Examining Impulse-Variability Theory and the Speed-Accuracy Trade-Off in Children's Kicking Performance

Background: The purpose of this study was to examine the applicability of impulse-variability theory and the speed-accuracy trade-off in children’s kicking performance. 

Methods: Forty-three children ages 9-11 were instructed to kick a ball at a target at 45%, 65%, 85%, and 100% of their maximum kicking speed. Results indicated a significant quadratic relationship in variable error across the target conditions (p=0.048), such that children demonstrated significantly lower variable error at 65% versus 100% max speed. Additionally, there was a significant inverse linear relationship was indicated for spatial error (p<.0001), with post-hoc analyses indicating that mean radial error at <59%, 60-69%, and 70-79% of maximum speed was higher than at >90% of maximum speed. 

Results: These data demonstrated that principles of impulse-variability theory (i.e., inverted-U function) and the speed-accuracy trade-off were not supported for the multi-joint ballistic skill of kicking in this sample of children. 

Conclusion: These results, along with other recent data, imply a need to reevaluate instructional emphases when promoting the learning of multi-joint ballistic skills such as kicking.