Temporary Disabled. :) please Go back Author:("Jeon, Hyeong-Min") - IOS Press www.fgks.org » Address: [go: up one dir, main page] Include Form Remove Scripts Accept Cookies Show Images Show Referer Rotate13 Base64 Strip Meta Strip Title Session Cookies You are viewing a javascript disabled version of the site. Please enable Javascript for this site to function properly. Go to headerGo to navigationGo to searchGo to contentsGo to footer In header section. Select this link to jump to navigation Help About us Contact us In navigation section. Select this link to jump to content Menu Home Journals Cart € title="Change currency to USD - US Dollar"$ Log in / Register Search Search Published between: Published from year: and Published to year: Search syntax help Searching for just a few words should be enough to get started. If you need to make more complex queries, use the tips below to guide you. Boolean operators This OR thatThis AND thatThis NOT that Must include "This" and "That" This That Must not include "That" This -That "This" is optional This +That Exact phrase "This That" "This That" Grouping (this AND that) OR (that AND other) In content section. Select this link to jump to navigation Your search for: 'author:("Jeon, Hyeong-Min")' has returned 5 results. (0.034s) Save search Sort by: Relevance Most recent Submit Mark all Add marked to cart Export marked citations Select this result for bulk action Energy absorption at lower limb joints in different foot contact strategies while descending stairs Authors: Jeon, Hyeong-Min | Lee, Ki-Kwang | Lee, Jun-Young | Shin, Ju-Hwan | Eom, Gwang-Moon Article Type: Research Article Abstract: BACKGROUND: Joint loads in different walking strategies during stair descent have been investigated in terms of the joint moment in association with the risk of osteoarthritis. However, the absorption mechanisms of the potential energy loss are not known. OBJECTIVE: This study aims to compare the mechanical energy absorptions in lower limb joints in different initial foot contact strategies. METHODS: Nineteen young subjects walked down on instrumented stairs with two different strategies, i.e., forefoot and rearfoot strike. Power and energy at lower limb joints during stance phase were compared between strategies. RESULTS: Lower limb joints absorbed 73 ± 11% of the …potential energy released by descending stairs and there was no difference between strategies. Rearfoot strategy absorbed less energy than forefoot strategy at the ankle joint in the 1st phase, which was compensated mainly by more energy absorption at the knee in the 2nd phase and less energy generation at the hip joints in the 3rd phase. CONCLUSION: The results suggest that a leg absorbs most of the potential energy while descending stairs irrespective of the walking strategies and that any reduction of energy absorption at one joint is compensated by other joints. Greater energy absorption at the knee joint compared to the other joints suggests high burden of knee joint muscles and connective tissues during stair-descent, which is even more significant for the rearfoot strike strategy. Show more Keywords: Energy absorption, mechanism, stair descent, foot strike strategy, osteoarthritis DOI: 10.3233/THC-218041 Citation: Technology and Health Care, vol. 29, no. S1, pp. 433-440, 2021 Get PDF Select this result for bulk action Analysis of antagonistic co-contractions with motorized passive movement device in patients with parkinson's disease Authors: Kwon, Yuri | Kim, Ji-Won | Ho, Yeji | Jeon, Hyeong-Min | Bang, Min-Jung | Eom, Gwang-Moon | Koh, Seong-Beom Article Type: Research Article Abstract: Patients with Parkinson's disease (PD) suffer from an increased resistance to passive movement of a joint, called as rigidity. Stretch reflex and shortening reaction were suggested to be associated to the rigidity, however, the mechanism is still poorly understood. We hypothesized that the co-contraction of antagonistic muscle pairs is enhanced in patients with PD and this induces resistance persisting throughout its range of motion. To test the hypothesis, we developed a motorized device for application of passive movement of the wrist joint and investigated the co-contraction of muscles during passive movement. It consisted of a servo motor connected to a …rotating axis with a timing belt, load cell for the measurement of resistance, and other elements for the fixation of arm and hand. Repetitive passive movement was applied to the wrist joint of patients. Co-contraction of antagonistic muscle pairs was significantly greater in patients than in normal subjects (p<0.001), suggesting that the enhanced co-contraction is associated with the mechanical resistance during passive movement, i.e. rigidity. Co-contraction during extended state was greater than the other states (p<0.001), which implies that the length-feedback mechanism may play the important role in co-contraction. Show more Keywords: Parkinson's disease, rigidity, co-contraction, motorized device, passive movement DOI: 10.3233/BME-141042 Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2291-2297, 2014 Get PDF Select this result for bulk action The effect of sitting posture on the loads at cervico-thoracic and lumbosacral joints Authors: Kwon, Yuri | Kim, Ji-Won | Heo, Jae-Hoon | Jeon, Hyeong-Min | Choi, Eui-Bum | Eom, Gwang-Moon Article Type: Research Article Abstract: BACKGROUND: The sitting in an awkward posture for a prolonged time may lead to spinal or musculoskeletal disease. It is important to investigate the joint loads at spine while sitting. OBJECTIVE: The purpose of this study was to investigate the joint moment and antero-posterior (AP) reaction force at cervico-thoracic and lumbosacral joint for various sitting postures. METHODS: Twenty healthy males participated in this study. Six sitting postures were defined from three spinal curvatures (slump, flat, and lordosis) and two arm postures (arms-on-chest and arms-forward). Kinematic and kinetic data were measured in six sitting postures from which joint moment and AP …reaction force were calculated by inverse dynamics. RESULTS: In the cervico-thoracic joint, joint moment and AP reaction force were greater in slump than the flat and lordosis postures (p < 0.001) and also in arms-forward posture compared to arms-on-chest posture. In the lumbosacral joint, joint moment and AP reaction force were greater in slump than flat and lordotic posture (p < 0.001) but there was no difference between different arm postures. The joint loads (moment and AP reaction force) at the cervico-thoriacic joint were closely related to the head flexion angle (r > 0.86) while those at the lumbosacral joint were correlated to the trunk flexion angle (r > 0.77). In slump posture, the joint moments were close to or over the extreme of the daily life such as sit-to-stand and walking. Consequently, if the slump is continued for a long time, it may cause pain and diseases at the cervico-thoracic and lumbosacral joints. CONCLUSIONS: The results of the study indicated that the lordosis or flat would be better spinal postures. Also, keeping arms close to body would be desirable to reduce joint loads. Show more Keywords: Sitting posture, cervico-thoracic joint, lumbosacral joint, joint moment, joint reaction force DOI: 10.3233/THC-174717 Citation: Technology and Health Care, vol. 26, no. S1, pp. 409-418, 2018 Get PDF Select this result for bulk action Age–gender differences in the postural sway during squat and stand-up movement Authors: Kim, Ji-Won | Kwon, Yuri | Ho, Yeji | Jeon, Hyeong-Min | Bang, Min-Jung | Jun, Jae-Hoon | Eom, Gwang-Moon | Park, Byung Kyu | Cho, Yeong Bin Article Type: Research Article Abstract: Incidence of falling among elderly female has been reported to be much higher than that of elderly male. Although the gender differences in the elderly were reported for the static postural sway, there has been no investigation of the gender difference for the dynamic postural sway. This study investigates how age and gender affect the postural sway during dynamic squat and stand-up movement. 124 subjects (62 subjects for each of young and elderly) performed consecutive squat and stand-up movement, 2 times in one session, and 2 sessions per subject. Center of pressure (COP) was measured using force platform during the …test. Outcome measures included peak-to-peak sways of the COP (COP sway) in the sagittal plane (anteroposterior) and frontal plane (mediolateral) and also those normalized by body height. Two-way ANOVA and post-hoc comparisons were performed for the outcome measures with the independent factors of age and gender. All outcome measures, excluding mediolateral COP sway, showed significant interaction of age and gender (p<0.05). Post-hoc test revealed that only female showed increase in COP sway with age. When normalized by height, increase in COP sways (both directions) with age significant only in women resulted in greater sways in elderly female than elderly male. This may be related to the greater fall rate of elderly female than that of elderly men while performing dynamic activities. Show more Keywords: COP sway, dynamic activities, squat and stand-up, gender difference DOI: 10.3233/BME-141088 Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2707-2713, 2014 Get PDF Select this result for bulk action Quantitative evaluation of parkinsonian rigidity during intra-operative deep brain stimulation Authors: Kwon, Yuri | Park, Sang-Hoon | Kim, Ji-Won | Ho, Yeji | Jeon, Hyeong-Min | Bang, Min-Jung | Koh, Seong-Beom | Kim, Jong-Hyun | Eom, Gwang-Moon Article Type: Research Article Abstract: This study aims at the quantification of fine change in parkinsonian rigidity at the wrist during deep brain stimulation (DBS) using a portable measurement system and objective mechanical measures. The rigidity of fourteen limbs was evaluated during DBS surgery. The resistive torque to imposed movement was measured for every setting where a reduction in rigidity was perceived by a neurologist. Quantitative mechanical measures derived from experimental data included viscoelastic properties, work, impulse and mechanical impedance. Most mechanical measures could discriminate the optimal setting from baseline (electrode at stereotactic initial position without electrical stimulation) and the highest significance was achieved by …viscous damping constant (p<0.001). Spearman correlation coefficients between mechanical measures and clinical score for multiple settings (averaged for 14 limbs) were 0.51–0.77 and the best correlation was shown for viscosity (ρ=0.77±0.22). The results suggest that intraoperative quantification of rigidity during DBS surgery is possible with the suggested system and measures, which would be helpful for the adjustment of electrode position and stimulation parameters. Show more Keywords: Intraoperative, quantification, rigidity, DBS surgery, Parkinson's disease DOI: 10.3233/BME-141040 Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2273-2281, 2014 Get PDF Filter by publication date Since 2021 (1) Since 2018 (2) Since 2014 (5) Filter by journal Bio-Medical Materials and Engineering (3) Technology and Health Care (2)
Searching for just a few words should be enough to get started. If you need to make more complex queries, use the tips below to guide you.
