Parâmetros biomecânicos indicadores de desenvolvimento motor do salto vertical em escolares de cinco a sete anos

Abstract

The knowledge about motor development, as well as the identification of the child motor state, allows the teacher to detect the real demands of his students. However, the instruments available in the literature present limitations from a scientific quality. Experts in the field believe that studies of biomechanics can contribute to its improvement in scientific quality, but there are few investigations of this topic. Therefore the aim of this work was to identify whether kinematic indicators can be used as determinants of vertical jump motor skill in children between five and seven years old. The sample consisted of 30 children aged 5 to 7 years old. For the measurement of angular displacements and height of the jump, the positioning of 5 markers on anatomical points of the right lower limb was adopted. As instrumentation, a camera was positioned in perpendicular angle to the jump area. To identify the motor state, we used the qualitative test of Gallahue and Ozmun (2005), which allows children to be classified in three stages. The ADE was applied as a model for the identification of vertical jump phases and a proficient biomechanical pattern. Through the SkillSpector software, the markers on the images were scanned and then the kinematic data of the hip, knee and ankle joint displacements were treated using MATLAB software. As results of the motor state, the two-stage prevalence is identified. It is observed that the children of the initial stage present smaller averages of joint flexion in Duration 1 compared to the other stages. In Duration 2 it is identified that the averages in extension seem to increase between the stages, specially for knee and ankle. In Duration 5, children in the initial stages have lower average angular displacement for hip and knee flexion in comparison to the other stages. The vertical jump height findings suggest that the more developed the motor state, the greater its range. The motor status identification data do not corroborate with the literature. These differences may be related to the lack of individuals' motor experiences. The data on Durations 1 and 2 correspond to the developmental proposal of Gallahue. However the data of Duration 5 are not described qualitatively by the author. The comparisons between the averages of the kinematic characteristics are only hypotheses, as the study is descriptive. In addition, the sample is considered small which could bring difficulties to respond some gaps. However it is hoped that the results serve to construct a quantitative and accurate examination for the classification of the motor status of children