# Effect of Instruction and Target Position on Penalty Kicking Performance in Soccer
## 1 Introduction  
When a soccer team is given a penalty kick, it is considered a strong scoring opportunity, which is logical, since 70-80% of the penalties in international elite soccer in Europe result in a goal [1; 2; 3; 4]. For the penalty taker, there are different issues to consider before executing the penalty: speed, accuracy, direction, high or low in the goal, or to wait for the movement of the keeper and put the ball in the opposite direction. [PERSON] and [PERSON] [1] found that shooting with 75% of maximal velocity is more efficient than 50 or 100%. Furthermore, penalty kicks high in the goal increase the chances of scoring [5; 3], while the method of delaying the decision about where to place the ball related to the keeper's action is doubtful and results are often less successful [5; 6]. Therefore, based upon these findings it is suggested that penalty takers use 75% of maximal kicking velocity and aim for the upper third of the goal, because a shot like that would have low chances of being saved, since in 95% of the penalties taken in international matches the goalkeeper chooses one of the sides in the goal [7]. In soccer as well as other sports, to be able to create both speed and accuracy is vital for high performance. According to [PERSON] law, there is a speed-accuracy trade-off, which indicates that when the movement speed increases in, e.g., a penalty kick, the accuracy is reduced, while when the accuracy of execution is prioritized the speed is reduced [8]. Several studies on speed-accuracy in penalty kicking have confirmed [PERSON] law. [PERSON] and [PERSON] [9] and [PERSON] and [PERSON] [10] also found a reduction in the speed of the ball (to 85%) when players were instructed to prioritize accuracy, compared to shots where speed was prioritized. Furthermore, [PERSON] and [PERSON] [10] reported that when accuracy was prioritized by instruction, accuracy was also enhanced, and ball velocity was higher when kicking to the contralateral side of the goal. Moreover, these results, following [PERSON] law, were similar when kicking with the favorite or less favoritefoot [11]. In all these studies, speed and accuracy were measured when kicking to either one (middle) or two targets (left and right corner), while kickers were instructed to aim for speed or accuracy or a combination of both. The height of the targets in the corners was low [10], while the height of the target in the middle [11] was 1.25 m high, exactly where the goalkeeper would stand during a penalty kick. Therefore, nothing is known about speed and accuracy in kicking low or high in the corners, which in overarm throwing has been shown to be affected by target height [12]: higher ball velocity when instructed to throw ipsilaterally to the upper corner compared to contralaterally to the lower corner, together with lower accuracy when throwing contralaterally up compared with throwing down. In soccer it is found that when taking a penalty kick against a goalkeeper the success rate increases when the kick is towards the upper one-third height of the goal (1.64-2.44 m above the ground) [3,5]. However, it is not known whether kicking at these heights is more successful because of a higher kicking velocity or because of greater accuracy. Therefore, the purpose of the study was to investigate the effect of instructions prioritizing kicking velocity or hitting accuracy on penalty kicking performances (speed and accuracy) at five different targets in a goal by experienced soccer players. Furthermore, would kicking performance be affected whether the target was placed high compared to low in the goal? It was hypothesized that there would be a speed-accuracy trade-off, meaning that accuracy decreases when the focus is on velocity and, based on earlier studies, the opposite would be true for all targets [9, 10, 11]. Furthermore, it was expected that ball velocity would be higher when kicking to the contralateral side due to the more natural kicking trajectory [11].