테니스 양손 백핸드 스트록의 3차원 운동학적 분석

신제민 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.6

The purpose of this study was to analysis 3-d kinematic characteristics of two hand backhand stroke in tennis, 3 skilled subjects who were performed 3 successful trials were filmed with three dimensional cinematography. Kinematic variables computed were three dimensional displacements of racquet and angles of joints participated in the stroke. The 3-d angles were calculated by vector projected with the least squares solution in order to de fine complex joint movements, specially shoulder joints. The following conclusion were reached; 1. The direction of racquet at the impact was reverse to the aimed direction of a ball in the transverse plane. The role of trajectory of racquet after impact was also important to decide the ultimate direction of ball. 2. The angular motion in the horizontal adduction/abduction of the shoulder joints was affected to axial rotation of trunk the angle of internal/external rotation in the shoulder joints increased around the impact without increasing until the impact. 3. The angles of elbows joint were flexed below 150˚ at the impact, not fully extending. 4. The angle of internal/external rotation of trunk was external of trunk was rotated over 90˚ at the impact while insignificant angular oration in the other planes. 5. The pattern of ante of knee joints showed variability within subjects and trials without typical angular pattern during the total movement phase. But the magnitude and time of peak flexion were appeared before the impact at the left bide. 6. Both of foots were closed over 180˚ from the base line among local as at the impact. The right foot was much closed than left foot at impact as well as all of the phase, and almost keep fixed hat changing the angle until the impact.

축구 페널티킥 시 속임동작의 유무에 따른 운동학적 변화

신제민 한국스포츠리서치 2005 한국 스포츠 리서치 Vol.16 No.6

방향전환 동작 시 골반 사전운동이 하지분절 운동역학적 변인에 미치는 영향

신제민 한국사회체육학회 2020 한국사회체육학회지 Vol.0 No.79

Purpose: The purpose of this study is to analyze the effect of pre-orientation of the pelvis on kinematic and kinetic variables of the lower extremity injury during 90˚SSC (side step cutting). This study is also to investigate the relationship between pelvic pre-orientation and lower extremity injury during the SSC. Method: Nine healthy male college students participated in this study T. hree dimensional motion analyses were used to analyze the kinematic and kinematic variables of A-SSC (typical SSC) and B-SSC (SSC which suppressed pre-orientation of the pelvis) during WAP (weight acceptance phase). Results: The approach velocity reached to side cutting point was not significantly different between the two SSCs. Pelvic pre-orientation significantly decreased in the B-SC. The maximum ground reaction force and the location of the center of gravity significantly increased laterally in the A-SSC. Landing distance and last step length both increased with the B-SSC. The maximum angles of knee and hip were not significantly differen t except the valgus angle of knee joint. The knee valgus and inrtneal rotation moment increased significantly in the A-SSC. Conclusion: The length of the last step increased laterally in the B-SSC, but did not increase with the valgus and internal rotation moment of the knee joint. Therefore, even if the pelvic pre-orientation is suppressed during the SSC, it does not seem to have any negative effect on the non-contact knee injury.

착지 시 착지높이 증가에 따른 하지분절의 운동학 및 운동역학적 특성과 회귀관계

신제민 한국사회체육학회 2019 한국사회체육학회지 Vol.0 No.75

Purpose: The purpose of this study is to analyze the kinematic characteristics and regression relationship of the lower extremity joints when the landing height increased during landing. Method: In order to analyze landing motion at 40, 60, 80, and 100 cm landing height, 10 healthy male college students were selected as subjects and analyzed by 3-D cinematography procedure. As the landing height increased, the peak value and the impulse of the vertical ground reaction force increased significantly but did not increase strongly and linearly. Results: The results of this study are as follows. First, the peak angle and the peak angular velocity of the joints increased significantly in knee and hip joints. In particular, the peak angular velocity of the knee and hip joints showed the strongest regression in relation to the increase of the landing height. 2) The peak negative power and the peak negative work of the joints showed a tendency to increase as the landing height increased, but did not show a strong regression relationship. 3) Analysis of the percentage of negative work of the joints showed that the proportion of the ankle and hip joint increased with the increase of the landing height, but the proportion of the knee joint decreased. Conclusion: In summary, the increased angular velocity of the knee & hip joints and the increased role of the negative work in the ankle & hip joints are important characteristics to alleviate the impact force when the landing height increased.

수직점프에서 팔 스윙형태가 점프높이에 미치는 영향

신제민 한국사회체육학회 2023 한국사회체육학회지 Vol.- No.91

Purpose: The purpose of this study is to analyze the effect of the arm swing direction on the jump height during a vertical jump and to suggest an efficient arm swing pattern (ASP). Method: Ten infrared cameras including two force plates were used to analyze the jumping motion. The subjects of the research were 10 male university students. The experiment task was to jump as high as possible by swinging from front to back, from back to front, and fixing their arms without swinging. A 3D cinematography was performed, and biomechanical variables were analyzed by dividing the entire motion period into a braking phase and an accelerating phase to efficiently compare changes at ASP. Results: Among the three arm swings, the jump height and the vertical velocity increased the most just before the take-off when the arm swung from back to front, and the jump height tended to increase with the magnitude of the impulse. However, the duration of the braking and accelerating phases, joint angle, torque, and power of the lower extremity did not show any characteristic results depending on the ASP. The work done by the lower extremity joint also did not show a significant difference in the change of the ASP. Conclusion: The swing from back to front is the most efficient ASP because it increases jump height and vertical velocity just before take-off. However, other biomechanical variables do not show a clear difference even when the ASP is changed. In contrast to the hip and ankle joints, the knee joint continued to exhibit eccentric contraction even during the accelerating phase, and this characteristic is evident when the arm is fixed. The decrease in eccentric contraction of the knee joint during the arm swing in the accelerating phase can be positive in that it suppresses energy absorption in the vertical jump.

