Kinematic Analysis of Skiing with Different 2 Type of Ski Simulator

Lee, Hyo-Taek(이효택),Roh, Hyo-Lyun(노효련),Heo, Bo-Seob(허보섭),Kim, Yong-Jae(김용재) 한국사회체육학회 2014 한국사회체육학회지 Vol.0 No.58

본 연구는 두 가지 시뮬레이터에서 스키 동작 시 스키어의 하지 관절각 변화와 근활성도에 어떠한 영향을 미치는지 분석하고, 이를 토대로 시뮬레이터에서 보다 안전하고 정확하게 자세를 유지하며, 관절의 가동범위와 주동근을 효율적으로 활용할 수 있도록 도움이 되고자 하였다. 연구대상자는 대한스키지도자협회 지도자 자격을 소지하고 있는 남성 8명으로 선정하였다. 각 구간별 스키 동작의 소요시간, 하지관절각의 변화, 근활성도를 산출한 결과를 다음과 같다. 첫째, 프로시뮬레이터에서의 스키 동작 시 스키어스에지에 비해 오랜 시간 스키 동작을 수행하였으며 통계적으로도 유의한 차를 나타냈다. 둘째, 하지 관절각을 살펴보면, 최초 준비자세 E1, 좌측 최대구간 E2 그리고 우측 최대구간 E4에서 유의한 차를 보였으며, 스키어스에지 보다 프로시뮬레이터에서 더 큰 변화폭을 보였다. 셋째, 하지 근활성도의 경우 프로시뮬레이터에서 대퇴직근(p< .001), 대퇴이두근(p< .001), 전경골근(p<.05), 및 비복근(p< .001)로 %MVIC 값이 높게 나타났다. 대다수의 피험자들이 프로시뮬레이터에서의 스키 동작시 더 큰 %MVIC 값을 유지하며 동작을 반복한 것으로 나타났다. 스키시뮬레이터에서의 스키 동작을 효율적으로 수행하기 위해서는 양발의 스키 수행시간을 최대한 활용하면서, 고관절과 무릎관절을 최대한 굴곡 시킨 후 빠르게 신전시키는 능력이 요구된다. 하지만 스키기술 수준에 따라 개별성의 차이가 있으므로, 본 연구결과에서는 숙련자의 경우 프로시뮬레이터, 비숙련자의 경우 스키어스에지의 운동 수행이 보다 안정적으로 이뤄질 수 있다고 판단되며, 향후 본 연구와 관련하여 부상 예방을 위한 근력 트레이닝 프로그램 및 보다 안전하고 효율적인 동작을 가져갈 수 있기 위한 부가적인 조절장치의 개발도 필요할 것으로 사료된다.

수상안전을 위한 Sculling 동작의 전산유체역학적 연구

이효택(Hyo-Taek LEE),김용재(Yong-Jae KIM) 한국수산해양교육학회 2012 水産海洋敎育硏究 Vol.24 No.1

This study analyses the effects of various angles in sculling on human body lift and drag by means of computational fluid dynamics, discusses the importance of sculling and provides a basis for the development of future water safety education programmes. Study subjects were based on the mean data collected from males in the age of 20s from a survey on the anthropometric dimensions of the Koreans. Moreover, lift, drag as well as coefficient values, all of which were governed by the angle of the palm, were calculated using 3-dimentional modelling produced by computational fluid dynamics programmes i.e. CFD. Interpretations were performed via general k-ε turbulence modelling in order to determine lift, drag and coefficient values. Turbulence intensity was set to one per cent as per the figures from preceding research papers and 3-dimentional simulations were performed for a total of five different angles 0°, 15°, 30°, 45° and 60°. The drag and lift values for the differing angles of the hands during sculling movement are as follows. The lift and drag values gradually increased with the increasing angle of the palm, however, the magnitude of increase for drag started to predominate lift from 45° and lift gradually decreased from 60°. Overall, it is concluded that the optimal efficiency of sculling can be achieved at the angles 15° and 30°, and it is anticipated that greater safety and informative education can be ensured for Life saving trainees if the results were to be applied to practical settings. However, as the study was conducted using simulation programmes which performed analyses on the collected anthropometric dimension, the obtained results cannot be made universal, which warrants furthers studies involving varied study subjects with actual measurements taken in water.

