Rate of isometric knee extension strength development and walking speed after stroke

The relationship between lower-limb weakness and walking speed after stroke is not clear. This may be related to the measurement used to quantify weakness, typically peak strength. This study examined the relationship between two measures of isometric knee extension strength, i.e., peak torque and the rate of torque development and walking speed in adults with stroke. This study had 83 stroke survivors who participated. For the affected lower limb, rate and peak torque explained 12% of the variance in gait speed. Removing rate from the model significantly reduced the explained variance; in contrast, removing peak torque did not reduce the variance. For the less affected lower limb, rate tended to be more predictive of gait speed than peak torque. Diminished ability to rapidly generate knee extension torque contributes more to decreased walking speed after stroke than does maximal strength. Of note, 88% of the variance in gait speed is not explained by rate and peak isometric knee extension strength. Further studies are needed to determine if rehabilitation poststroke can increase the rate of knee strength development and if it results in faster walking speeds.