Nonuniform Weakness in the Paretic Knee and Compensatory Strength Gains in the Nonparetic Knee Occurs after Stroke

Background: This study was designed to quantify torque production at different joint angles in the paretic and nonparetic knee joints of individuals with stroke. Methods: Extension and flexion torques were measured at 6 angles of the knee joint and normalized to peak torque in 19 subjects with stroke and 19 controls. Results: Paretic knee extension torque was lower than controls when the knee was positioned near extension. In contrast, nonparetic knee extension and flexion torques were higher than controls when the knee was positioned near full flexion. Conclusions: The paretic knee extensors demonstrated exaggerated weakness at short muscle lengths and the nonparetic knee extensors and flexors demonstrated selective strength gains. Clinicians should therefore consider paretic knee extensor strengthening near full extension and promote symmetrical use of the legs to prevent compensatory overuse of the nonparetic leg.