스컬링 수행 시 손바닥 각도에 따른 수중에서의 체중 변화

이효택(Hyo-Taek LEE),김용재(Yong-Jae KIM) 한국수산해양교육학회 2013 水産海洋敎育硏究 Vol.25 No.2

In this study, the researcher tried to analyse the effects of various palm angles in sculling on the variation of underwater weighting. An experiment was conducted on the study subjects of 14 males with life guard licences issued by the Korean Red Cross, living in B district with their spontaneous consent after explaining the purpose and method of this study sufficiently. The effects of various angles in sculling on underwater weighting is as follows; The underwater weighting in sculling gradually decreased with the increasing angle of the palm from 0°to 45°during sculling(p< .001). Overall, it is concluded that the optimal efficiency of sculling can be achieved at the angles 30°and 45°. But, it is a little limited that we generalize the result drawn from variation of underwater weighting depending on the angles as an actual lift and drag value, which warrants further studies on the measuring of overall swimming movement of rotary kick of our lower body as well as sculling, along with various subjects.

회외족의 Wedge Insole 각에 따른 보행 시 접지 시간, 접지면적 및 족저압력의 비교

이효택(Hyo-Taek LEE),김용재(Yong-Jae KIM) 한국수산해양교육학회 2010 水産海洋敎育硏究 Vol.22 No.4

This study was conducted on male college students with supinated foot to measure the foot pressure by having them wear three kinds of wedge insoles (0°, 3.5°, 7°). Foot contact time, foot contact area, peak pressure and mean pressure were measured using a foot pressure distribution measuring instrument. And the surface of the foot sole was divided into 10 areas. Regarding foot contact time, there was no statistically significant difference by showing 0.69±0.004 seconds at 3.5°and 0.68±0.006 seconds at 0°and 7°. Regarding the foot contact area, it appeared broad in the inside area of the foot according to wedge insole, and there was statistically significant difference in the area 1 of the rear foot(p< .01) and the area 3 of the middle foot(p< .05). The peak pressure by foot area decreased in the outside of the foot according to wedge insole, while increasing in the inside of the foot. Among the areas, there was statistically significant in the area 2 of the rear foot (p< .01) and the area 3 of the middle foot (p< .05). Regarding the mean pressure by foot area, the pressure roughly increased in the inside area of the foot according to wedge insole, while decreasing in the outside of the foot.

수상안전사고 예방을 위한 스컬링 동작의 운동학적 분석

이효택(Lee, Hyo-Taek),김용재(Kim, Yong-Jae) 한국사회체육학회 2014 한국사회체육학회지 Vol.0 No.58

In this study, the researcher tried to analyse the sculling motion for prevent water safety accident, and suggest the most efficient sculling method through 3-dimensional motion analysis. An experiment was conducted on the study subjects of 7males with life guard licences issued by the Korean Red Cross, living in B district with their spontaneous consent after explaining the purpose and method of this study sufficiently. The effects of various angles in sculling on 3-dimensional motion analysis areas follows; It took 1.61 sec to perform the sculling, and the variation of angle of the elbow showed 22.86° in the left and 15.48° in the right in P1 section, while 21.95° in the left and 21.77° in the right in P2 section. On the other hand, the variation of angle of the shoulder showed 13.93° in the left and 12.82° in the right in1 P section, while 16.05° in the left and 12.46° in the right in P2 section. Though sculling movements were analyzed by collecting anthropometric data through 3-dimensional motion analysis, it is a little limited that we generalize the result drawn from the laboratory experiment as an actual under water sculling value, which warrants further studies on the measuring of over all swimming movement of rotary kick of our lower body as well as sculling, along with various subjects.

스쿼트 동작 시 웨이트 벨트 착용 전·후에 따른 운동역학적 분석

이정기(Jeong-Ki LEE),허보섭(Bo-Seob HEO),김용재(Yong-Jae KIM),이효택(Hyo-Taek LEE) 한국수산해양교육학회 2016 水産海洋敎育硏究 Vol.28 No.4

