• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3833-3838
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• 2009

This paper introduces a measurement system for mechanical properties of sport shoes using an industrial robot. The robot system used in this paper is a commercial Puma type robot system(FARA AT2 made by SAMSUNG Electronics) with 6 joints and the end-effector is modified to produce a human walking motion. After analyzing human walking with a high speed video camera, each joint angle of the robot system is extracted to be used in the robot system. By using this system, ground impact forces were measured during stepping motion with 3 different shoe specimens made of 3 different hardness outsoles, respectively. As other mechanical properties, both bending moments to bend the toe part of the same specimen shoes and pronation quantities during walking motion were measured as well. In the impact test with the same depth of deformation under the ground level, the effect of the outsole hardness was clearly appeared such that the harder outsole produces the higher ground reaction force. The bending test and the pronation test also show proportional increments in the bending stiffness and the moment Mx according to the outsole hardness. Throughout such experiments, the robot system has produced consistent results so that the system could be used in obtaining valuable informations for a shoe designing process.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.167-177
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• 2009

The purpose of this study was to investigate effect of golf shoe design on kinematic variables during golf swing. Five professional male golfers with shoe size 270mm were recruited for the study. Swing motion was collected using 8 high speed camera motion analysis at a sampling of 180Hz. Kinematic variables were calculated by EVaRT 4.2 software. Driver swing was divided into four events; El(adress), E2(top), E3(impact) and E4(finish). Time, peak velocity, velocity of center of mass, velocity of the foot and ankle angle during Phase 1(El-E2), Phase 2(E2-E3), and Phase 3(E3-E4) were analyzed in order to investigate the relationship between golf shoe design and swing performance. The findings indicated that type C golf shoes would be beneficial for stability and control of movement during address and swing performance. Furthermore, faster speed of golf shoes, center of mass, and both feet were observed with Type C golf shoes. It is expected that golfers with Type C golf Shoes provide greater force as they control the center of mass faster and increase rotational force during impact compared to other golf shoes.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.397-403
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• 2011

The purpose of this study is to analyze the immediate effects of five toed shoes on foot structure. Subjects consisted of 26 college-aged women with pes planus. X-ray analysis of student feet were performed both barefooted and with five toed shoes. Dependent variables were hallux valgus angle, calcaneal inclination angle, 1st metatarsal declination angle, and intermetartarsal angle. Independent t-test was used for statistical analysis along with SAS. Overall, there were statistically significant changes of test subject's dependent variables when wearing five toed shoes. Specifically, the hallux valgus angle decreased, the calcaneal inclination angle and 1st metatarsal inclination angle increased, and intermetatasal angles both increased and decreased, shifting towards normal range. In every case the dependent variables shifted towards a more normal range while subjects wore five toed shoes. This study only examined the immediate corrective effects of five toed shoes on foot structure, but long-term studies are needed to understand the prolonged effects of five toed shoes on foot structure.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1210-1215
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• 2016

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.89-97
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• 2008

The purpose of this study was to analyze the foot-pressure distribution of Tennis Shoes for assessing their functionality. 10 university male students (shoe size: 265mm) who had no history of injury in the lower extremity and a normal gait pattern participated in this study. Four types of tennis shoes, most popular in Korea (A, B, C & D company), were selected and tested. Using the PEDAR-X system and PEDAR-X insoles, 4 different motion stages were analyzed for the foot-pressure distribution: (a) straight running; (b) c-cut($45^{\circ}$ left turn running; (c) forehand stroke; and (d) backhand stroke. Results revealed that in all stages, there were no statistically significant differences among the types of shoes; however, descriptive statistics indicated that functionality of shoe types was somewhat different depending on the type of stages. The order in functionality found was C>A>B>D.

• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.193-205
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• 2006

This study was to analysis the kinematic and kinetic differences between new walking shoe(NWS : RYN) and general walking shoe(GWS). The subjects for this study were 10 male adults who had the walking pattern of rearfoot shrike with normal foot. The movement of one lower leg was measured using plantar pressure and Vicon Motion Analysis Program(6 MX13 and 2 MX40 cameras : 100 f / s) while the subjects walked at the velocity(1.5m/s. on 2m).. The results of this study was as follows : 1. The NWS was better than the GWS that caused injuries such as adduction, abduction and pronation are reduced While walking on a perpendicular surface, the landing angle and the knees angles were extensive which makes walking more safe which reduces anxiety and uneasiness. 2. The bottom of the NWS were now made into a more circular arch which supports the weight of the body and reduces the irregular angles when wearing GWS. This arch made the supporting area more wide which made the upholding the trunk of the body more effective. The whole bottom of the foot that supports the weight is more flexible in addition, increases the safeness of walking patterns and the momentum of the body. 3. The moment the heel of the foot of the NWS touch the ground, the range of the pressure were partially notable and the range of the pressure on the upper part of the thigh were dispersed The injuries that occurred while walking. primary factors when a shock related injuries are reduced Judgements of the impacts of the knees and the spinal column dispersing could be made.

