Dissertação
Efeitos imediatos de uma órtese elástica no tronco na biomecânica e no desempenho do chute em praticantes de futebol: um estudo de viabilidade
Fecha
2020-10-22Autor
Sabrina Penna Cintra
Institución
Resumen
Considering the trunk’s participation in football kicking biomechanics, an elastic orthosis for the trunk, developed for kicking, can improve this task's performance. This intervention can have immediate effects; however, there is a greater potential for the effects to emerge after the learning period, in the mid and long-terms. Before conducting longitudinal studies, it is necessary to test the feasibility of investigating an orthosis’s effects on the biomechanics and kicking performance. This study investigated whether the use of elastic orthosis: allows collecting the kinematics of the trunk and pelvis; generates biomechanical changes in the trunk according to the proposed mechanism of action; restricts the range of motion of the trunk; impairs the biomechanics of the lower limb and the performance of the kick. The orthosis consisted of four elastic bands crossing the trunk and hips, and fixed by inelastic anchors. Twenty-six men participated in the study (24 ± 13 years; experience time 13 ± 6 years) and performed seven instep kicks with maximum strength in four conditions: control, “comfortable tension”, “optimal tension”, and “high elastic tension”. Angles and moments of the thoracolumbar, lumbopelvic, and kicking limb joints were measured in the sagittal plane. The same variables were calculated for the upper and lower trunk in the transverse plane. Amplitudes of joint movement of the trunk and kicking limb, and the ball velocity were computed. Repeated measures analysis of variance (ANOVAs) and paired t-tests, using the Parametric Statistical Mapping method, were used to compare time series. Repeated measures ANOVAs were used to compare the range of motion. Comparisons were made between experimental conditions and the control condition, and the level of significance was 0.05. The kinematic data collection of the trunk and pelvis segments was feasible using the orthosis. The condition of high tension significantly increased the extension angle of the thoracolumbar joint (p = 0.027). At optimal and high tension conditions, the orthosis increased the rotation of the thoracolumbar joint to the side of the supporting limb (p <0.01) and increased the rotator torque of the trunk to the same side (p = 0.045). There was no significant effect on the other angles, amplitudes and articular moments, and ball velocity. It is concluded that the use of the trunk elastic orthosis (a) did not make the collection of laboratory data unfeasible, (b) produced effects consistent with the proposed mechanism of action, despite having occurred only for the thoracolumbar joint (and not for lumbopelvic), (c) did not restrict the joints’ ranges of motion, and (d) did not lead to unexpected or unwanted changes in the biomechanics of the kicking limb and kick performance. Thus, it can be considered that the study of the effects of elastic orthosis is feasible and that the mid- and long-term effects, after the learning period, should be investigated.