• 한국터널지하공간학회 논문집
• /
• 제11권1호
• /
• pp.1-9
• /
• 2009

절리암반에시 기존 터널에 근접하여 사면굴착시 터널의 거동은 절기와 굴착사면상태의 영향을 받는다. 본 논문에서는 기존터널에 근접하여 지반을 굴착시, 절리각도와 굴착사면 경사의 영향을 파악하기 위하여 2축 실대형 모형시험장치(3.1 m*3.1 m*0.50 m(폭*높이*길이))를 이용한 시험을 수행하였다. 절리암반은 콘크리트 블록을 사용하여 모사하였으며 터널은 1/10축척(직경 0.6 m)으로 제작하였다. 절리각도는 $0^{\circ}$부터 $90^{\circ}$까지 변경이 가능하며, 굴착사면 경사는 $30^{\circ}$에서부처 $90^{\circ}$까지 가능하도록 되어 있다. 실대형 시험을 통하여 절리각도와 사면경사에 따른 터널거동과 수평지중변위를 계측, 분석하였다. 분석결과 절기각도와 사면경사가 크면 클수록, 터널 내공변위와 터널 라이닝 모멘트가 커지는 경향이 있었으며 수평지중변위 또한 절리각도와 사면경사에 많은 영향을 받고 있어 향후 사면보강에 있어 효율적 방안제시를 위한 기초자료로 활용이 가능할 것이다.

• 대한기계학회논문집B
• /
• 제41권3호
• /
• pp.153-160
• /
• 2017

보행 분석은 다양한 지형에서 수행되고 있으나 지형이 변화되는 시점에서의 보행 분석 연구는 보고된 바 없다. 본 연구의 목적은 삼각경사 보행 시 지형이 변화되는 시점에서 발목 및 무릎 관절의 운동학과 운동역학을 평지 보행과 비교 분석하는 것이다. 3차원 동작분석 시스템과 지면 반력기를 사용하여 성인 남성 18명의 하지 운동학 및 운동역학 자료를 획득하였다. 삼각경사 보행에서 최대 발목 배측굴곡각 및 모멘트와 최대 무릎 신전 모멘트가 평지보행과 비교하였을 때 증가하였다(p<0.05). 삼각경사의 상승경사 보행 시 $50^{\circ}$가 넘는 무릎 굽힘각과 그 시기에 발생하는 큰 무릎 신전 모멘트는 슬개대퇴증후군의 위험을 높일 수 있을 것으로 보인다. 또한 삼각경사의 하강경사 보행에서 증가된 발목 배측굴곡 운동범위는 비복근과 아킬레스건 부상 위험을 높일 수 있을 것으로 보인다.

• 한국운동역학회지
• /
• 제18권1호
• /
• pp.203-212
• /
• 2008

본 연구의 목적은 자진모리장단에 맞추어 3단 디딤새동작의 적합한 모델을 제시하고 이상적인 발 디딤새 동작수행을 위한 자료제공을 목적으로 하였다. 신체중심의 위치변화는 발을 내딛는 순간 신체중심의 높이를 낮추고 발의교차 전진시 전방으로 향하는 직선운동을 수직운동으로 전환하여 동작의 안정성을 유지하며, 좌 우 흔들림 없이 이동하는 것으로 나타났다. 신체중심에 대한 속도변화는 수평방향으로 발을 딛는 순간 신체유동을 작게 하고 전방으로 급격한 이동을 통제하여 안정된 동작을 취하고, 슬관절과 족관절을 수직으로 들어 올려 종골이 지면에 닿을 때 무게중심의 속도가 수평방향으로 빠르게 전진하지 못하게 하는 것으로 나타났다. 관절의 각도변화는 하퇴의 과신전을 막기 위해 고관절은 신전시키고 슬관절은 굴곡 시켜 동작의 안정성을 확보하여 굴곡과 신전이 원활히 이루어지며, 족관절은 중족 에서 발바닥 전체로 무게중심이동시 좌측 발은 배측굴곡을 이룰 때 안정적인 동작이 이루어지는 것으로 나타났다.

