• Korean Journal of Applied Biomechanics
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• v.13 no.1
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• pp.205-221
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• 2003

본 연구는 축구화 겉창의 스터드개발시 운동역학적 연구가 스터드개발에 어떻게 영향을 끼치었는가를 국외 선행연구문헌을 고찰함으로서 그 과정을 발견하는데 그 목적을 두었다. 지난 70년간 축구화 스터드가 연구개발되는 과정에서 압력분포측정 실험 및 기타 상해유발요인을 분석함으로서 스터드의 형태을 변화시키는 과정에 있어서 축구장 바닥과 축구화 겉창과의 마찰력이 중요한 변수로 작용하였다. 징이 선수들의 미끄럼을 방지하고 순발력을 향상시켜 경기력 향상에 결정적인 도움을 준 것이다. 이후 징박힌 축구화가 보편화하면서 선수들은 공격수냐 수비수냐 또는 잔디 상태에 따라 징의 개수와 길이가 다른 축구화를 신게 되었는데, 그라운드 컨디션에 따라 신발이 개발되었다. 축구화는 징의 종류에 따라 길고 푹신한 잔디($5{\sim}7$월 잔디)에 신는 50(soft ground)형, 짧고 단단한 잔디(가을철 잔디)에 적합한 FG(firm ground)형, 인조잔디나 아주 짧은 잔디에 좋은 터프(Turf)형, 맨땅에 쓰는 HG(hard ground)형으로 대별되는데, SG형은 15mm가 넘는 마그네슘 징을 6개 박는데 순발력과 파워를 극대화하기 때문에 수비수에 어울리는 스타일이다. 짧은 플리우레탄 징 12개를 다는 FG형은 넓은 그라운드 접촉면을 이루면서도 잔디에 깊게 박히지 않아 유연성을 필요로 하는 공격수와 미드필더들에게 애용된다. 그라운드 상황이 좋지 않은 곳에서 뛰는 국내 고교, 대학 선수들은 12개의 징이 달린 축구화를 선호한다. 스터드가 많을 수록 그라운드에 닿는 면적이 넓어 안정감도 있고 발목이 꺾이는 현상을 줄여주기 때문이다. 지금까지의 연구현황은 압력분포 및 지면반력실험을 이용한 결과치를 이용하여 새로운 타입의 축구화 스터드의 개발결과를 기존결과와 비교 분석하여 상해유발발생요인이 적은 스타일의 스터드를 선호하였다. 이에 향후 연구개발시 운동역학적 연구의 디자인 시 상해유발요인분석과 운동역학적 연구결과의 조합을 결과를 비교분석해서 국내에서도 축구화 겉창 스터드 연구개발시 경기력을 향상시키고, 상해유발요인을 감소시킬 수 있는 연구디자인이 지속되는 것이 중요하다고 사료된다.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.513-518
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• 2016

The Mechanisms of whole body vibration on the human body is not clearly presented despite of the research result and there is not enough research that shows the effects of vibration on the kinetic changes of the lower joint. Therefore, this study focuses on finding out which lower joint is related with kinetic vertical jump ability. Five male and five female who didn't have orthopedic history were selected as the subjects. The subjects carried out three squat jumps before and after 5minutes of 30Hz whole body vibration. We have utilized a 3D motion analysis system to analyze the kinetic changes of the lower joint in the vertical jump. The height of subjects squat jump was improved after whole body vibration treatment. Also, the lower joint moment and power increased. However, there were no statistically significant changes in GRF, hip joint moment and power after the whole body vibration proved to have positive effect on the ankle and knee joints but showed negative effect on the hip joint.

• 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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1391-1398
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• 2011

Biomechanical analysis of arm motion during steering was performed using a motion analysis technique. Three-dimensional position data for each part of arm are fed into an interactive model combining a musculoskeletal arm model and the mechanical steering system to calculate joint angles and torques using inverse kinematic and dynamic analyses, respectively. The analysis shows that elbow pronation/supination, wrist flexion/extension, shoulder adduction/abduction, and shoulder flexion/extension have significant magnitudes. Sensitivity analysis of the arm joint motion with respect to seating posture and steering wheel configuration is carried out to investigate the qualitative influence of the seating posture and driver's seat configuration on the steering behavior.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.1
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• pp.21-27
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• 2013

