Tiago Dutra Leite-Nunes, Michele Forgiarini Saccol, Silvana Corrêa Matheus, Daniela Lopes dos Santos, Fábio Juner Lanferdini

SUMMARY
Background. Isokinetic dynamometer is a widely used and valid method to evaluate bilateral torque symmetries and agonist-antagonist muscular ratios that may be impli­cated in injury risk. Therefore, this study aimed to evaluate the inter-limb strength asymmetries and the conventional hamstring:quadriceps ratio (H:Q) of dominant and non-dominant limbs at two angular velocities (60 and 300°/s) in athletes of basketball (BA), American football (AF), futsal (FT) and running (RU).
Methods. Fifty-seven athletes participated in the study. All athletes underwent body composition assessments and, subsequently, were tested in an isokinetic dynamometer. After warming up, all athletes performed two maximal voluntary isometric contrac­tion of knee extension-flexion during five seconds each. The subjects also performed five repetitions of concentric knee extension-flexion in two angular velocities (60 and 300°/s). All analysis used a significance level of α = 0.05.
Results. There was no imbalance (higher than 15%) between limbs in any of the evaluated athletes. None of the evaluated groups showed imbalances in convention­al H:Q ratio during high angular speed. AF, FT and RU demonstrated convention­al H:Q asymmetries in low angular velocity. The BA group was the only one that showed a balanced conventional H:Q ratio in both limbs and in both angular veloci­ties evaluated.
Conclusions. None of the evaluated groups had inter-limb strength limb asymmetry. The BA group was the only one fully balanced in both angular velocities while AF, FT and RU were imbalanced only for concentric H:Q ratio in low angular velocity.

Keywords: Bilateral symmetries; concentric torque; hamstring:quadriceps ratio torque; hamstrings injury risk; sports,