Variabilidade na fase aérea da braçada do nado costas em diferentes estágios da aprendizagem motora

Abstract

Nowadays, the variability that had been seen as a negative factor of the performance for a long time has been emphasized in the motor learning, since its presence in the parameters of the movement is essential for a skillful performance and because it is inherent among all biological systems. So the control of the movement through the development analysis becomes necessary to check such variability in any motor ability. In this sense, the objective of this paper was to check if the time of the movement is a variant aspect in the aerial phase of arm stroke of backstroke of subjects in different stages of movement. The sample is composed by 8 subjects with average ages of 25,5 and they were classified by researchers of the area through a matrix of analysis of the backstroke. After that, 4 subjects composed the intermediate group and 4 subjects, the advanced group. The task was to swim in backstroke in a distance of 75 meters individually at natural speed, and for the recording the first 5 meters of the end and the last 5 meters of the start of each way - with 25 meters long - were not considered. To analyze the aerial phase of the arm stroke, it was considered 21 semicycles (aerial phase) for each subject and in order to make easy the observation, it was used external markers to cover the distal phalanxes of both hands with isolating ribbon. The data was recorded in a camera of Peak Motus system (JVC – LABS model: 180 NS) with a capture of 60 pictures a second and it was carried by a person in a distance of 2 meters of the edge to make easy the trajectory of the swimmer. In order to check if the differences between the groups refer to both the arms, the actions of right and left arm strokes were singly analyzed. The used measure corresponded to the total time of movement during the aerial phase of the arm stroke of backstroke. For the statistical analysis of the data it was used the arithmetical average, the variation coefficient (vc) and deviation. After checking the normality of the data through the Lilliesors’ test, U Mann-Whitney test for the comparision between the groups (independent groups) and the comparision between the arms was tested with Wilcoxon’s test, considering a significance level of 0,05 for them. . In the results, it was noticed that there is difference between the groups the for the right arm (p = 0,004) the same for the left arm (p = 0, 00395). It means that the advanced group had a larger time of movement in the aerial phase (right arm and left arm) compared to the intermediate group. Comparing time between arms for the same group, it was noticed that there is no difference between them, i.e., there is no difference (p = 0, 1441) between the time of left and right arms for the intermediate group and that is true for the advanced group (p = 1, 00). In synthesis, conclude there was more variability in the pattern of movement in what refers to time in the advanced group compared to the intermediate group in the backstroke.