• 한국운동역학회지
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• 제19권1호
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• pp.87-98
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• 2009

본 연구는 남자고등학생 숙련자와 비 숙련자의 던지기 동작을 역학적으로 비교 분석하기 위해 3차원 영상분석 및 지면반력분석을 수행하였다. 연구 결과 숙련자는 공 던지기 동작의 총 소요 시간이 비숙련자보다 짧게 나타났으며, 숙련자는 (1) 왼발 착지 시 신체중심의 수평속도 (2) 전 구간에서 전완 분절의 수평속도 (3) 착지 시 손 분절의 수평속도가 비숙련자보다 빠르게 나타난 반면, 비숙련자는 (1) 착지이후에 신체중심의 수평속도 (2) 왼발이 지면에 닿는 시점에서 손 분절의 수평속도가 숙련자보다 빠르게 나타났다. 전후경각도에서 숙련자는 전 구간에서 후경자세를 취하는 것으로 나타났으나, 비 숙련자는 릴리즈 전까지는 후경자세를 취하다 릴리즈 순간에서는 전경자세를 취한 형태에서 릴리즈를 하는 것으로 나타났다. 또한 숙련자는 공 던지기 동작에서 (1) 어깨각도 (2) 이지 후 오른발의 착지에서 팔꿈치 각도 (3) 최대수직지면반력 (4) 오른발의 착지 시 최대전후지면반력이 비숙련자보다 크게 나타났다. 이와 같은 결과에서 숙련자는 비숙련자보다 안정된 자세로 신체의 중심을 후방에 위치시키는 후경자세를 유지하고 신체의 중심이동을 부드럽게 전환하는 효과적인 던지기 동작이 이루어짐을 알 수 있다.

• 한국운동역학회지
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• 제30권2호
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• pp.165-172
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• 2020

Objective: The purpose of this study was to provide quantitative and objective data of throwing movement in baseball catcher through biomechanical analysis. Method: Eight high school baseball catchers (age: 17.3±0.7 yrs, height: 175.3±4.5 cm, weight: 82.5±9.0 kg, Career: 7.4±2.1 yrs) participated and 3-dimentional motion capture system and electromyography (EMG) were used in this study. Results: The maximum center of mass position displacement was observed in forward direction. The linear velocity magnitude of the upper extremity segments were showed as "wrist>elbow>shoulder" which is indicative of kinematic chain. For kinetic EMG data, we also observed the greater muscle activation in the left brachioradial and erector spine muscles muscle that during throwing movement. Conclusion: We expect that biomechanical data from this study will provide important training implications to baseball coaches and trainers in order to effectively train their baseball catchers.

• 대한의용생체공학회:의공학회지
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• 제34권2호
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• pp.55-62
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• 2013

Wrist joints consist of irregularly shaped carpal bones and other complicated structures. Thus, evaluating the motion of a wrist joint is a challenging task. In this study, we used an infrared camera to perform a kinematic analysis of a dart-throwing motion. We measured the difference between the movement of a normal wrist and constrained wrist (wrist with a wrist glove) in the dart-throwing motion with thirty six healthy participants. We measured the ulna flexion - radial extension motion using the attached passive marker and analyzed it using Polygon software and SPSS. The pitch and yaw motions with a glove was bigger than the ones without a glove by 20 and 15 degrees, respectively. On the other hand, the roll motion without a glove was bigger than the one with a glove by 7 degree. Wilcoxon signed rank test (p<0.05) confirmed that there are significant differences between the motion with and without a glove. It was found that the magnitude of the pitch and yaw motion with a constrained wrist joint toward radial extension in dart-throwing motion is smaller than the one with a normal wrist joint. However, a normal wrist joint showed a bigger movement in the roll direction.