기술수준에 따른 태권도 돌려차기 기술의 협응과 제어형태 비교

신제민,김로빈 한국운동역학회 1999 한국운동역학회지 Vol.9 No.1

The early studies of kicking skills in Taekwondo were simple two dimensional kinematic skills. But the later studies focused on three dimensional kinetic skills. These studies have acquired a lot of data concerned with kicking skills. These studies tended to investigate patterns of movement with comparison of between-skill or in-skill. The studies of movement patterns could systematically explain in motor controls which was focused on a mechanism of a skilled motor behavior. This study analyzed a pattern of Doelyochagi movement by 3D cinematograph and approached the movement as function of skill level in the view of motor control. The researcher selected six novices and six experts, and analyzed the change of coordination and control patterns with kinematic data. While the coordination variables were qualitatively analyzed by angle to angle graphs, control variables were qualitatively analyzed by angles. And the control variables were divided into the spatial and temporal factors which were consisted of the positive and negative maximal values, and timing the positive and negative maximal values. The researcher used t-test in order to find significant differences between two groups among the control variables. As the results of analyzing the coordination variables, the angle to angle graphs of expert group showed clearly to be froze between two joints in the flexion/extension and abduction/adduction, and showed to be released in the internal/external rotation during the third phase. Angles as control variables revealed significant differences in the flexion/extension while there no differences in the other two planes in the hip joint. But all of planes on the knee joint showed significant differences between two groups. As indicated by analyses of angles, the segments of experts tended to be frozen in the flexion/extension and abduction/adduction, and to be released in the internal/external rotation during the third phase.

착지 시 낙하높이와 발의 지면 접촉 형태에 의한 하지분절의 변화

신제민 한국사회체육학회 2018 한국사회체육학회지 Vol.0 No.71

The purpose of the study is to investigate the changes in lower extremities to attenuate an impact force by landing heights and foot strike patterns during drop landing. Twelve male university students were instructed to perform drop landing tasks from 30 to 60cm heights using forefoot strike landing (FFL) and midfoot strike landing (MFL). Force plates and motion capture system were used to obtain kinematic and kinetic data. Landing phase duration showed an increase only at MFL for 30cm height whereas peak ground reaction force caused an increase at MFL and 60cm height, respectively. Both kinematic and kinetic variables displayed a general increase with an increment in landing heights. With regard to foot stride patterns, the angles in knee and hip joints at MFL increased at an initial contact as well as the lowest height of the body’s mass center while the angle in an ankle joint at FFL grew only at an initial contact. An upward change in the peak angular velocity of ankles was observed at FFL and that of knee and hip joints was found at MFL. In terms of the mean extension moment of hip and knee joint and the mean plantar flexion moment of ankle joint and the mean negative power of three joints, the present study also found that hip and knee joint showed an increase at MFL, whereas ankle joint showed an increase at FFL. In conclusion, the FFL produces the stronger eccentric power by increasing angle and angular velocity of ankle joint, replacing that of hip and knee joints for attenuating the ground reaction force.

태권도 옆차기와 돌려차기의 3차원 운동형태의 비교

신제민,진영완 한국운동역학회 2000 한국운동역학회지 Vol.9 No.2

The study compared to skills of Yeopchagi and Dolyeochagi in Taekwondo with the 3d kinematic analysis. To compare both of two skills, the study was analyzed as the relative time during the skills performed, the kinematic characteristics of individual segment, the relationship of inter-segment and the ranges of motion in 3d space. A performance time was mort shortened Dolyeochagi than Yeopchagi. A relative time that the time minimized angle of shank was later Dolyeochagi than Yeopchagi. The characteristic of kinematic of Individual segments showed clearly different in the flexion/extension plane. The angle of thigh increased continuously at an impact in Yeopchagi, but the angle stopped or decreased in Dolyeochagi at that time. The relationship of inter-segment showed difference largely between two skills in the flexion/extension plane, but the other plane showed no difference. These results were due to anatomical functional difference between two joints. The ranges of motion in 3d space were different at the abduction/adduction and the internal/external rotation.

테니스 플랫서브시 운동학적 변수의 관계특성

신제민 상명대학교 산업과학연구소 2003 産業科學硏究 Vol.- No.14

축구 페널티킥에서 초보자와 숙련자의 3차원 운동학적 비교

신제민 한국운동역학회 2005 한국운동역학회지 Vol.15 No.4