Influência de 12 semanas de treinamento excêntrico nas razões de torque concêntrico e excêntrico de flexores/extensores do joelho

Abstract

Eccentric training changes the force production capacity in different ways between antagonistic muscle groups. Torque ratios allow for the identification of these adaptations of eccentric training between antagonistic muscles. This study investigated the influence of eccentric training on the knee flexors/extensors torque ratios. Twenty-two volunteers were divided into a control (n = 10) and an experimental (n = 10) group. The experimental group underwent a 12-weeks eccentric training program at an angular velocity of -60°/s. The torque ratios were evaluated at the concentric angular velocities of 60°/s e 420°/s and eccentric velocities of -60°/s and -300°/s. The concentric torque ratio increased at the angular velocity of 420°/s from pre to post-training due to an increased torque capacity of the hamstrings compared to that of the quadriceps at this angular velocity post-training. The eccentric torque ratio at -60°/s reduced from pre to post-training due to the higher increase in the quadriceps torque compared to that of the hamstrings with training. The smaller fiber length of the quadriceps compared to that of the hamstrings seems to have been responsible for the increased eccentric torque at the training velocity post-training, whereas the increase in the concentric torque ratio at the angular velocity of 420°/s seems to be associated to the higher fiber length of the hamstrings, giving this muscle group a mechanical advantage to produce force at high angular velocities. We conclude that eccentric training changes the torque ratios of knee antagonistic muscle groups according to their structural characteristics.