• 한국운동역학회지
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• 제20권1호
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• pp.101-108
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• 2010

Recently, core and neuromuscular training(CNT) is emerging as a clinically relevant tool to improve neuromuscular control and to prevent sports injuries. The purpose of this study was to examine the effect of a 12 weeks CNT program on the dynamic stability after drop landing. The subjects attempted drop landing onto the force platform on single foot from a 40 cm height distance. The collected data was used to calculate the dynamic stability index. The Dynamic stability index was derived by measuring the medial-lateral stability index(MLSI), anterior-posterior stability index(APSI), and the vertical stability index(VSI). In comparison to the control group, the MLSI and APSI showed no difference, yet, it resulted in higher VSI. The results of this study suggest that CNT is worthwhile to be considered as a way to improve neuromuscular control and to prevent traumatic injuries. However, the results are taking into consideration to discuss the limitations of CNT and suggested future approaches.

• 한국운동역학회지
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• 제23권3호
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• pp.219-223
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• 2013

The purpose of the study was to investigate the effects of gymnasts shoes on risk factors of anterior cruciate ligament injuries during drop-landing followed by vertical jump in female gymnasts. Thirteen female gymnasts were recruited and performed randomly drop-landing followed by vertical jump in height of her knee with and without shoes. Kinematics and ground reaction data were collected to estimate the anterior cruciate ligament injuries risk factors. Data were analyzed with paired samples t-test with Bonferroni correction. Female gymnasts with shoes showed more reduced thigh maximum adduction angle, and knee maximum extension moment than without shoes. Female gymnasts with shoes showed more increased shank maximum abduction angle than without shoes. In conclusion, Female gymnasts with shoes reduced anterior cruciate ligament injuries risk factors.

• 감성과학
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• 제10권4호
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• pp.539-554
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• 2007

대형 비행기 조종사들은 지상으로부터 높은 조종실의 위치, 빠른 접근속도와 수직강하속도로 인하여 불충분한 시각정보를 바탕으로 착륙 조작을 하여야만 한다. 본 연구에서는 이러한 대형 비행기의 특징으로 인하여 비행기 착륙의 최종 조작인 당김(flare) 조작을 할 때 대형 비행기 조종사들이 정확한 높이지각을 하기 어렵다는 사실을 검증하였다. 연구 1에서는 조종석 외부로 보이는 공항에 대한 사진을 제시하고 높이 추정을 하도록 하여 정적 시각 단서만으로 정확한 높이지각이 가능한지를 살펴보았다. 85feet의 고도에서는 정확한 높이지각을 하나 당김 조작을 준비해야 하는 높이인 55feet부터 낮은 고도에서는 정확한 높이를 추정하지 못하였다. 연구 2에서는 착륙의 전 과정을 녹화한 화면을 보여주어 높이 추정을 하도록 하여 동적 시각 단서와 정적 시각 단서를 모두 제공하여 주었다. 시각단서가 연구 1보다 풍부하였으므로 50feet까지 정확한 높이지각을 하였으나 연구 1의 결과와 마찬가지로 당김 조작을 시작하는 높이인 30feet 이하의 저고도에서의 높이지각이 모두 부정확하였다. 시각 단서의 해석에 경험이 중요한 요인이므로 경험이 많은 기장과 경험이 적은 부기장 간의 높이 추정에 차이가 있는지를 연구 1과 연구 2에서 모두 비교하여 보았으나 차이는 유의하지 않았다.

