• The Journal of Korean Physical Therapy
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• v.9 no.1
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• pp.127-145
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• 1997

The purpose of this study wa9 to analyse the gait patterns of two female children with hemiplegic cerebral palsy by using the three-dimensional video motion analysis technique. Case 1 has mild spastic hemiplegia on the right side while Case 3 has moderate spastic hemiplegia on the left side. A group of 10, normal female children of the same age(7-8 years old) were selected as the control group for comparison. Time and distance variables as well as the Center of Mass displacement, and the pelvic and joint motions in three anatomical planes were analysed for this purpose. The following observations were made through the analysis : Case 1 revealed an asymmetrical gait pattern in which the step length of the unaffected side was shorter than that of the affected side, which wan a result of the effort to minimize loading on the affected leg by shortening the swing phase of the unaffected leg. Case 1 scored similar phase ratios, cadence and walking velocity to the normal group. A slight posterior tilt of the pelvis was observed throughout the gait cycle. Less hip and knee flexion than the normal group was observed, and demonstrated hyperextension of the knee in the terminal stance phase. The main problem in case 1 originated from the insufficient dorsiflexion of the affected foot during the swing phase. Therefore, Case 1 has difficulty with foot clearance in the swing phase. Usually, this is compensated for by using exessive hip abduction and medial rotation in conjuction with trunk elevation as well as increased vortical displacement of the center of mass. Case 1 revealed a foot-flat initial contact pattern. Case 2 was characterized by a consistent retraction ef the affected aide of the body througout the gait cycle, As a result, an asymmetrical gait pattern with increased stance phase ratios of the unaffected side was observed. In spite of this the step lengths of both sieds were similar. Case 2 scored lower cadence and walking speed than the normal group with lower gait stability. The main problem in Case 2 originated from an excessive plantaflexion of the affected foot which, in turn, rebutted in high hip and knee flexion. Hyperextension of the knee was observed at mid-stance, and execessive anterior tilt of the pelvis throughout the gait cycle was noticed. A gait pattern with high hip abduction and medial circumduction was maintained for the stability in the stance phase and foot clearance in the swing phase. Case 2 revealed a forefoot-contact initial contact pattern.

• The Journal of Korean Physical Therapy
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• v.27 no.2
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• pp.124-127
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• 2015

Purpose: The emphasis on gait rehabilitation after stroke depends on training support through the lower limbs, balance of body mass over the changing base of support. However, muscle weakness, lack of control of lower limb, and poor balance can interfere with training after stroke. For this case study report, a wearable robot orthosis was applied to stroke patients in order to verify its actual applicability on balance and gait ability in the clinical field. Methods: Two stroke patients participated in the training using the wearable robot orthosis. Wearable robot orthosis provides patient-initiated active assistance contraction during training. Training includes weight shift training, standing up and sitting down, ground walking, and stair up and down Training was applied a total of 20 times, five times a week for 4 weeks, for 30 minutes a day. Gait ability was determined by Stance phase symmetry profile, Swing phase symmetry profile, and velocity using the GAITRite system. Balance ability was measured using the Biodex balance system. Results: Subjects 1, 2 showed improved gait and balance ability with mean individual improvement of 72.4% for velocity, 19.4% for stance phase symmetry profile, 9.6% for swing phase symmetry profile, and 13.6% for balance ability. Conclusion: Training utilizing a wearable robot orthosis can be useful for improvement of the gait and balance ability of stroke patients.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.10
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• pp.948-956
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• 2010

The purpose of this study was to test the effectiveness of a prototype KAFO (Knee-Ankle-Foot Orthosis) powered by two artificial pneumatic muscles during walking. We had previously built powered AFO (Ankle-Foot Orthosis) and KO (Knee Orthosis) and used it effectively in studies on assistance of plantaflexion and knee extension motion. Extending the previous study to a KAFO presented additional challenges related to the assistance of gait motion for rehabilitation training. Five healthy males were performed gait motion on treadmill wearing KAFO equipped with artificial pneumatic muscles to power ankle plantaflexion and knee extension. Subjects walked on treadmill at 1.5 km/h under four conditions without extensive practice: 1) without wearing KAFO, 2) wearing KAFO with artificial muscles turned off, 3) wearing KAFO powered only in plantaflexion under feedforward control, and 4) wearing KAFO powered both in plantaflexion and knee extension under feedforward control. We collected surface electromyography, foot pressure and kinematics of ankle and knee joint. The experimental result showed that a muscular strength of wearing KAFO powered plnatarfexion and knee extension under feedforward control was measured to be lower due to pneumatic assistance and foot pressure of wearing KAFO powered plnatarfexion and knee extension under feedforward control was measured to be greater due to power assistance. In the result of motion analysis, the ankle angle of powered KAFO in terminal stance phase was found a peak value toward plantaflexion and there were difference of maximum knee flexion range among condition 2, 3 and 4 in mid-swing phase. The current orthosis design provided plantaflexion torque of ankle jonit in terminal stance phase and knee extension torque of knee joint in mid-swing phase.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.9
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• pp.926-934
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• 2006

