The Effect of Shoe Heel Types and Gait Speeds on Knee Joint Angle in Healthy Young Women - A Preliminary Study

츄음반타 ( Vantha Chhoeum ),왕창원 ( Changwon Wang ),장승완 ( Seungwan Jang ),민세동 ( Se Dong Min ),김영 ( Young Kim ),최민형 ( Min-hyung Choi ) 한국인터넷정보학회 2020 인터넷정보학회논문지 Vol.21 No.6

The consequences of wearing high heels can be different according to the heel height, gait speed, shoe design, heel base area, and shoe size. This study aimed to focus on the knee extension and flexion range of motion (ROM) during gait, which were challenged by wearing five different shoe heel types and two different self-selected gait speeds (comfortable and fast) as experimental conditions. Measurement standards of knee extension and flexion ROM were individually calibrated at the time of heel strike, mid-stance, toe-off, and stance phase based on the 2-minute video recordings of each gait condition. Seven healthy young women (20.7 ± 0.8 years) participated and they were asked to walk on a treadmill wearing the five given shoes at a self-selected comfortable speed (average of 2.4 ± 0.3 km/h) and a fast speed (average of 5.1 ± 0.2 km/h) in a random order. All of the shoes were in size 23.5 cm. Three of the given shoes were 9.0 cm in height, the other two were flat shoes and sneakers. A motion capture software (Kinovea 0.8.27) was used to measure the kinematic data; changes in the knee angles during each gait. During fast speed gait, the knee extension angles at heel strike and mid-stance were significantly decreased in all of the 3 high heels (p<0.05). The results revealed that fast gait speed causes knee flexion angle to significantly increase at toe-off in all five types of shoes. However, there was a significant difference in both the knee flexion and extension angles when the gait in stiletto heels and flat shoes were compared in fast gait condition (p<0.05). This showed that walking fast in high heels leads to abnormal knee ROM and thus can cause damages to the knee joints. The findings in this preliminary study can be a basis for future studies on the kinematic changes in the lower extremity during gait and for the analysis of causes and preventive methods for musculoskeletal injuries related to wearing high heels.

The effects of the angles of the knee and heel-off on the muscle activity during a bridge exercise

( Byeong Jo Kim ),( Su Kyoung Lee ),( Jung Hoon Lee ),( Hae Yeon Kwon ) 대한물리의학회 2015 대한물리의학회지 Vol.10 No.3

PURPOSE: The purpose of this study is to investigate the effects of the angles of the knee and heel-off on the muscle activity during a bridge exercise. METHODS: 15 healthy adult men and women with the balance ability and joint working range required for performing a bridge exercise participated in this study, in which 120°, 90° and 60° angles of the knee-flexion and heel-off were applied during the bridge exercise. RESULTS: Our data showed that there were significant differences in muscle activities of elector spinae and rectus abdominis when 120°and 60°angles of the knee were applied, of internal oblique when 120°and 60°were applied, and external oblique when 90°and 60°were applied. When heel-off was applied, there were significant differences in muscle activities of elector spinae and rectus abdominis when 120°and 60°were applied, of internal oblique when 120°and 60°were applied, and external oblique when 90°and 60°were applied. CONCLUSION: In this study on an application of heel-off to the bridge exercise, we showed that the effect of the angles of the knee on the muscle activities of elector spinae, rectus abdominis, internal oblique and external oblique were all similar to the regular bridge exercise, but overall muscle activities were increased with heel-off when compared with the regular bridge exercise.

