• 한국운동역학회지
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• 제15권2호
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• pp.185-196
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• 2005

Recently among several tennis techniques forehand stroke has been greatly changed in the aspect of spin, grip and stance. The most fundamental factor among the three factors is the stance which consists of open, square and closed stance and it is very important to know the patterns of plantar pressure distribution for the better understanding of forehand stroke. Therefore, the purpose of this study was to investigate the change of plantar pressure distribution according to close, square and open stance patterns during forehand stroke in tennis. Three high school tennis players were recruited for the study and required to perform forehand stroke five consecutive trials in the condition of open, square and close stance. The forehand strokes were filmed with two digital video cameras and measured with pedar system for plantar pressure. The plantar regions under the foot were divided into 3 regions, which were forefoot, midfoot, and rear foot.. In conclusion, the first hypothesis, "The plantar pressure of close stance during forehand stroke would be distributed more largely to the left foot.", was rejected and the result showed that The plantar pressure of close stance during forehand stroke was distributed transferring from right foot to left foot similar to square stance. The second hypothesis, "The plantar pressure of square stance during forehand stroke would be distributed transferring from right foot to left foot." was accepted. The third hypothesis, "The plantar pressure of open stance during forehand stroke would be distributed more largely to the right foot.", was accepted.

• 대한족부족관절학회지
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• 제12권1호
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• pp.41-46
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• 2008

Purpose: This study was designed to evaluate characteristics of foot pressure distribution with or without partial prosthetic foot in transmetatarsal amputee. Materials and Methods: The subjects were 9 transmetatarsal amputees. Foot pressures were measured at hallux, the $1^{st}-5^{th}$ metatarsal head (MTH), mid-foot, condyle area by F-scan system in amputated or contralateral foot during active walking. Results: In amputated foot, mean peak pressure was greatest in midfoot without prosthetic foot but it was greatest in hindfoot with prosthetic foot. In unaffected foot, although mean peak pressure was higher in hallux, and $1-5^{th}$ MTH compared to amputated foot, it was greatest in hind foot both with and without prosthetic foot. However, in unaffected foot, mean peak pressure significantly decreased in hallux and $5^{th}$ MTH after wearing the prosthetic foot. There was a significant difference in mean peak pressure in hallux and $5^{th}$ MTH between amputated and unaffected foot after wearing prosthetic foot. However, other region had no significant difference with or without prosthetic foot between feet. Conclusions: The use of partial prosthetic foot tends to shift weight bearing from the heel area to forefoot and could significantly reduce hind foot peak pressure and redistributed to peak pressure. The partial prosthetic foot can also offer the peak pressure to reduction both amputated foot and unaffected foot and help to toe off during walking.

• 한국운동역학회지
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• 제30권1호
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• pp.7-16
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• 2020

Objective: It is to find factors related to stability through analysis of plantar pressure factors according to the level of instability when performing Snatch. Method: Foot pressure analysis was performed while 10 weightlifters performed 80% of the highest level of Snatch, and motion was classified and analyzed in 3 grades according to the level of instability. Results: First, in Bad Motion, the movement distance of the pressure center in the direction of ML and AP was larger significantly in Phase 2. Second, in Phase 2, the number of zero-crossing in the AP direction was larger statistically significantly in Good Motion. Third, in the bad motion in Phase 3, the number of zero-crossing in the ML direction showed a significantly larger value. Fourth, in Phase 4, it was found that the more stable the lock out motion, the greater the activity of foot controlling in the left and right directions. Fifth, Phase 3, the greater the Maximum/Mean foot pressure value, the more stable the pulling action. Sixth, in Phase 2, the foot pressure was concentrated with a wide distribution in the midfoot and rearfoot. Seventh, the triggering number of the forefoot region was small in the last pull phase. Eighth, the number of triggers in the toe area was significantly higher during Good Motion in Phase 4. Conclusion: Summarizing the factors of instability in Snatch, there was no significant difference in Phase 1 for each condition. In order to enhance the stability in Phase 2, the sensory control ability in the AP direction is required, and focusing the foot pressing motion with a wide distribution in the middle and rear parts increases the instability. In Phase 3, it was found that the more unstable, the more sensory control activity was performed in the ML direction, the stronger the forefoot pressing action should be performed for a stable Snatch. In Phase 4, It is important that the feet sensory control activity in ML directions and the control ability of the toes in order to have stable Lock out motion.

