# Effect of Instruction and Target Position on Penalty Kicking Performance in Soccer
## 3 Results  
The two instructions had a significant effect on kicking velocity (F = 142, \(p\) \(<\) 0.001, \(\eta^{2}\) = 0.9). In addition, a significant interaction effect (F = 5.8, \(p\) \(<\) 0.001, \(\eta^{2}\) = 0.28) was found, while target position had no significant effect (F = 2.05, \(p\) = 0.098, \(\eta^{2}\) = 0.12). Post hoc comparison revealed that velocity was significantly higher for all targets when the instruction was to kick for velocity compared with accuracy. Furthermore, with the velocity instruction no significant difference in velocity between any targets (F = 2.05, \(p\) = 0.098, \(\eta^{2}\) = 0.12) was found, while a significant effect of target position was found when accuracy (F = 4.9, \(p\) = 0.002, \(\eta^{2}\) = 0.25) was the main priority in which kicking velocity to the bottom left position was significantly higher than to the middle and top right (Figure 2). When viewing accuracy measured in distance to the center of the targets, an effect of instruction was also found (F = 29.9, \(p\) \(<\) 0.001, \(\eta^{2}\) = 0.66), but no significant target (F = 0.59, \(p\) = 0.67, \(\eta^{2}\) = 0.04) or interaction effects (F = 1.4, \(p\) = 0.23, \(\eta^{2}\) = 0.09) were found. The post hoc comparison revealed that only the placements in the left and right corners were significantly worse (greater distance from the center) when kicking for velocity compared with accuracy (Figure 3A). When measuring the accuracy in scoring in the goal when aiming at the different targets, a significant effect of target position (F = 6.82, \(p\) \(<\) 0.001, \(\eta^{2}\) = 0.31) was found, but no significant instruction (F = 3.45, \(p\) = 0.083, \(\eta^{2}\) = 0.19) or interaction effects (F = 0.46, \(p\) = 0.76, \(\eta^{2}\) = 0.03) were found. The post hoc comparison showed that hit percentage was significantly lower in the up  
Figure 2: Mean (\(\pm\)SD) ball velocity (km/h) at the different targets averaged per instruction for velocity and accuracy over all participants. * Indicates a significant difference between the two instructions at all targets on a \(p\)\(<\) 0.01 level. \(\dagger\) Indicates a significant difference between these two targets for this instruction on a \(p\)\(<\) 0.05 level. compared with the other three targets. Furthermore, a higher hit percentage was found when aiming at the target in the middle when kicking for velocity compared with kicking for accuracy (Figure 3B). When the targets' positions were divided into high and low, the analysis demonstrated that both velocity and distance to the center of the target were significantly affected by instruction (F \(\geq\) 36.2, \(p\) < 0.01, \(\eta^{2}\)\(\geq\) 0.71). No significant effect of shooting high or low was found for either velocity (F = 3.97, \(p\) = 0.065, \(\eta^{2}\) = 0.21) or distance to the center of the target (F = 0.51, \(p\) = 0.48, \(\eta^{2}\) = 0.03). However, a significant interaction effect was found for both velocity and distance to the center of the target (F \(\geq\) 5.9, \(p\)\(\leq\) 0.028, \(\eta^{2}\)\(\geq\) 0.28). Post hoc comparison showed that ball velocity and distance to the center of the target were higher when aiming for velocity compared with aiming for accuracy and that, when aiming for accuracy, ball velocity significantly decreased while kicking high. Furthermore, distance to the center of target decreases with high target positions while shooting for velocity, whereas the opposite was found when shooting for accuracy (Figure 3), resulting in an interaction effect. When evaluating the percentage of scoring in the goal with the different instructions and aiming high or low, only a significant effect of target position (low-high) was found (F = 20.8, \(p\) < 0.01, \(\eta^{2}\) = 0.58), with no significant effects of instructions or interaction (F \(\leq\) 3.6, \(p\)\(\geq\) 0.077, \(\eta^{2}\)\(\leq\) 0.03). Post hoc comparison revealed that aiming high resulted in fewer hits in the goal compared with aiming low for both instructions (Figure 4).