Kinematic Characteristics Analysis On Take-off Techniques Of Elite Junior Male Long Jumpers In Liaoning Province

The take-off technique is the core of long jump. In recent years, the articles on approach and take-off technique of outstanding men's long jumpers abound at home and abroad, but it's very seldom for juvenile. Excellent men long jumpers' technical parameters and characteristics can not be applied to the juvenile. In this paper, the top eight athletes of men's long jump Group A in Liaoning province juvenile track and field competition are the research objects in July 2009.By the use of literature, investigation and interview, video analytics, mathematical statistics, comparative analysis, and other research methods, this article analyzed on kinematic features of long jump approach to the last two strides and take-off technique of juvenile men's long jumpers. The purpose is to sum up juvenile men's long jump athlete's technical characteristics and to provide reference on scientific training. After analysis, the following conclusions:1. Liaoning province outstanding juvenile men's long jumpers have a strong sense of the last two strides of speeding up the board on the approach. In a certain range, properly shortening the strides of the last stride on the approach phase can speed up the rate of take-off leg on the board, and is an effective way to improve athletic performance.2. Liaoning province outstanding juvenile men's long jumpers spend too long in the Take-off and amortization, too short in the transformation and extension. The time index on extension, angle above the land and angle of treading from the land are too small. The sector angle of take-off is too large. These things sufficiently explain their take-off legs are short of strength.3. The take-off legs of Liaoning province outstanding juvenile men's long jumpers do not have enough work ability on giving way and the sense of positive pawing in the touchdown stage. In an instant of leaving the ground, the extension of coax, knee and ankle is not enough.4. The free legs of Liaoning province outstanding juvenile men's long jumpers swing too late and have small angular velocity of swing. The time of free leg's bracing action is too late or without.5. The absolute speed of approach of Liaoning province outstanding juvenile men's long jumpers'is small. Their horizontal take-off speed, vertical take-off speed, transform rate of horizontal speed and take-off angle are relatively small.6. The body center of gravity of Liaoning province outstanding juvenile men's long jumpers fluctuate gently in the last stride of approach and the curve volatility of take-off. In the premise of without affecting the approach and take-off and integrating athletes'own characteristics, they can increase the vertical distance and angle of take-off, then improve their performance in an instant of touchdown properly reducing the body center of gravity.