• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.177-195
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• 2005

The purpose of this study was to analyze the kinematic variables of ankle joints and EMG signal of the lower limbs muscle activity for the different walking speed. The subjects were 6 males of twenties. It was classified into three different walking speed-0.75m/s, 1.25m/s, 1.75m/s. The walking performances were filmed by high speed video camera and EMG signal was gained by ME3000P8 Measurement Unit. Tibialis anterior(TA), Gastrocnemius medial head(GM), Gastrocnemius lateral head(GL), Ssoleus(SO) were selected for the dorsiflexion and plantarflexion of the ankle joint. The result of this study were as follows: 1. In the gait cycle, The time parameters for the phases were showed significant difference without the terminal stance phase and terminal swing phase for the different walking speed. 2. The angle of ankle joint was no significant difference for each time point and MDF, MPF but increasing walking speed the angle had the increasing pattern slightly. 3. The angular velocity of ankle joint was showed the significant difference for LHC, RTO, RKC, LHU, MPF and MDF point along the walking speed. 4. TA was showed about 2-3 times muscle activity at the 1.75m/s than 1.25m/s in some phases. And it was showed the similar muscle activity between the 0.75m/s and 1.25m/s but, showed a little much muscle activity in the 0.75m/s. GM was showed about 2-3 times muscle activity in the 1.75m/s than 1.25m/s, and even much muscle activity at the 0.75m/s than 1.25m/s in some phases. GL was showed increasing pattern of muscle activity specially in the initial swing phase as the walking speed increased. SO was showed about 3 times muscle activity in the 1.75m/s than 1.25m/s during the plantarflexion of ankle joint. It was showed the similar muscle activity between the 0.75m/s and 1.25m/s but, showed a little much muscle activity in the 1.25m/s.

• Journal of Korean Physical Therapy Science
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• v.12 no.4
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• pp.33-41
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• 2005

The purpose of this report was to describe the gait pattern and parameters of the complicated bilateral amputee with right transtibial and left tarsometatarsal amputation. Using a Vicon 370 three dimensional gait analysis system, the gait analysis was performed at pre and post-test. Treadmill Training with 15 degree, incline was practiced for 8weeks, 3times per week. In linear parameters, the Velocity, Stride length and Single limb support were increased than pre-test. but Cadence and Double limb support were less post-test than pre-test. In kinematics, the maximal pelvic tilt angle showed right side $21.87^{\circ}$, left side $20.67^{\circ}$ at pre-swing phase, and decreased as compared with pre-test. Especially, the inimal hip flexion angle showed right side $-6.83^{\circ}$, left side $1.52^{\circ}$ at pre-swing phase and increased as compared with pre-test. The maximal knee flexion angle disclosed right side $2.66^{\circ}$, left side $21.71^{\circ}$ at stance phase, and decreased as compared with pre-test. In kinetics, the hip extension moment on initial contact stage was right side 0.938NM/Kg, left side 0.09NM/Kg, which was impaired compared with normal person.

• Physical Therapy Korea
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• v.8 no.4
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• pp.81-89
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• 2001

There are two independent mechanisms to control the segmental reflex gain in humans during gait. They are presynaptic inhibition and homosynaptic depression. Through the mechanism of the presynaptic inhibition, the muscle spindle afferent feedback can be properly gated during eccentric phase of gait. The modulation of the presynaptic inhibition is reflected in the level of H-reflex at a constant EMG level. During the eccentric muscle activation presynaptic inhibition should increase to account for the lower amplitude level of H-reflex at a constant level of EMG. Homosynaptic depression is another mechanism responsible for regulating the effectiveness of the muscle spindle afferent feedback. Both the presynaptic inhibition and the monosynaptic depression are responsible for modulating reflex gain during gait initiation. Reflex modulation is influenced not only as a passive consequence of the alpha motor neuron excitation level, but also through supraspinal mechanisms. Spastic paretic patients show the impaired soleus H-reflex modulation either during the initial stance phase, or during the swing phase. This abnormal modulatory mechanism can partially and artificially be restored by the application of peripheral stimulus to the sole of the foot, provided that the segmental circuitry remains functional.

• 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.

• PNF and Movement
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• v.18 no.3
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• pp.383-392
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• 2020

Purpose: Balance and gait dysfunction caused by aging affect elderly individuals' independent life, which, in turn, can reduce their overall quality of life. The purpose of this study is to compare the differences in the vestibular function of healthy elderly and young adults based on the subjective visual vertical (SVV) test as well as to compare and analyze the gait ability between these two groups to study the differences and association between vestibular, dizziness, and balance ability. Methods: The subjects were 18 young and 16 elderly adults with no neurological or musculoskeletal damage. To evaluate vestibular function, a subjective visual vertical test was performed. To evaluate the gait function, the step time, step length, stride length, stance phase ratio, and swing phase ratio were measured. Balance was evaluated using the Berg Balance Scale (BBS), and dizziness was evaluated using a dizziness handicap inventory (DHI). Results: There were significant differences in the SVV, BBS, and DHI between the young and elderly adults (p < 0.05). The gait variables of the older adults were all significantly different (except for the swing phase ratio) than those of the young adults (p < 0.05). As the result of correlation analysis, the SVV values of the young adults showed a significant negative correlation with step length and stride length (p < 0.05), while the SVV values of the elderly adults only showed a significant positive correlation with the DHI (p < 0.05). Conclusion: The elderly appeared to show a decrease in vestibular function when compared to the young adults, and it is thought that walking and balance function declined, while dizziness increased. Moreover, it is believed that these results can be used as basic data for vestibular rehabilitation in the future.

