07/08/2017. Goalkeepers (GK) in soccer. Goal kicking of soccer? Previous study. The goal kicking of professional GK. Introduction

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1 ICCE Global Coach Conference th July 2017, Liverpool (GK) in soccer Introduction INDIVIDUAL KICKING TECHNIQUES ASSOCIATED WITH IMPROVED KICKING DISTANCE IN ELITE YOUTH SOCCER GOAL KEEPERS Catching Punching Punt kicking Keiko Sakamoto, Adam Clansey, Gabriel Lozano-Berges, Kenichi Hirose, Mark Lake Throwing Diving Goal kicking (GK) in soccer Introduction Goal kicking of soccer? Introduction Punching Punt kicking Goal kicking The goal kicking of professional GK Catching Diving Throwing Goal kicking A long goal kicking technique is a very useful means of attacking strategy because sending the ball closer to their attacking goal can increase the chance of scoring the goal. Previous study Previous study Reviews in soccer kicking Long kicking in Australian Rules football Punt kicking of goalkeeper in soccer Reviews in soccer kicking Long kicking in Australian Rules football Punt kicking of goalkeeper in soccer No studies have reported the goal kicking distance for goalkeepers. Thus, the goal kicking techniques have not yet been documented. 1

2 Purpose The purpose of the present study was to evaluate kicking techniques that maximise the kicking ball distance of goalkeepers. The techniques of all data (mean of 6 players) The techniques of player 1 The techniques of player 2 The techniques of player 3 The techniques of player 4 The techniques of player 5 The techniques of player 6 Force platform (Kistler Instruments, Hook, UK) (1000 Hz) Force platform (Kistler Instruments, Hook, UK) (1000 Hz) 2

3 Definition of lab and joint co-ordinate systems (Lees et al., 2010) At each joint, Z = interval/external rotation, Y = abduction/adduction and X = flexion/extension. Lean angle of kicking and support leg Deformation of ankle joint during ball contact Lean angle of kicking leg Outward lean (+) / inward lean (-) Lean angle of support leg Deformation of plantar flexion 3

4 Multiple regression analysis An entered liner multiple regression analysis was conducted with ball distance as the dependent variable and with two variables (combination) as independent variables for all six players at different phases of the kick in swing motion data model. These combination parameters chosen to represent the best regression were based on R-squared and P values. The significant level for statistical analysis was set at p < kicking distance Variable 1 Variable 2 Multiple regression analysis An entered liner multiple regression analysis was conducted with ball distance as the dependent variable and with two variables (combination) as independent variables for all six players at different phases of the kick in swing motion data model. These combination parameters chosen to represent the best regression were based on R-squared and P values. The significant level for statistical analysis was set at p < Multiple regression Variables at MHE, SFTD, MNF, and FT phase kicking distance Variable 1 Variable 2 R 2 = highest value p < 0.05 MHE, SFTD, MNF, and FT phase Angle of hip and knee (flexion/extension; abduction/adduction) Angular velocity of hip and knee (flexion/extension; abduction/adduction) Lean angle of kicking and support leg All statistical tests were processed using SPSS 23.0 Software (SPSS Inc., Chicago, IL, USA). 4

5 Angular velocity (rad/s) 07/08/2017 Multiple regression Variables at BC phase Significant variables of all player BC phase Angle of hip and knee (flexion/extension; abduction/adduction) Angular velocity of hip and knee (flexion/extension; abduction/adduction) Lean angle of kicking and support leg + Increased outward lean of kicking leg from MHE to MKF Increased knee angular velocity at BC Typical of knee angular velocity from SFTD to BC Increased outward lean of kicking leg Greater knee extension at BC Extend the moment of kicking leg Easier hit the ball contact (avoid toe of kicking foot from hitting the ground) contact Extension Increased knee extension angular velocity Follow throw phase Follow throw phase Keeping generated knee extension and hip abduction angular velocity until the end of kicking might be a key point to enhanced kicking ball distance. Though the players cannot involve the ball behaviour after ball contact, it might be useful as success performance of kicking for coaching. 5

6 Angle (deg.) Angle (deg.) Best ball distance kicking Worst ball distance kicking 07/08/2017 Significant variables of each player Significant variables of each player Increased inward lean of support leg Increased inward lean of support leg Lean of support leg from SFTD to BC Best ball distance Worst ball distance Outward lean contact 44 Decreased lean of support leg Decreased lean support and kicking leg may contribute to enhanced the foot velocity by lifting motion. Significant variables of each player in regression analysis Deformation of plantar flexion of ankle Ankle deformation from before BC to after BC contact -30 Peak Deformation Plantar flexion Decreased plantar flexion during ball contact 6

7 Angle (deg.) Best ball distance kicking Worst ball distance kicking 07/08/2017 Deformation of plantar flexion of ankle Deformation of plantar flexion of ankle Ankle deformation from before BC to after BC -20 contact Peak Deformation Centre of mass of foot -35 Plantar flexion -40 Decreased plantar flexion during ball contact Decreased plantar flexion during ball contact Enhanced ball contact techniques that was caused by keeping plantar flexion of the ankle at a minimum is considered to have improved the ball velocity. Summery The present study examined the technical contributors of individual ball distance in kicking. Two variables at different phases of the kick was observed for each player (p < 0.05). These key variables have potential to be used as rapid feedback to the player to aid improved kicking performance. 7