• Korean Journal of Applied Biomechanics
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• v.15 no.3
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• pp.1-7
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• 2005

Excessive pronation and impact force during running are related to various running injuries. To prevent these injuries, three type of running shoes are used, such as cushioning, stability, and motion control. Although there were may studies about the effect of midsole hardness on impact force, no study to investigate biomechanical effect of motion control running shoes. The purpose of this study was to determine biomechanical difference between cushioning and motion control shoes during treadmill running. Specifically, plantar and rearfoot motion, impact force and loading rate, and insole pressure distribution were quantified and compared. Twenty male healthy runners experienced at treadmill running participated in this study. When they ran on treadmill at 3.83 m/s. Kinematic data were collected using a Motion Analysis eight video camera system at 240 Hz. Impact force and pressure distribution data under the heel of right foot were collected with a Pedar pressure insole system with 26 sensors at 360 Hz. Mean value of ten consecutive steps was calculated for kinematics and kinetics. A dependent paired t-test was used to compare the running shoes effect (p=0.05). For most kinematics, motion control running shoes reduced the range of rearfoot motion compared to cushioning shoes. Runners wearing motion control shoe showed less eversion angle during standing less inversion angle at heel strike, and slower eversion velocity. For kinetics, cushioning shoes has the effect to reduce impact on foot obviously. Runners wearing cushioning shoes showed less impact force and loading rate, and less peak insole pressure. For both shoes, there was greater load on the medial part of heel compared to lateral part. For pressure distribution, runners with cushioning shoes showed lower, especially on the medial heel.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.189-195
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• 2007

The purpose of this study was to analyze the effects of shoes with curved out-sole on the pressure, reaction force(sum of pressure) on foot and relations between the rolling speeds and pronation of foot. The foot pressure, reaction force and pressure center on the foot surface of shoe were measured with NOVEL padar system, and 3 type shoes were used to compare the position and speed of pressure center and the foot reaction force, which were s(target) shoe with soft cushions in middle part of out-sole and curved out-sole, m shoes with two type- soft, hard, hardness out-sole and curved out-sole and n shoes with flat out-sole. The subjects were 13 female university students, had weared the 3 type shoes for 6 weeks on two-weeks shifts for adaptation before experiment and put on 3-type shoes repeatedly and randomly and walked on treadmill with 3.5km/h and 80 steps/min. The data were captured with 30Hz and readjusted with 5kgf threshold reaction force. The results can be summarized as follow. 1. There were no difference in maximum reaction force on initial contact period and total foot impact, but statistical difference in maximum reaction force on takeoff period : s, m, n in ascending order. 2. There were some difference in rolling speeds for support periods. At initial contact, the rolling speed of s shoes was fastest but at periods between first and second maximum reaction force, that of m shoes fastest. 3. There was a negative relation between rolling speeds and the length of lever arm on initial reaction force related to pronation. It seems shoes with various curved shapes and hardness could make effects on the rolling features and the rolling speed also have some relationships with walking efficiency, absortion of impact and pronation.

• 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.

• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.153-168
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• 2005

The purposes of this study were to determine the influence of midsole hardness and sole thickness of sports shoes on ball flex angle and position with increment of running velocity. The subjects employed for this study were 10 college students who did not have lower extremity injuries for the last one year and whose running pattern was rearfoot striker of normal foot. The shoes used in this study had 3 different midsole hardness of shore A 40, shore A 50, shore A 60 and 3 different sole thickness of 17cm, 19cm, 21cm. The subjects were asked to run at 3 different speed of 2.0m/sec, 3.5m/sec, 5.0m/sec and their motions were videotaped with 4 S-VHS video cameras and 2 high speed video cameras and simultaneously measured with a force platform. The following results were obtained after analysing and comparing the variables. Minimum angle of each ball flex position were increased with the increment of running velocity and shoe sole thickness(P<0.05), but mid-sole hardness did not affect minimum ball flex angle. The position which minimum angle was shown as smallest was 'D'. Midsole hardness and sole thickness did not affect time to each ball flex minimum angle, total angular displacement of ball flex angle, and total angular displacement of torsion angle(P<0.05). The position which minimum angle was appeared to be earliest was similar at walking velocity, and E and F of midfoot region at running velocity. Total angular displacement of ball flex position tended to increase as shifted to heel. It was found that running velocity had effects on ball flex angle variables, but shoe sole thickness partially affected. It would be considered that running velocity made differences between analysis variables at walking and running when designing shoes. Also, it was regarded that shoes would be developed at separated region, because ball flex angle and position was shown to be different at toe and heel region. It is necessary that midsole hardness and thickness required to functional shoes be analyzed in the further study.