• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.395-406
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• 2010

The purpose of this study was to analyze the changes in kinematic and kinetic parameters of lower extremity joint according to rehabilitation period. Fourteen collegiate male athletes(age: $22.1{\pm}1.35$ years, height: $182.46{\pm}9.45cm$, weight: $88.63{\pm}9.25kg$) and fourteen collegiate athletes on functional ankle instability(age: $21.5{\pm}1.35$ years, height: $184.45{\pm}9.42cm$, weight: $92.85{\pm}10.85kg$) with the right leg as dominant were chosen. The subjects performed drop landing. The date were collected by using VICON with 8 camera to analyze kinematic variables and force platform to analyze kinetic variables. There are two approaches of this study, one is to compare between groups, the other is to find changes of lower extremity joint after rehabilitation. In comparison to the control group, FAI group showed more increased PF & Inversion at IC and decreased full ROM when drop landing. Regarding the peak force and loading rate, it resulted in higher PVGRF and loading. FAI group used more increased knee and hip ROM because of decreased ankle ROM to absorb the shock. And it used sagittal movement to stabilize. In terms of rehabilitation period, FAI group showed that landing patterns were changed and it increased total ankle excursion and used all lower extremity joint close to normal ankle. Regarding the peak force and loading rate, FAI group decreased PVGRF and loading rate. and also showed shock absorption using increased ankle movement. And COP variable showed that proprioception training increased stability during 8 weeks. The results of this study suggest that 8 weeks rehabilitation period is worthwhile to be considered as a way to improve neuromuscular control and to prevent sports injuries.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.163-180
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• 2003

This paper aims at collecting the guantitative data of kenematic variables by analysing the gait patterns of the normal adult men and the handicapped. The gait motions were taped with 4 video cameras, the cinematographic analyses were performed by the DLT technique of three dimensional image treatment. The following results were obtained in the analysis of the variables: 1. The ratio of stance time and swing time did not show any significant difference in the groups of the normal men and the handicapped when both foot of the former and the right feet of the latter were compared. The stride peeriod time of these two groups were 1.12 and 1.11 second, respectively. 2. In the handicapped group, the step width was wider, the step length and stride length were shorter, and especially, the step length of the right foot was shorter, 3. The small vertical displacement of left toes of the handicapped group showed that the heal contact and the left midstance are almost simultaneous. 4. The two groups have almost the same horizontal displacement of the center of gravity and the same vertical rate of extension. In view of the velocity of the center of gravity the normal adults showed the constant speed of movement. However, the handicapped adults were reduced from the right midstance to the right toe-off. 5. The handicapped showed prominently low angle on the left toe-off in the ankle joint angle, they also had the tendency to walk in the patterns of extended knee in the knee joint angle. Both the handicapped and the normal had the hyperextension on the toe-off in the hip joint angle. In the back and front angle of body, both showed the slightly back-sided walking positions. 6. Both groups had the abduction of both feet in foot placement angle, but the handicapped did not show serious abduction of left midstance.

• Korean Journal of Applied Biomechanics
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• v.30 no.1
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• pp.51-61
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• 2020

Objective: The purpose of this study is to analyse and comparison the differences of kinematic variables for Fente skill in Fencing. Method: For this, 15 people were selected as 5 beginners with less than 2 years of experience, 5 intermediate-class people with more than 2 years and less than 4 years, and 5 experts-class people with more than 4 years. Through the comparison of Marche Fente motion according to proficiency, for the necessary time, travel distance, the kinematical factor of joint angle, oneway ANOVA was performed in order to identify differences according to variables by phase. Results: The time required for each phase was shown to be shorter for all phases experts than for beginners and intermediates. At the horizontal displacement of the foot, the right foot left out the last phase and the experts appeared long. The left foot showed short beginners in all phases. The angle of forward lean showed that the angle of forward lean was tilted forward by the experts of all phases. There was a difference between the left and right joint angles of the lower limb, both of the ankle, knee and hip joints. Conclusion: In overall, Beginners should quickly widen the distance of their feet when they make a Fente movement. The beginner shall tilt the upper body forward in order to increase the angle of forward lean. The beginner shall, in the last phase, have a smaller angle on the hip joint.