• 대한족부족관절학회지
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• 제17권2호
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• pp.121-129
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• 2013

Purpose: To evaluate the radiographic characteristics of the tarsometatarsal osteoarthritis with hallux valgus deformity and report the clinical results of the operative treatment. Materials and Methods: This is a retrospective study of 20 patients, 22 feet who had been operated for non-traumatic tarsometatarsal osteoarthritis with hallux valgus (TMT group) and control group of hallux valgus patients without tarsometatarsal osteoarthritis (26 patients, 28 feet) from April 2004 to July 2011. Radiographic characteristics were compared between the groups, using hallux valgus angle, $1^{st}-2^{nd}$ intermetatarsal angle, metatarsal length ratio, metatarsus adductus angle, talonavicular coverage angle, talus-$1^{st}$ metatarsal angle, calcaneal pitch angle and medial cuneiform height. Pre- and postoperative difference of $1^{st}-2^{nd}$ metatarsal declination angle and distance between the $1^{st}-2^{nd}$ metatarsal head were evaluated. The clinical results were evaluated by American Orthopaedics Foot and Ankle Society (AOFAS) midfoot scale and visual analogue scale (VAS). Results: Metatarsal length ratio was significantly larger in TMT group (p<0.001). Metatarsus adductus angle, talonavicular coverage angle, talus-$1^{st}$ metatarsal angle on lateral radiograph, calcaneal pitch angle and medial cuneiform height were different from control group (p<0.001, p<0.001, p=0.001, p=0.010, p=0.006). Postoperative declination of the $2^{nd}$ metatarsal and distance between the $1^{st}-2^{nd}$ metatarsal head were increased (p=0.009, p=0.001). The AOFAS and VAS score were improved (p<0.001, p<0.001). Conclusion: Non-traumatic osteoarthritis of the tarsometatarsal joints seems to be associated with long 2nd metatarsal length, metatarsus adductus and flatfoot deformity. Spur excision may be successful to relieve symptoms when the arthritis was diagnosed in early stage.

• 대한족부족관절학회지
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• 제17권2호
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• pp.100-105
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• 2013

Purpose: To present radiographic characteristics and report the clinical results of the operative treatment of M$\ddot{u}$ller-Weiss disease. Materials and Methods: This is a retrospective study including 13 patients, 14 feet who had been operated for M$\ddot{u}$ller-Weiss disease between April 2006 and December 2011. Osteoarthritis of the peri-navicular joints were radiographically evaluated. Various range of peri-navicular fusion and joint-preserving surgeries according to patients' symptoms and radiographic findings were done. The clinical results were evaluated by American Orthopaedics Foot and Ankle Society (AOFAS) midfoot scale and visual analogue scale (VAS). Results: On radiographs, osteoarthritic changes were presented at talonavicular joint in 11 cases, calcaneocuboid joint in 7 cases, subtalar joint in 6 cases, naviculo-cuneiform joint in 1 case. The mean anteroposterior talocalcaneal angle was 16.6 degrees. On hindfoot alignment view, 6 cases were varus, 5 cases were neutral and 3 cases were valgus alignment. Fusion comprised 6 cases in triple fusion, 1 case in talonavicular-cuneiform fusion, 2 cases in talonavicualr fusion and 1 case in talonavicular & calcaneocuboid fusion. Joint-preserving surgeries were bony fragment excision of the lateral part of navicular & medial displacement calcaneal osteotomy in 1 case, bony spur excision of talonavicular joint in 1 case and medial displacement calcaneal osteotomy in 2 cases. The postoperative AOFAS and VAS score were improved significantly (p=0.000, p=0.000). Conclusion: In cases of M$\ddot{u}$ller-Weiss disease without osteoarthritic changes at peri-navicular joints, fragment excision of navicular, bony spur excision with or without medial displacement calcaneal osteotomy were effective operative treatments.

• 한국전문물리치료학회지
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• 제8권3호
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• pp.1-10
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• 2001

The purpose of this study was to compare the static pressure, dynamic pressure, dynamic pressure-time integral, relative impulse, and contact time between the sound lower limb and amputated lower limb in trans-tibial amputee subjects using Parotec system. Seventeen trans-tibial amputee subjects wearing endoskeletal trans-tibial prosthesis voluntarily participated in this study. The results were as follows: 1) In static standing condition, there were significantly higher static pressure in sound lower limb insole sensor of 10, 14, 15, 18, 19, 23, and 24 and in amputated lower limb insole sensor of 9, 12, and 16 (p<.05). 2) In dynamic gait condition, there were significantly higher dynamic pressure in sound lower limb insole sensor of 2, 18, 22, 23, and 24 and in amputated lower limb insole sensor of 5, 9, 10, 11, 12, 14, 15, and 16 (p<.05). 3) In dynamic gait condition, there were significantly higher pressure-time integral in sound lower limb insole sensor of 2, 4, 18, 19, 20, 21, 23, and 24 and in amputated lower limb insole sensor of 5, 11, 12, and 15 (p<.05). 4) In dynamic gait condition, there were significantly higher relative impulse in sound lower limb insole sensor of 18, 19, 20, 22, 23, and 24 and in amputated lower limb insole sensor of 5, 9, 10, 11, 12, and 15 (p<.05). 5) In dynamic gait condition, there was significantly higher percentage of contact time in push off phase of sound lower limb and in support phase of amputated lower limb (p<.05). These results suggest that trans-tibial amputee subjects had characteristics of shortened push off phase due to unutilized forefoot and of lengthened support phase with higher pressure in the midfoot.

