• Korean Journal of Applied Biomechanics
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• v.24 no.4
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• pp.455-461
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• 2014

The purposes of this study were to reveal the kinematic and kinetic difference of hard ground soccer shoe, firm ground soccer shoe and soft ground soccer shoe. Soccer players were shoes of varying stud designs with some preferring the bladed studs while others opting for the conventional studded stud. Statistics were used one way-ANOVA and Tukey's Honestly Significant Difference Method. Seven healthy college soccer players were attended a test. All parameters were recorded using the Zebris system. Spatio-temporal variables were no significant difference. Lateral symmetry was statistically significant differences (p<.05). Vertical GRF parameters were no significant difference. Medial midfoot pressure, lateral midfoot pressure and central forefoot pressure were statistically significant differences (p<.05). This study demonstrates that playing surface significantly affects difference soccer shoes during soccer game. Furthermore, epidemiological investigation is warranted to determine the effects of playing surfaces on sport specific injury mechanisms.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.173-180
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• 2007

The purpose of study was to compare plantar pressure during walking wearing the curved rear balance and normal shoes. Twelve university students(height: $177.2{\pm}4.6cm$, weight: $68.4{\pm}5.8kg$, age: $26.2{\pm}1.6yrs.$) who have no known musculoskeletal disorders were recruited as the subjects. Plantar foot pressures were evaluated using the Tekscan's pressure measurement systems while subjects walked upright position wearing the curved rear balance and normal shoes in random order at a speed of 1.3 m/s. The contacting dimension, the mean plantar pressure, and the peak plantar pressure were determined for each trial. For each dependent variable, paired t-test was performed to test if significant difference existed between shoe conditions (p<.05). As a result, the curved rear balanced shoes showed as large as 38 up to 50 % of area at the rear side of feet than the normal shoes when measuring the contact area with upright position. In the distribution of average pressure, the curved rear balanced shoes displayed fairly low pressure compared to other normal shoes in general except for one area, which is M2, and especially, the measured pressures at the both rear (M1) and middle (M5) side of feet were low and statically significant. The contact area of the curved rear balanced shoes when walking was significantly larger at the rear (M1) and fore (M6, M7) side of feet. When considering pressure distribution at walking, low pressure was detected at the rear side of feet with the curved rear balanced shoes and at the fore side of feet for other normal shoes. The results showed that the contacting dimension of the curved rear balance shoes that acts between shoes and feet was higher than the corresponding value for the normal shoes in general; therefore it would reduce the pressure to the feet by allowing the each sole of the foot on the ground evenly.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.581-592
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• 2009

The purpose of this study is to examine the effect of the functional shoes through the kinetic comparison of normal-design running shoes and spring-loaded running shoes. For this, 12 healthy females from the age from 30 to 40 years participated in the EMG and ground reaction force experiment with testing kinetic variables. 12 subjects walked at the velocity of 1.7m/s. After analyzing variables in the spring-loaded running shoes and normal-design running shoes, the following conclusions were obtained; For the ground reaction force, spring-loaded running shoes have larger antero-posterior GRF than normal-design running shoes in the first and second apexes of antero-posterior ground reaction force. For the analysis of EMG, spring-loaded running shoes showed the higher muscle activation of rectus femoris muscle than norma-design running shoes. So the spring-loaded running shoes help improvement muscle strength of knee extensor.

• Korean Journal of Applied Biomechanics
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• v.31 no.3
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• pp.205-213
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• 2021

