• 한국운동역학회지
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• 제22권1호
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• pp.105-111
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• 2012

The purpose of this study was to investigate the effect that difference in forefoot of shoe flexibility during the quick lunge from a jump smashing on the lower limbs and the plantar pressure distribution. For this 10 elite badminton players with over 10 years experience and right handed participated. Two kinds of badminton shoes were selected and tested mechanical testing for the forefoot flexibility. Motion analysis, ground reaction forces and plantar pressure distribution were recorded. It was required to conduct lunge movement after jumping smashing as possible as high. Photo sensor was located in 3 meter away from standing position and its height was 40 cm. Subjects were conducted to return original position after touching the sensor as under clear movement as possible as fast. Forefoot stiffness had an effect on shoe peak bending degree and peak bending angular velocity in propulsion phase. Forefoot flexibility had an effect on ankle plantar flexion and knee flexion moment. It appears that joint power on lower limb and peak plantar pressure were not influenced by the flexibility of shoes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.169-170
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• 2006

The purpose of this study was to evaluate the smoothness of the gait pattern according to shoe, walking speed, and slope. Eleven male university students used three types(running shoes, mounting climbing boots, elevated forefoot walking shoes) of shoes at various walking speeds(1.19, 1.25, 1.33, 1.56, 1.78, 1.9, 2.0, 2.11, 2.33m/s) and gradients (0, 3, 6, 10%) on a treadmill. Three-dimensional motion analysis (Motion Analysis Corp, Santa Rosa, CA, USA) was conducted with 4 Falcon high speed cameras. The results showed that elevated forefoot walking shoes had the lowest value of normalized jerk at the heel, which means that elevated forefoot walking shoes had the smoothest walking pattern at the heel. In contrast, elevated forefoot walking shoes had greater normalized jerk at the center of mass (COM) at most walking speeds, which means that the smoothness of gait pattern at the center of mass is the lowest for the elevated forefoot walking shoes. This movement at the COM might even have a beneficial effect of activating muscles in the back and abdomen more than other shoes.

• 대한족부족관절학회지
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• 제4권2호
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• pp.55-60
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• 2000

Purpose: To investigate the effect of heel elevation on the radiographic parameters of the forefoot. Materials and Methods: Forty feet in twenty-one adults were studied. Weight bearing dorsoplantar radiograph was taken with the foot on a flat surface and with the heel of the foot elevated by 5cm. Various parameters were measured and compared between the results with and without heel elevation. Result: The hallux valgus angle was increased by $5.0{\pm}3.5$ degrees with heel elevation and the change was statistically significant(p<0.01). There was no statistically significant changes in the other parameters. Conclusion: The results of this study suggest that high-heeled shoes might contribute in causing or aggravating the degrees of the hallux valgus.

• 대한족부족관절학회지
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• 제6권1호
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• pp.129-133
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• 2002

Extraskeletal myxoid chondrosarcoma is an unusual soft tissue sarcoma with distinctive histologic features. It once was called chordoid sarcoma because it resembles chordoma histologically. The lesion has been shown to be of chondroblastic origin. This lesion shown to have ultrastructural and molecular features distinct from that of myxoid chondrosarcoma of bone. We report a case of extraskeletal myxoid chondrosarcoma in forefoot.

• The Korean Journal of Physiology
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• 제18권1호
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• pp.81-96
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• 1984

