A comparative study of instep kicking swings, ball impacts, and ball speeds in male and female football players

This research aims to compare swings, ball impacts, and ball velocities of instep kick between male and female players. The research used comparative design method, in which two groups of males and females were compared. This research used eight Indonesian football players as sample: four males and four females. The instrument used for data collection in this research is football long pass test. Video documentation was taken with high-speed camera unit with 1000 fps ability. The data collected were then analyzed through Kinovea, in which swing angles, foot angular velocities, ball impact times, ball velocities, and resulting ball distances were calculated. Non-parametric Mann-Whitney test were used to compare each instep kick of male and female players. Results show that no difference on instep long pass swing and ball impact between male and female players was observed. On average, male players performed instep kicking with kicking foot knee flexion angle of 104.750, hip angle of 77.250, kicking foot knee extension angle of 1580, kicking foot steepness angle of 58.250, average power of 209.38 J/s (watt), and average kicking foot angular velocity of 0.11 rad/s, which resulted in average ball impact of 10.27 Ns that caused average post-impact ball velocity of 22.83 m/s and average ball distance of 26.63 meters. Meanwhile, female players performed instep kicking with kicking foot knee flexion angle of 930, hip angle of 74.250, kicking foot knee extension angle of 1480, kicking foot steepness angle of 56.250, average power of 237.28 J/s (watt), and average kicking foot angular velocity of 0.11 rad/s which resulted in average ball impact of 10.32 Ns that caused average post-impact ball velocity of 22.94 m/s and average ball distance of 26.87 meters. The results show that the average ball distance of male players was closer to 25-meter target than those of female players. In order to achieve 25-meter kicking accuracy, female players contributed greater power and steeper kicking foot angle than their male counterparts. In conclusion, to master instep kicking technique, female players need to pay attention to their power and body position during kicking.