• 한국전문물리치료학회지
• /
• 제25권3호
• /
• pp.19-26
• /
• 2018

Background: Genu varum is also known as bow leg. It is a deformity wherein there is lateral bowing of the legs at the knee. it does give rise to pain, and persistent bowing can often give rise to discomfort in knees, hips and ankles. Objects: This study investigated the effect of narrow squats on the knee joint during a gait and distance between the knees of person with genu varum. Methods: This study analyzed 23 patient with genu varum that grade III, 12 narrow squat group and 11 genenal squat group in motion analysis laboratory. The subjects of experiment took gait before and after intervention, the range of joint motion, moment of knee joint adduction, power, distance of the knees were measured. And in order to make an analysis between groups, an paiered t-test and independent t-test was carried out. For statistical significance testing, it was decided that significance level ${\alpha}$ be .05. Results: It was shown that the group of narrow squat exercise significantly decreased in distance of knees (p<.05),In moment of adduction of knee joint, it was shown to significantly decrease in two groups (p<.05), was significantly decreased in adduction, abduction, and rotation (p<.05). In relation of peak-knee adduction moment and valgus angle, there was significant decrease in narrow squat group (p<.05). Conclusion: When the above result of study were examined, a narrow squat exercise given to the genu varum patients significantly decreased the distance between the knees, range of knee adduction and abduction, knee adduction moment, knee power. And stability gains through the decrease of excursion of knee medial part be effective for the correction of genu varum deformation.

• 한국운동역학회지
• /
• 제23권1호
• /
• pp.85-90
• /
• 2013

Efficient gait is compensate for a lack of exercise, but the wrong walking can cause disease that joints, muscles, brain and body structure(Scott & Winter, 1990). Also many researchers has been studied gait of positive mechanism using analytical methods kinetic, kinematic. This study is to identify nature of knee adduction moment, depending on different foot progression angle and the movement of rotation of pelvis and body. Health study subject conducted intended walking with three different angles. The subjects of this study classified three types of walking; walk erect, pigeon-toed walk and an out-toed gait. Ten university students of K without previous operation and disease record selected for this study. For accuracy of this study, three types of walking carried out five times with 3D image analysis and using analysis of ground reaction force to analyze nature of knee adduction moment and the movement of rotation of pelvis and body. Firstly, the HC(heel contact) section value of intended walk erect, pigeon-toed walk and an out-toed gait was not shown statistically significant difference but TO(toe off) section value was shown that the pigeon-toed walk statistically significant. The value of pigeon-toed walk was smallest knee adduction moment(p< 0.005). Secondly, X axis was the change of rotation movement body and pelvis when walk erect, pigeon-toed walk and an out-toed gait. Shown statistically Y axis was not shown statistically significant but Z axis statistically significant(p<0.05). These result show the significant differences on TO section when walking moment reaches HC, it decides the walking types and rotates the foot.

• 한국운동역학회지
• /
• 제33권3호
• /
• pp.110-117
• /
• 2023

Objective: The purpose of this study was to find out kinematic and kinetic differences the lower extremity joint according to the landing type during vertical jump movement after jump landing, and to present an efficient landing method to reduce the incidence of injury in youth players. Method: Total of 24 Youth players under Korean Sport and Olympic Committee, who used either heel contact landing (HCG) or toe contact landing (TCG) participated in this study (HCG (12): CG height: 168.7 ± 9.7 cm, weight: 60.9 ± 11.6 kg, age: 14.1 ± 0.9 yrs., career: 4.3 ± 2.9 yrs., TCG height: 174.8 ± 4.9 cm, weight: 66.9 ± 9.9 kg, age 13.9 ± 0.8 yrs., career: 4.7 ± 2.0 yrs.). Participants were asked to perform jump landing consecutively followed by vertical jump. A 3-dimensional motion analysis with 19 infrared cameras and 2 force plates was performed in this study. To find out the significance between two landing styles independent t-test was performed and significance level was set at .05. Results: HCG showed a significantly higher dorsi flexion, extension and flexion angle at ankle, knee and hip joints, respectively compared with those of TCG (p<.05). Also, HCG revealed reduced RoM at ankle joint while it showed increased RoM at knee joint compared to TCG (p<.05). In addition, HGC showed greater peak force, a loading rate, and impulse than those of TCG (p<.05). Finally, greater planta flexion moment was revealed in TCG compared to HCG at ankle joint. For the knee joint HCG showed extension and flexion moment in E1 and E2, respectively, while TCG showed opposite results. Conclusion: Compared to toe contact landing, the heel contact landing is not expected to have an advantage in terms of absorbing and dispersing the impact of contact with the ground to the joint. If these movements continuously used, performance may deteriorate, including injuries, so it is believed that education on safe landing methods is needed for young athletes whose musculoskeletal growth is not fully mature.