As the crippled persons work mostly in a sitting position and would be engaged in a foot-pressing job, it is necessary to assess their degree of participation of important muscles in various modes of foot activities. In this regard, it deems to be urgent to establish the reference standards for healthy persons. The present study has been undertaken to determine the degree of participation of the M. tibialis anterior, M. gastrocnemius and M. soleus in heel pressing, foot-flat pressing and forefoot pressing motion under varying forces, and in order to compare the electrical activities of three muscles with each other, and to analyse the time sequence between force and appearance or disappearance of EMG recording. Sixty-three healthy young women ranging from age of 18 to 23 were examined. The results obtained were as follows: 1. Participation of three muscles in foot movement under varying forces: A) Both gastrocnemius muscles or left soleus muscle did not contribute to heel pressing motion. Activity of both tibialis anterior muscles was the greatest among three muscles at heel pressing motion and the degree of their activities was proportional to force. B) Activities of left tibialis anterior muscle and both gastrocnemius muscles were negligible under 3 kg force at foot-flat pressing movement. Left gastrocnemius muscle did not contribute to foot-flat pressing under 6 or 9 kg force. Although activities of both soleus muscles and both tibialis anterior muscles were small, the degree of their activities increased with force at foot-flat pressing movement. C) Activities of both tibialis anterior muscles were negligible under 3 kg force at forefoot pressing motion. Activity of both soleus muscles was the greatest among 3 muscles and the degree of their activities increased with force at forefoot pressing motion. Both tibialis anterior muscles participated in forefoot pressing motion with severe exertion. 2. Electrical activities by foot movement under varying forces : A) Electrical activities were prominent in both tibialis anterior muscles and the level of their activities was linear with force at heel pressing motion. The degree of participation of both soleus muscles was small at heel pressing motion. B) Electrical activity of tibialis anterior muscle was the greatest among 3 muscles at foot-flat pressing movement and was followed by that of soleus muscle. Level of electrical activities increased with force in left soleus muscle and right tibialis anterior muscle at foot-flat pressing movement. C) Electrical activity of both soleua muscles was the greatest among 3 muscles at forefoot pressing movement and that of tibialis anterior muscle was next to soleus muscle. Level of electrical activities was proportional to force in left tibialis anterior muscle, right gastrocnemius muscle and both soleus muscles at forefoot pressing movement. 3. Time between starting signal and initiation of contraction of heel pressing and forefoot pressing motion in 3 muscles was longer than that of foot-flat pressing movement. Time of relaxation in 3 muscles was longer than that of contraction under varying forces. EMG recording appeared before initiation of contraction in both tibialis anterior muscles at heel pressing motion and in both soleus muscles at forefoot pressing movement under varying forces. Time of initiation of contraction was similar in both sides of tibialis anterior muscles under varying forces and time of onset of contraction at foot-flat pressing motion was the shortest. 4. Forefoot pressing movement would be encouraged in paralysis of tibialis anterior muscle, while heel pressing motion would be encouraged in paralysis of triceps surae muscle.

• 한국운동역학회지
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• 제16권2호
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• pp.1-8
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• 2006

The purpose of this study was to evaluate normalized jerk according to shoes, slope, and velocity during walking. Eleven different test subjects used three different types of shoes (running shoes, mountain climbing boots, and elevated forefoot walking shoes) at various walking speeds(1.19, 1.25, 1.33, 1.56, 1.78, 1.9, 2, 2.11, 2.33m/sec) and gradients(0, 3, 6, 10 degrees) on a treadmill. Since there were concerns about using the elevated forefoot shoes on an incline, these shoes were not used on a gradient. Motion Analysis (Motion Analysis Corp. Santa Rosa, CA USA) was conducted with four Falcon high speed digital motion capture cameras. Utilizing the maximum smoothness theory, it was hypothesized that there would be differences in jerk according to shoe type, velocity, and slope. Furthermore, it was assumed that running shoes would have the lowest values for normalized jerk because subjects were most accustomed to wearing these shoes. The results demonstrated that elevated forefoot walking shoes had lowest value for normalized jerk at heel. In contrast, elevated forefoot walking shoes had greater normalized jerk at the center of mass at most walking speeds. For most gradients and walking speeds, hiking boots had smaller medio-lateral directional normalized jerk at ankle than running shoes. These results alluded to an inverse ratio for jerk at the heel and at the COM for all types of shoes. Furthermore, as velocity increased, medio-lateral jerk was reduced for all gradients in both hiking boots and running shoes. Due to the fragility of the ankle joint, elevated forefoot walking shoes could be recommended for walking on flat surfaces because they minimize instability at the heel. Although the elevated forefoot walking shoes have the highest levels of jerk at the COM, the structure of the pelvis and spine allows for greater compensatory movement than the ankle. This movement at the COM might even have a beneficial effect of activating the muscles in the back and abdomen more than other shoes. On inclines hiking boots would be recommended over running shoes because hiking boots demonstrated more medio-lateral stability on a gradient than running shoes. These results also demonstrate the usefulness of normalized jerk theory in analyzing the relationship between the body and shoes, walking velocity, and movement up a slope.

