Contribuições biomecânicas do tronco e do quadril do membro de apoio na execução e desempenho de chutes máximos e submáximos com o dorso do pé em jogadores de futebol amadores

Abstract

Soccer is a dynamic sport that requires a high level of technical and physical skill, with the kick being one of the most important actions for player performance. The biomechanics of the kick involves mechanical adjustments in the trunk and lower limbs that vary with the level of effort. This thesis investigates how the trunk and the hip of the supporting limb contribute to the execution and performance of maximal and submaximal instep kicks in amateur soccer players, focusing on kinematic and kinetic adjustments and energy transfer between body segments. The first study investigated the kinematic (KmS) and kinetic (KnS) strategies integrating the trunk and lower limbs to achieve maximal kicking performance. Fifty amateur soccer players were assessed. Peak joint angles and moments of the trunk, the hip of the supporting limb, the hip and knee of the kicking limb, and foot and ball velocities were recorded. Canonical Correlation Analysis was used to assess the relationships between sets of variables. A combination of greater hip extension and knee flexion of the kicking limb, as a KmS, correlated with better kick performance (Rc = 0.60, p = 0.004). Furthermore, a combination of larger moments of trunk flexion and rotation, internal rotation of the supporting hip, hip flexion, and knee extension of the kicking limb, as a KnS, were associated with better kick performance (Rc = 0.74, p < 0.001). The explained variance was 43% for the KmS and 59% for the KnS. The second study investigated the kinematic and kinetic adjustments in the trunk (thoracolumbar and lumbopelvic joints), the supporting hip, and the hip and knee joints of the kicking limb during instep kicks performed at three levels of effort. Forty-four amateur soccer players performed kicks at maximal effort, 70-80% of maximal effort, and 50-60% of maximal effort. Comparisons of the time series of angular velocity, angle, momentum and joint and segmental power were performed using statistical parametric mapping with repeated measures ANOVA. The results revealed significant adjustments in all the joints analyzed. Considering the resources that contribute to driving the kicking limb forward, the axial moments of the trunk and supporting hip, as well as the sagittal moments of the supporting hip, hip and knee of the kicking limb, were recruited at all three levels of effort, intensifying with increasing demand. The sagittal moment of the trunk was used exclusively in maximum-effort kicks. The studies in this thesis show that the trunk and hip of the supporting limb contribute significantly to the execution and performance of maximal and submaximal instep kicks in amateur soccer players.