Authors: Jeon, Hyeong-Min | Lee, Ki-Kwang | Lee, Jun-Young | Shin, Ju-Hwan | Eom, Gwang-Moon
Article Type: Research Article
Abstract: BACKGROUND: Joint loads in different walking strategies during stair descent have been investigated in terms of the joint moment in association with the risk of osteoarthritis. However, the absorption mechanisms of the potential energy loss are not known. OBJECTIVE: This study aims to compare the mechanical energy absorptions in lower limb joints in different initial foot contact strategies. METHODS: Nineteen young subjects walked down on instrumented stairs with two different strategies, i.e., forefoot and rearfoot strike. Power and energy at lower limb joints during stance phase were compared between strategies. RESULTS: Lower limb joints absorbed 73 ± 11% of the …potential energy released by descending stairs and there was no difference between strategies. Rearfoot strategy absorbed less energy than forefoot strategy at the ankle joint in the 1st phase, which was compensated mainly by more energy absorption at the knee in the 2nd phase and less energy generation at the hip joints in the 3rd phase. CONCLUSION: The results suggest that a leg absorbs most of the potential energy while descending stairs irrespective of the walking strategies and that any reduction of energy absorption at one joint is compensated by other joints. Greater energy absorption at the knee joint compared to the other joints suggests high burden of knee joint muscles and connective tissues during stair-descent, which is even more significant for the rearfoot strike strategy. Show more
Keywords: Energy absorption, mechanism, stair descent, foot strike strategy, osteoarthritis
DOI: 10.3233/THC-218041
Citation: Technology and Health Care, vol. 29, no. S1, pp. 433-440, 2021
Authors: Kwon, Yuri | Kim, Ji-Won | Ho, Yeji | Jeon, Hyeong-Min | Bang, Min-Jung | Eom, Gwang-Moon | Koh, Seong-Beom
Abstract: Patients with Parkinson's disease (PD) suffer from an increased resistance to passive movement of a joint, called as rigidity. Stretch reflex and shortening reaction were suggested to be associated to the rigidity, however, the mechanism is still poorly understood. We hypothesized that the co-contraction of antagonistic muscle pairs is enhanced in patients with PD and this induces resistance persisting throughout its range of motion. To test the hypothesis, we developed a motorized device for application of passive movement of the wrist joint and investigated the co-contraction of muscles during passive movement. It consisted of a servo motor connected to a …rotating axis with a timing belt, load cell for the measurement of resistance, and other elements for the fixation of arm and hand. Repetitive passive movement was applied to the wrist joint of patients. Co-contraction of antagonistic muscle pairs was significantly greater in patients than in normal subjects (p<0.001), suggesting that the enhanced co-contraction is associated with the mechanical resistance during passive movement, i.e. rigidity. Co-contraction during extended state was greater than the other states (p<0.001), which implies that the length-feedback mechanism may play the important role in co-contraction. Show more
Keywords: Parkinson's disease, rigidity, co-contraction, motorized device, passive movement
DOI: 10.3233/BME-141042
Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2291-2297, 2014
Authors: Kwon, Yuri | Kim, Ji-Won | Heo, Jae-Hoon | Jeon, Hyeong-Min | Choi, Eui-Bum | Eom, Gwang-Moon
Abstract: BACKGROUND: The sitting in an awkward posture for a prolonged time may lead to spinal or musculoskeletal disease. It is important to investigate the joint loads at spine while sitting. OBJECTIVE: The purpose of this study was to investigate the joint moment and antero-posterior (AP) reaction force at cervico-thoracic and lumbosacral joint for various sitting postures. METHODS: Twenty healthy males participated in this study. Six sitting postures were defined from three spinal curvatures (slump, flat, and lordosis) and two arm postures (arms-on-chest and arms-forward). Kinematic and kinetic data were measured in six sitting postures from which joint moment and AP …reaction force were calculated by inverse dynamics. RESULTS: In the cervico-thoracic joint, joint moment and AP reaction force were greater in slump than the flat and lordosis postures (p < 0.001) and also in arms-forward