• 한국콘텐츠학회논문지
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• 제10권2호
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• pp.268-276
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• 2010

본 연구의 목적은 경사로를 오르는 동안 슬관절 굴곡각도와 족저압의 차이를 각각 다른 경사도에 따라 분석하고자 하는 것이다. 24명의 건강한 성인 참가자들에게 각각의 경사도($0^{\circ},\;3^{\circ},\;6{\circ},\;9^{\circ}$)를 걷게 한 후, Parotec system을 이용하여 족저압을 측정하였으며, 걷는 모습을 캠코더로 녹화 한 후 Dartfish system을 이용하여 슬관절 각도를 분석하였으며, 수집된 데이터는 SPSS/PC 통계 프로그램을 이용하여 일원배치분산분석으로 분석하였다. 결과는 각 경사로에 따라 슬관절 굴곡 각도는 통계학적으로 유의한 차이가 나타났으며, 족저압은 좌측 하지의 발뒤꿈치 외측 부위(1번 감지기), 중족부 내측 부위(9번 감지기), 전족부 내측 부위(15번, 16번 감지기), 그리고 우측 하지에서는 발뒤꿈치 외측 부위(3번 감지기)에서 통계학적으로 유의한 차이를 보였다. 슬관절 각도가 $10{\sim}20^{\circ}$ 사이에서 발뒤꿈치 외측 부위 및 내측 부위의 족저압이 통계학적으로 유의하게 높게 나타났다.

• 한국정밀공학회지
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• 제30권4호
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• pp.442-449
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• 2013

This study was to compare a domestic comfort shoes to the popular import(SAS$^{(R)}$) to gain a better understanding in biomechanical characteristics for shoe design for the elderly. For each shoe type, morphologic dimensions, shock absorption, and flexibility were assessed. From subjects(n = 20, $72.4{\pm}5.5$ years, $67.7{\pm}7.9$ kg), mean peak pressure(MPP) and contact area(CA) at the plantar surface were analyzed. The domestic shoes reflecting anatomic contour of the plantar surfaces of Asians resulted in wider CA(by 30.4 $cm^2$), higher shock absorption(by 2.4%) and stiffness(by 0.5 N/mm) than the import. With the domestic shoes, significantly less MPPs were found at the forefoot(by 42~49%) regions(p < .05) and higher CA was noted additionally at hallux and lessor toes(by 26~63%). More anatomically-contoured insole and favorable mechanical characteristics may help reduce the plantar pressures more effectively and more evenly, especially across the central forefoot and midfoot regions of the plantar surface, especially for the design of the comfort shoes for the elderly.

• 한국운동역학회지
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• 제21권1호
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• pp.67-75
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• 2011

The purpose of this study was to find the difference in gait patterns when elderly and young people walk by analyzing COP, Gait Line, Foot pressure pattern, and ensuring the original biomechanics technology of developing high performance footwear for the elderly. The subjects who took part in the test consist of 20 elderly people and 20 young people. The physical features of the elderly people that were recruited for the study are as below: 20 healthy male subjects(elderly people) with an average age of 75.43 yrs(S.D 6.46 yrs), weight of 68.10 kg(S.D 0.94 kg) and a height of 168.65 cm(S.D 1.47 cm). Foot pressure pattern data was collected using a EMED-AT system(Novel Gmbh, Germany) operating at the 50 Hz during walking. The results are as follow : COP route of the elderly leans to lateral compared to the young, and Gait Line from heel to toe is not clear and laterally curved. At the same time, a contact are aonthe midfoot is high compared to the young, and maximum force of the forefoot is low. As a result of analysis, in order to develop high performance footwear for the elderly, it is necessary to develop lasts and soles reflecting the elderly's gait patterns.

• Physical Therapy Rehabilitation Science
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• 제9권1호
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• pp.10-17
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• 2020

Objective: Hallux valgus (HV) is a common musculoskeletal deformity that is accompanied with pain and continues to decrease one's quality of life and ability to perform daily life activities by affecting gait and static stability. Therefore, this study aimed to investigate the effect of the angle of HV (HVA) and to compare the one-legged stance and gait parameters in young adults with less HV and severe HV. Design: Cross-sectional study. Methods: Forty young adults were divided into two groups, where HVA ≥15° (n=20) was defined as HV, and HVA <15° (n=20) was defined as normal. For balance ability, the center of pressure (COP) path, velocity, length of axis of the COP path, deviation of the x-axis and y-axis, and percentage of foot pressure were measured, and gait, the foot rotation angle, step length, percentage of each phase of the gait cycle, time change from the heel to forefoot, and maximum pressure of the forefoot and midfoot were measured. Results: Significant differences were found in sway length and time change from heel to forefoot during walking between the normal and HV groups (p<0.05). Most parameters were not associated with the HVA, but parameters such as length of axis and time to change from heel to forefoot were significantly associated with the HVA (p<0.05). Conclusions: These results suggest that most one-legged stance and gait parameters were not significantly affected by the HVA in young adults; therefore, future studies are needed in order to address other dynamic parameters and other methods of gait analysis for detecting clinically meaningful conditions.