a total of 30 subjects participated(football players: 10, baseball players: 10, general students: 10). All subjects were in their 20's. The subjects sat on a chair with lumbar support in a neutral position and bent to the right. As a result, for baseball players, coupled motions were observed in the opposite direction of the lateral bending in all parts of thoracic spine. For both football players and general students, coupled motions were observed in the same direction. These results confirmed that unilateral movements like baseball could affect coupled motions.