跳远前旋角动量研究

Study on the Angular Momentum of Forward Rotation of the Long Jump

运用录像解析法对跳远运动员起跳过程中导致身体前旋角动量的变化进行定量分析.研究发现,运动员着板—垂直支撑阶段由于制动力的作用,使人体产生向前翻转的角动量,且增长幅度较大.通过垂直支撑面后制动力转变为动力,由于偏心力矩的作用,角动量出现一定的增加或减小,但幅度较小;运动员的实际成绩和理论成绩的差值与离板时身体前旋角动量成正相关,说明减小起跳离板时的前旋角动量有助于维持身体在空中的平衡,从而能够更有效地利用身体质心抛物线所能达到的距离,提高跳远成绩.

Based on the quantitative analysis towards the changing characteristics of the angular momentum when the long jumpers are turning around the centre of mass horizontal axis in the process of the take-off by video analysis method,the study finds that influenced by the breaking force,the body gets the angular momentum of turning forward in the stage from touching down to the vertical support in long jump,and the rate of growing is very large. After passing through the vertical support surface,the breaking force changes to the motivate power,as it is affected by the moment of eccentric force,the angular momentum increases or decreases,but in a small range;the difference between the actual achievement and theory achievement is positively related to the plate body of spin angular momentum,which shows that the reducing the take-off from the board before the spin angular momentum helps to maintain the body in balance in the air,so that atheletes can improve performance by making more effective use of the achievng distance of body mass parabola.