• 한국운동역학회지
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• 제17권1호
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• pp.69-79
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• 2007

The purpose of this study was to examine the characteristics of throwing motion in the elementary school students from the developmental point of view. For the purpose of this, total of nine subjects(each of three students in five, third, and first grades) were participated. They were asked to throw the ball as far as they can and the motions were videotaped with the 30frames/sec and 1/500 shutter speed. The successful motions for each subject were selected for three dimensional analysis. The collected data were analyzed using DV express 1.0 and Kwon3D 3.0 softwares. The results obtained from this study were as follows; 1. Total time for the throwing motion of the first grade was longer than that of the fifth and third grades. 2. The resultant displacement and velocity of COM for the fifth and third grades were greater than that of the frist grade. 3. The first grade tended to flex the trunk forward excessively during the throwing motion. 4. The fifth grade tended to place the upper arm close to the sagital plane and move the forearm and hand freely. 5. Looking at the greater variability of the angular velocity of the hand segment, the fifth grade seemed to have faster and more flexible movement of the wrist. 6. There were somewhat differences in the patterns and magnitudes of ground reaction forces among the different grades.

• 한국운동역학회지
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• 제27권1호
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• pp.19-23
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• 2017

Objective: The aim of this study was to investigate the relationship between the ball velocity and the upper extremity kinematics for both dominant and non-dominant side in inexperienced participants about an overarm throwing task. Method: Seven women who are inexperienced in overarm throwing participated in this study (Age: $25.1{\pm}2.4years$, Height: $160.8{\pm}3.5$; Weight $56.5{\pm}7.8$). Participants visit the laboratory for three days with one day rest between test sessions. Whole body 3-dimensional (3D) motion capture was recorded during the overarm throwing trials with ten cameras Vicon motion analysis system (T-10, T40, Oxford Metrics Ltd, UK). Total 45 overarm throwing were recorded for each side for each test session. Ball speed also was measured 3 meters away behind the subjects and recorded for every trial. Results: Mean ball velocity was higher for dominant hand compared to non-dominant hand (p <.05). Trunk segment variables (maximum angles and angular velocities) showed the most consistent relationship with the ball velocity. Conclusion: The importance of the trunk segment during the throwing activities can be seen in some individuals. But inconsistent results between subjects emphasize the importance of the individuals' movement patterns especially for bilateral sports. The future studies should be conduct about the sequence of segments, kinetic variables and effect of training.

• 한국운동역학회지
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• 제18권2호
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• pp.125-139
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• 2008

본 연구는 선천적 시각장애인과 후천적 시각장애인 그리고 정안 인을 대상으로 운동학적 특징을 비교 분석해보아, 시각장애인들의 운동지도와 운동능력의 향상 그리고 부상방지를 목적으로 한다. 비디오카메라는 3대를 사용하여 촬영속도는 60field/sec로 하였으며 가장 멀리 던진 자세를 선택하여 Kwon 3D ver. 3.1프로그램으로 자료를 분석 하였다. 실험의 결과는 1. 릴리스 시의 공의 속도는 정안 인이 가장 빠르고 후천 맹, 선천 맹의 순서로 나타났다. 2. 정안 인은 손목관절을 잘 이용하고 몸의 회전범위가 크며 서로 비슷한 동작 패턴을 보이고 있으나 선천 맹 은 전혀 그렇지 못했다. 3. 정안 인은 제2국면(P2)에서 허리가 어깨를 리드하며 공을 던지고 있으나, 선천 맹 과 후천 맹의 일부는 허리가 어깨를 리드하지 못했다. 4.정안 인들은 공이 날아 갈 방향을 쳐다보며 공을 던지나, 시각장애인들은 공이 날아 갈 방향을 쳐다보지 못했다. 5. 정안 인이 비교적 비슷한 패턴을 보이며 던지는데 비해, 후천 맹은 정안 인과 일부 비슷한 패턴을 보이고 있고, 선천 맹 은 각기 전혀 다른 패턴을 보이고 있다. 6. 정안 인의 체중이동이 잘되고 있는데 비해, 후천 맹 은 정안 인보다 좋지 못하고 선천 맹은 체중이동이 안 되고 있다. 이상을 종합해 보면 실명 시기가 던지기 동작에 많은 영향을 미친 다는 것을 알 수 있다.