하이힐이 요부 및 천골경사각에 미치는 영향

이태식,송민영,김미소,Lee, Tae-Sik,Song, Min-Young,Kim, Mi-So 대한물리치료과학회 2011 대한물리치료과학회지 Vol.18 No.4

Purpose : This study is to know how position change in high-heels affects sacral tilt angle. 15 healthy women aged 21.87(standard deviation=3.54) were tested. Method : Lumbar and sacral tilt angle was measured by radiography barefooted, and after 15 mins of application time, they were measured in the same way in high-heels. Result : There was not notable difference in lumbar lordosis, lumbosacral angle, and sacral tilt angle. However, there was differences in change degree, which was measured by estimation data of [post-pre)/pre]${\times}$100. Conclusion : There was no notable difference in lumbar lordosis, lumbosacral angle, and sacral tilt angle, but as there were differences in change degree, research about how women's lumbar change when heel height increases is needed.

시뮬레이션 데이터를 이용한 횡경사 각도 예측 방법 연구

윤동협,박충환,임남균 한국항해항만학회 2019 한국항해항만학회지 Vol.43 No.4

As ships become bigger, faster, and diverse, transportation has increased the usage of marine vehicles. However, ship accidents are increasing. Ship accidents cause loss of life and property as well as environmental disasters. The occurrence of ship accidents causes enormous economic and environmental impacts. Notably, in the case of passenger ships, methods for preventing ship accidents are being discussed to avoid losing numerous human lives. The purpose of this study is to provide essential data for evacuation before reaching the dangerous time by predicting the time to reach the risk of capsizing based on the heeling angle of the passenger ship. Based on sinking accidents between 2012 and 2016, we set up specific scenarios and simulated the PRR1 data using commercial software MOSES V20. In the case of the linear equation, the simulation results showed a low error rate because the simulation data showed the linear graph. In the case of the quadratic equation, the error rate was low at the beginning but showed a high error rate at the subsequent angle. 선박의 대형화, 고속화 및 선종의 다양화는 운송수단 중 해양 운송수단의 비중을 크게 증가시켰으나 동시에, 선박사고의 발생도 같이 증가 되었다. 선박사고의 발생은 생명과 재산의 손실뿐만 아니라 환경재해까지 일으키기 때문에 막대한 경제적, 환경적인 영향을 끼치게 된다. 특히, 여객선의 경우 인명의 피해가 크게 발생하기 때문에 선박사고를 예방하기 위한 방법들이 논의 되어 지고 있다. 본 연구에서는 여객선의 횡경사 각도를 바탕으로 전복의 위험까지 가게 되는 시간을 예측하여 위험시간에 도달하기 전에 인명을 대피할 수 있는 기초 자료를 제공하고자 하였다. 2012년~2016년 사이 침몰사고를 바탕으로 특정 시나리오를 설정하였으며, PRR1의 데이터를 MOSES V20을 이용하여 시뮬레이션을 수행하였다. 시뮬레이션 결과는 시간에 따른 횡경사 각도이며, 횡경사 에측을 위한 1차, 2차 방정식을 이용하여 시뮬레이션 결과와 비교하였다. 1차방정식의 경우 시뮬레이션 데이터가 선형적인 그래프를 나타내었기 때문에 낮은 오차율을 보이고 있으며, 2차방정식의 경우 초기에는 낮은 오차율을 보이고 있으나 추후 발생되는 각도에 대해서는 높은 오차율을 보이고 있었다.

무릎관절 굽힘 각도에 따른 뒤꿈치 들기 동안 종아리 세갈래근의 활성도

권유정 ( Yu Jeong Kwon ),송민영 ( Min Young Song ) 대한물리의학회 2013 대한물리의학회지 Vol.8 No.4

PURPOSE: The purpose of this study was to investigate the change of triceps surae activation during heel raise test in standing among knee flexion angles(0°, 30°, 45°,60°). METHODS: Twenty healthy individuals performed unilateral plantarflexion in standing with 0°, 30°, 45°, 60° knee flexion. Activity of medial gastrocnemius(MG), lateral gastrocnemius(LG), soleus(Sol) was recorded with surface electromyography(EMG). RESULT: The muscle activations induced the four different positions were compared and results showed that was significant difference MG and LG while the angle increase from 0° to 30°, 45°, 60° but Sol did not show significant differences in every angle. CONCLUSION: This study suggest that 30° knee flexion is required to induce a significant mechanical disadvantage of gastrocnemius.

