Comparação de diferentes procedimentos na determinação do desempenho no salto de ataque no voleibol

Abstract

During the volleyball spike jump there is an asymmetry between lower limbs, which must be taken into account to identify the factors that contribute to the performance. The variables that influence the performance are measured by the kinemetry throughimages acquisition determining the center of gravity location by an anthropometric model implementation. The impulse-moment theorem calculates the center of gravity trajectory through force platforms without a model implementing. In the spike jump, the center of gravity velocity at the beginning of the impulse is non-zero, being necessary to know this velocity, that can only be calculated by kinemetry. Thus, to verify the performance in the spike jump, it is necessary to adopt these boothprocedures in a combined way. The kinemetry may present errors whenimplementing an anthropometric model, being necessary to verify its reliability, accuracy and validity when calculating the velocity at the beginning of the impulse. Thus, we compared the kinemetry with the impulse-momentum, during jumps that the initial velocity is zero, as countermovement jump with and without upper limbs aid. There are strategies that estimate the center of gravity location using simplifiedanthropometric models that have been little applied during jumps and may be an option for a faster and simple analysis. Thus, the objectives of this study were to verify the reliability, accuracy and validity between the velocity of the center of gravity calculated by the kinemetry using a whole body anthropometric model and simplified anthropometric models, with the impulse-moment, in certain instants, during the countermovement with and without upper limbs aid. We also verified the reliability,accuracy and validity between take off velocity using simplified anthropometric models with the kinemetry in the spike jump and combined procedures. 12 cameras, 2 force platforms were used to calculate the center of gravity velocities and the simplified anthropometric model. 10 female volleyball athletes, adult category of the 1st national league of Austria, aged: 19.85 (± 3.46) years and 70.47 (± 11.02) kgperformed the three types of jump. The reliability and accuracy were calculated by the intraclass correlation coefficient and the standard error of the measurement respectively. For the validity was used the Bland - Altman plot. In regarding of performance, the results showed high reliability, high accuracy and validity between kinematics and the impulse-moment procedures in jumps with countermovement withand without the aid of the upper limbs. The simplified anthropometric model using the point at the posterior superior iliac spine was reliable, accurate and valid only for countermovement jump. In the spike jump, the simplified anthropometric model at the antero-superior iliac spine presented high reliability, accuracy and was valid with the velocity at the beginning of impulse, calculated by the kinemetry. Most of thecombined procedures presented high reliability, accuracy and validity with kinemetry. We concluded that the combined procedure was similar to the takeoff velocity in spike jump calculated by the kinemetry.