Sports Biomechanics Of Human Body In Javelin Throw During The Final Thrust Phase

Javelin throw is a kind of complicated sport in track and field events. In order to study the technique of javelin throw and improve achievement, we divided the process of javelin throw into several operations. According to the effect to whole javelin throw technique, the process of javelin throw is divided into: grasp position, momentum building phase, transfer phase (final thrust phase), recovery. Among the four parts, the final thrust phase is the key to the whole process of javelin throw. Researchers always pay close attention to the final thrust phase.The final thrust phase of three javelin throwers was recorded by high-speed camera operating at 500 frames per second. In this paper, A few rules of human body during the final thrust phase weregot on analysis of recorded pictures. A program was made to analyze the pictures. The rod-pictures of javelin throwers during the final thrust phase were graphed in this program. At the same time, the graphs of sports parameters (contrail, velocity, acceleration) of each joint of human body were got.According to anatomical structure of locomotor system of human body and experiences of modeling in biomechanics, the human body was simplified as a multi-rigid system with simple rotate joints. Parts of human body were simplified as spheroid and columns; articulations were simplified as spherical hinges and universal joint. The dynamic equations of the multi-rigid system were founded with R/W method.Conclusion: During the final thrust phase, the velocity of hip joint, shoulder joint, elbow joint, wrist joint achieved their peak value. The change of velocity of these joints is coinciding with the theory of whip in Biomechanics. These joints was accelerated and broken in turn.