• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.25-29
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• 2011

The purpose of this study was to analyze quantitative and qualitative differences according to shoe type for the grand jete landing in ballet. The subjects for this study were 9 female ballet majors with an average of 12 years of experience. Subjects jumped, performing a front split, and landed on 1 foot, a movement called the grand jete. Analysis was performed on the students' landing. Independent variables were 3 shoe types: split sole, traditional out sole, and 5-toed forefoot shoes, with bare feet as a control group. Dependent variables were vertical passive ground reaction force and qualitative elements. Passive ground reaction force variables(maximum passive peak value, number of passive peaks, passive force-time integral, and center of pressure) were measured by the Kistler 9281B Force Platform. Qualitative elements were comfort, cushioning, pain, and fit. Statistical analysis included both 1-way ANOVA and Tukey's test for follow-up. Finalized data demonstrated that the 5-toed forefoot shoe allows the forefoot to expand and the toes to individually press down upon landing, increasing foot contact with the surface. Five-toed forefoot shoes minimize passive peaks and pain, while increasing comfort, cushioning, and fit. Most ballet movements are composed of jumping, balancing, landing, and spinning. Wearing 5-toed forefoot shoes allows for a natural range of movement in each toe, to improve both technique and balance. Pain and injuries from ballet can be minimized by wearing the correct shoe type. According to this analysis, it is possible to customized ballet shoes to increase the efficiency of techniques and movements.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.4
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• pp.427-439
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• 2014

This study identifies the foot side shapes of elderly men by classifying foot types according to 3D foot shapes and analyzing individual characteristics. The subjects were 284 elderly men over 60 years of age who lived in Gwangju and did not have foot related diseases. They were measured with a scanner (Nexcan$^{(R)}$ of K&I Technology) to obtain three dimensional feet shapes. Anthropometric measuring items consisted of 28 items estimated on the right foot of each subject. 3D scan data were analyzed by various statistical methods such as factor analysis, ANOVA and cluster analysis using the statistical program SPSS 19.0. A total of 7 factors were extracted through a factor analysis and these factors represent 77.56% of total variance. The 8 factors were: inside height and side gradient, ankle thickness, size from foot center to ankle, lateral malleolus height, forefoot height, instep and heel height and gradient. A total of 3 clusters (as foot type) were categorized using 7 factor scores by cluster analysis. Type 1 was classified as high forefoot and low midfoot compared to the length. Type 2 was classified as low forefoot and high midfoot, and type 3 was classified as low forefoot and low midfoot.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.3
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• pp.305-320
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• 2014

This study identifies the foot shapes of elderly women by classifying foot type according to the 3D shape of the foot and 2D sole type analyzing individual characteristics. The subjects were 295 elderly women over 60 years of age who live in Gwangju. A foot scanner (K&I Technology $Nexcan^{(R)}$) was used to obtain three-dimensional shapes of feet and a flat bad scanner (HP Scanjet G2410) was used to obtain the two-dimensional shapes of soles. The anthropometric measuring items consisted of 59 items estimated on the right foot of each subject. Data were analyzed by various statistical methods such as factor analysis, ANOVA and cluster analysis using the SPSS 19.0 statistical program. To classify the side type of elderly women's feet, three-dimensional measurement data were analyzed for the 27 measurement items using factor analysis and 6 factors were extracted (inside height and side gradient, ankle thickness, toe height and midfoot size, lateral malleolus height, instep, and heel height and gradient). A cluster analysis resulted in three types: 36.5% belonged to Type 1 (high forefoot and high midfoot), 31.1% belonged to Type 2 (high forefoot and low midfoot), and 32.4% belonged to Type 3 (low forefoot and high midfoot). The distribution was relatively even. For the sole, 8 factors were extracted (ball width and medial foot protrusion, lateral foot protrusion, forefoot and hindfoot length ratio, ball gradient, heel size, toe breadth, lateral ball length, and foot length) and a cluster analysis resulted in three Types (Type H, Type D, and Type A). The largest proportion (42.7%) belonged to Type H, which is the same as the elderly men's case.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1810-1814
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• 2017

This paper develops an approach to the algorithm of Gait pattern Analysis and step measurement with Multi-Pressure Sensors. The process of gait consists of 8 steps including stance and swing phase. As 3 parts of foot is supporting most of human weight, multiple pressure sensors are attached on the parts of foot: forefoot, big toe, heel. As 3 parts of foot is supporting most of human weight, multiple pressure sensors are attached on the parts of foot: forefoot, big toe, heel. normal gait proceed from heel, forefoot and big toe over time. While normal gait proceeds, values of heel, forefoot and big toe can be changed over time. So Each values of pressure sensors over time could discriminate whether it is normal or abnormal gait. Measuring Device consists of non-inverting amplifiers and low pass filter. Through timetable of values, normal gait pattern can be analyzed, because of supported weight of foot. Also, the peak value of pressure can judge whether it is walking or running. While people are running, insole of shoes is floating in the air on moment. Using this algorithm, gait analysis and step count can be measured.

• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.9-16
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• 2011

The purpose of this study is to analyze the effects of both various shoe types and bare feet on ground reaction force while walking. Ten first-year female university students were selected. A force platform(Kistler, Germany) was used to measure ground reaction force. Six types of shoe were tested: flip flops, canvas shoes, running shoes, elevated forefoot walking shoes, elevated midfoot walking shoes, and five-toed shoes. The control group was barefooted. Only vertical passive/active ground reaction force variables were analyzed. The statistical analysis was carried out using the SAS 9.1.2 package, specifically ANOVA, and Tukey for the post hoc. The five-toed shoe had the highest maximum passive force value; while the running shoe had the lowest. The first active loading rate for running shoes was the highest; meanwhile, bare feet, the five-toed shoe, and the elevated fore foot walking shoe was the lowest. Although barefoot movement or movement in five toed shoes increases impact, it also allows for full movement of the foot. This in turn allows the foot arch to work properly, fully flexing along three arches(transverse, lateral, medial), facilitating braking force and initiating forward movement as the tendons, ligaments, and muscles of the arch flex back into shape. In contrast movement in padded shoes have a tendency to pound their feet into the ground. This pounding action can result in greater foot instability, which would account for the higher loading rates for the first active peak for padded shoes.

• Korean Journal of Applied Biomechanics
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• v.14 no.3
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• pp.99-118
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• 2004

The aim of this study is to evaluate tennis shoes's plantar pressure distribution in tennis prayers and to determine the influence of the shoe on various tennis movements. When investigating the biomechanics of movement in tennis, one of the first things to do is to understand the movement patterns of the sport, specifically how these patterns relate to different tennis shoes. Once these patterns are understood, footwear company can design tennis shoes that match the individual needs of tennis players. Plantar pressure measurement is widely employed to study foot function, the mechanical pathogenesis for foot disease and as a diagnostic and outcome measurement tool for many performance. Measurements were taken of plantar pressure distribution across the foot and using F-Scan(Tekscan Inc.) systems respectively. The F-Scan system for dynamic in-shoe foot pressure measurements has enabled us to assess quantitatively the efficacy of different types of footwear in reducing foot pressures. The Tekscan F-Scan system consists of a flexible, 0.18mm thick sole-shape having 1260 pressure sensors, the sensor insole was trimmed to fit the subjects' right, left shoes. For this study 4 university male, high level tennis players were instructed to hit alternated forehand stroke, backhand stroke, forehand volley, backhand volley, smash, service movement in 4 different tennis shoes. 1. When impact in tennis movement, peak pressure distribution of landing foot displayed D>C>B>A, A displayed the best low pressure distribution. A style's tennis shoes will suggest prayer with high impact. If prayer with high impact feeling during pray in tennis wear A style, it will decrease injury, will have performance improvement. 2. When impact in tennis movement, plantar pattern of pressure distribution in landing foot displayed B>A>C>D in stability performance. During tennis, prayer want to stability movement suggest B style tennis shoes when tennis movement impact keep stability of human body. B style tennis shoes give performance improvement 3. When impact in tennis movement, plantar pattern of center of force(C.O.F.)trajectory in landing foot analyzed this : 1) When stroke movement and volley movement in tennis, prayer better to rearfoot movement. 2) when service movement, prayer midfoot strike movement. 3) when smash movement, prayer have forefoot strike movement.

• Journal of Korean Foot and Ankle Society
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• v.23 no.4
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• pp.159-165
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• 2019

Purpose: This study investigated the recurrence rate after performing hallux valgus correction using scarf and Akin osteotomy, and also identified the correlation and cut-off values of both the preoperative and postoperative radiographic parameters as risk factors for the recurrence of hallux valgus. Materials and Methods: We reviewed 87 hallux valgus patients (122 feet) who received scarf and Akin osteotomy from January 2007 to August 2015. The clinical outcomes were evaluated using the visual analogue scale (VAS) and American Orthopaedic Foot and Ankle Society (AOFAS) scores. The radiological outcome measures included the hallux valgus angle (HVA), intermetatarsal angle (IMA), and distal metatarsal articular angle (DMAA) as determined on the serial weight bearing radiographs. Recurrence was defined as more than 20 degrees of HVA noted on the final follow-up radiograph. Those radiological factors associated with recurrence were evaluated and analyzed. Results: The mean follow-up duration was 20.6 months (12.0~46.5 months) and the mean age was 44 years (13~80 years). The VAS and AOFAS scores were significantly improved at the time of the final follow-up (7.0 to 2.0, p<0.001; 78.0 to 92.0, p<0.001; respectively). Significant corrections in the HVA, IMA, and DMAA were obtained (p<0.001). Eleven (9.0%: 11/122) cases experienced recurrent hallux valgus deformity. The postoperative IMA, DMAA and HVA showed significant moderate to strong correlation with HVA at the final follow-up (Pearson correlation coefficient: 0.44, 0.70, and 0.88, respectively; p<0.001). Postoperative HVA>16.7 degrees, postoperative DMAA>13.9 degrees, and postoperative IMA>8.2 degrees showed statistically significant correlation with radiological recurrence at the last follow-up, and the odds ratio of each variable was high in order. Conclusion: Our radiographic results indicated that postoperative HVA>16.7 degrees, postoperative DMAA>13.9 degrees, and postoperative IMA>8.2 degrees can be risk factors for hallux valgus recurrence. These risk factors may be helpful for modifying surgical procedures and preventing the recurrence of hallux valgus.