Experimental procedures

The data was collected at the goalkeepers’ training site. Initially the cameras, ball launcher machine and cloth for goalkeeper’s vision obstruction was positioned in a standardized setup (Fig. 1). In sequence, the volunteers answered to the IPLAG to identify the lower limbs lateral preference. Before starting the dives execution, the goalkeepers performed a 5–10 min warm-up structured for the muscles to reach an optimal state for the collection task demand⁴⁴. The final part of the warm-up was the execution of 2 jumps to the right and 2 to the left, to familiarize the goalkeeper with the penalty save dynamics with balls launched. For data collection, the goalkeeper was instructed to stay at the center of the goal, facing away from the penalty mark while the ball launcher machine was directed to the side the goalkeeper should jump. Then the goalkeepers were instructed to turn facing the penalty mark and advised that the collection had started and the ball would be launched.

Participants were instructed to perform the dive with maximum impulsion regardless of where the ball is released and were advised that the number of defenses made was not the focus of the study. The trials were only validated when the goalkeepers dived to the correct side in which the ball was launched. The final distribution of the balls launch sites in the validated dives are presented in Fig. 1. It is worth mentioning that several dives in region B and D were discarded because the ball launch harmed the goalkeepers’ impulsion biomechanics. Those who were kept had the balls thrown close to quadrants A and E. In relation to quadrant 1, there were also dives discarded when goalkeepers showed a vertical movement pattern inadequate for the analysis pretended and those who were kept had the ball thrown near quadrant 2. The final height that the balls were launched was close to a normal penalty distribution being respectively: lower third 55.64% and 56.6%, middle 36.29% and 30.4%, and upper third 8.06% and 12.9% (Fig. 1)⁹.

The VG performed a total of 20 dives, 10 before (VGPRE) and 10 after the video instruction (VGPOST). Totalizing 10 right dives, 5 before and 5 after the instructional video and 10 for the left side with the same number of trials in each condition. The diving execution side order was chosen randomly to not influence the results. The recovery time between attempts was equal or greater than 90 s. During the instructional video execution, VG participants were able to clear any doubts with the researchers and they could perform 2 dives to each side for the instructions given adaptation. The CG performed the same procedures as the VG, however, at the moment that the instructional video would be shown the volunteers had a rest period equivalent to the video's runtime, without receiving any kind of instruction or feedback. In other words, they performed the 10 initial dives (CGPRE), rested, and performed another block of 10 trials (CGPOST).