• 디지털융복합연구
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• 제17권12호
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• pp.555-563
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• 2019

본 연구는 플라잉디스크의 포핸드와 백핸드 던지기 동작에 대한 정량적 기초자료를 제공하기 위해 수행하였으며 이를 위해 3차원 동작분석 기법을 활용하여 운동학적 변인을 산출하였다. 연구 변인을 종합하여 분석한 결과 플라잉디스크는 멀리 던지는 것뿐만 아니라 정확하게 던지는 것이 중요하므로 P2와 P3에서는 전방으로의 이동을 제어하고 관절의 회전 운동에 집중해야하는 것으로 나타났다. 또한 효율적인 회전 운동을 위해 골반에서 몸통으로 회전력 전이가 중요한 것으로 판단된다. 포핸드는 상지 관절의 움직임을 주로 활용하여 던지기 동작을 수행하는 반면 백핸드 던지기는 비교적 몸통 및 골반의 회전을 주로 활용하여 던지는 것으로 나타났다. 본 연구의 정량적 자료를 바탕으로 플라잉디스크 현장 교육을 위한 기초자료로 활용될 수 있기를 기대한다.

• 한국운동역학회지
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• 제33권4호
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• pp.175-184
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• 2023

Objective: The purpose of this study is to investigate the effects of human motion and javelin kinematics during the energy transfer in javelin throwing on records, and to provide evidence-based training insights for athletes and coaches to enhance records. Method: Three javelin throw athletes (age: 22.67 ± 0.58 years, height: 178.33 ± 7.37 cm, weight: 83.67 ± 1.15 kg) were recruited for this study. Each athlete attempted ten maximum record trials, and the kinematic data from each performance were analyzed to determine their influence on the records. The Theia3d Markerless system was used for motion analysis. Results: Key factors were modeled and identified at each moment. In E1, main variables were COM Y (𝛽 8.162, p<.05) and COM velocity Z (𝛽 -72.489, p<.05); in E2, COM X (𝛽 -17.604, p<.05); in E3, COM X (𝛽 -18.606, p<.05), COM velocity Y (𝛽 38.694, p<.05), and COM velocity X (𝛽 66.323, p<.05). For the javelin throw dynamics in E3, key determinants were Attitude angle and Javelin velocity in the Y-axis. Conclusion: The study reveals that controlled vertical movement, center of mass management during braking, and enhanced pelvic rotation significantly improve javelin throw performance. These kinematic strategies are critical for record enhancement in javelin throwing.

• 로봇학회논문지
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• 제14권2호
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• pp.81-86
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• 2019

Robots are used in various industrial sites, but traditional methods of operating a robot are limited at some kind of tasks. In order for a robot to accomplish a task, it is needed to find and solve accurate formula between a robot and environment and that is complicated work. Accordingly, reinforcement learning of robots is actively studied to overcome this difficulties. This study describes the process and results of learning and solving which applied reinforcement learning. The mission that the robot is going to learn is bottle flipping. Bottle flipping is an activity that involves throwing a plastic bottle in an attempt to land it upright on its bottom. Complexity of movement of liquid in the bottle when it thrown in the air, makes this task difficult to solve in traditional ways. Reinforcement learning process makes it easier. After 3-DOF robotic arm being instructed how to throwing the bottle, the robot find the better motion that make successful with the task. Two reward functions are designed and compared the result of learning. Finite difference method is used to obtain policy gradient. This paper focuses on the process of designing an efficient reward function to improve bottle flipping motion.

• Journal of Multimedia Information System
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• 제5권2호
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• pp.115-120
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• 2018

Recently, ways for accurately measuring the three dimensional movements of hand are actively researched so as to utilize the measurement data for therapeutic and rehabilitation programs. This research paper aims to introduce a product called Myo Armband, a wearable device comprised of a 3-axis accelerometer, a 3 axis gyroscope, and electromyographic sensors. We compare Armband's performance with that of the Motion Capture System, which is known as a device for providing fairly accurate measurements for angular movements of objects. Dart throwing and wrist winding motions comprised movement scenarios. This paper also discusses one of Armband's advantages - portability, and suggests its potential as a substitute for previously used devices. Decent levels of measurement accuracy were obtained which were comparable to that of three dimensional measurement device.