The purpose of this study is to investigate the effect of wearing a weightlifting belt, which is an auxiliary equipment used during squat, by measuring and analyzing biomechanical difference in lower limb and proposing safer and to suggest a more effective exercise method for general population. Selected 8 male participants in their 20s who have not performed regular resistance exercise for at least a year, but have experience of performing squat. The comprehensive method of study is as follows: subjects were notified of the purpose of the study and were told to practice warm-up and the squat motion for the experiment for 20 minutes. When the participant believed they were ready to begin, the experiment was started. At controlled points, foot pressure distribution sensor has been installed. Then left and right feet have been placed on the pressure distribution sensor, from which data for successful squat position that does not satisfy the criteria for failure have been collected and computed with Kwon3D XP program and TPScan program. For data processing of this study, SPSS 21.0 was used to calculated mean (M) and standard deviation (SD) of the analyzed values, and paired t-test has been conducted to investigate the difference before and after wearing the weightlifting belt, with p-value of α< .05. As for time consumed depending on usage of weightlifting belt in squat, statistically significant difference has been found in P2, which is recovery movement. Lower limb angle depending on usage of weightlifting belt in squat has shown statistically significant difference in E1 foot joint(p<. 001). There has been statistically significant difference in E2 knee joint. Foot pressure percentage depending on usage of weightlifting belt in squat were found to be statistically significant (p<. 01) in both regions of anterior and posterior foot.

쇼트트랙 스피드 스케이트 운동시 하지 관절각 분석

박정훈(Jung-Hoon PARK),이효택(Hyo-Taek LEE),김용재(Yong-Jae KIM) 한국수산해양교육학회 2013 水産海洋敎育硏究 Vol.25 No.3

This study, which is conducted on two groups of skilled people and unskilled people, is purposed to analyze joint angle of lower extremity during short track speed skating in order to find out efficient body position and propose ideal training method. Short Track Speed Skating has a wide range of research areas, but their findings indicate a promising area for further research. Targeting 8 people who are skilled in short track speed skating and 8 people who are not skilled in it, this study analyzes three dimensional images using super-high speed camera to compare differences between these two groups of people. In this study, 6 sections of body positions including right foot push-off, right foot recovery, right foot basic position, left foot push-off, left foot recovery, and left foot basic position were analyzed using 8 super-high speed cameras of VICON. These body positions were analyzed in order to find out joint angles of the hip joint, the knee joint, and the ankle joint. In the section 4 of the inner and outer parts of the left hip angles showed significant difference, and most of the sections of knee joint angles also showed significant difference. In the section 1 and 2 of the plantar flexion, dorsiflexion of ankle joints showed significant difference(p<.001) It was found out that there were differences between groups of skilled people and unskilled people in terms of lower extremity’s joint angles such as angles of the hip joint, the knee joint, and the ankle joint.

스텝업 운동이 무릎넙다리 통증증후군을 가진 축구선수의 근활성도에 미치는 영향

황일균(Il-Gyoon HWANG),이효택(Hyo-Taek LEE),허보섭(Bo-Seob HEO),김용재(Yong-Jae KIM) 한국수산해양교육학회 2015 水産海洋敎育硏究 Vol.27 No.1

The purpose of this study was to examine EMG activities and VMO/VL ratio of the vastus medialis oblique, and vastus lateralis during step up exercise according to ankle and knee positions in soccer players with patellofemoral pain syndrome. Methods: Subject(patellofemoral pain syndrome, PFPS: n=8 and without PFPS, non PFPS; NPFPS: n=8) perfomed step up exercise at each knee and ankle position(knee flexion 30°, 60°, and 90°, ankle internal rotation 30°, neutral, and external rotation 30°) while EMG activity was collected. The EMG signals were expressed by the % maximal voluntary isometric Contraction(%MVIC) values. Statistical analysis consisted of two way repeated measures analysis of variance with post hoc analysis. Results: Main results were as follows: 1) EMG of VMO, and VL was tend to be lower in PFPS compared to NPFPS. 2) EMG of VMO and VL with knee flexrion 60° was significantly higher the results with knee flexion 30°, and 90°. VMO and VL with ankle external rotation 30° was significantly higher the results with internal rotation 30° and neutral position. Conclusion: Considering the EMG activity was reduced due to the to the PFPS and that performing step up with knee flexion 60° with ankle external rotation 30° position may provide the most effective condition for patients with patellofemoral pain syndrome.

