• 대한미세수술학회:학술대회논문집
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• 1998.11a
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• pp.193-193
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• 1998

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.495-501
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• 2011

The purpose of this study was to develop the inertial sensor module system to detect gait event using single angular rate sensor(gyroscope), and evaluate the accuracy of this system. This sensor module is attached at the heel and gait events such as heel strike, foot flat, heel off, toe off are detected by using proposed automatic event detection algorithm. The developed algorithm detect characteristics of pitch data of the gyroscope to find gait event. To evaluate the accuracy of system, 3D motion capture system was used and synchronized with sensor module system for comparison of gait event timings. In experiment, 6 subjects performed 5 trials level walking with 3 different conditions such as slow, preferred and fast. Results showed that gait event timings by sensor module system are similar to that by kinematic data, because maximum absolute errors were under 37.4msec regardless of gait velocity. Therefore, this system can be used to detect gait events. Although this system has advantages of small, light weight, long-term monitoring and high accuracy, it is necessary to improve the system to get other gait information such as gait velocity, stride length, step width and joint angles.

• Horticultural Science & Technology
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• v.16 no.1
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• pp.33-36
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• 1998

This study was carried out to examine the effects of cutting dates and rooting promoters on rooting of the Rhododendron mucronulatum Turcz. The rooting percentage in greenwood cutting was high in June and decreased after July 3, when reproductive growth began. The best rooting percentage(92.5%) occurred when cutting was completed on June 12. There was no difference in rooting potentials between the greenwood straight cutting and the greenwood heel cutting. Cuttings of R. mucronulatum for. albiflora showed high rooting percentage(85%) similar to the cuttings of R. mucronulatum. Dipping cuttings in NAA $2,000mg{\cdot}L^{-1}$ solution for 15 sec increased the rooting percentage up to 97.5%, and also promoted root growth.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.2
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• pp.93-102
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• 2016

PURPOSE: The purpose of this study is to evaluate the functional effects of action observation plus functional electrical stimulation (FES) treatment on the weight distribution indexes (heel and toe; right and left), stability indexes, gait velocities, and stride lengths of stroke patients. METHODS: The subjects, who were all more than six months post stroke, were randomly divided into two groups of ten each: an experimental group and a control group. TETRAX (Tetrax Interactive Balance System) and GAITRite (GAITRite$^{TM}$ computerized gait analysis system) were measured at baseline, six weeks after treatment. Participants in both the groups received functional electrical stimulation treatment, but the experimental group was provided with additional action observation. Independent t-tests were used to compare the differences between the groups, and repeated measured two-way ANOVA was used to compare the interaction between the groups. RESULTS: The result of the interactions between the groups and the periods showed significant increases in the weight distribution indexes (heel and toe; right and left), stability indexes, gait velocities and stride lengths (p<0.05). However, a comparison between the groups showed no significance in the weight distribution indexes (heel and toe), stability indexes, and stride lengths (p>0.05). CONCLUSION: Action observation plus functional electrical stimulation treatment should be considered as a therapeutic method for physical therapy for stroke patients to improve the weight distribution indexes, stability indexes, gait velocities, and stride lengths.

• Fashion & Textile Research Journal
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• v.20 no.1
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• pp.75-82
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• 2018

This study was attempted to clarify differences in sizes and shapes of foot between 20's and 60-70's women and analyzed the characteristics of elderly women's foot shapes as compared with those of young. The 2D data were 101 elderly and 101 young women in Seoul and Gyeonggi-do. The results are as follows: Firstly, the foot length of the elderly was shorter than that of the young, the foot breadth and the heel width were widened, but the toes breadth became smaller and the deformity of the toe 1 and the first metatarsal part appeared. Secondly, in the Foot Index, there was a significant difference in age group, the young is more than the elderly in the narrow type, standard type, the elderly women showed more than three times the young in the wide type. Thirdly, in the factor analysis for the foot type classification, 'foot length' factors in both age groups were large. Next, young group were influenced by 'toes breadth', lateral ball breadth' factors, elderly group was influenced by the 'lateral ball breadth', 'medial ball breadth' factors. Lastly, in the cluster analysis of the elderly group, the types of sole were classified as W-Type(20.8%, wide foot and toes, large heel), H-type(20.8%, small toes breadth, heel), D-type(31.7%, long length and wide lateral ball) and A-Type(26.7%, which is found only in the elderly, small length and large toes angle). As a result, it is necessary to design the shoes that match the characteristics of the soles of the elderly women.

• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.289-293
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• 2004

In the present study, knee varus torque and mediolateral accelerations were measured using the three-dimensional motion analysis system and a linear accelerometry in odor to determine the effect of heel wedges during walking. Wedges were inclined with 10$^{\circ}$ and 15$^{\circ}$ in medial and lateral directions respectively Both knee varus torques and mediolateral accelerations showed two distinct positive peaks in loading response and preswing. Medial wedges resulted in significantly increased both knee varus torque and lateral acceleration in loading response, compared with the barefoot walking(p<0.05). On the other hand, lateral wedges decreased them in loading response(p<0.05). This became more significant for more inclined wedges. However, no significant correlations were found between knee varus torque and lateral acceleration according to the angle of heel wedges in preswing. From this study, it was found that a lateral wedge would be helpful to treat osteoarthritis, decreasing knee varus torque in loading response. In addition, lateral acceleration of the knee joint might be an alternative to determine the effect of wedges and the alignment of the knee joint during walking, instead of measuring knee torque by the three-dimensional motion analysis.