Objective: The aim of this study was to analyze body stability Joint coordination pattern though as bending stiffness of shoes during stance phase of running. Method: 47 male subjects (Age: 26.33 ± 2.11 years, Height: 177.32 ± 4.31 cm, Weight: 65.8 ± 3.87 kg) participated in this study. All subjects tested wearing the same type of running shoes by classifying bending stiffness (A shoes: 3.2~4.1 N, B shoes: 9.25~10.53 N, C shoes: 20.22~21.59 N). They ran 10 m at 3.3 m/s (SD ±3%) speed, and the speed was monitored by installing a speedometer at 3 m intervals between force plate, and the measured data were analyzed five times. During running, ankle joint, MTP joint, coupling angle, inclination angle (anterior-posterior, medial-lateral) was collected and analyzed. Vector coding methods were used to calculate vector angle of 2 joint couples during running: MTP-Ankle joint frontal plane. All analyses were performed with SPSS 21.0 and for repeated measured ANOVA and Post-hoc was Bonferroni. Results: Results indicated that there was an interaction between three shoes and phases for MTP (Metatarsalphalangeal) joint angle (p = .045), the phases in the three shoes showed difference with heel strike~impact peak (p1) (p = .000), impact peak~active peak (p2) (p = .002), from active peak to half the distance to take-off until take-off (p4) (p = .032) except for active peak~from active peak to half the distance to take-off (p3) (p = .155). ML IA (medial-lateral inclination angle) for C shoes was increased than other shoes. The coupling angle of ankle angle and MTP joint showed that there was significantly difference of p2 (p = .005), p4 (p = .045), and the characteristics of C shoes were that single-joint pattern (ankle-phase, MTP-phase) was shown in each phase. Conclusion: In conclusion, by wearing high bending stiffness shoes, their body instability was increased during running.

• Korean Journal of Applied Biomechanics
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• v.14 no.2
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• pp.85-103
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• 2004

This study was conducted to determine what effects would the midsole hardness of running shoes have on shoe flex angle and maximum propulsive force. Furthermore, the relationship between the shoes flex angle and maximum propulsive force was elucidated in order to provide basic data for developing running shoes to improve sports performances and prevent injuries. The subjects employed in the study were 10 college students majoring in physical education who did not have lower limbs injuries for the last one year and whose running pattern was rearfoot strike pattern of normal foot. The shoes used in this study had 3different hardness, shore A 40(soft), 50(medium) and 60(hard). The subjects were asked to run at a speed of $4{\pm}0.08m/sec$, and their movements were videotaped with 2 S-VHS video-cameras and measured with a force platform. And the following results were obtained after analyzing and comparing the variables. 1. Although the minimum angle of shoes flex angle was estimated to appear at SFA4, it appeared at SFA2 except in those shoes with the hardness of 40. 2. The minimum angle of shoes flex angle was $145.1^{\circ}$ with barefoot. Among the shoes with different hardness, it was the smallest when the hardness was 50 at $149.9^{\circ}$. The time to the minimum angle was 70.7% of the total ground contact time. 3. Maximum propulsive force according to midsole hardness was the largest when the hardness was 50 at $1913.9{\pm}184.3N$. There was a low correlation between maximum propulsive force and shoes flex angle.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.319-330
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• 2002

A toe spring and ball girth data, when marathone shoes research, development, and production in Korea, is a important point in athlete shoe research. It is clear from the results presented that any differences between MA3 and MA1, MA4 in 70%, 80% session in forepart last comparision. Especially the more 70%-80% session getting wide, the more 90% session getting up, Also, To development for high performance marathones shoes last, in all session, in korean style, 70%, 80%, and 90% session part function changed and consequently there is a need for normative last data that desribe foot, last shape, dimension. this leads to the conclusion that unique shoe lasts for both marathone shoes developmented last comparison are required for optimal marathone shoe comfort. The more ball girth construction will wide in forepart in last, the more comfort characteristic sill development. But relative with performance ability, it is need to research. The further study of Korea marathoner forefoot measurements(70% session ~ 90% session) among toe spring's angular difference of marathone last to north american and Korea marathone shoes last is required to develop and improve athletes performance in an effective way of study and to prevent forefoot injury.

