Conventional Ratio of Knee Flexors and Extensors Obtained Using an Isokinetic Dynamometer and Isoinertial Devices

Abstract

This study aimed to analyze the conventional ratio values of knee flexors and extensors obtained using an isokinetic dynamometer (IsoRatio), an adjusted torque test of 5RM (Ratio5RM), and absolute values of 5RM (Ratio5RML). Fifteen male volunteers (28.47 ± 5.78 years; 78.30 ± 6.59kg; 1.79 ± 0.65m) performed a 5RM test on leg extension and leg curl machines. The volunteers executed knee flexion and extension movements at 60°/s angle speed without significant differences between protocols. Regression analysis showed that the Ratio5RML correlates with the isokinetic reference ratio (r=0.649; p=0.009). The result of the paired t-test showed no significant difference between the means of the isokinetic ratio and the ratio predicted by the equation. The results of the present study suggest that the 5RM test performed with isoinertial machines can be used to estimate conventional ratio and identify imbalance between the knee flexors and extensors muscles.