A NEW BIOMECHANICAL ASPECT FOR ASSESSING MECHANICAL PARAMETERS IN LONG JUMP

Abstract

INTRODUCTION: In order to make a comparison between Iranian jumpers with the world champions, in the absence of Motion Analyzer, we made a Biomechanical Model with which we were able to assess the mechanical parameters such as : final run-up velocity, initial take off velocity and angle , initial velocity components, time of the last touch - down, force applied by jumpers and their height of flight. This could be feasible just by measuring run-up time tr, flight time tf, total flight distance R and the total time of run-up, and flight , tt. METHOD: The subjects were ten male jumpers belonging to Iranian track team. Each jumper, ran his run-up distance which with measured run-up time and mechanics formulae, we could obtain the final run-up velocity. By measuring the total range of flight and its time of flight and combining the formulae , we got for the angle of take off : q = Arctan gt2 f / 2R Knowing q, R and tf , we can get , not only the flight mechanical parameters but also the force applied for jumping. This force can be achieved by measuring the total run-up and flight time and make the difference with the sum of the tr and tr separately measured, and then dividing difference momentum to difference of time , we obtain with F = dp/dt the force in question. In fact, this force is applied by the jumper, in order to change the direction of the final run-up velocity, which is horizontal to a velocity with an angle of q, previously obtained. RESULTS: Most of our jumpers could reach velocities more than 10 m/s as final run-up velocity, but at take off they lost about 2 m/s, although their take of velocity components are comparable. CONCLUSION: Our biomechanical model can easily be , in the absence of expensive 2D or 3D, used and would help to achieve effective mechanical parameters. [table]