• Journal of Biomedical Engineering Research
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• v.28 no.5
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• pp.647-656
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• 2007

The purpose of this study was to analyze the effects of vibratory stimulus as somatosensory inputs on the postural control in human standing. To study these effects, the center of pressure(COP) was observed while subjects were standing on a stable and an unstable support with co-stimulated mechanical vibrations to flexor ankle muscles(tibialis anterior tendon, achilles tendon) and two plantar zones on both foot. The COP sway measurement was repeated twice in four conditions: (1) with visual cue and vibration, (2) without visual cue and vibration, (3) with visual cue and without vibration, (4) without visual cue and with vibration. The calculated parameters were the COP sway area and the distance, the median frequency and the spectral energy of COP sway in three intervals $0.1{\sim}0.3,\;0.3{\sim}1,\;1{\sim}3Hz$. The results showed that vibratory stimulus affect postural stability. The reduction rate of the COP sway with vibratory stimulus were higher on the unstable support because the effect of postural stability increases when afferent nervous flow is more activated by vibration on unstable support. If unclear visual or vibratory information is received, one type of information is compared with the other type of sensory information. Then the input balance between visual and vibratory information is corrected to maintain postural stability. These findings are important for the rehabilitation system of postural balance control and the use of vibratory information.

• Physical Therapy Rehabilitation Science
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• v.5 no.3
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• pp.149-154
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• 2016

Objective: The arm swing is associated with gait ability in healthy young adults. The purpose of this study was to examine the effects of arm swing during gait in healthy young adults. Design: Cross-sectional study. Methods: Forty-five subjects without any orthopedic or neurological injuries participated in this study. All subjects performed all three conditions according to the arm swing type as follows: first procedure (condition 1), walking as usual without arm swing constraint; second procedure (condition 2), constraint of dominant arm swing walking as usual; third procedure (condition 3), constraint of both arm swing walking as usual. Gait parameters such as gait velocity, stride length, cadence, step time, single limb support, and double limb support were measured in all arm swing conditions performed randomly, with the mean value obtained from three measurements. A rest period of 5 minutes was given to prevent repetition of each condition and learning effect. All data was analyzed using repeated measures ANOVA to notice the changes between arm swing conditions. Results: Within walking conditions, significant difference of gait velocity, stride length, cadence, and double limb support was noticed (p<0.05), except step time and single limb support. Gait velocity and stride length were significant reduced, and in cadence and double limb support were increased (p<0.05). Condition 3 had the most significant decrease of gait ability compared with condition 1 (p<0.05). Conclusions: These finding suggested that constraint arm swing conditions reduced gait ability in healthy young adults. Also, these findings can be utilized as a reference to future studies that not only pelvic, knee and ankle, but also upper limb affect to gait ability.

• Journal of Korean Foot and Ankle Society
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• v.14 no.2
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• pp.177-181
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• 2010

Purpose: The author evaluated the clinical and radiological results after wearing the medial arch supports in children. Materials and Methods: 103 patients who had symptomatic flat feet were evaluated from march, 2002 to may 2009. All patients wore the medial arch supports according to the symptoms. We measured parameters at weight-bearing radiographs before and after medial arch support were worn. We also evaluated the clinical scores using the AOFAS score. Results: Mean age of patients was 97 months (11-204 months), all foot of patients involved bilaterally. Mean talo-first metatarsal angle of right foot was $17.7{\pm}9.4$ and left foot was $19.96{\pm}9.5$ degrees at AP radiograph in pre-wearing state. Mean calcaneal pitch angle of right foot was $12.0{\pm}5.3$ and left foot was $11.9{\pm}5.8$ degrees at lateral radiograph in pre-wearing state. Mean talo-first metatarsal angle of right foot was $14.4{\pm}8.05$ and left foot was $13.1{\pm}8.77$ degrees at AP radiograph in post-wearing state. Mean calcaneal pitch angle of right foot was $16.4{\pm}5.75$ left foot was $16.5{\pm}5.6$ degrees at lateral radiograph in post-wearing state. The radiographic angles between pre-wearing and post-wearing state were statistically significant (p<0.05). Mean pre-wearing AOFAS hindfoot score was $66.7{\pm}9.25$, midfoot score was $60.0{\pm}9.34$ forefoot score was $57.1{\pm}11.8$. Mean post-wearing AOFAS hindfoot score was $73.2{\pm}9.73$, midfoot score was $68.1{\pm}10.1$, forefoot score was $67.2{\pm}11.4$. The forefoot score was highest improving scores among the AOFAS scores. Conclusion: From our study, we concluded that medial arch support was effective for symptomatic flat feet of children in radiological and clinical results from our study.