• 한국운동역학회지
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• 제24권4호
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• pp.375-383
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• 2014

The purpose of this study was to assess the inter-segmental trunk motion during which multi-segmental movements of the spinal column was designed to interpret the effect of segmentation on the total measured spine motion. Also it analyzed the relative motion at three types of the spine models in drop landing. A secondary goal was to determine the intrinsic algorithmic errors of spine motion and the usefulness of such an approach as a tool to assess spinal motions. College students in the soccer team were selected the ten males with no history of spine symptoms or injuries. Each subject was given a fifteen minute adaptation period of drop landing on the 30cm height box. Inter-segmental spine motion were collected Vicon Motion Capture System (250 Hz) and synchronized with GRF data (1000 Hz). The result shows that Model III has a more increased range of motion (ROM) than Model I and Model II. And the Lagrange energy has significant difference of at E3 and E4 (p<.05). This study can be concluded that there are differences in the three models of algorithm during the phase of load absorption. Especially, Model III shows proper spine motion for the inter-segmental joint motion with the interaction effects using the seven segments. Model III shows more proper observed values about dynamic equilibrium than Model I & Model II. The findings have shown that the dynamic stability strategy of Model III toward multi-directional spinal motion supports for better function of the inter-segmental motor-control than the Model I and Model II.

• 한국운동역학회지
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• 제18권4호
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• pp.31-39
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• 2008

이 연구는 국내에서 개최한 국제육강대회의 110m 허들 결승을 대상으로 대회 우승자(중국),2위 입상자(미국), 3위 입상자(한국) 총 3명을 대상자로 선정하였다. 국외 우수선수와 국내 우수선수의 허들링 동작을 분석하기 위해 3차원 영상분석을 이용하였으며, 기술적 특징을 분석한 결과 다음과 같은 결론을 얻었다. 허들을 넘기 전 질주동작인 준비구간에서 국내 우수선수는 도약 접지에서 도약이지까지 신체 무게중심의 수평거리가 1.04m로 국외 우수선수보다 0.13m 길게 질주하는 것으로 나타났다. 허들을 넘는 비행구간에서 국내 우수선수는 도약에서 비행정점까지 신체 무게중심의 수평거리가 1.63m로 나타났으며, 국외 우수선수보다 0.33m 짧게 도약하는 것으로 나타났다. 비행정점에서 착지까지는 국내 우수선수가 1.59m로 국외 우수선수보다 0.33m 길게 착지하는 것으로 나타났다. 또한 허들을 넘는 동안 신체 무게중심의 수평속도는 도약에서 착지까지 국내 우수선수가 0.75m/s 감소하는 것으로 나타났으며, 도약비율과 착지비율은 53:47로 나타났다. 허들을 넘은 후 질주하는 가속구간은 국내 우수선수가 착지이지에서 신체 무게중심의 수평속도가 8.78m/s로 나타났으며, 국외 우수선수보다 0.54m/s 느린 것으로 나타났다.

• 한국운동역학회지
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• 제23권4호
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• pp.285-294
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• 2013

The purpose of this study was to provide fundamental information for success factors of techniques through kinematic analysis including coordination of lower extremities and landing stability according to the success and failure of $540^{\circ}$ Dwihuryeochagi in Taekwondo. Twenty Taekwondo athletes: ten success group (S, age: $22.3{\pm}1.8$ yrs, height: $172.1{\pm}5.4$ cm, body mass: $64.4{\pm}4.2$ kg) and ten failure group (F, age: $22.3{\pm}1.8$ yrs, height: $172.1{\pm}5.4$ cm, body mass: $64.4{\pm}4.2$ kg) participated in this study. Three-dimensional motion analysis using a system of 3 video cameras with a sampling of 60 fields/s was performed during the competition of $540^{\circ}$ Dwihuryeochagi. Motions were divided into five events: pivot foot landing (E1), pivot foot toe off (E2), COM max height (E3), kick impact (E4) and landing (E5). At E1, the stride width was greater for S than for F (p<.05) while the time was greater for S than for F during P4 (p<.05). At E4, knee angle was greater for S than for F (p<.05). At E5, hip angle was greater for S than for F (p<.05) while kick distance was greater for S than for F (p<.05). Furthermore, at P3, the time would be related to kicking velocity (p<.05), while at P4, the time, range of hip angle and knee angle would be related to kick distance (p<.05). At P1, COM horizontal velocity would be related to COM vertical velocity of P1 and P2 (p<.05). Based on the findings, success factors of $540^{\circ}\acute{y}$ Dwihuryeochagi were COM horizontal velocity of P1, COM vertical velocity of P2, the time, kick distance, velocity, angle of lower extremities and coordination of P3-P4.