This paper proposes intelligent control of a virtual walking machine that can generate infinite floor for various surfaces and can provide proprioceptive feedback of walking to a user. This machine allows users to participate in a life-like walking experience in virtual environments with various terrains. The controller of the machine is implemented hierarchically, at low-level for robust actuator control, at mid-level fur platform control to compensate the external forces by foot contact, and at high-level control for generating walking trajectory. The high level controller is suggested to generate continuous walking on an infinite floor for various terrains. For the high level control, each independent platform follows a man foot during the swing phase, while the other platform moves back during single stance phase. During double limb support, two platforms manipulate neutral positions to compensate the offset errors generated by velocity changes. This control can, therefore, satisfy natural walking conditions in any direction. Transition phase between the swing and the stance phases is detected by using simple switch sensor system, while human foot motions are sensed by careful calibration with a magnetic motion tracker attached to the shoe. Experimental results of walking simulations at level ground, slope, and stairs, show that with the proposed machine, a general person can walk naturally on various terrains with safety and without any considerable disturbances. This interface can be applied to various areas such as VR navigations, rehabilitation, and gait analysis.

• Journal of Biomedical Engineering Research
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• v.22 no.1
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• pp.29-34
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• 2001

본 연구의 목적은 대퇴부가 절단된 다리의 생체 역학적 기능을 복구할 수 있게 하는 의지의 개발을 위하여 5축 링크, 슬관절 완충장치를 사용하여 보행시 입각기를 제어할 수 있는 대퇴 의지 시스템 개발에 있다. 이를 위하여 입각기시 대퇴의지와 지면간 접촉 중 충격 에너지 흡수를 하는 슬관절 완충장치의 기계적 특성 및 거동을 분석하였다. 임상시험을 통하여 개발된 대퇴의지의 성능을 검증한 결과 대퇴 절단 피검자들의 보행특성은 정상인의 보행에 근접한 경향을 보였다. 결론적으로 본 연구에서 개발된 입각기 대퇴의지는 입각기시 현저한 보행 안전성을 보였다.

• The Journal of Korea Robotics Society
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• v.15 no.4
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• pp.323-329
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• 2020

This paper presents a control algorithm for a wearable walking aid robot for subjects with paraplegia after stroke. After a stroke, a slow, asymmetrical and unstable gait pattern is observed in a number of patients. In many cases, one leg can move in a relatively normal pattern, while the other leg is dysfunctional due to paralysis. We have adopted the so-called assist-as-needed control that encourages the patient to walk as much as possible while the robot assists as necessary to create the gait motion of the paralyzed leg. A virtual wall was implemented for the assist-as-needed control. A position based admittance controller was applied in the swing phase to follow human intentions for both the normal and paralyzed legs. A position controller was applied in the stance phase for both legs. A power controller was applied to obtain stable performance in that the output power of the system was delimited during the sample interval. In order to verify the proposed control algorithm, we performed a simulation with 1-DOF leg models. The preliminary results have shown that the control algorithm can follow human intentions during the swing phase by providing as much assistance as needed. In addition, the virtual wall effectively guided the paralyzed leg with stable force display.

• PNF and Movement
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• v.6 no.3
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• pp.29-35
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• 2008

Purpose : To describes the important aspects of the foot and ankle movement and function used when git and balance strategy. Method : The foot and ankle was a very important roles in the lower limb movement and gait. This study summarizes the physiologic movement of knee to the PNF lower extremity patterns. Result : The ankle joint composed of the talocural joint, the subtalarl joint, transverse tarsal joint, talocalcaneonavicular joint. The onset of dorsiflexion muscle activity starts in pre swing gait patterns. First contract muscle is the extensor hallucis. Activity of tibialis anterior and extensor digitorum longus quickly follows in mid swing gait phase. During stance phase, the soleus and gastrocnemius muscle provided plantar flexor torque, which muscle reacts quickly to restrain ankle dorsiflexion, and contributes modulated control of the ankle motion in gait patterns. Conclusions : The understanding of ankle kinematics, could provide a good therapeutic approach for improving gait patterns in patients with various pathological condition.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.193-195
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• 2006