태권도 앞꼬아서기 옆차기의 운동역학적 분석

허보섭(Heo, Bo-Seob),이효택(Lee, Hyo-Taek),김용재(Kim, Yong-Jae) 한국사회체육학회 2015 한국사회체육학회지 Vol.0 No.61

This paper is to establish the kinetic and kinematic factors of Apkkoaseogi(front cross stance) Yeopchagi(side kick) in Taekwondo through factors such as movement of the center of the whole body, the angle of the kicking foot, the supporting foot in the lower body, and the muscle activity and then describe the improvement in the skill for the Taekwondo Poomsae players. The study was performed targeting 6 awarded players who had the experience of winning at the national team competition and other nationwide competitions and 6 players who had no experiences at those competitions. After explaining to them the purpose and procedure of the test and getting the written consents from them, the test was conducted. For the test, 5 high speed digital cameras(Motion Master 100) and wireless EMG(QEMG-4, Lxtha Korea) were used to collect the data on 5 practices of Apkkoaseogi(front cross stance) Yeopchagi(side kick) in Taekwondo focusing on the movement of the center of the body, the angle of the hip joint, knee joint and the ankle joint, and the muscle activity of the femoral rectus muscle, biceps femoris, gastrocnemius muscle and tibialis anterior. Among them, 1 action which was judged to be the most perfect was chosen for analysis. By removing the first and last 2 seconds in the signal of surface electromyography stet, the root mean square(RMS) and the % MVIC value were obtained for analysis. For the processing of the data, SPSS 21.0 software was used and the analyzed values were obtained including the average(M) and standard deviation(SD). For the identification of the difference between the awarded players and the non-awarded players, the independent sample t-test was conducted and the significant statistical level was set as(p< .05). The results were as follows. 1. Duration of Apkkoaseogi Yeopchagi in Taekwondo The duration of Apkkoaseogi Yeopchagi in Taekwondo at each phase showed a significant difference at the phase of P4(p< .05). 2. The Movement of the center of the body at Apkkoaseogi Yeopchagi in Taekwondo 1) As for the change in the movement of the center of the body of the longitudinal axis(Y axis), there were statistically significant differences in E1 Phase(p< .01), E2 Phase(p< .01), E3 Phase(p< .01), E4 Phase(p<.01), E5 Phase(p< .05) and E6 Phase(p<. 05). 2) There were also statistically significant differences in the change in the movement of the center of the body of the vertical axis(Z axis) at the stages of E2 Phase(p< .05), E3 Phase(p< .05), and E4 Phase(p< .01). 3. Angle of lower body in the action of Apkkoaseogi Yeopchagi in Taekwondo 1) There were statistically significant differences in the right hip joint in E2 Phase(p< .01), E3 Phase(p< .01), and E6 Phase(p<. 01). There was a statistically significant difference in the left hip joint at the Phase E4(p<.01). 2) There was a statistically significant difference at the right knee joint in E6 Phase(p< .01) while there was a statistically significant difference(p< .05) at the left knee joint in Phases E2 and E6. 3) There was also a statistically significant difference at the right ankle joint in the phase E4(p< .05). 4. Muscle activity in the lower body at Apkkoaseogi Yeopchagi in Taekwondo 1) There were big muscle activities in the left and right side of the femoral rectus muscle and the statistically significant difference between them. 2) There were big muscle activities in the right side of the biceps femoris and the statistically significant difference. 3) There were big muscle activities in the right side of the gastrocnemius muscle and the statistically significant difference. In conclusion, the Apkkoaseogi(front cross stance) Yeopchagi(side kick) in Taekwondo needs a stable movement of the upper body and a stable posture of the kicking foot as well as the balance of the supporting foot. For a strong, fast Yeopchagi of 170°, there is a need for a strong power of repulsive power

태권도 주춤서기 후 앞꼬아서기 옆차기의 운동학적 분석

허보섭(Bo-Seob HEO),이효택(Hyo-Taek LEE),이정기(Jeong-Ki LEE),김용재(Yong-Jae KIM) 한국수산해양교육학회 2014 水産海洋敎育硏究 Vol.26 No.3

The purpose of this study was to analyze the movements of the lower extremity joints during a taekwondo kick motion called Juchumseogi hu Apkkoaseogi yeopchagi, which was administered to players to improve their balance, stability, and range of motion for the prevention of injuries. Eight professional players and amateur players were recruited as the subjects. Kinematic data were collected by four real-time infrared cameras. The hip joint, knee joint, and ankle joint angles were measured using instruments. During the Juchumseogi hu Apkkoaseogi yeopchagi kick motion, there were small and inconsistent effects on each joint. This study processed the data using the Windows SPSS Ver. 18.0 to get an independent t-test, with the setting, p< .05. Results indicated that hip joint, knee joint, and ankle joint angles were almost significantly different between professional and amateur player during Juchumseogi hu apgeule Apkkoaseogi kick motion.