• 한국운동역학회지
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• 제32권1호
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• pp.24-30
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• 2022

Objective: The purpose of this study was to determine the factors of successful and unsuccessful movements through the analysis of kinematics and muscle activity of the Free Aerial Cartwheel on the balance beam. Method: Subjects (Age: 22.8 ± 2.4 yrs., Height: 158.7 ± 5.0 cm, Body mass: 54.1 ± 6.4 kg, Career: 13 ± 2.4 yrs.) who were currently active as female gymnasts participated in the study. They had no history of surgical treatment within 3 months. Subject criteria included more than 10 years of professional experience in college and professional level of gymnastics and the ability to conduct the Free Aerial Cartwheel on the Balance Beam. Each subject performed 10 times of Free Aerial Cartwheel on the balance beam. One successful trial and one unsuccessful trial (failure) among 10 trials were selected for the comparison. Results: It was found that longer time required in case of unsuccessful trial when performing the Free Aerial Cartwheel on the balance beam compared with successful trial. It is expected to be the result of movement in the last landing section (i.e. phase 5). In addition, it was found that the center of gravity of the body descends at a high speed to perform the jump (i.e. phase 2) in order to obtain a sufficient jumping height when the movement is successful while the knee joint is rapidly extended to perform a jump when movement fails. In the single landing section after the jump (i.e. phase 4), if the ankle joint rapidly dorsiflexed after take-off and the hip joint rapidly flexed, so landing was not successful. Conversely, in a successful landing movement, muscle activity of the biceps femoris was greatly activated resulting no shaking in the last landing section (i.e. phase 5). Conclusion: In order to succeed in this movement, it is necessary to perform a strong jump after rapidly descending the center of gravity of the body using the force of the biceps femoris muscle. Further improvement of the skills on the balance beam requires the analysis of the game-like situation with continuous research on kinematic and kinematic analysis of various techniques, jumps, turns, etc.

• 한국운동역학회지
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• 제12권1호
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• pp.47-61
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• 2002

The purpose of this study was to determined the force and moment of the ankle and the knee joint at different step length relative to the length of the lower extremity during a steady running. Six digital cameras(Qualisis) and a forceplatform(A.M.T.I) were used to obtain the kinematic data of the segments and kinetic data on the running at speed of 5.18m/s. The force and moment measured from six subjects participated in this study were limited to the support phase and their values were averaged at the moment of heel strike, mid stance, and toe off of a running for making a comparison between the condition 1(relative step length 1.1) and the condition 2(relative step length 1.4). It was concluded that internal forces except mediolateral force of the condition 2 were greater in the ankle and the knee joint than those of the condition 1, but all moments of condition 2 were greater from the descriptive statistic point of view. For the future study, it was needed to consider a number of subjects, a various running speed, and a individual step preference for applying generally results to the running strategy.

• 한국운동역학회지
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• 제16권3호
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• pp.125-135
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• 2006

This study was to analyze the effect of dancesport heel-shoes heights on Rumba Cucarachas Movement in terms of analysis, and to provide the essential information to decide the proper heel-shoes heights for individual. six female subjects participated in this study. Dependent variables were set and divided into the amount of movement regarding the velocity and angle of the right elbow, pelvis, ankle, and knee. The following conclusion was drawn blow. 1) Angle: We all appeared in 5, 7, 9cm heel height so that we were similar in a knee and elbow angle and no significantly. The plantar flexion appeared greatly as an ankle angle's shoe high and significantly. 2) Velocity: An elbow velocity all appeared in a three shoes so that it was similar. We speed fast speed some in a 7cm heel height. A knee velocity expressed fast speed some in a 5cm heel height. The pelvis velocity in a that it was similar. Generaly, The aspect to be a dancesport competition o'clock and aesthetic is the height. and the muscular strength train after we need the thing to choose suitable to the individual shoe height. It is logical that the decision of heel-shoes heights should be made by anthropometric and sport dynamic analysis in order to maximize the dynamic and aesthetic aspect of dance sport.