• Journal of the Korea Safety Management & Science
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• v.11 no.2
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• pp.103-110
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• 2009

The purpose of this study is to suggest a proper tread of stairs using kinematic factors and moments of the lower-limb joints in the stair decent with the 3 different treads with boimechanical method in ergonomics. 9 subjects (body masses; $59.41{\pm}7.49$, $64.03{\pm}6.65$, $67.26:{\pm}7.58$, heights; $160.50{\pm}6.35$ ages; $31.22{\pm}2.99$; parity; $1.67{\pm}0.71$) participated in three experiments that were divided by physiological symptoms (the early (0-15 weeks), middle (16-27 weeks) and last (18-39 weeks). and they walked at self-selected pace on 4 staircases 3 trials. As extending the pregnancy period, cadence was shorter but cycle time were longer more and more. As extending treads of stair decent during pregnancy, speed, stride lengths and cycle time were increased. As extending the treads of stair decent, hip and ankle moments increased but knee moments decreased in sagittal plane. There were increasing or decreasing of moments by means of treads. These changes may account for relation between the treads of stair and moments in pregnant women. The main changes of pregnant women were joint moments and kinematic factors during pregnancy period because pregnancy makes them physical changes. It is possible that joints have connection with compensation each other to maximize stability and to control gait motion. In conclusion, we suggest that the tread of stair is longer than 26cm tread. and exercise programs to improve muscle activity were necessary where joint moments were small.

• Physical Therapy Korea
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• v.25 no.4
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• pp.19-26
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• 2018

Background: Alignment of the lower limb is an important factor, influencing balance and gait in kinematics and kinetics, in patients with and without a flat arched foot. Flat arched foot are associated with the range of motion (ROM) of the hip and alignments of the knee joints, is strongly influenced. Objects: The purpose of this research was to investigate the relationship between hip joint ROM and quadriceps angle (Q-angle), by dividing them into two groups according to the presence or absence of flat feet, using a navicular drop test (NDT) and resting calcaneal stance position (RCSP). Methods: Forty elderly patients were allocated to the experimental group (flat foot group, n1=20) or the control group (non-flat group, n2=20). Universal and digital goniometer, tractograph and tape measure were used to determine the related changes in the hip ROM, Q-angle, NDT and RCSP. Results: Data were analyzed using the Pearson correlation coefficients. Active internal ROM of the hip joint (right, r=.803, p<.001), (left, r=.951, p<.001) were highly correlated with NDT, and also, was moderately correlated with Q-angle (right, r=.562, p=.019), (left, r=.757, p<.001). Passive internal ROM of the hip joint (right, r=.742, p=.001), (left, r=.922, p<.001) were highly correlated with NDT, and also, was moderately correlated with RCSP (right, r=-.530, p=.029) and with Q-angle (right, r=.710, p=.001), (left, r=.698, p=.002) in the flat foot group. However, no strong correlation among the hip ROM, NDT, RCSP and Q-angle were found in the non-flat foot group. Conclusion: This research may provide evidence of the correlations between hip internal ROM and flat foot.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.3
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• pp.177-185
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• 2014

In this study, the exoskeleton orthosis for the assistance of dorsiflexion torque in ankle joint to prevent foot-drop was developed. It was consist of three part; 1) the power part using artificial pneumatic actuator, 2) wearing part of ankle and knee joints to fix the orthosis, and 3) control part to detect the gait phase using physiological signal. The dorsiflexion torque was generated by the artificial pneumatic actuator connected with wearing part between ankle and knee joint. The accurate timing to assist dorsiflexion torque is made up of physiological signal in foot sole part that detect the gait phase, that is, stance and swing phase in each foot. We conduct the experiment to investigate the effect of exoskeleton orthosis to the 7 elderly people and 10 healthy people. The result showed that the muscular activities in tibialis anterior muscle were reduced because of the assistance of dorsiflexion torque in ankle joint using the exoskeleton orthosis.

