BALL VELOCITY AND KINETICS OF THE SUPPORTING FOOT DURING TWO SOCCER KICKS, PERFORMED BY FEMALE SOCCER PLAYERS

INTRODUCTION: This study compared the ground reaction forces (GRFs) of the plant foot during soccer inside and instep kicks performed by experienced collegeaged female soccer players. METHODS: Eleven college-aged female soccer players performed six inside kicks and sixinstep kicks. A KISTLER piezoelectric force platform was used to sample the GRFs at 500 Hz. Video images of the twelve kicks performed were recorded from a sagittal view at 60 fields/s. An Ariel Performance Analysis system (APAS) was used to collect and analyze the kinetic and kinematic data from all trials. A 2 x 6 (kicking-style x trial) ANOVA with repeated measures on both factors was used to analyze the data information for each of the following variables; peak vertical GRFs during heel-strike and during toe-off, peak anterio-posterior and mediallateral GRFs, time of the supporting foot contact, and ball velocity. RESULTS: The mean vertical GRFs during heel-strike of the plant foot were 199% BW and 218% BW during the inside and instep kicks. Mean plant foot vertical GRFs during toe-off were 154% BW and 170% BW for the inside and instep kicks. Significantly greater peak antero-posterior GRFs (p=.019) were applied by the supporting foot during the instep kick. The video calculated ball velocities were 14.6 m/s and 14.4 m/sec for the inside and instep kicking techniques. CONCLUSIONS: The instep kicking technique generated greater plant foot vertical and antero-posterior GRFs. These increased forces were due to a larger kicking leg preparatory windup combined with a more vertical body position during a quicker instep kicking movement