# MEASURING OPTIMAL TAKE-OFF ANGLE ABOUT THE HURDLE

• J. Xin
• Y. Pan
• J. Niv

## Abstract

INTRODUCTION Take off technique is very important in the hurdle race. Success or failure is closely related to take-off angle. If the take-off angle is too big, the time is increased over the hurdle and velocity is lowered. If take-off angle is too small, hurdler can possibly knock down a hurdle and velocity is lowered. So it is necessary to have an optimal takeoff angle. We named this the optimal take-off angle or the least take-off angle. METHOD The method of mathematical simulation was adopted Mathematical simulation of human sports was based on dynamical theory of multiple rigid bodies. Body's joint friction and tissue deformation was ignored. All body segments were looked at as a rigid body. We knew the body's movement process and simulate to count body's movement parameter of kinematics and kinetics. We simulated possible body movement form and effect so that we can realize the forecast of sports result. It can forecast to provide with quantitative basis for optimal take-off angle about the hurdle. RESULTS AND DLSCUSSION The equation that optimally defines take-off angle was "4".Acos4 θ +Bcos3 θ sin = Ccos3 B+Dcos2sin θ +Ecos2+Fcos θ sin θ +Gcos θ +Hsin θ +Ttg θ +K=0 We named ti equation of optimal take-off angle. The cofficients A,B.C,E,F,G,H,T, are functions of parameters of physical qualitym,ho,Ao, and parameters of powerstereotype V0, S0, h1,. V,f,t,ho.h: Highness of the hurdle. RESULT We make use of optimal theory to evaluate and appraise technical exercise because it is an important issue or concept in biomechanics of sports. By building a mathematical simulation and inferring a formula we define the general formulas about the optimal take-off angle of the hurdle. Thus, through quantitative relationships of mechanical characteristics, technical exercise and results are built.

Methodology