• The Journal of Korean Physical Therapy
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• v.21 no.2
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• pp.87-95
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• 2009

Purpose: This study reports the basic reference data of the specific gait parameters for Korean normal adults. Methods: The basic gait parameters were extracted from 73 Adults (35 men and 38 women), 18 to 33 years of age, using a Vicon MX motion analysis system. The segment kinetics, such as joint moment and power, was analyzed at the hip, knee and ankle. Results: The motion patterns are typically associated with a specific phase of the gait cycle. The temporal-spatial gait parameters of Korean normal adults, such as cadence, walking speed, stride length, single support and double support, were similar to the other western reference data. The kinetic parameters of Korean normal adults, such as joint moments of force, joint mechanical power generation or absorption and ground reaction forces, were also similar to other western reference datasets. Conclusion: This study demonstrates that objective gait analysis can be used to document the gait patterns of normal healthy adults. The techniques of 3-dimensional temporal-spatial gait parameters and kinematic parameters analysis can provide a detailed biomechanical description of a normal and pathological gait.

• Korean Journal of Applied Biomechanics
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• v.20 no.2
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• pp.129-137
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• 2010

The purpose of this study is to investigate the effect of a 12-week aquatic exercise on obstacle gait in older women. Originally, 20 healthy female elderly participated this study but 12 of them completed the program. All participants were trained in the aquatic exercise program by an authorized trainer. They had come to the authors' lab three times during training period(0, 6, 12 weeks) and performed obstacle gait with three different height(0, 30, and 50% of leg length). After performed 3-Dimensional motion analysis following results were found. (1) For the CV, MVHC, TC, HC, statistically significances were shown in obstacle height. Although significant training effects were not shown, all variables showed typical patterns and it was considered as efficient motion to overcome the height obstacles. (2) The anterior-posterior and vertical GRF of support leg during support phase were revealed in height effect but in training one. However, differences between Peak 1 and Peak 2 in vertical GRF increased as training period increased. (3) Knee and hip resultant joint moments were affected by training but ankle resultant moments remained unchanged.

• Journal of the Ergonomics Society of Korea
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• v.32 no.3
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• pp.245-252
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• 2013

Objective: This paper analyzes the changes on stride parameters, joint angles, and trajectories of the body parts due to high heels during walking and explains the causal relationship between the changes and high heels. Background: This study aims to indicate the comprehensive gait changes by high heels on the whole body for women wearing high heels and researchers interested in high-heeled walking. Method: The experiment was designed in which two different shoe heel heights were used for walking (1cm, 9.8cm), and twelve women participated in the test. In the experiment, 35 points on the body were tracked to extract the stride parameters, joint angles, and trajectories of the body parts. Results: Double support time increased, but stride length decreased in high-heeled walking. The knee inflexed more at stance phase and the spine rotation became more severe. The trajectories of the pelvis, the trunk and the head presented outstanding fluctuations in the vertical direction. Conclusion: The double support time and the spine rotation were changed to compensate instability by high heels. Reduced range of motion of the ankle joint influenced on the stride length, the knee flexion, and fluctuations of the body parts. Application: This study can provide an insight of the gait changes by high heels through the entire body.