• Korean Journal of Applied Biomechanics
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• v.25 no.4
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• pp.475-482
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• 2015

Objective : The purpose of this study was to investigate mean plantar foot pressure, maximum plantar pressure and ground reaction force, and center migration path of pressure according to the type of trekking shoes for the development of shoes. Method : Subjects of the study averaged $22.10{\pm}2.05years$ of age. Their average height was $169.27{\pm}7.62cm$ and their average weight was $64.34{\pm}10.22kg$. The method of this study was administered measuring 50 steps, at once, 3 times at a speed of 4 km/h and using the data of 30 steps. Pedar-X system measured the mean foot pressure, maximum foot pressure, mean maximum force, and center migration path of pressure by subjects' position while walking. Statistical analysis was performed by SPSS 23.0 using a paired t-test. Results : Results of the study showed Nestfit trekking shoes lower foot pressure of both feet in mean foot pressure and maximum foot pressure. Nestfit trekking shoes showed high ground reaction force (p<.001) in the midfoot, and low mean ground reaction force in the rearfoot. The center migration path of pressure showed the Nestfit trekking shoes were more stable than flat insole trekking shoes. Conclusion : It can be concluded that wearing Nestfit trekking shoes spreads pressure efficiently and induces walking stability because Nestfit trekking shoes spread the pressure of the forefoot and rearfoot to the midfoot and the center migration path of pressure shows regularly.

• 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.26 no.4
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• pp.413-420
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• 2016

Objective: The purpose of this study was to analyze and compare different kinds of outdoor walking shoes in terms of muscle fatigue and ground reaction force on walking, and to provide foundational data for developing and choosing outdoor walking shoes that fit the users. Method: The study subjects were 30 healthy men. The experiment was conducted by using outdoor walking shoes with different inner and outer harnesses of the midsole, and shapes of the outsole. For data collection, electromyography was used to measure the muscle fatigue of the anterior tibial muscle and gastrocnemii, which contribute to the dorsiflexion and plantarflexion of the ankle joint, and the biceps muscle of the thigh and lateral great muscles, which contribute to the flexion and extension of the knee joint. A GRF measurement device was used to measure the X, Y, and Z axes. Results: In the type A outdoor walking shoes, regarding the hardness of the midsole, the inner part was soft, while the outer part was hard. The vertical ground reaction force was the lowest, which means least impact while walking and light load to the knees and ankles. The type C outdoor walking shoes were intended to provide a good feel in wearing the shoes. The tibialis anterior, biceps femoris, and gastrocnemii indicate low fatigue, which means that during a long-distance walk, it will minimize the fatigue in the muscles of the lower limbs. Conclusion: To sum up the study results, the different types of outdoor walking shoes indicate their unique characteristics in the biomechanical comparison and analysis. However, the difference was not statistically significant. Thus, a systematic and constant follow-up research should be conducted to cope with expanding market for outdoor walking shoes. Lastly, this study is expected to present foundational data and directions for developing outdoor walking shoes.

• Journal of Sport and Applied Science
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• v.3 no.2
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• pp.17-27
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• 2019

Purpose: This study is to conduct usability evaluations from the perspective of developing comfort-shoes for the middle-aged and elderly to identify key factors and derive implications for optimal comfort-shoes production. Research design, data, and methodology: A total of 10 middle-aged and elderly women in their 50s and 60s were selected as eligible for the rescue. For data collection, the study was conducted in a Gang Survey, where pre-explanations, shoes test, and interviews were conducted. The collected data were analyzed in a total of four stages. In step 1, the contents obtained through interviews with the subjects were recorded in text, organized and analyzed systematically, and in step 2, unnecessary vocabulary, sentences, and overlapping opinions were eliminated. In step 3, we classified areas around key functions and carried out categorization tasks. Finally, in Step 4, the results and implications of the study were derived by classifying each usability evaluation shoe as positive and negative text around categorized data. Results: There are a total of seven factors for comfort-shoes usability evaluation, which are categorized as cushion, fitting, stability, flexibility, lightweight, comfort, and pressure. Positive/negative factors for the derived usability evaluation factors were shown in the form of a positive-centered, negative-centered, and positive-mixed mix for each of the four products. Positive-focused products are VA products, which are seven times more positive than negative factors. Negative-centered products are CL and SA products, which are five times more negative than positive factors. Positive mixing was a CA product with a ratio of 1:1. Text-based usability evaluations allow us to proceed with analysis based on more scientific data rather than simply listening to opinions and judging by comments. Conclusions: The study discussed implications of developing comfort-shoes for middle-aged consumers and future directions were discussed.