• Journal of Korean Orthopaedic Sports Medicine
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• v.9 no.2
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• pp.121-124
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• 2010

In athletes, repetitive low-energy impacts in plantar lesion lead often to tendinitis, stress fracture, or overuse syndrome. The major cause of heel pain in athletes is plantar fasciitis. And it is most often attributable to repetitive low energy impact, but the vast majority patients with heel pain achieve symptomatic relief with conservative treatment and return to full activities. Not commonly, Nerve entrapment may be occurred from repetitive low energy trauma in athletes, and is not as easily diagnosed. The authors observed a basketball player who complained of chronic heel pain that do not respond to conservative treatment, he had the lesions both plantar fasciitis and lateral plantar nerve entrapment. The authors described an unusual mechanism of entrapment of the lateral plantar nerve combined with a chronic plantar fasciitis in a basketball player and reported with review of literature.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.515-528
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• 1995

Slips and falls are the major causes of the pedestrian injuries in the industry and the general community throughout the world. With the awareness of these problems, the friction coefficients of the interface between floorings and footwear have been measured for the evaluation of slip resistant properties. During this measurement process, the surface texture has been shown to be substantially effective to the friction mechanism between shoe heels and floor surfaces under various types of walking environment. Roughness, either of the floor surface or shoe heels, provides the necessary drainage spaces. This roughness can be designed into the shoe heel but this is inadequate in some cases, especially a wear. Therefore, it is essential that the proper roughness for the floor surface coverings should be provided. The phenomena that observed at the interface between a sliding elastomer and a rigid contaminated floor surface are very diverse and combined mechanisms. Besides, the real surface geometry is quite complicate and the characteristics of both mating surfaces are continuously changing in the process of running-in so that a finite number of surface parameters can not provide a proper description of the complex and peculiar shoe - floor contact sliding mechanism. It is hypothesised that the interface topography changes are mainly occurred in the shoe heel surfaces, because the general property of the shoe is soft in the face of hardness compared with the floor materials This point can be idealized as sliding of a soft shoe heel over an array of wedge-shaped hard asperities of floor surface. Therefore, it is considered that a modelling for shoe - floor contact sliding mechanism is mainly depended upon the surface topography of the floor counterforce. With the model development, several surface parameters were measured and tested to choose the best describing surface parameters. As the result, the asperity peak density (APD) of the floor surface was developed as one of the best describing parameters to explain the ambiguous shoe - floor interface friction mechanism. It is concluded that the floor surface should be continuously monitored with the suitable surface parameters and kept the proper level of roughness to maintain the footwear slip resistance. This result can be applied to the initial stage of design for the floor coverings.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.165-172
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• 2006

The purpose of this study was to determine effects of 12-week wearing of unstable shoe on the standing posture and gait mechanics. Nine healthy men were asked to wear the unstable shoes for 12-week and walk for 30 minute everyday. Their standing posture and gait mechanics were measured before and after treatment. Standing posture was measured for each side(anterior, posterior, lateral) for standing position. And gait analysis was measured joint angle of a right lower limb between first right heel contact and second right heel contact. Kinematic data were collected using video camera at 30 frame per seconds. Statistical analysis was paired t-test(p<.05) to compare before training with after that. A head tilt angle was significantly decreased for posterior side(p<.05). The angle of between center of line and surface was significantly decreased at midstance and take off during walking(p<.05). Ankle dorsiflexion significantly increased at heel contact2(p<.05) and ankle plantarflexion significantly increased at midstance and midswing(p<.05). The increase of ankle dorsiflexion showed that our results consisted with previous study. In conclusion, there was not large significant difference in static standing posture but joint angle of lower limb represented many changes with increasing of ankle motion during walking. These were of benefit to body by increasing leg muscle activity but it was necessary for man having a ankle problem to consider. Further studies concerning optimum outsole angle of unstable shoes are necessary.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.3
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• pp.165-175
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• 2008

An ankle-foot orthosis(AFO) is a brace for persons with gait disabilities to support or replace the function of ankle joint. Ankle-foot orthoses(AFO's) are usually prescribed to alleviate the drop-foot by constraining the excessive plantar flexion. The shape and the strength of the AFO are often based on 'trial and error' due to a lack of knowledge of the stress distribution in the AFO. In this study, an improved stress-freezing method was proposed to measure the stress distribution characteristics in the AFO. As a result, a photoelastic material with low freezing temperature was developed to measure the stresses under a person's direct contact loading condition. The three-dimensional stress-1rozen photoelastic models of AFO's for five stages of stance phase such as heel contact, foot flat, mid stance, heel off, and toe off were produced. The results of photoelastic analysis revealed that the stresses developed in the AFO were varied considerably from tensile to compressive or vice versa, during walking. At the posterior part of ankle joint in the AFO, the maximum compressive stress of 1.81MPa was observed in the mid stance, and the maximum tensile stress of 0.74MPa was observed during heel contact. The overall stress levels in the AFO's were low in the toe off phase. The results suggested that the posterior part of ankle joint might be the most fragile part in the AFO.