The Free Kick Kinematics of Elite Football Players

Dujaka Aziz,Sokoli Bylbyl

doi:10.11648/j.ijsspe.20190402.11

Abstract

We have considered the kinematics parameters for the free instep kick of the elite footballer (Cristiano Ronaldo), in the pace of the swing leg movement and the supporting leg with linear velocity measurement, angular displacement and angular velocity of the joints (ankle, knee, hip). We used the cinematographically method through Kinovea-0.8.26-win32. exe and Photo Suite 4 Platinum Editor from MGI Software of filming of a free instep kick (10. LaLiga, vs. Villarreal, 21/02/2010), and where as the caliber size we have taken the diameter of the ball, creating its kinograms in stages of movement. We have especially analyzed the Approach phase which Cristiano Ronaldo traverses at a distance of 4.0 m, which is passed in 3 steps (1.14 m; 1.72 m; 2.75 m). Angle of approach is 40 degrees, the free-kick distance is 30 m. During the contact of foot/ball, knee angle of the swing leg is 132 degrees (support leg 153 deg), while the ball is hit by a linear velocity of ankle joint 17.5 m/s, giving the ball a speed of 13.7 m/s. Result of this research is the way of execution the second step of approach phase which Cristiano Ronaldo is performing with the placement of the right foot in the ground only with the tip of the fingers and not with the whole foot, passing quickly backs winging phase, and phase of hip flexion and knee extension during downward motion.

Highlights

According to studies published on biomechanical analysis of ball kicking in football it is noteworthy that these studies are largely oriented to following numerous variables in different categories of players with the purpose of determining optimal variables for executing a successful kick and in most cases this is determined by the speed of the ball after the strike [1,2,3,4,5,6,7,8,9,10,11,12]
As we are dealing with an elite player such as Cristiano Ronaldo, who is known for the efficiency of goal scoring from various positions of free kicks, we have selected his 30
Dujaka Aziz and Sokoli Bylbyl: The Free Kick Kinematics of Elite Football Players best free blows since 2010, and have chosen those that are best suited for biomechanical analysis from the footage that are found on You Tube

Summary

Introduction

According to studies published on biomechanical analysis of ball kicking in football it is noteworthy that these studies are largely oriented to following numerous variables in different categories of players with the purpose of determining optimal variables for executing a successful kick and in most cases this is determined by the speed of the ball after the strike [1,2,3,4,5,6,7,8,9,10,11,12]. Important are free kicks since they are executed by special positions for which specialist’s players, one of whom is obviously Cristiano Ronaldo. The good biomechanical knowledge of ball strikes in football matches is very important in the process of technical perception with young people and in the process of perfection [28]

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Conclusion