Relationship of muscle strength for knee extension to walking capacity in patients with spastic hemiparesis.

Muscle strength for knee extension, both isokinetic and isometric, and walking capacity, maximum velocity and walking rate, were examined in 11 post-stroke hemiparetic patients. The degree of spasticity of the affected lower extremity was not related to the isokinetic and isometric torques, or to the walking capacity. Although both the isokinetic and isometric torques decreased on the affected side compared to the non-affected side, the rate of decrease was remarkable in isokinetic torque at fast velocities. The walking capacity was well correlated with isokinetic torque of the affected side at fast velocities but not isometric torques. These results suggest that reduction of muscle strength at rapid movements is an essential feature of spastic paresis and is primary cause of motor disabilities such as impaired locomotor function.