구두 굽 높이가 20대 여성의 요천추부 각도에 미치는 영향

김병곤 ( Byoung Gon Kim ),공원태 ( Won Tae Gong ),김한수 ( Han Soo Kim ) 대한물리의학회 2007 대한물리의학회지 Vol.2 No.1

Automatic NC-Date Generation Method for 5-axis Cutting of Turbine-Blades by Finding Safe Heel-Angles and Adaptive

Piao, Cheng-Dao,Lee, Cheol-Soo,Cho, Kyu-Zong,Park, Gwang--Ryeol The Korean Society of Mechanical Engineers 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.5

In this paper, an efficient method for generating 5-axis cutting data for a turbine blade is presented. The interference elimination of 5-axis cutting currently is very complicated, and it takes up a lot of time. The proposed method can generate an interference-free tool path, within an allowance range. Generating the cutting data just point to the cutting process and using it to obtain NC data by calculating the feed rate, allows us to maintain the proper feed rate of the 5-axis machine. This paper includes the algorithms for: (1) CL data generation by detecting an interference-free heel angle, (2) finding the optimal tool path interval considering the cusp-height, (3) finding the adaptive feed rate values for each cutter path, and (4) the inverse kinematics depending on the structure of the 5-axis machine, for generating the NC data.

뒷굽 길이가 짧은 캔틸레버 옹벽의 Coulomb 토압 산정에 대한 영향 인자 분석

유건선,Yoo, Kun-Sun 한국지반공학회 2017 한국지반공학회논문집 Vol.33 No.11

본 연구에서는 사질토 뒷채움재의 캔틸레버 옹벽에서 뒷굽 끝단 연직면에 작용하는 주동토압을 산정하는 방법을 제안하였다. 캔틸레버 옹벽에서 뒷굽길이에 따른 전단 영역의 변화는 벽체의 벽마찰력, 뒷채움 경사에 따라 뒷굽 끝단 연직면에 작용하는 주동토압에 영향을 준다. 뒷굽길이에 따라 변하는 파괴면각도를 가정하여 토압을 산정하는 한계평형법은 적용하기에 매우 복잡하므로 본 연구에서는 한계해석법을 사용하여 토압을 구하였다. 한계해석법으로 뒷굽길이에 따라 실제 파괴면각도가 고려된 토압을 정확히 산정하고, 이로부터 뒷굽 끝단 연직면에 작용하는 수평토압과 연직토압을 분석하였다. 본 연구결과에 의하면, 뒷굽길이가 짧아짐에 따라 내측 파괴면 경사각은 이론식보다 증가한 반면에 외측 파괴면 경사각은 영향을 받지 않았다. 뒷굽 끝단의 연직면에 작용하는 배면마찰각은 지표면 경사각과 벽면마찰각 사이의 값을 나타내었으며, 주동토압 또한 감소하였다. 최종적으로 상대적인 뒷굽길이와 뒷굽 끝단의 연직면에 작용하는 마찰각(연직토압/수평토압의 비)의 상관관계를 사용함으로써 Coulomb 토압을 간편하게 산정할 수 있도록 하였다. In this study, the calculation method of the active earth pressure acting on the imaginary vertical plane at the end of the heel of the wall is proposed. For cantilever retaining wall, a change of shear zone behind the wall affects the earth pressure in the vertical plane at the end of heel of the wall depending on wall friction and angle of ground slope. It is very complicated to calculate the earth pressure by a limit equilibrium method (LEM) which considers angles of failure planes varying according to the heel length of the wall. So, the limit analysis method (LAM) is used for calculation of earth pressure in this study. Using the LAM, the earth pressures considering the actual slope angles of failure plane are calculated accurately, and then horizontal and vertical earth pressures are obtained from them respectively. This study results show that by decreasing the relative length of the heel, the slope angle of inward failure plane becomes larger than theoretical slope angle but the slope angle of outward failure plane does not change. And also the friction angle on the vertical plane at the end of the heel of the wall is between the ground slope angle and the wall friction angle, thereafter the active earth pressure decreases. Finally, the Coulomb earth pressure can be easily calculated from the relationship between friction angle (the ratio of vertical earth pressure to horizontal earth pressure) and relative length of the heel (the ratio of heel length to wall height).