• 대한족부족관절학회지
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• 제26권3호
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• pp.130-135
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• 2022

Purpose: Smart insoles are wearable devices that are inserted into shoes. Smart insoles with built-in pressure and acceleration sensors can measure the plantar pressure, stride length, and walking speed. This study evaluated the validity and reliability of the plantar pressure measurements of smart insoles during walking on flat ground. Materials and Methods: Twenty one subjects were included in this study. After wearing smart insoles, I-SOL^® (Gilon, Seongnam, Korea), the subjects walked a 10 m corridor six times at a rate of 100 steps/min, and the middle three steps, free from direction changes, were chosen for data analysis. The same protocol was repeated after wearing Pedar-X (Novel Corporation, Munich, Germany), an insoletype plantar pressure measurement equipment with proven validity. The average maximum pressure (P_peak, kPa) and the time at which P_peak appeared (P_time, %stride) were calculated for each device. The validity of smart insoles was evaluated by using the interclass correlation coefficient (ICC) of P_peak and P_time between the two instruments, and Cronbach's alpha was obtained from the P_peak values to evaluate the reliability. Results: The ICC of P_peak was 0.651 (good) in the hallux, 0.744 (good) in the medial forefoot, 0.839 (excellent) in the lateral forefoot, and 0.854 (excellent) in the hindfoot. The ICC of P_time showed 0.868 (excellent) in the hallux, 0.892 (excellent) in the medial forefoot, 0.721 (good) in the lateral forefoot, and 0.832 (excellent) in the hindfoot. All ICC values showed good or excellent results. The Cronbach's alpha of P_peak measured in the smart insoles was 0.990 in the hallux, 0.961 in the medial forefoot, 0.973 in the lateral forefoot, and 0.995 in the hindfoot; all indicated excellent reliability in all areas. Conclusion: The plantar pressure measurements of smart insoles during walking on a flat ground showed validity compared to Pedar-X, and high reliability after repeated measurements.

• 대한미세수술학회:학술대회논문집
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• 대한미세수술학회 1997년도 제17차 학술대회
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• pp.133-134
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• 1997

• 한국의류학회지
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• 제38권4호
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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.

• 대한족부족관절학회지
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• 제9권1호
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• pp.13-19
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• 2005

Purpose: To determine the radiographic changes in forefoot geometry with weight-bearing. Materials and Methods: The forefoot radiographs of 100 normal Korean adults, 50 male and 50 female volunteers, were evaluated both in nonweight-bearing and weight-bearing. The mean age was 27 years with range of 21-39 years. Those with normal feet were selected from volunteers having no history of foot problems or other musculoskeletal diseases. Results: The changes of measured angle between phalanges and metatarsals with weight-bearing were as follows; Hallux valgus angle was noted to increase in 20% of the feet, decrease in 59%, and remained unchange in 21%. Intermetatarsal angle $1{\sim}2$ was noted to increase in 76% of the feet, decrease in 3%, and remained unchange in 21%. Intermetatarsal angle $1{\sim}5$ was noted to increase in 95% and remained unchange in 5%. Shift in medial sesamoid on weight-bearing was also not consistent. Lateral shift was noted in 27%, no shift in 66%, medial shift in 7%. Conclusion: The generalized concept that the angles between bones and shift of medial sesamoid in the forefoot will change consistently with weightbearing was not found.