Comparação da cinemática angular de saltos verticais em atletas de voleibol de praia para diferentes granulometrias de areia

Abstract

Vertical jumps are crucial components in the performance of volleyball athletes due to the fundamentals of blocking, serving and attacking. The practice of beach volleyball has external variables, such as temperature, wind, humidity, sun and sandy surface, which interfere in the vertical jumps and displacements of the ball and athletes, thus, in the performance and speed of the game. The sandy surface (unstable) has different mineralogical, physical and chemical characteristics for the different competition venues in beach volleyball. In this sense, the objective of the present study was to compare different types of sand grain size in the angular kinematics of vertical jumps in beach volleyball athletes. 116 countermovement jumps were analyzed in three sand pits with different grain sizes. Seven female professional beach volleyball athletes participated in the study (age = 26.3 ± 6.0 years, height = 178.2 ± 4.0 cm, body mass = 69.7 ± 3.3 kg, years of practice = 9.7 ± 5.3 years). The variables analyzed were

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BIOMOTRIZ, Cruz Alta, RS | ISSN 2317-3467 Template de submissão de manuscrito

joint angles and angular velocity of movement (in the ankle, knee and hip joints), from filming and the Kinovea software. Statistical analysis by generalized mixed model (GLMM) showed significant variation in the minimum ankle angle (p = 0.01) in fine sand in relation to coarse sand, angles of departure from the ground to the hip (p < 0.001) in fine sand in relation to coarse sand and from the reference sand in relation to coarse sand and angles of departure from the ground to the knee (p < 0.001) in fine sand in relation to coarse sand and from the reference sand in relation to coarse sand for countermovement jumps. Highlighting that in coarse sand the angles of departure from the ground to the hip and knee are smaller and the minimum angle of the ankle is larger, compared to fine sand, without variation in angular velocity.