posture compared to arms-on-chest posture. In the lumbosacral joint, joint moment and AP reaction force were greater in slump than flat and lordotic posture (p < 0.001) but there was no difference between different arm postures. The joint loads (moment and AP reaction force) at the cervico-thoriacic joint were closely related to the head flexion angle (r > 0.86) while those at the lumbosacral joint were correlated to the trunk flexion angle (r > 0.77). In slump posture, the joint moments were close to or over the extreme of the daily life such as sit-to-stand and walking. Consequently, if the slump is continued for a long time, it may cause pain and diseases at the cervico-thoracic and lumbosacral joints. CONCLUSIONS: The results of the study indicated that the lordosis or flat would be better spinal postures. Also, keeping arms close to body would be desirable to reduce joint loads. Show more
Keywords: Sitting posture, cervico-thoracic joint, lumbosacral joint, joint moment, joint reaction force
DOI: 10.3233/THC-174717
Citation: Technology and Health Care, vol. 26, no. S1, pp. 409-418, 2018
Authors: Kim, Ji-Won | Kwon, Yuri | Ho, Yeji | Jeon, Hyeong-Min | Bang, Min-Jung | Jun, Jae-Hoon | Eom, Gwang-Moon | Park, Byung Kyu | Cho, Yeong Bin
Abstract: Incidence of falling among elderly female has been reported to be much higher than that of elderly male. Although the gender differences in the elderly were reported for the static postural sway, there has been no investigation of the gender difference for the dynamic postural sway. This study investigates how age and gender affect the postural sway during dynamic squat and stand-up movement. 124 subjects (62 subjects for each of young and elderly) performed consecutive squat and stand-up movement, 2 times in one session, and 2 sessions per subject. Center of pressure (COP) was measured using force platform during the …test. Outcome measures included peak-to-peak sways of the COP (COP sway) in the sagittal plane (anteroposterior) and frontal plane (mediolateral) and also those normalized by body height. Two-way ANOVA and post-hoc comparisons were performed for the outcome measures with the independent factors of age and gender. All outcome measures, excluding mediolateral COP sway, showed significant interaction of age and gender (p<0.05). Post-hoc test revealed that only female showed increase in COP sway with age. When normalized by height, increase in COP sways (both directions) with age significant only in women resulted in greater sways in elderly female than elderly male. This may be related to the greater fall rate of elderly female than that of elderly men while performing dynamic activities. Show more
Keywords: COP sway, dynamic activities, squat and stand-up, gender difference
DOI: 10.3233/BME-141088
Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2707-2713, 2014
Authors: Kwon, Yuri | Park, Sang-Hoon | Kim, Ji-Won | Ho, Yeji | Jeon, Hyeong-Min | Bang, Min-Jung | Koh, Seong-Beom | Kim, Jong-Hyun | Eom, Gwang-Moon
Abstract: This study aims at the quantification of fine change in parkinsonian rigidity at the wrist during deep brain stimulation (DBS) using a portable measurement system and objective mechanical measures. The rigidity of fourteen limbs was evaluated during DBS surgery. The resistive torque to imposed movement was measured for every setting where a reduction in rigidity was perceived by a neurologist. Quantitative mechanical measures derived from experimental data included viscoelastic properties, work, impulse and mechanical impedance. Most mechanical measures could discriminate the optimal setting from baseline (electrode at stereotactic initial position without electrical stimulation) and the highest significance was achieved by …viscous damping constant (p<0.001). Spearman correlation coefficients between mechanical measures and clinical score for multiple settings (averaged for 14 limbs) were 0.51–0.77 and the best correlation was shown for viscosity (ρ=0.77±0.22). The results suggest that intraoperative quantification of rigidity during DBS surgery is possible with the suggested system and measures, which would be helpful for the adjustment of electrode position and stimulation parameters. Show more
Keywords: Intraoperative, quantification, rigidity, DBS surgery, Parkinson's disease
DOI: 10.3233/BME-141040
Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2273-2281, 2014