• 대한물리치료과학회지
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• 제19권1호
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• pp.63-69
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• 2012

Background : The purpose of this study was to investigate the frequency domain characteristics of ground reaction forces during quiet standing on inclined surfaces twenty healthy individuals(10 elderly women $68.78{\pm}3.29$ years and 10 young women $20.90{\pm}0.74$ years) participated. Methods : Subjects stood in quiet stance over a force platform positioned in one of three different fixed positions: flat, down and up. Healthy participants completed with eyes open for 120 s trials. Evaluation of postural control were generally based on the interpretation of center of pressure(COP) time series. The COP have been determined using an experimental setup with 3D kinematic and the ground reaction force system. All the data were expressed means and standard deviation by using SAS package program. Results : SEF 50% were not significant in AP and ML direction according to surface slope of both groups. SEF 95% were showed highest frequency in AP direction on down slope of both groups. MEF were not significant all direction according to surface slopes of elderly women. There was no difference between young and elderly women. Conclusion : Elderly women used to ankle strategy during a quiet stance according to COP perturbation of AP direction showed more expanded than ML direction. SEF 95% were showed highest frequency on down slope in elderly women who showed more used ankle strategy for postural control on down slope.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1993년도 춘계학술대회논문집
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• pp.1-9
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• 1993

A human gait study is required for the biomechanical design of running shoes. A tow-dimensional dynamic model was developed in order to analyze lower extremity kinematics and loadings at the right ankle, knee, and hip joints. The dynamic model consists of three segments, the upper leg, the lower leg, and the foot. Each segment was assumed to be a rigid body with one or two frictionless hinge joints. The lower extremity motion was assumed to be planar in the sagittal plane. A young male subject was involved in the gait test and his anthropometric data were measured for the calculation of segement mass and moment of inertia. The experimental data were obtained from three trials of walking at 1.2m/s. The foot-floor reaction data were measured from a Kistler force plate. The kinematic data were acquired using a three-dimensional motion measurement system (Expert Vision) with six markers, five of which were placed on the right lower extremity segments and the rest one was attached to the force plate. Based on the model and experimental data for the stance phase of the right foot, the calculated vertical forces reached up to 492, 540, and 561 N at the hip, knee, ankle joints, respectively. The flexion-extension moments reached up to 155, 119, and 33 Nm in magnitude at the corresponding joints.

• 한국운동역학회지
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• 제31권2호
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• pp.126-132
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• 2021

Objective: The purpose of this study was to investigate how three gaze directions (bottom, normal, up) affects the coordination and stability of the lower limb during drop landing. Method: 20 female adults (age: 21.1±1.1 yrs, height: 165.7±6.2 cm, weight: 59.4±5.9 kg) participated in this study. Participants performed single-leg drop landing task on a 30 cm height and 20 cm horizontal distance away from the force plate. Kinetic and kinematic data were obtained using 8 motion capture cameras and 1 force plates and leg stiffness, loading rate, DPSI were calculated. All statistical analyses were computed by using SPSS 25.0 program. One-way repeated ANOVA was used to compared the differences between the variables in the direction of gaze. To locate the differences, Bonferroni post hoc was applied if significance was observed. Results: The hip flexion angle and ankle plantar flexion angle were significantly smaller when the gaze direction was up. In the kinetic variables, when the gaze direction was up, the loading rate and DPSI were significantly higher than those of other gaze directions. Conclusion: Our results indicated that decreased hip and ankle flexion angles, increased loading rate and DPSI when the gaze direction was up. This suggests that the difference in visual information can increase the risk of injury to the lower limb during landing.

• 한국운동역학회지
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• 제15권1호
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• pp.259-274
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• 2005

The purpose of this study was to compare the kinematic and kinetic parameters of lower extremity joints between novice and experienced sports aerobic dancers during two heights of depth jumps. Four male dancers were participated in this study and they performed 40cm and 60cm height depth jump three times, respectively. Four ProReflex MCU cameras (100frame/sec) and a Kistler force plate (1000Hz) were used for data collection. The results indicated that the duration of contact phase of experienced group was shorter than that of novice group regardless of jump height. For minimum angle of hip, knee, and ankle joints, the novice group had tendency to decrease the angle but the experienced group had increased the joint angle with jump height. There was no difference of total ground reaction force between the groups but the reaction force had tendency to increase with jump height. Thus, this study implied that repetition of jump and landing may induce joint related injury and further study such as. EMG analysis of lower extremity can be needed to verify the relationship between injury and ground reaction force.