In this study, we developed an active controlled ankle-foot orthosis(AAFO) which can control the dorsiflexion/plantarflexion of the ankle joint during gait to prevent foot drop and toe drag for paralysis patients. To prevent dropping foot after heel strike, ankle joint was actively controlled to minimize forefoot collision with the ground. It was also controlled to provide toe clearance and to help push-off during late stance. The 3D gait analysis was performed on two healthy subjects equipped with the developed AAFO to compare with the normal gait and the conventional AFO gait. In the developed AAFO gait, differently from the conventional AFO gait, significant push-off was observed during pre-swing and the maximum flexion moment during pre-swing phase was similar to that of normal gait. A remarkable dorsiflexion also occurred during initial swing. These results indicated that the developed AAFO could have certain clinical benefits to prevent foot drop for paralysis patients, compared to conventional AFOs.

• Journal of Korea Entertainment Industry Association
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• v.14 no.6
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• pp.221-230
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• 2020

The purpose of this study was to investigate the effect of resistance exercise with vibration stimulation methods on static balance and gait parameters in experienced back pain adults. This study was Three group pretest-posttest design. A total of 30 experienced back pain adults voluntarily participated in the study. Subjects were randomly assigned to the resistance exercise with 8 Hz vibration stimulation(n=10), resistance exercise with 30 Hz vibration stimulation(n=10), and lumbar stabilization exercise groups(n=10). The static balance and the gait parameters, as such stance phase, swing phase, stride length and cadence, were measured using balance measuring equipment and gait analysis treadmill at before and after 6 week. Intervention of each group were performed, three times a week for 6 weeks, and 30 minutes a day. The effect of intervention on static balance, stance phase, swing phase, stride length and cadence were significantly differences after 6 weeks in each group(p<.05). In the comparison of the effects between the groups, static balance and stance phase were significantly difference after 6 weeks(p<.05), but in the swing phase, stride length and cadence, there were no significant differences. As a result, it is considered that resistance exercise with vibration stimulation improved leg muscle strength by a mechanism causing muscle contraction, and the strengthened leg muscle enhanced had a positive effect on balance ability. And improved balance ability was considered a more positive effect on walking ability by allowing the body to stably control posture while moving.

• The Journal of Korean Physical Therapy
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• v.17 no.4
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• pp.633-650
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• 2005

The aim of this study was to investigate the kinematics of young adults during ascent ramp climbing at different inclinations. Twenty-three subjects ascended a four step at four different inclinations(level, $8^{\circ},\;16^{\circ},\;24^{\circ}$). The 3-D kinematics was analysed by a camera-based falcon system. Groups difference was tested with one -way ANOVA and SNK test. The different kinematic patterns of ramp ascent were analysed and compared to level walking patterns. The kinematics of ramp walking could be clearly distinguished from the kinematics of level walking. In sagittal plane, Ankle joint was more dorsiflexed at initial contact and Max. dorsiflex. during stance phase with $16^{\circ},\;24^{\circ}$ inclination and more plantarflexed at toe off and Max. plantarflex. during swing phase with $24^{\circ}$(p<.001). Knee joint was more flexed at initial contact with $16^{\circ},\;24^{\circ}$ inclination(p<.001). Hip joint was more flexed at initial contact and Max. flex. during swing phase with $16^{\circ},\;24^{\circ}$ inclination and at toe off with $24^{\circ}$(p<.001) and was more extended at Max. ext. during stance phase with $24^{\circ}$(p<.05). In frontal plane, ankle joint was more everted at Max. eversion. during stance phase with $16^{\circ},\;24^{\circ}$ inclination(p<.001). Knee joint was more increased at Max. varus. during stance phase with $16^{\circ},\;24^{\circ}$ inclination(p<.001). Hip joint was not differentiated with different inclinations. In horizontal plane, all joints were not differentiated with different inclinations. Conclusionally, In ascent ramp walking, the different gait pattern generally occurred at over $16^{\circ}$ on the ascending ramp in sagittal and frontal plane. These results suggest that there is a certain inclination angle or angular range where subjects do switch between a level walking and a ascent ramp walking gait pattern. This shows their motor control strategy between level and ascent ramp walking. Further studies are necessary to confirm and detect the ascent ramp gait patterns.