Manual wheelchair propulsion can lead to pain and injuries of users due to mechanical inefficiency of wheelchair propulsion motion. The kinetic analysis of the upper limbs during manual wheelchair propulsion needs to be studied. A two dimensional inverse dynamic model of upper limbs was developed to compute the joint torque during manual wheelchair propulsion. The model was composed of three segments corresponding to upper arm, lower arm and hand. These segments connected in series by revolute joints constitute open chain mechanism in sagittal plane. The inverse dynamic method is based on Newton-Euler formalism. The model was applied to data collected in experiments. Kinematic data of upper limbs during wheelchair propulsion were obtained from three dimensional trajectories of markers collected by a motion capture system. Kinetic data as external forces applied on the hand were obtained from a dynamometer. The joint rotation angles and joint torques were computed using the inverse dynamic model. The developed model is for upper limbs biomechanics and can easily be extended to three dimensional dynamic model.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.3
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• pp.153-160
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• 2017

Gait analysis has been conducted in various environments, but the biomechanics during the transition from uphill walking to downhill walking have not been reported. The purpose of this study is to investigate the knee and ankle joint kinematics and kinetics during walking on a triangle-shaped slope compared with those during level walking. Kinematic and kinetic data of eighteen participants were obtained using a force plate and motion capture system. The greater peak ankle dorsiflexion angle and moment and the peak knee extension moment were observed (p<0.05) during both uphill and downhill walking on the triangle-shaped slope. In summary, uphill walking on a triangle-shaped slope, which showed a peak knee flexion of more than $50^{\circ}$ with greater peak knee extension moment, could increase the risk of patellofemoral pain syndrome. Downhill walking on a triangle-shaped slope, which involved greater ankle dorsiflexion excursion and peak ankle dorsiflexion, could cause gastrocnemius muscle strain and Achilles tendon overuse injury.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.11
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• pp.1085-1089
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• 2017

Juryeonggu is a cuboctahedral die that was used during the Silla period in ancient Korea. This cuboctahedral die consists of two different penal servitudes of 14 sides; however, its equal probability distribution enables it to be used as a die. In this paper, a precise cuboctahedral die, Juryeonggu, was manufactured, and its probability was measured through experiments. Next, the probability was verified through Multibody-dynamics (MBD) modeling and analysis, and the effect of the coefficient of friction on the probability distribution was studied.

• Journal of the Korean Applied Science and Technology
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• v.37 no.2
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• pp.232-240
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• 2020

The purpose of this study was to analyze the effect of using standing step condition on biomechanical variables during jab in boxing. For this purpose, eight orthodox type college boxers(age = 20.38±0.52 yrs, height = 172.38±5.80 cm, body mass = 63.45±8.56 kg, career = 6.00±1.07 yrs) who without injury to the musculoskeletal system participated in the experiment over the last year. In order to verify the effect of biomechanical variables using standing step during jab in boxing, the paired t-test (α = .05) statistical method was used. First, W.S(with-step) showed a greater impact force than N.S(non-step), and muscle activity was analyzed to be low. Second, it was analyzed that the pelvis and foot segments move faster because W.S affects the velocity of the anterior segment of the human body. Third, the rotational movement of the pelvis was faster in W.S. Fourth, W.S was analyzed to have greater ground reaction force in the anterior caused by the right and left foot than N.S. Through this, it was found that the use of the standing step during jab increases the ground reaction force the velocity and rotational movement of the human segment. Therefore, it was confirmed that it allowed a faster and more agile movement, and thus produces a greater impact force with relatively less muscle activity. Therefore, in order to effectively deliver a greater impact force to the opponent during the jab, it was effectively analyzed to accompany the standing step.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.749-759
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• 2009

The purpose of this study was to provide basic information for improving a soft tennis forehand middle volley technique based on kinematic and kinetic analyses of volleys performed by four male national tennis players($33.3{\pm}2.16$ years). The results are as follows. The first phase of the stroke was the longest, covering 64.7% of the stroke time. The displacement of the center of gravity was 48.1% to the right and 54% to the front in the first phase. When impacted, the elbow joint showed the highest average velocity, 3.67m/s, and the upper arm segment displayed the highest angular velocity, $201^{\circ}/s$. The average of the elbow angle and the ball velocity were $149^{\circ}$ and 18.9m/s, respectively. In the ground reaction force, the left and right foot forces in both the x and y directions showed a statistically significant difference. This result seems to indicate that when the left foot is pushed to the right, the force of the right foot is proportional and symmetrical to the left, serving as a supporter.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.681-688
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• 2009

To better delineate the changes in corticospinal excitability when older adults are asked to observe and/or imagine actions, 22 right-handed older adults without neurological abnormalities were included in this study. The amplitude and latency of motor evoked potentials (MEPs) by transcranial magnetic stimulation were recorded in the abductor pollicis brevis of the dominant hand during passive observation/imagery/active observation of slow/fast action of abduction of right thumb and also at resting state. Thus, active observation showed better changes than passive, but slow and fast action revealed no difference at all.