As estratégias biomecânicas de tronco e membro inferior para o chute máximo do futebol são complementares?

Abstract

Background: The instep soccer kick is the main offensive action in football. It is a complex, repetitive movement that involves downward transmission of kinetic energy between segments. The upper segments of the body play an important role in kick performance. The biomechanical strategies (kinematic and kinetic) of the trunk and kick limb (KL) appear to be complementary since both contribute to the anterior displacement of the kicking limb. However, it is not yet known whether there are associations between the biomechanical strategies of the trunk and the MI during soccer kicking. Aim: Investigate associations between the kinematic and kinetic strategies of the trunk and MI for the execution of the maximum soccer kick. Materials and Methods: Three-dimensional kinematics (300 Hz) and ground reaction force (1000 Hz) were measured in 50 amateur football players (age: 23.7 ± 4.61 years; height: 1.77 ± 0.05 m; body mass: 75.40 ± 9.88 kg; BMI: 24.17 ± 2.86 kg/m²). For trunk biomechanical strategies, peaks of extension and left rotation (kinematic strategy) and flexor and right rotator moments (kinetic strategy) were computed. For the KL biomechanical strategies, peaks of hip extension and knee flexion (kinematic strategy) and hip flexor and knee extensor moments (kinetic strategy) were computed. Canonical Correlation Analysis was used to evaluate associations between trunk and KL biomechanical strategies. Canonical Correlation Analysis was used to evaluate associations between kinematic strategies of the trunk and KL. A second canonical correlation was performed to investigate associations between kinetic strategies of the trunk and KL. Results: No association was found between kinematic strategies of the trunk and KL. Associations were found between kinetic strategies, with the complete canonical model explaining 59% of the variance. A first relationship (Rc=0.730, p<0,001), considered excellent, it showed that the greater flexion and rotation moments of the trunk, the greater hip flexor and knee extensor moments. This pattern was found in 39 (78%) participants. A second relationship (Rc=0.364, p=0.010), weaker and present in 11 (22%) participants, is characterized by a lower peak trunk flexion torque associated with a higher knee extension and lower hip flexion moment peaks (and vice versa). Conclusion: The results of this study indicate that kinematic strategies of the trunk and KL are not complementary in the studied population. On the other hand, kinetic strategies of the trunk and KL, for performing the maximum kick, are complementary and can present two complementary patterns. The most common pattern is a direct relationship between moments of the trunk and MI, in a complementary way to kick with the greatest possible power. The second most common pattern is an inverse relationship in which the extensor knee moment is compensatory to the flexor moments of the trunk and hip, which may be related to overload in these joints.