Method: Twenty-eight young (mean age = 20.3 yrs) adults (23 men) were tested for maximum kicking speed using a radar gun and were familiarized with the testing protocol on day 1 of testing. One week later, participants kicked a playground ball at six different percentages of their max speed (50, 60, 70, 80, 90, and 100%) in random order for a total of 10 blocks of trials at a target on a wall located 9.1 meters away. Participants were instructed to hit the target and kick at the specified percentage of maximum speed. Speed feedback was provided on every trial.
Analysis/Results: Kicking speed variable error and spatial error (accuracy) were calculated using repeated measures ANOVA with built-in polynomial contrasts. Results indicated there was a significant inverse linear trajectory for kicking speed variability (p < 0.001, η2 = .345) where 50% and 60% maximum speed percentages had significantly higher variability than the 100% condition. A significant quadratic fit was found for spatial error scores of mean radial error (p < .0001, η2 = .474) and subject-centroid radial error (p < .0001, η2 = .453) indicating the general lack of a speed-accuracy trade-off as kicking speed increased.
Conclusions: Overall, these data support other recent studies (Juras et al., 2009; Urbin et al., 2012; van den Tillaar and Ettema, 2006) indicating that variability and accuracy of multijoint, ballistic skill performance may not follow the general principles of impulse-variability theory (i.e. inverted-U function) or a speed-accuracy trade-off. These data have instructional implications for promoting the acquisition of multijoint ballistic skills.