• Journal of Korean Physical Therapy Science
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• v.6 no.3
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• pp.25-40
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• 1999

The hub of weight bearing in the human body for both static and dynamic activities is the lumbopelvic region. It is a key region of extraordinary stability, since the trunk and ground forces converage in this region. The two sacroiliac joints form an integral part of this lumbopelvic unit. Considerable effort has been expended to study and quantify the normal range of movement of the sacroiliac joints Mitchell suggests that the ilium rotates in a posterior direction at heel strike and progresses in an anterior direction as the individual passes through the stance phase. The overall key appears to lie in determining the weight-bearing pattern of the sacroiliac (lumbopelvic) region from above and below that results in the familiar pain of sacroiliac dysfunction, assessing the status of the injured tissues, and intervening with the proper treatment protocols that maximize the body's healing processes. The purpose of this chapter is to provide a comprehensive overview of the sacroiliac joint's tissues and biomechanics, as well as concepts of evaluation and treatment. This overview is aimed at assisting the clinician in identifying the forces that are potentially destructive to the lumbopelvic tissues.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.8
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• pp.104-110
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• 2008

The aim of this study ultimately is verifying that PGO gait is more efficient than RGO fur paraplegics because the air muscle assists hip flexion power in heel off movement. The gait characteristics of the paraplegic wearing the PGO or RGO are compared with that of a normal person. PGO with air muscles was used to analyze the walking of patients with lower-limb paralysis, and the results showed that the hip joint flexion and pelvic tilt angle decreased in PGO. In comparison to RGO gait, which is propelled by the movements of the back, PGO uses air muscles, which decreases the movement in the upper limb from a stance phase rate of 79$\pm$4%(RGO) to 68$\pm$8%. The energy consumption rate was 8.65$\pm$3.3 (ml/min/Kg) for RGO, while it decreased to 7.21t2.5(ml/min/Kg) for PGO. The results from this study show that PGO decreases energy consumption while providing support for patients with lower-limb paralysis, and it is helpful in walking for extended times.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.2
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• pp.165-171
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• 2016

A prosthetic knee for above-knee (AK) amputee is categorized into passive and active type. The passive prosthetic knee is generally made by elastic material. Although AK amputee can easily walk by using passive prosthetic leg, knee joint motions are not similar to ordinary persons. The active prosthetic leg can control the knee angle owing to the actuator and microprocessor. However, the active type is not cost-effective and the stability may be lost due to the malfunction of sensors. In order to resolve these disadvantages of passive and active type, a semi-active prosthetic knee which can control the knee angle is proposed in this work. The proposed semi-active one requires a less input energy but provides active type performance. In order to achieve this goal, in this work, a semi-active prosthetic knee using magneto-rheological (MR) damper for AK amputees is designed. The MR damper can support the weight of body by using less energy than actuator of active prosthetic. It can control knee angle by inducing the magnetic field at the time of stance phase. This salient characteristic is evaluated and presented in this work.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.3
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• pp.93-98
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• 2017

PURPOSE: This study investigated the activities of lower limb muscles according to the angle of a medio-lateral ramp while walking to promote awareness of the risks associated with a medio-lateral ramp. METHODS: This study was conducted on 20 healthy male adults. The muscle activities of the vastus medialis oblique (VMO), vastus lateralis oblique (VLO), tibialis anterior (TA) and peroneus longus (PL) were measured while the subjects were walking on a 3 m medio-lateral ramp. Five angles (flat, $2^{\circ}$, $5^{\circ}$, $10^{\circ}$, and $15^{\circ}$) were selected for the angle conditions of the experiment on a medio-lateral ramp. The activities were measured during the stance phase only in the middle cycle of a three-cycle walking experiment. The mean value obtained from the three walking tests was used for the analysis. RESULTS: Results showed that walking on a mediolateral ramp required more muscle activities than walking on a flat surface, through which balanced walking was achieved. CONCLUSION: Walking on a medio-lateral ramp requires proper muscle activation and control, without which the risks of injury to the joints of the lower limbs and falls are likely to increase. Therefore, special attention should be given to older people and the disabled under the condition of traversing a ramp.

• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.47-61
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• 2002

The purpose of this study was to determined the force and moment of the ankle and the knee joint at different step length relative to the length of the lower extremity during a steady running. Six digital cameras(Qualisis) and a forceplatform(A.M.T.I) were used to obtain the kinematic data of the segments and kinetic data on the running at speed of 5.18m/s. The force and moment measured from six subjects participated in this study were limited to the support phase and their values were averaged at the moment of heel strike, mid stance, and toe off of a running for making a comparison between the condition 1(relative step length 1.1) and the condition 2(relative step length 1.4). It was concluded that internal forces except mediolateral force of the condition 2 were greater in the ankle and the knee joint than those of the condition 1, but all moments of condition 2 were greater from the descriptive statistic point of view. For the future study, it was needed to consider a number of subjects, a various running speed, and a individual step preference for applying generally results to the running strategy.