Introduction The incidence of knee injuries is very high in young adults. Anterior cruciate ligament (ACL) rupture is the most frequent of them. The isokinetic dynamometry evaluation determines the functional patterns of strength and muscle balance.Objective To compare the isokinetic hamstring/quadriceps peak torque and work ratios of young adults after surgical reconstruction of the anterior cruciate ligament.Methods We selected 33 medical records filed by the Isokinetic laboratory of the Physiotherapy Clinic of the Catholic University of Paraná (PUCPR), which belonged to patients who had undergone isokinetic assessment at the request of a physiotherapist or physician in Curitiba, Paraná. The tabulated data were: Hamstring/Quadriceps peak torque and work ratios of all injured and non-injured limbs at an angular velocity of 60°/s. Data were processed by the statistical software LHstat. Inferential statistics was used in order to apply the comparison test between means (unpaired t-test) with a confidence interval of 95%.Results The average flexion-extension ratio of the non-involved limb was lower than the involved limb both for peak torque (peak torque ratio of the non-involved limb: 56.1%; peak torque ratio of the involved limb: 66.3%; difference: 10.2%) and work (work ratio of the non-involved limb: 60.1%; work ratio of involved limb: 66.1%; difference: 6%).Conclusion : The average flexion/extension ratio found was adequate for both limbs and variables, however, the subjects presented a greater number of muscle asymmetries in the involved limb than in the non-involved limb.