• Fashion & Textile Research Journal
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• v.2 no.5
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• pp.430-436
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• 2000

The purpose of the study was to obtain the basic data on the self-adjusting ability of the support panty stockings. Ten healthy women in the twenties were selected as subjects and clothing pressure of 9 support panty stockings made of single covered yarn (SCY) and double covered yarn (DCY) were measured under the standard environmental condition for the study. Data was analysed statistically according to body postures, sides, and parks. The results were as follows: Clothing pressure according to body posture was order of 'sitting-on-a-chair', 'stepping-up-a-stair', and 'standing'. High clothing pressure was obtained in the parts of calf ($9.4gf/cm^2$) in 'standing' and knee (9.7 and $16.5gf/cm^2$) in both 'stepping-up-a-stair' and 'sitting-on-a-chair', respectively. The order of clothing pressure with body sides was 'front', 'side', and 'back'. The highest clothing pressure was knee ($18.8gf/cm^2$) on the front, thigh ($8.8gf/cm^2$) on the side, and calf ($6.4gf/cm^2$) on the back. Clothing pressure of DCY at abdomen and knee was a little higher than those of SCY 3. In terms of material structure variation, clothing pressure of thigh, calf and ankle with SCY was a little higher than those with DCY, while clothing pressure of abdomen and knee with DCY was a little higher than those with SCY.

• Journal of Acupuncture Research
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• v.30 no.1
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• pp.35-41
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• 2013

Objectives : This study aimed to perform descriptive analysis on demographic characteristics and symptom distribution of 199 marathon participants in Pusan, Korea. Methods : Brief medical charts of 199 marathon participants in 11 marathon rallies who had visited the emergency medical support team of Korean Medicine Hospital, Pusan National University were collected. Participants' demographic and clinical characteristics were descriptively analyzed. Results : More than two third of participants who have visited the support team was male(71.9 %) and their mean age was 44.0(years). The main intervention was manual acupuncture with vigorous stimulation techniques. Most of treated symptoms were lower extremity pain(77.0 %). Knee pain was the most frequently recorded symptoms, following the ankle pain. No information on the safety of acupuncture treatments were reported in the records. Conclusions : Symptom distribution of marathon participants who have visited the emergency medical support team of Korean Medicine Hospital was similar to previous literatures of acute injuries of marathon athletes and runners. The role of acupuncture for emergency support care of acute injuries in marathon participants should be further explored in well-designed clinical studies.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.9
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• pp.886-892
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• 2008

In this paper, a closed-loop observer to extract the center of mass (CoM) of a bipedal robot is suggested. Comparing with the simple conversion method of just using joint angle measurements, it enables to get more reliable estimates by fusing both joint angle measurements and F/T sensor outputs at ankle joints. First, a nonlinear-type observer is constructed to estimate the flexible rotational motion of the biped in the extended Kalman filter framework. It adopts the flexible inverted pendulum model which is appropriate to address the flexible motion of bipeds, specifically in the single support phase. The predicted estimates of CoM in terms of the flexible motion observer are combined with measurements (that is, output of the CoM conversion equation with joint angles). Then, we have final CoM estimates depending on the weighting values which penalize the flexible motion model and the CoM conversion equation. Simulation results show the effectiveness of the proposed algorithm.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.55-62
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• 2010

In this paper, the structure of a new gravity compensator was studied, and the biped walking robot applying a gravity compensator was presented to improve the performance of the robot. The robot had 13 degree of freedom and is driven by the joint actuator with the gravity compensator. Each leg of the robot is composed of six joints three joints at the hip, a joint at the knee, and two joints at the ankle. The leg of the robot was designed to support 74kg weight including 30kg payload thanks to the gravity compensator. The performance of the robot was presented by reducing the payload applied to the leg joint of the robot thanks to the gravity compensator.