• Transactions of the KSME C: Technology and Education
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• v.1 no.2
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• pp.153-165
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• 2013

The established gait analysis studies have regarded leg as one single spring. If we can design a knee-ankle actuating mechanism as a primary actuator for supporting knee extension, it might be possible to revolutionary store or release elastic strain energy, which is consumed during the gait cycle, and as a result leg stiffness is expected to increase. An ankle joint actuating mechanism that stores and releases the energy in ankle joint is expected to support and solve excessive artificial leg stiffness caused by the knee actuator (primary actuator) to a reasonable extent. If unnecessary kinematic energy is released with the artificial speed reduction control designed to prevent increase in gait speed caused by increase in time passed, it naturally brings question to the effectiveness of the actuator. As opposed to the already established studies, the authors are currently developing knee-ankle two actuator system under the concept of increasing lower limb stiffness by controlling the speed of gait in relative angular velocity of the two segments. Therefore, the author is convinced that compensatory mechanism caused by knee actuating must exist only in ankle joint. Ankle joint compensatory mechanism can be solved by reverse-examining the change in metatarso-phalangeal joint (MTPJ) tilt angle (${\theta}_1=0^{\circ}$, ${\theta}_2=17^{\circ}$, ${\theta}_3=30^{\circ}$) and the effect of change in gait speed on knee activity.

• Journal of Korea Game Society
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• v.13 no.1
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• pp.19-30
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• 2013

This paper proposes a serious game for rehabilitation training targeting old persons and patients for rehabilitation. The serious game suggested for rehabilitation training provides the whole body movement recognition-based interface using the 3D depth camera. When the user stands before the camera, it distinguishes the user from the background and then recognizes the user's whole body with 15 joints. By analyzing the changes of location and direction of each joint, it recognizes gestures needed for the game. The game contents consist of the games for upper limb training, lower limb training, whole body training, and balance training, and it was realized in both 2D and 3D games. The system suggested in this article works robustly even with the environmental changes using the 3D depth camera. Even with no separate device, the game recognizes the gestures only using the whole body movement, and this enhances the effect of rehabilitation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7285-7292
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• 2015

The purpose of this study was to investigate possibility of a forward gait with backward mechanism(dance gait) as rehabilitation and/or walking exercise by means of biomechanical variables. Thirteen professional women dancers(age, $21.1{\pm}1.3yrs$; height, $159.3{\pm}7.2cm$; body mass, $45.1{\pm}8.4kg$)participated in this study. We found that speed, stride length and double limb support time of a dance gait were more greater than backward gait, but stride width of dance gait less than a backward gait. Maximum RoMs, moments and powers of the lower limb joints on a dance gait were more frequent than a backward dance. These results were judged to be sufficient by the possibility of dance gait as rehabilitation and walking exercise.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.691-700
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• 2016

This study was performed to provide data for developing a more effective and practical pilates exercise program for young women. To meet this purpose, 20 young women were assigned to both groups. The experiment was conducted according to the experimental procedure. Ten subjects in the pilates exercise group performed exercise for 60 minutes everyday at a frequency of 3 days per week for 8 weeks. The subjects in both groups were measured for their physical composition, isokinetic muscular strength in legs, and body balance before and after the experiment. After 8 weeks, the pilates exercise group's body composition showed significantly increased muscular amount (p <.01). There was a statistical increase in knee joint muscle function. For the right knee joint and left knee joint, right knee joint extensor muscle's maximum muscular strength and total work significantly increased under conditions of $60^{\circ}/sec$ (p<.05). Under conditions of $180^{\circ}/sec$, there were statistically significant increases in left knee joint flexor muscle's maximum muscular strength (p<.05). For balance, balance of both legs and right leg showed statistically increases (p<.05).