• 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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• 제27권1호
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• pp.9-18
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• 2017

Objective: The purpose of this study was to identify kinematic variables that govern successful performance and judges' scores and to establish correlative relationships among those of Yurchenko layout with a full twist in female vaults. Method: Four video cameras with sampling rate of 60 Hz collected 32 motion data of Yurchenko vaults from twenty-two female participants (age: $18.6{\pm}3.6years$, height: $153.0{\pm}6.5cm$, mass: $44.7{\pm}7.3kg$) during national competition. Posting processing and calculations of kinematic variables were performed in Kwon 3D XP and $Matlab^{(R)}$ programs. Correlation and regression analyses were applied to find the relationships between the obtained scores and kinematic variables. Deterministic model (Hay & Reid, 1988) was used to investigate the strength of correlative relationships among kinematic variables. Results: The obtained scores from the judges' decision were mainly affected by post-flight peak height, horse contact time, knee angle at landing, and horse takeoff angle. Strong blocking during horse contact was required to get successful performance and obtain high scores. Modified deterministic model showed that round-off entrance and takeoff angles and resultant velocity of the center of mass (CM) during the roundoff phase were the starting variables affecting performance in the following kinematics. Knee angle at landing, a highly influential variable on the obtained point, was only determined by judges' decision without significant correlative relationship with previous kinematic variables. Conclusion: The obtained scores highly depended on kinematic variables of post-flight and horse contact phases that were affected by those from the previous phases including round-off postures and resultant velocity of the body center of mass.

• 한국운동역학회지
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• 제21권2호
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• pp.173-179
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• 2011

This study aims to analyse difference in biomechanical factors between dominant legs and recessive ones according to muscular imbalance during drop landing targeting talented children in sports. The subjects of the study were ten primary students who are attending to Sports Program for Talented Children organized by C university (age: $12.28{\pm}0.70$ year, height: $1.52{\pm}0.11$ m, and weight: $45.2{\pm}4.9$ kg). Strength legs were classified into dominant side and strengthless legs were classified into non-dominant legs. For three-dimensional analyses of the data collected, 6 video cameras(MotionMaster200, Visol, Korea) were used. To analyse ground reaction force, two force platforms(AMTI ORG-6, MA) were used and to analyse electromyograghy a 8-channeled wireless Noraxon Myoresearch made in USA was used at 1000 Hz for sampling. As a result, it was discovered that the dominants legs controlled knee bending motions more stably than strengthless legs as the maximum vertical ground reaction force was significantly high in dominant legs(p<.05), and joint moment of knee joints of the dominant legs was high(p<.05). Therefore, this study suggested that injury prevention program focusing on muscular balance as well as the existing sports programs for talented children should be developed based on results of the study and it is expected that the results will be useful for improvement of sports programs for talented children.

• 한국지능시스템학회논문지
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• 제25권6호
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• pp.536-541
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• 2015

본 논문은 실내에서 미니드론의 영상기반 자동 비행 및 이 착륙 제어시스템을 제안한다. 천정 카메라와 지면에 마커가 있는 환경에서 미니드론의 자동 비행 제어시스템을 구성하였다. 천장에 설치된 카메라영상을 기반으로 착륙 위치와 드론을 인식할 뿐만 아니라 드론의 움직임을 추적한다. PC서버는 드론의 위치를 계산하여 드론에 제어 명령을 전송한다. 드론의 비행 제어기는 상태 머신 기법, PID 제어와 웨이포인트-위치 제어기법을 사용하여 구현하였다. 실제 미니드론을 사용하여 제안한 자동제어시스템을 검증하였다. 바닥의 마커를 인식하여 ㄱ, ㄷ, ㅁ자 등의 특정 형상의 궤적을 따라 비행하는 것을 실험으로 확인하였으며, 높이의 차이가 있는 두 개의 착륙지점에도 착륙하는 실험에서도 우수한 성능을 보여 주었다.