여객선형의 선회 중 횡경사 추정에 관한 실선 실험 연구

김홍범,이윤형,박용선,공길영 해양환경안전학회 2018 해양환경안전학회지 Vol.24 No.5

여객선과 실습선은 많은 인원이 승선한다는 점에서 서로 공통적인 특성을 갖고 있다. 이러한 이유로 여객선형 선박의 안전한 운항이 대단히 중요하다. 정상적인 항해 중, 선박은 다양한 형태의 타각을 사용하여 변침하고, 위험 물표와의 충돌 회피를 위해 선회하기도 한다. 선박이 선회하면 횡경사가 발생하고, 운항 당시 여건이 불리할 경우 위험횡경사가 발생하거나 전복사고로 이어질 수 있다. 본 연구에서는 여객선과 유사한 두 척의 실습선을 대상으로 실선 선회 실험을 통해 횡경사를 계측하였고, 이를 선회 중 횡경사 이론식과 비교 분석하였다. 그 결과, IMO 복원성 성능기준에 제시된 선회 중 횡경사 계산식을 이용한 최대횡경사 예측의 한계점을 확인하였다. 또한, 선회 중 횡경사 이론식에 전타 당시 선속을 반영하고, 계산된 결과값에 우 선회시 1.4배, 좌 선회시 1.1배를 적용하면 최대횡경사 예측이 가능함을 확인하였다. 본 연구는 선회 중 위험횡경사 예방에 관한 안전운항기준을 마련하는데 기초 자료로 활용될 것으로 기대된다. Passenger ships and training ships have a common feature in that they serve many passengers. Thus, safe navigation is very important. During normal sailing, a ship may turn using various types of steering, including maneuvers to avoid collisions with dangerous target. When a ship turns, a heeling angle occurs. If trouble arises during sailing, a dangerous heeling angle may result or a capsizing accident. In this study, the heeling angle during turning was measured through experimentation with two training ships similar to passenger ships. These findings were compared with theoretical formulas for heeling angle when turning. We confirmed that the limit of the maximum heeling angle estimation using heeling angle formula when turning presented in IMO stability criteria. In addition, it was confirmed that the maximum estimated heeling angle can be reached by applying the result calculated in the theoretical formula 1.4 times when turning right and 1.1 times when turning left to reflect sailing speed when of rudder hard over. It is expected that this study will provide basis data for establishing safe operation standards for the prevention of dangerous heeling angles when turning.

정적, 동적운동에 따른 발 형태에 관한 비교분석

전유섭(Jun Yu-Sub) 한국체육과학회 2006 한국체육과학회지 Vol.15 No.4

The purpose of this study was to examine whether there were any differences between static(SE) and dynamic exercise(DE) following various exercise type of foot's form. The subjects in this study were 40 male middle school students in wonju. Athlete's responding date of various exercise on foot's form was entered into a person computer and analyzed using the SPSS software. Differences for DE and SE of foot shape length, foot width, eversion angle, heel angle, hallux angle, arch angle scores were analyzed using unparied t-test(p<.05). The conclusions of this research was as following; In average length, width, heel and arch angle of foot, SE between DE middle school student is a little difference in result levels, however, it is p<.05 which means valuable no difference as a statistical level. In average eversion and hallux angle of foot, SE between DE middle school student is significant difference in result levels, therefore, it is p<.001 and p<.05 which means valuable difference as a statistical level.