• 한국운동역학회지
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• 제16권2호
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• pp.9-19
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• 2006

The purpose of this study was to analyze the kinematic variables of the lower limbs joints and the muscle activity for lower limbs during the level and downhill running. The subjects were 6 males of twenties and required to run on the level and downhill which was -7% grade treadmill at 8.3km/h. The running performances were filmed by high speed video camera and EMG signal was gained by ME3000P8 Measurement Unit. Rectus femoris(RF), Vastus lateralis(VL), Gluteus medius(GLU), Biceps femoris(BF), gastrocnemius medial head(GM), gastrocnemius lateral head(GL), Soleus(SO), Tibialis anterior(TA) were selected. The result of this study were as follows: 1. Ankle, knee, hip joint in downhill running showed less movement than the level running but, no significant difference. 2. VL and BF during the support phase in downhill running showed Iess muscle activity than the level running. but RF showed the opposite result. 3. GM, GL, SO adn TA during the supports phase in downhill running showed less muscle activity than the level running.

• 한국운동역학회지
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• 제19권2호
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• pp.399-406
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• 2009

본 연구의 목적은 롤러 신발과 조깅 신발 착용 후 보행 시 운동학적 변인에 대하여 비교 분석 하는데 있다. 이를 위해 하지 근골격계에 이상이 없는 중학생 8명을 피험자로 선정하여 3차원 동작 분석을 실시하였다. 분석 결과, 활보장, 인체무게 중심변위 및 선속도, 관절각 및 각속도에서 집단 간 통계적으로 유의한 차이를 보였다. 특히 롤러 집단의 경우 지지 시 발목 관절각이 증가하고 무릎각의 각속도가 감소하는 결과를 나타내었다. 이는 롤러 신발의 경우 장착된 휠에 의해 지지 시 적절한 배측굴곡이 이루지지 못하고, 불안정성을 극복하기 위해 무릎의 과도한 굴곡이 나타난 것으로 사료되어 진다. 이러한 운동학적 변인의 차이는 롤러 신발 보행 시 정상 패턴과는 다른 불안정한 보행 동작을 유발시키고 이러한 동작이 지속적으로 이루어진다면 하지 근골격계에 변화를 유발시켜 부상 유발의 가능성이 있을 것으로 생각된다. 따라서 본 연구 결과를 토대로 향후 보다 안정성 높은 롤러 신발을 개발할 수 있을 것으로 기대된다.

• 대한기계학회논문집 C: 기술과 교육
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• 제1권2호
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• pp.153-165
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• 2013

기존의 보행분석 연구들은 하지를 하나의 스프링으로 간주하였다. 만약 슬관절 신전을 보조할 수 있는 슬관절 액추에이팅 메커니즘을 개발할 수 있다면 보행에 필요한 탄성-변형률에너지를 혁신적으로 저장-방출할 수 있고, 그 결과 보행 중 하지강성은 더욱 증가할 것이다. 게다가 족관절 액추에이팅 메커니즘까지 추가되어 있다면 슬관절 액추에이터에 의한 과도한 인공하지강성을 능동적이고 적절한 수준으로 보상해주는 기전으로 작동할 것이다. 만약 가속도에 의한 보행속도 증가를 방지하기 위해 인위적 감속통제를 작동시킨다면 불필요한 운동에너지의 방출이 발생되고 하지강성 액추에이터의 실효성은 의심을 받게 된다. 따라서 본 저자는 보행속도를 2개의 세그먼트에 의한 상대 각속도 조절기법을 이용하여 하지강성을 증가시킨다는 기본개념으로 슬-족관절 액추에이터 시스템을 개발하였다. 또한 족관절에 슬관절 액추에이팅에 대한 보상기전이 존재하는 경우, 족관절의 보상기전이 중족지절관절 경사각 및 보행속도 변화에 미치는 상호영향을 연구하였다.