Judo the roads to Ippon

Abstract: In this invited lecture the biomechanical analysis of tactical tools utilized by top athletes in high level competition is presented. In the first part, the lecture starts with a very short summary of the researches carried out on biomechanics, thermal exchange and metabolic energy expenditure related to judo throwing technique. In the second part it is developed the specific analysis of the technical tactical support tools.These tools allow to enhance the effectiveness of the athletes special throwing techniques,Tokui Waza,increasing the probability to obtain Ippon. The last part of the lecture emphasizes,the physics and biomechanics connected to judo competition that is defined as:an interacting complex nonlinear system, with chaotic and fractals aspect.This system must be analyzed studying the motion of couple of athletes system and evaluating their interaction,throws.Brownian tools are today the actual most sophisticated way of modeling motion in competition, starting from fractals till to multifractals aspects.If we study the specific mechanics of several throwing action in real competitions we can face some interesting physical aspects not totally well known, like almost plastic collision between extended bodies and for some Lever techniques we have to solve dynamical problem of bodies with variable mass that differs from the well known Classical Mechanics with constant mass. In effect, in such a situation,the general methodological approach of mechanics must be properly modified; considering a deformable body with a finite extension, where special emphasis is given to the variable rotational inertia during throw, with interesting consequences about balance, linear and rotational momentum and motion of center of mass.