Kinematic Kicking Differences Between Elite Female and Male Soccer Players

The goal of this study was to determine instep kicking kinematic differences on dominant (D) and nondominant (ND) sides between elite female soccer players and similarly skilled males. Six members of the US women's national team pool and two highly skilled male soccer players, all free of physical injury or orthopaedic problem, voluntarily agreed to participate in the study. Following a period of warm-up, each player took a two-step angled approach on D and ND sides and instep kicked a stationary soccer with as much power as possible into netting draped from the ceiling. Data collection started at support foot contact (SFC) with a force platform and ended when the ball left the camera view field following ball contact (BC) by the kicking foot. The 3 kicks with highest velocity (out of five) from both the D and ND sides were used in the analysis. Kinetic data from this study will be reported separately. Ball velocity (BV) was significantly different when comparing between sides and genders. Male D BV was 25.3 m/s (+1.51) and female D BV was 21.49 m/s (+2.44; P < 0.001). ND BV for the male was 23.56 ms/ (+1.57) and female ND BV was 18.99 m/s (+2.05) (P < 0.001). Kinematic variables captured were: maximum toe velocity, toe velocity at BC, mean toe velocity between SFC and BC, mean toe acceleration, ankle velocity at BC and angular velocity at the knee at BC. D and ND comparisons demonstrated that males had statistically significant (P < 0.05) greater kinematic values than the females in 4 of the 6 variables on D and ND sides. Angular velocity at the knee at BC was greater among the females than among the males on the D side (1133.73 degrees/s +257.46 & 1112.96 degrees/s +107.36), but less on the ND side (923.57 degrees/s +229.43 & (938.03 degrees/s +81.73) although the differences were not statistically significant. One elite female's variables closely mimicked those seen in the males. The slower knee angular velocity for male D may be indicative of a protective mechanism to slow the limb prior to ball contact to reduce potential injury. Based on our results, elite female players do not generally possess the same instep kicking power as males, however there are exceptions. Sponsored by a grant from the USOC Sports Sciences and Technology Program