Relação entre nível de flexibilidade, produção de potência e desempenho no countermovement jump realizado em distintas angulações de joelhos

Abstract

Flexibility is a physical ability capable of assisting in the athletic performance of several sports on the court, allowing athletes greater speed and fluidity of the required movement. For the vertical jump, this ability can generate an increase in the jump height, due to mechanisms capable of accumulating energy during the eccentric phase and using the jump at the moment of propulsion, in addition to assisting in the power generated during the movement. Therefore, the objectives of the present study were to correlate flexibility with lower limb power and performance in the countermovement jump (CMJ) at three different angles of knee flexion in the eccentric phase, and to compare lower limb power and performance between the same conditions tested. Twenty-two female volleyball, basketball or handball players participated in the research. Initially, the flexibility test was performed on the Wells bench and, later, the vertical jump tests were performed in three different knee flexion conditions: CMJ80º, CMJ90º and CMJ100º. The conditions were adjusted with the aid of a manual goniometer and an amplitude controller, in order to limit the eccentric phase of the CMJ to the desired angulations. Three maximum jumps were performed for each condition, with selection of the best CMJ of each amplitude for the analysis. Data normality was analyzed using the Shapiro-Wilk test and sphericity using the Levene test. Pearson's test was used to correlate flexibility with lower limb power and performance in the CMJ, with the correlation strength (FC) established by Malina's criterion (Strong = >0.6; moderate = 0.3 to 0 .6; and weak = <0.3). Comparisons were performed using ANOVA of repeated measures with post-hoc Bonferroni, considering a significance level of 5% for all tests. A strong correlation was observed between performance in the CMJ80º and flexibility (FC = 0.644; p = < 0.01) and moderate relationships between flexibility and performance in the CMJ90º (FC = 0.563; p = < 0.01) and CMJ100° (FC = 0.552; p = < 0.01). However, no correlations between flexibility and potency were found in the three conditions tested. A better performance and power level was observed in the CMJ80º (height = 24.55±5.06 cm; power = 1671.68±369.99 W) and performance of the CMJ90º (height = 23.78±4.35 cm; power = 1647.31±376.26 W) compared to CMJ100º (height = 22.95±4.76 cm; power = 1610.26±378.12 W) (p ≤ 0.026). While the CMJ80º and CMJ90º conditions showed no differences between them (p ≥ 0.157). In conclusion, it was verified that in this evaluated group, the athletes of court sports with greater flexibility presented better performance in the jumps that require greater amplitudes of movement.