# Effect of Instruction and Target Position on Penalty Kicking Performance in Soccer
## 2 Materials and Methods
### Procedure  
Before testing, the participants took part in a 15 min warm-up program, comprising a general part that included running with increased intensity and a part involving passing and shooting to avoid muscular injury. Afterwards, the test-leader informed the participants of the procedure of the test and described the 10 different instructions they could be given before each penalty. The instructions were modified according to previous studies of speed-accuracy studies in soccer by including the height of the target and direction [10,11].  
All testing was conducted over a two-week period, with each test session involving four players. A total of four test days were carried out, encompassing 16 players in total. The order of instructions before each penalty kick was randomized and different for each player. The test was executed at an indoor handball ground, with a Gerllor Taraflex Sport M Plus floor (Gerllor, Lyon, France), and the players wore futsal shoes during the test. Similar soccer balls (Macron Solstice XI, size 5, Macron S.P.A., Crespellano, Italy) with the same air-pressure (13 PSI) were used during the tests.  
A soccer goal was marked with tape (244 cm \(\times\) 732 cm) on a soft separation wall together with the five targets. This made it very easy to identify the place of impact in the goal and to evaluate whether the penalty kick ended up in the goal or outside. The targets were the left and right corner bottom and top and one in the middle of the goal. The center of the targets was placed 0.5 m from the goalposts and, for the targets low in the goal, 0.25 m above the ground (Figure 1). To avoid too many kicks from each player, the target in the middle of the goal was not included as this had already been investigated [11].  
Before each penalty kick, the participants were instructed where to kick the ball (five different targets) with the instruction to either (1) kick as hard as possible while trying to hit the center of the target or (2) aim to hit the target. Every participant took eight penalties for each instruction (2) at each target (5), resulting in a total of 8 \(\times\) 2 \(\times\) 5 = 80 penalty kicks. These instructions and targets were given in a random order for each participant with an approximately one-minute rest between each attempt, and the participants were instructed to always perform the kick with the inside of their preferred foot. The participants were permitted to determine the length and direction of their run-up prior to each penalty kick, in accordance with the given instructions, and no goalkeeper was utilized during the tests to avoid extra constraints that could influence kicking performance.  
To measure kicking speed, a laser gun (Stalker Pro II+, Stalker Sport, Richardson, TX, USA) was placed 12 m from the goal, while ball placement was recorded for each kick with a video camera (Sony PXW-Z90, Sony, Tokyo, Japan) (Figure 1). Accuracy was measured as the absolute distance from where the ball hits the wall to the center of the aimed-for target for each attempt using the Kinovea software v. 2013.1 (www.Kinovea.org), and the average was taken for each target and instruction. Furthermore, accuracy was measured as either a goal or no goal based on whether the ball hit the goal or not. This was then measured as the percentage of hits per instruction.