• 한국운동역학회지
• /
• 제24권2호
• /
• pp.121-129
• /
• 2014

The purpose of this study was to investigate the effect of the toe headings on the biomechanics of knee joint in drop landing in an attempt to find the potential risk of non-contact anterior cruciate ligament (ACL) injury. Seventeen male college students ($20.5{\pm}1.1$ yrs; $175.2{\pm}6.4$ cm; $68.8{\pm}5.8$ kg), having no neuromuscular injury within an year, participated in this study. Three different toe headings such as toe-in (TI), neutral (N), and toe-out (TO) positions were tested. Motion capturing system consisting of eight high speed cameras and two force platforms were used to collect three-dimensional motion data and ground reaction force data during landing. Results indicated joint angles and peak joint moments were significantly affected by the toe headings. TI position produced larger valgus angle due to reduce knee distance in addition to higher flexion and valgus moment than other positions, which was somewhat vulnerable to the potential risk of non-contact ACL injury. TO position caused the largest internal rotation angle with smaller joint moments. Therefore, it is recommended that athletes need to land on the ground with neutral toe-heading position as possible in order to minimize the potential risk of non-contact ACL injury.

• 항공우주시스템공학회지
• /
• 제2권2호
• /
• pp.35-41
• /
• 2008

The structural stability for preliminary model of supersonic rocket which has large L/D ratio is investigated. Large L/D ratio can cause a critical problem on the structural stability by the increase of bending-moment. By using the ANSYS and the CFX codes, we inspected the structural stability for Ma=2 and angle of attack for $20^{\circ}$. The optimum number of bolts and their joints required on the rocket surface are predicted.

• 대한인간공학회:학술대회논문집
• /
• 대한인간공학회 1997년도 추계학술대회논문집
• /
• pp.393-397
• /
• 1997

본 연구에서는 손동작(Hand Motion)과 수작업(Manual Task) 분석에 VR환경에서 사용되는 각도 측정 장갑(3-D Glove)을 이용하는 방법을 제안하였다. 본 연구에서 개발된 손동작(Hand Motion)과 수작업(Manual Task)의 분석 시스템은 18-sensor $Cyberglove^{TM}$정 시스템으로부터 측정된 angle data를 기초로 손동작이나 수작업에 대한 totalmuscle moment값과 total muscle excursion값을 구하고, digit와 joint의 moment값을 X,Y.Z방향별고 구하는 기능을 가지고 있다. 시스템의 구성은 : (1) $Cyberglove^{TM}$ System과 분석 시스템의 digital data 처리를 기반으로 하는 손동작의 측정 시스템 ; (2) $Cyberglove^{TM}$ System에서 얻어진 자료를 바탕으로 3차원 공간에서 손동작을 표현할 수 있는 Kinematic Hand Model ; (3) Hand Model과 $Cyberglove^{TM}$ Systme을 기반으로 3차원에서 손동작의 역학적 분석을 할 수 있는 3-D Hand Biomechanical Model ; 등으로 되어있다. 본 시스템은 Telerobotics, Medicine, Virtual Reality 등 다양한 분야에 응용이 가능하며, 수작업에 관련되는 Product Design, Manual Control Device, Computer I/O Device의 설계에도 도움이 될 것으로 기대된다.

• 한국운동역학회지
• /
• 제28권3호
• /
• pp.175-180
• /
• 2018

Objective: Anterior cruciate ligament reconstruction (ACLR) has been considered the primary treatment for anterior cruciate ligament (ACL) injured patient. However, there is little biomechanical evidence regarding bilateral knee joint biomechanics during landing and cutting task after ACLR. Method: Eighteen females with ACLR participated in this investigation. Double leg jump landing (DLJL) and single leg jump cut (SLJC) biomechanics were assessed. Results: During DLJL, the healthy knee showed greater knee valgus angle at initial contact ($^{\circ}$) compared to the injured knee (Injured: $2.93{\pm}2.59$, Healthy: $4.20{\pm}2.46$, t=2.957, p=0.009). There was a significant difference in anterior tibial shear force ($N{\times}N^{-1}$) with greater in the injured knee (Injured: $1.41{\pm}0.39$, Healthy: $1.30{\pm}0.35$, t=2.201, p=0.042). During SLJC, injured knee showed greater knee extension moment ($N^*m{\times}[N^*m]^{-1}$) compared to healthy knee (Injured: $0.51{\pm}0.19$, Healthy: $0.47{\pm}0.17$, t=2.761, p=0.013). However, there was no significant differences between the knees in the other variables. Conclusion: ACLRfemales exhibited a greater knee valgus angle at initial contact and lesser anterior tibial shear force on the healthy knee during double leg jump landing. In addition, ACLR females showed a greater knee extension moment on the injured knee during single leg jump cut.