스키 스타트 동작의 운동학적 분석 = Kinematic Analysis of Start Technigues for Skiers

다국어 초록 (Multilingual Abstract)

The purpose of this study is to contribure to the development and training of the starting technique in Alpine ski. The subjects of the study were male and female outstanding skiers. Their starting motion was flimed in high speed and the kinematic data was evaluated and analyzed to suggest a ski training strategy.
Jumping start and recreation start were filmed at 100FPS as side. It was analyzed by a motion analyzer NAC 200 A and computer smoothing process to attain the locomotive graph of the each joint, velocity, angular velocity, interval time in motion, time the air.
1. Time spent by each styles of start, genda, and phase.
Male skiers' level of the technique varied. And the time of the jumping start motion was quite long at the entrance situation while the flight time and gliding time were short.
In females skiers, the correlation was very high.
According to the result, it important to do the poling very strongly hitting the ground and jump and simultaneously unlock the knee joint to make the full use of the reaction force produced at the moment when the heels of the feet hit the ground to accelerate.
2. Velocity of each styles of start, genda, and each phase
Male skiers velocity at each situation showed linear graph. However, increasing velocity at the landing point indiacated poor landing technique.
Almost none of the Female skiers could jump start.
Eventhough when they did, the gliding velocity after the landing decreased. Therfore, training is needed not to decrease the velocity too rapidly.
3. Relationship between the flight time and the velocity at each phase in jumping start
There is a (+) correlation between the time spent at the entrance situation and the velocity of the starting gate passing moment in the jumping start. Also there is a (-) correlation between the flight time and the landing velocity. According to the result of the study it is proven that certain amount of time is needed at the entrance situation to jump for the jumping start. However, when the time spent in the air is longer it causes the decrease of the landing velocity.
4. Relationship between the flight distance and the velocity at each phase of the jumping start
Thre is (+) correlation between the flight distance at the entrance situation and the velocity at the start line passing moment. However, there is (-) corelation between the flight distance from the start line to landing mark and the landing velocity. Total flight distance and the velocity at each situation had (-) correlation. The flight distance at the entrance section is needed for a powerful poling, however, execssively longer distance of flight will decrease the velocity.
5. The relationship between the flight height, landing point and landing velocity of the jumping start
There are (+) correlation between the maximal jump flight height and the velocity at the starting line However, Korean skiers cause waste of time when they pass the starting gate not being able to speed up to the maxium velocity due to the maxium flight height at the starting gate or right after that. Therefore, it is necessary to practice at a starting gate to obtain the highest height within the starting gate by powerful poling.
6. Relationship between the angle of each phase and the velocity in jumping start
There is (+) correlationship between the knee joint angle and the velocity when the heel of the feet is departing the ground. And there is (-) correlation between the body angle and the hipjoint velocity at the starting gate. There is (+) correlation between the joint angle and joint velocity at the pole passing moment. It is necessary to train to decrease the resistance by lowering the form.